Neurology Update

Lorin Friesen, March 2025

The cognitive model of mental symmetry was mapped onto neurology in a 2019 paper (Friesen, 2019). This essay summarizes some of the neurological findings that have been made since then. One minor correction needs to be made to the 2019 paper. It was suggested that mental networks are associated with the orbitofrontal cortex. A more recent paper on mental networks (Friesen, 2024) suggests that the orbitofrontal cortex deals with specific emotional memories while mental networks are located within the ventromedial prefrontal cortex (vmPFC). This essay does not provide a complete mapping of mental symmetry on to neurology. Instead, it should be viewed as an appendix to the 2019 paper that adds some more recent details.

I have included links to all the papers but I have not included page numbers for the quotes.

Ventrolateral Prefrontal Cortex (vlPFC)

Mental symmetry suggests that Teacher thought comes up with a general theory by focusing upon some idea and then interpreting the context in the light of this idea. This can be compared to taking a commoner off the street, making him a monarch, and then seeing how well he reigns. This formulating of a new theory is different than the emotions generated by a theory. If some theory continues to be used, then it will turn into a Teacher mental network which will use emotional pressure to impose itself upon the mind when triggered. The formulating of a theory happens in the left vlPFC while mental networks, including presumably Teacher mental networks (TMNs), are located within the vmPFC.

A general theory applies the same simple explanation to many specific situations. Fairness is an example of a general theory because everyone is supposed to be treated in the same manner. (Fairness is actually an example of Teacher overgeneralization because the same general theory is being applied to everyone regardless of any factual details.) Himichi & Nomura (2015) found that fairness is associated with left vlPFC activation. “Left VLPFC activation mediated the correlation between norm of restitution toward helping and the amount of money distributed to the target person. These results were only observed in the lose condition.” Stated cognitively, a person is noting unfairness and is responding by using Teacher thought to impose a theory of fairness upon the situation. In contrast, Teacher thought does not have to impose a theory of fairness when the situation is fair. “Left VLPFC activation did not correlate with emotion evaluation in the draw condition.”

The right vlPFC carries out a similar function with Mercy thought. Mercy thought will choose to focus upon some experiential memory and then regard this as the focus of attention. Consistent with this, Burunat et al. (2024) associate a lack of right vlPFC activity with choosing not to focus upon some memory or goal in Mercy thought. “During immersive listening experiences that emphasize aesthetics and emotions, the VLPFC may show reduced activation or deactivation, potentially reflecting a shift of attention away from internal cognitive processes to allow listeners to fully engage with the music.” Teacher thought uses the left vlPFC to come up with new verbal theories while Mercy thought uses the right vlPFC to analyze regularities in nonverbal situations such as music.” “Activations observed in the right fronto-opercular area (BA44/45) are believed to contribute to music-syntactic analysis and the detection of harmonic rule violations, as discussed earlier. Considering the background research on the role of the right hemispheric counterpart of Broca’s area, the differential engagement observed in nonmusicians and musicians during different transition phases suggests distinct boundary processing strategies.”

Dumontheil et al. (2022) point out that the right vlPFC does more than simply inhibit response. “Although right VLPFC/inferior frontal gyrus (IFG) was initially thought to specifically implement response inhibition, more recent work suggests that it may play a broader role in maintaining goals and modulating activity of other brain regions.” Maintaining goals and modulating activity describes the functioning of Mercy thought.

Hansenne & Emilie (2020) found that enhancing right vlPFC activity makes it easier to focus upon positive experiences rather than negative ones. This was a core trait of my mother, a Mercy person, who would always focus upon the good side of some situation. “tDCS [transcranial direct current stimulation] over the rVLPFC reduced the perception of specific negative emotions such as fear and sadness, compared to other negative or positive feelings, arguing that the rVLPFC is particularly relevant for regulating negative emotions, mostly associated with the anticipation of dangerous situations.” Mercy thought plays a major role in evaluating and guiding social interaction. “The role of the rVLPFC was also demonstrated while participants used emotion regulation strategies to reappraise pictures of social exclusion.”

Rahrig et al. (2024) point out that the right vlPFC can either choose not to focus upon painful experiences or else fixate upon painful experiences. “Right vlPFC stimulation has been shown to attenuate negative emotions and aggression provoked by frustration and social exclusion, but in situations when individuals feel unable to express anger, right vlPFC activity may actually enhance anger rumination as an avoidance-based coping method.”

The role of the vlPFC is especially apparent in cognitive reappraisal. Cao et al. (2025) summarize that there is “evidence for a correlation between the left ventrolateral prefrontal cortex (VLPFC) and a specific type of cognitive reappraisal strategy, positive reappraisal.” “Cognitive reappraisal, one of the most important cognitive strategies of emotion regulation, aims to reinterpret the meaning of an emotional event or stimulus... Positive reappraisal as a specific cognitive strategy aims to reinterpret negative emotional stimuli in a more positive light, which has commonly been used in previous studies.” In other words, Teacher thought is coming up with a new theory in the left vlPFC to interpret emotional experiences. A basic principle of mental symmetry is that the positive emotions of a Teacher theory make it possible to face the negative emotions being generated by unpleasant Mercy experiences.

Cheng et al. (2022) compare the role of Teacher thought with the role of Mercy thought in cognitive appraisal. “While the left VLPFC is responsible for the linguistic especially semantic process of generating and selecting appraisals according to the goal of emotion regulation, the right VLPFC plays a critical role in inhibiting inappropriate negative emotions and thoughts generated by the effective scenarios.” Teacher thought is coming up with a new theory, while Mercy thought is choosing a different focus of attention. Most Teacher theories involve words and speech. Similarly, Cheng et al. add that “This study found that the lVLPFC is responsible for both the internal (semantic processing) and external (spoken language) language processes during cognitive reappraisal.” Mercy thought, in contrast, chooses a new focus of attention that avoids painful Mercy experiences. “When receiving negative emotional stimuli, the rVLPFC quickly initiates the inhibition process by orienting attention from the goal-irrelative information and blocking inappropriate negative emotions and thoughts.”

He et al. (2023) used electrical stimulation to enhance vlPFC activity. “We observed in the brain activity data that the TMS-evoked [transcranial magnetic stimulation] neural stimulation not only emerged at the TMS target (i.e., VLPFC), but also propagated to connected remote regions, including the VMPFC, amygdala, and insula. Specifically TMS caused enhanced activity in the VLPFC and VMPFC under the reappraisal, but not in the no-reappraisal condition... We also observed that TMS caused reduced activity in the amygdala and insula under the reappraisal versus the no-reappraisal condition.” Stated cognitively, new Teacher theories and/or a change of Mercy focus are having an impact upon mental networks in the vmPFC, as well as immediate emotions in the amygdala and gut feeling in the insula. In the words of the authors, “The VLPFC serves as an essential brain region to support the voluntary ER [emotional regulation] process, while the downstream propagation of reappraisal unfolds as a ‘chain reaction’ from the prefrontal control network into the emotion integrative area VMPFC and to the subcortical affective regions.”

Rahrig et al. (2024) describe cognitive reappraisal from a political perspective. “By definition, cognitive reappraisal involves the deliberate modulation of thoughts, and in a political context, may manifest as rationalization of the status quo, minimization of perceived impact, or reframing of events as meaning-making opportunities” Rationalization comes up with a Teacher theory that explains the existing situation. Mental symmetry distinguishes between rationalization and rational thought. Both are guided by Teacher theories but rational thought ensures that the Teacher theory is consistent with the Perceiver facts while rationalization ensures that the Teacher theory does not question existing mental networks.

Mania can be interpreted cognitively as being guided by Teacher theories that lack the support of Perceiver facts and Server sequences. Arora et al. (2025) found that “Left vlPFC activity was positively associated with mania/hypomania risk.” More specifically, “We also found a significant positive association between RE-related [reward expectancy] left vlPFC activity and the Mood Spectrum Self-Report Lifetime Questionnaire (MOODS-SR-L) manic domain scale up to 1 year postscan. This scale is an especially robust measure of lifetime vulnerability to mania/ hypomania” Thus, there is a correlation between excessive left vlPFC activity and a vulnerability to manic thought.

However, Cotovia & Oliveira-Maia (2022) observe that “The most consistent findings in mania relative to healthy subjects have been reduced activation on the right side of the brain or bilaterally in the ventrolateral prefrontal cortex (VLPFC).” The reduced right side activation makes sense because mania follows grandiose plans without thinking about the personal consequences in Mercy thought. Reduced bilateral activation sounds inconsistent with the idea of excessive Teacher thought but the authors mention elsewhere that “Across multiple lesion cohorts, we found that lesion locations associated with mania, when compared to control lesions, were more connected to the right OFC (VLPFC; BA47), right inferior temporal gyrus, and right frontal pole (VMPFC; BA11)” This is consistent with the hypothesis that mania is driven by Teacher theories that are not supported by personal Mercy experiences and emotions.

Steward et al. (2020) looked at cognitive reappraisal in the context of treating anorexia and concluded that the dlPFC (Perceiver and Server thought) is required for effective cognitive reappraisal. “Patients with mood and anxiety disorders recruited regulatory frontoparietal networks involved in cognitive reappraisal, an adaptive emotion regulation strategy to a lesser extent than controls.” This is consistent with the distinction between rationalization, which uses the vlPFC to come up with new Teacher theories and a different Mercy focus, and rational thought, which uses Perceiver facts and Server sequences within the dlPFC to come up with a new theory that is consistent with existing facts and sequences.

Steward et al. explain that effective cognitive behavior therapy requires the use of facts and sequences. “This identified relationship with dlPFC hypoactivity during cognitive reappraisal and treatment outcomes may be an indication of an inability of an at-risk subset of patients with AN [anorexia nervosa] to recruit the necessary cognitive resources to put CBT-based skills into practice.”

In summary, there is substantial evidence connecting Teacher thought with the left vlPFC and Mercy thought with the right vlPFC.

Dorsolateral Prefrontal Cortex (dlPFC)

Mental symmetry suggests that Server thought uses the left dlPFC while Perceiver thought uses the right dlPFC. New evidence supports this hypothesis. Cristofori et al. (2024) describe this kind of separation of function. “The left dlPFC is necessary for manipulating verbal and spatial knowledge in WM [working memory] (letter-number sequencing; spatial span backwards), while the right dlPFC is critical for verbal and spatial reasoning (arithmetic; matrix reasoning).” Notice that the left dlPFC emphasizes the sequences of Server thought while the right dlPFC emphasizes the spatial connections of Perceiver thought.

The dlPFC has traditionally been connected with ‘working memory’, with Server thought focusing upon sequences of Teacher words and Perceiver thought focusing upon Mercy experiences. This reflects the arrow going from Teacher to Server and from Mercy to Perceiver in the diagram of mental symmetry. “An important function of the DLPFC is related to working memory, which seems to be lateralized depending on the kind of information being maintained: a left hemispheric system for verbally coded content, partially overlapping with left hemispheric regions for language and speech generation and a right lateralized ‘visual sketchpad’ for nonverbal content that is predominantly linked to visual representations” (Hertrich et al., 2021). The term ‘working memory’ gives the impression that this area of the brain does nothing more than remember sequences of letters and numbers. But the following quotes show that the dlPFC provides the more general function of imposing and maintaining some context.

Hertrich et al. (2021) look at the role that the dlPFC plays in linguistics. Perceiver and Server thought build the connections that integrate various aspects of linguistics. “The DLPFC seems to be a key region for implementing functional connectivity between the language network and other functional networks, including cortico-cortical as well as subcortical circuits.” Perceiver and Server thought are not required during normal linguistic activity but are needed when connecting linguistics with other aspects of thought. “In many laboratory experiments on language processing, the DLPFC was not found activated, as has been shown in a meta-analysis of brain imaging studies on language comprehension... The multi-demand system gets involved only in case of ‘extraneous’ task demands such as plausibility judgments, sentence-picture matching, semantic associations, or complex memory tasks. Further studies have shown that prefrontal regions beyond the ‘classical’ Broca’s area are relevant for language at the level of discourse rather than single sentences.” This suggests that the traditional concept of ‘working memory’ should be viewed more generally as internally imposing some mental context upon thought. For instance, “The DLPFC is involved in inter-subject coupling when subjects have to cooperate, and the degree of coupling in the DLPFC reflects the degree of cooperativeness”. When people cooperate, then each partner has to maintain a mental context that goes beyond personal behavior to include the behavior of partners.”

Perceiver thought is required when maintaining the mental context of speaking another language. Hertrich et al. (2021) explain, “The DLPFC, particularly in the right hemisphere, plays a major role for language control and switching in bilingual speakers. Perceiver thought is primarily required when speaking a second language rather than one’s native language. “Presumably, this asymmetry is due to the case that switching from L1 into L2 requires a strong inhibitory effect of the right DLPFC onto left-hemispheric L1- processing mechanisms, while in the reverse case, due to the general preference for L1, no such inhibition is required”. In other words, speaking a primary language uses normal processing in Teacher thought while speaking a second language requires using Perceiver thought to replace normal language structure with a different mental context.

Server thought is required when dealing with homonyms where the same verbal sequence has several different meanings. Hertrich et al. (2021) clarify, The “left DLPFC concomitant with left angular gyrus was active during homonym processing in context, particularly, when a lexically dominant meaning has to be suppressed.” Perceiver thought is required when some meaning in Perceiver thought is being conveyed by a different Server sequence of words. The “right DLPFC was particularly associated with the aspect of ironic humor, presumably because of the cognitive demands to resolve some semantic incongruence.” More generally, “The DLPFC seems to come into play when the literal and the figurative meaning interact with each other in an unexpected way, in line with the finding that the DLPFC is involved in the inhibition of stereotyped responses”. Notice again that Perceiver and Server thought are required when the normal interpretation needs to be replaced by some alternative context.

Hertrich et al. (2021) summarize that “The DLPFC seems to be engaged in those aspects of language processing that exceed simple, rulebased, and highly automatized mechanisms of phonological, syntactic, and lexical–semantic processing. Such aspects come into play in case of certain stylistic features and in complex situations when language processing approaches its limits, for example, in case of ambiguity, novel, or nonliteral meanings, or garden path structures, when extra-linguistic cues have to be integrated, or when a speaker has to change into a different language.”

Turning now from linguistics to general thought, Perceiver thought often responds to unwanted memories by trying to suppress them. Anderson & Floresco (2021) report that “Effective connectivity analyses indicate that the right DLPFC modulates the amygdala and hippocampus (especially anterior hippocampus) in parallel as an integrated stopping response to the unpleasant scene and that this modulation is inhibitory, especially during intrusions”. Anderson & Floresco add that this Perceiver inhibition is different than the reappraisal of Teacher thought. “Controlling unwelcome memories by thought substitution, however, engages left VLPFC regions involved in retrieval. These left VLPFC regions resemble those involved in cognitive reappraisal of emotion, raising the possibility that reappraisal builds on substitution mechanisms”.

Perceiver thought imposes rules upon situations. Similarly, Christian (doctoral thesis, 2023) points out that the right dlPFC responds to norm violations. “rDLPFC enhances punishment of norm violations and sanction-induced norm compliance.” Perceiver thought looks for facts that are repeated. This expresses itself morally as imposing the same rules upon everyone. Hu et al. (2022) report that “Increasing the cortical excitability of the rDLPFC strengthens the inhibition of self-interest impulses, which promotes the processing of fairness, in turn, increasing fairness behavior and the maintenance of social norms.” This usually involves imposing rules that go against default behavior. “Individuals with rDLPFC enhancement appeared to be more able to resist the temptation to be selfish and make decisions to maintain social fairness norms in a deliberate way”.

It should be clarified that fairness can be viewed at the specific level of applying the same rule in Perceiver thought to everyone, but fairness can also be treated as the Teacher overgeneralization that everyone should get the same regardless of the facts. These two concepts of fairness can be easily differentiated by the willingness or non-willingness to look at factual details. I do not think that neurological papers differentiate between these two kinds of fairness. However, most of the experiments are dealing with the application of Perceiver rules to specific situations and not viewing fairness as an overgeneralized political philosophy.

Panish & Nam (2022) report that dlPFC activity is related to the Big Five trait of conscientiousness. “Functional connectivity between the ACC and the dlPFC facilitates higher levels of the personality trait of conscientiousness—characterized by orderliness and industriousness—by increasing the speed and accuracy with which the brain categorizes stimuli as relevant or irrelevant to current goals.” Conscientiousness can be described as imposing some context of rational Perceiver facts and careful Server sequences upon a situation. The ACC (anterior cingulate cortex) generates cost/benefit thinking for Contributor thought. Connectivity between the ACC and the dlPFC means that Contributor planning is being modified by Perceiver rules and Server procedures. Piretti et al. (2022) describe something similar. “Scholars suggested that the dorsal anterior cingulate cortex (dACC) may play a role in the appraisal of emotional stimuli together with subcortical regions, especially when stimuli are negatively valenced, and the dorsolateral prefrontal cortex (dlPFC) may play a role in regulating emotions.”

Rabin (2021) reports that increasing dlPFC activity leads to greater conservative thinking, which could be interpreted as imposing rules upon social behavior. Stimulation of the DLPFC produced “A significant increase in conservative values regardless of participant’s initial political orientation and the political campaign they were exposed to.”

Tanaka et al. (2023) describe the role of the right dlPFC more generally as suppressing default social behavior, similar to the way that right dlPFC activity suppresses default linguistic behavior. “Proself individuals have a low default prosociality preference and need to regulate it when performing prosocial behavior using right DLPFC. Meanwhile, prosocial individuals have a high default prosociality preference and need to regulate it when inhibiting prosocial behavior using right DLPFC.” This distinction can be seen when comparing children who are naturally selfish with adults who are naturally more prosocial. “One study showed that children who engaged in prosocial behavior had increased DLPFC activity and thicker cortices. Studies on adults showed the opposite. Those with decreased DLPFC activity and thinner cortices engaged in more prosocial behavior. Many studies have shown that children make selfish choices in resource allocation situations more often than do adults.”

Rahrig et al. (2024) clarify that the dlPFC activity can be related either to the imposition of rules or to the imposition of fairness. “Alignment of dlPFC activity may facilitate leader-follower behavioral coordination, and may underlie support for hostile intergroup action. However, when motivated to overcome biases, dlPFC engagement may instead override implicit prejudices in the service of egalitarian goals”. This relates to the distinction between absolute truth and universal truth. Perceiver thought can impose absolute rules that are emotionally backed up by the MMN of some authority figure, or Perceiver thought can impose universal rules that are emotionally backed up by the TMN of some general theory, such as a theory of fairness. For instance, mental symmetry reformulates Christianity from being a system of absolute truth based in Mercy respect for the Bible to being a system of universal truth based in Teacher respect for a theory of cognition. This kind of reformulation is a more general example of the cognitive reappraisal that was discussed earlier when looking at the vlPFC.

Zhao et al. (2021) compared the roles played by the vlPFC and the dlPFC in cognitive reappraisal. “Both the DLPFC and VLPFC highly facilitate the downregulation of affective responses caused by social exclusion, revealing a causal role of these lateral PFCs in voluntary emotional regulation of both non-social and social pain; and these two cortical regions showed relative functional specificity for distraction (DLPFC) and reappraisal (VLPFC) strategies”. Summarizing, two different strategies can be used to deal with unpleasant social experiences in Mercy thought. Perceiver and Server thought can attempt to change the mental context (distraction), or Teacher and Mercy thought can be used to rethink the situation (reappraisal). Effective cognitive appraisal involves the cooperation of both of these strategies, rethinking the situation in the light of universal Perceiver facts and Server sequences.

White et al. (2023) clarify the role that Perceiver and Server thought play in cognitive reappraisal. “Maintenance-like processes engaged by the left dlPFC may regulate emotion by supporting the active, effortful engagement of verbal emotion regulation strategies, like reappraisal. In contrast, suppression-like processes engaged by the right dlPFC may regulate emotion by supporting the automatic top-down filtering of negative affective information, resulting in reduced activity in emotional expression regions”. Server thought is giving stability to verbal Teacher theories of reappraisal, while Perceiver thought is attempting to suppress the expression of existing Mercy emotions. This description implies that Perceiver thought is functioning at the level of absolute truth rather than universal truth.

Xia et al. (2020) found something similar, concluding that “left DLPFC modulates the automatic action tendency while the right DLPFC modulates the direction of behavioral tasks”. In other words, Server thought is giving stability to sequences of behavior while Perceiver thought is changing the context.

Pugh et al. (2023) found that dlPFC activity differs between western females and Asian females. “Insofar as dlPFC connectivity could reflect automatic regulation, Chinese females align most strongly with a cultural drive to regulate emotion, while US females do not... A common explanation for cultural differences in emotion regulation has been that the collectivist aspect of Eastern cultures more strongly encourages group conformity, which entails regulating one’s own emotions”.

The dlPFC is also active when using scientific reasoning to suppress naïve concepts. Liu et al. (2023) summarize that “Inhibitory control plays a role in the scientific reasoning of mathematical subdomain concepts, and both response inhibition and semantic inhibition are involved in suppressing the interference of mathematical misconceptions”. Similarly, Meier et al. (2022) report that “For both mathematics and science, the correct evaluation of incongruent compared to congruent statements activated the same region in the left medial DLPFC. This result corresponds with the majority of studies on conceptual knowledge representation, which repeatedly found the DLPFC to be involved when inhibiting naïve concepts.” however, scientific thought does not just involve inhibition but is also guided by Teacher theories (vlPFC) as well as Contributor value (ACC). Meier et al. (2022) report that “Studies have shown that the anterior cingulate cortex (ACC, BA 24), ventrolateral prefrontal cortex (VLPFC, BA 44/45) and dorsolateral prefrontal cortex (DLPFC, BA 9/46) showed increased activity during scientific reasoning”.

A study that looked at treating alcohol addiction (Elton et al., 2019) concluded that “Treatments targeting the ventromedial prefrontal cortex and left dorsolateral prefrontal cortex may be most effective in individuals whose alcohol use is motivated by negative reinforcement.” I have found as a Perceiver person that suppressing unwanted memories or desires is not an effective long-term strategy. A more effective approach is to use Server thought within the left dlPFC to develop new habits—new sequences of response, as well as developing new mental networks in the vmPFC.

Grundinger et al. (2022) note that Server thought also plays a role in the expression of bad habits. “Cue-induced alcohol craving appears to consistently activate areas of the left hemisphere, with the greatest asymmetry involving the left dlPFC. Evidence suggests, that a well-functioning right hemisphere is a protective factor against drug seeking behavior.” Putting this together, using Perceiver thought to suppress some desire can be effective if a habit has not developed in Server thought. However, once a bad habit has emerged, then it becomes necessary to deal with the unwanted desire at the level of Server thought by replacing the unwanted habit with a new habit.

Server thought is also required when learning complex skills involving manual dexterity. Watanabe et al. (2023) report, “The left dorsolateral prefrontal cortex (DLPFC) is involved in early-phase manual dexterity skill acquisition when cognitive control processes, such as integration and complexity demands, are required.”

Server thought helps to maintain a positive mood. Piretti et al. (2022) compare suppressing Server thought with suppressing Contributor value. “Results showed that cathodal stimulation of dACC, but not the left dlPFC, was associated with reduced arousal ratings of emotional stimuli, both compared with the sham condition. Moreover, cathodal stimulation of left dlPFC decreased participant’s positive affective state after the session. These findings suggest for the first time, a dissociation between the dACC and dlPFC, with the former more involved in emotion appraisal, and the latter more involved in mood modulation.” Teacher thought can generate positive emotion by coming up with simple theories that explain the situation. Server thought gives stability to Teacher theory, resulting in a long-term positive mood. This can be seen in the Server person, who typically has a stable positive mood. Stated more generally, “It is a well-established finding that the hypoactivation of left dlPFC is a marker of depression. In addition, anodal stimulation of the same area was found effective in treating major depression disorder than sham stimulation”. Going the other way, “Left dlPFC cathodal stimulation was associated with the reduction of positive mood, as manifested by a decrease in the positive affective subscale of PANAS”. (Cathodal stimulation reduces activity while anodal stimulation increases activity.)

In summary, it is neurologically sound to connect the left dlPFC with Server thought and the right dlPFC with Perceiver thought.

Hippocampus and Amygdala

Mental symmetry suggests that the left hippocampus is the processor for Server thought, the right hippocampus is the processor for Perceiver thought, the left amygdala is the processor for Teacher thought, and the right amygdala is the processor for Mercy thought. Neurological evidence connecting the two hippocampi with Perceiver and Server thought remains good, as does evidence supporting the amygdalae as emotional processors. However, evidence regarding lateralization remains inconclusive.

My 2019 paper distinguished between the anterior hippocampus, which deals with general concepts, and the posterior hippocampus, which handles specific details. It also mentioned that the anterior hippocampus interacts with emotions generated by the amygdala while the posterior hippocampus does not. Recent papers look further at this distinction between anterior and posterior hippocampus.

Chaposhloo et al. (2023) report that “The predominant view amongst cognitive neuroscientists is that the anterior portion is more heavily involved in gist-like, schematic, or coarse-scaled contextual representations while the posterior portion is more heavily involved in finely detailed spatial representations”. This is consistent with what was mentioned in the 2019 paper. They report that “The anterior hippocampus (aHipp) was significantly more connected to affective brain regions (i.e., anterior and posterior insula and temporal pole) in PTSD compared to controls.” Thus, in posttraumatic stress, memories in the anterior hippocampus are heavily influenced by emotional experiences. Saying this cognitively, Perceiver thought is being overwhelmed by Mercy emotions.

Similarly, Nichols et al. (2023) looked at children and concluded, “Results indicated that emotion was more strongly localized to the anterior hippocampus, with memory being more strongly localized to the posterior hippocampus, demonstrating long-axis specialization with regard to memory and emotion in children similar to that seen in adults.” The posterior hippocampus matures later in children than the anterior hippocampus, providing a possible explanation for why we cannot remember specific events from our childhood. “The slow maturation of the pHPC [posterior hippocampal cortex] is thought to underlie childhood amnesia; that is, detailed episodic memory emerges alongside the protracted development of the pHPC. In contrast, other types of learning, such as statistical learning and generalized memory are purported to rely on the earlier-maturing aHPC, which also emerges earlier in development”.

Costa et al. (2021) measured activity in human epileptic patients and found that “Using simultaneous intracranial recordings from both structures in human patients, here we show that successful emotional memory encoding depends on the amygdala theta phase to which hippocampal gamma activity and neuronal firing couple.” Thus, the amygdala drives the hippocampus when remembering emotional memories. Similarly, mental symmetry suggests that factual processing by Perceiver thought can be emotionally overwhelmed by Mercy thought.

Daume et al. (2024) also measured human neuron activity and found that “In the hippocampus, but not in the amygdala, the level of WM [working memory] content-selective persistent activity during WM maintenance was predictive of whether the item was later recognized with high confidence or forgotten.” Thus, the hippocampus is responsible for remembering information, and both Perceiver and Server thought place a label of confidence upon remembered information.

Kleen et al. (2021) also measured human neuron activity in epileptics and noticed that activity spreads in waves along the hippocampus. They conclude, “In the hippocampus this ordered framework could suggest that while waves moving anteriorly are pre-weighted with detailed visuospatial information that may then integrate with some amount of emotional information waves moving posteriorly could be weighted more strongly by emotional information that is then tagged with visuospatial content.” Thus, factual information from the posterior hippocampus is colliding with emotionally related information that the amygdala is imposing upon the anterior hippocampus. Similarly, mental symmetry suggests that Perceiver and Server confidence interact with emotional intensity.

Li et al. (2022) compared the function of the amygdala with the hippocampus when forming memories. “The mnemonic representations in the amygdala were highly distinct and decreased from encoding to maintenance. The hippocampal representations, however, were more similar across different items but remained stable in the absence of the stimulus. WM [working memory] encoding and maintenance were associated with bidirectional information flow between the amygdala and the hippocampus in low-frequency bands.” Thus, the amygdala generates short-term activity based upon the emotional intensity of the specific situation, while the hippocampus looks for long-term connections. In the words of Li et al., “During encoding, the amygdala forms highly distinct representations for different encoding items and conveys this perceptual information to the hippocampus. During maintenance, the hippocampus can well retain the encoded representational patterns and transfers this memory information back to the amygdala.” The posterior hippocampus is responsible for making recollection more accurate. “Correct WM trials were associated with a unidirectional influence from the posterior to the anterior hippocampus, whereas error trials were correlated with bidirectional interactions.”

The amygdala can be separated into a basolateral region (BLA) and a central region (CeA). Smith & Torregrossa (2021) report that the BLA adds emotional details, while the CeA relates more to general motivation. “A large body of research concerning conditioned reward-approach responses has revealed that the BLA plays a more precise role in representing the affective value of the conditioned stimuli and this information is used to support the translation of conditioned associations into instrumental action while the CeA appears to more generally support Pavlovian conditioned responses”. Saying this another way, “BLA lesions in these animals abolished outcome specific effects of the cue while sparing its general motivational effects. On the other hand, lesions of the CeA eliminated the general motivational effects of the cues, but did not impact the specific effects”. Applying this to drug addiction, “The CeA is critical for integrating changes in reward associated with drug dependence studies highlight that while the BLA is not responsible for the primary reinforcing effects of drug, it is essential for a cue to elicit the affective representation of the drug reinforcer”.

Nawa & Ando (2020) found that hippocampal activity adds accuracy when triggering mental networks in the vmPFC. “When AM [autobiographical memory] search completed successfully (Hits), the effective connectivity of the hippocampus on the vmPFC and angular gyrus was up-modulated.” In contrast, mentally constructing imaginary events involves a bidirectional interaction between mental networks in the vmPFC and factual content in the hippocampus. “With regard to the vmPFC and hippocampus, evidence from studies focusing on the construction of imaginary events is so far mixed, with results showing both enhanced effective connectivity from the hippocampus to the vmPFC as well as in the reverse direction, from the vmPFC to the hippocampus”. Similarly, Parsons & Davies (2022) state that “Relational schemas are thought to be accessed through a neural pathway that links ventromedial prefrontal cortex (VMPFC) to the hippocampus”.

Looking more closely at the anterior hippocampus, Knudsen & Wallis (2021) “developed a paradigm that required animals to track changing reward values associated with sensory stimuli and showed that performance of the task was dependent on the anterior hippocampus, which is the part of the hippocampus that strongly projects to prefrontal areas responsible for processing reward information.” Notice the focus upon factually evaluating emotional value. Going further, “When subjects are performing the same task used in this paper, there is an increase in synchrony in the theta oscillation between orbitofrontal cortex and hippocampus, consistent with a transfer of information between the two structures. The current results suggest the nature of this transferred information: a concise neural code that represents the value of the potential outcomes relative to one another.” Interpreting this cognitively, the orbitofrontal cortex attaches internally generated emotional labels to specific memories. Mental symmetry suggests that Perceiver thought places emotional Mercy memories within an internal map of value. This generation of a map of value can be seen in interaction between the anterior hippocampus and the orbitofrontal cortex.

Distinguishing now between Server sequences and Perceiver facts, the hippocampus remembers temporal sequences, an expression of Server thought as well as spatial connections, an expression of Perceiver thought. O’Keefe & Krupic (2021) summarize, “At this point it is clear that the hippocampus incorporates a representation of time of different durations. Whether this is independent of the spatial mapping function is not clear, since in general the relevant experiments have not been done.” Reddy et al. (2021) recorded human neuron activity in the hippocampus and encountered time cells. Patients “learned predictable sequences of pictures. We report that human time cells fire at successive moments in this task. Furthermore, time cells also signaled inherently changing temporal contexts during empty 10 s gap periods between trials while participants waited for the task to resume. Finally, population activity allowed for decoding temporal epoch identity, both during sequence learning and during the gap periods. These findings suggest that human hippocampal neurons could play an essential role in temporally organizing distinct moments of an experience in episodic memory”. Applying this to personality, the Server person finds it easy to talk about the events of the day, describing exactly what happened when.

More generally, Tacikowski et al. (2024) summarize, “Neurons in the hippocampus and entorhinal cortex integrate the ‘what’ and ‘when’ information to extract durable and predictive representations of the temporal structure of human experience”. Perceiver thought focuses upon the ‘what’ of connections while Server thought focuses upon the ‘when’ of sequences. This focus upon space and time can be generalized to form more generic cognitive maps. “The present study is also in line with the idea that the hippocampal–entorhinal system is critically involved in the abstraction of knowledge. Such abstraction has been described as a cognitive map in the context of spatial navigation and ‘schemas’ or ‘learning sets’ in the context of human behaviour and memory research.”

Perceiver thought in the right dlPFC can be used to suppress the retrieval of memories from the hippocampus. “Effective connectivity analyses indicate that the right DLPFC modulates the amygdala and hippocampus (especially anterior hippocampus) in parallel as an integrated stopping response to the unpleasant scene and that this modulation is inhibitory, especially during intrusions.” Notice that the focus is upon using Perceiver thought to suppress the retrieval of emotionally colored memories from the anterior hippocampus.

Summarizing, there is good evidence connecting Perceiver and Server processing with the left and right hippocampi, but this evidence focuses upon remembering concrete experiences rather than abstract theories and it does not distinguish between left and right hippocampus. Similarly, evidence on the amygdala focuses exclusively upon Mercy emotions while unaware of the very concept of Teacher emotions. Thus, it makes sense that neurological evidence regarding amygdala lateralization would be incomplete./

Ventromedial Prefrontal Cortex (vmPFC)

The vmPFC appears to play a central role in mental networks. This role is discussed extensively in two papers that were written after the 2019 paper mapping of mental symmetry onto neurology. (Friesen 2021, 2024). Summarizing briefly, the orbitofrontal cortex assigns emotional labels to specific memories, while the vmPFC organizes emotional memories into mental networks. The dmPFC (dorsomedial PFC) integrates information from various mental networks to guide theory of mind (ToM). This is slightly different than what was stated in the 2019 paper, which associated the orbitofrontal cortex with mental networks. A should be emphasized that mental networks within the vmPFC integrate information that comes from other regions of the brain.

Going further, my two papers on the vmPFC did not distinguish between various subregions of the vmPFC. More current research shows that the pregenual cingulate cortex is an aspect of the vmPFC that deals with more emotional and subjective topics, which will be discussed when looking at striosomes.

A mental network uses emotional pressure to impose its content upon the mind when triggered. Hogeveen et al. (2021) suggest something similar. “A prominent functional model of vmPFC is that it encodes the anticipated value of obtainable outcomes.” In other words, triggering a mental network activates a schema of what is expected to happen.

A Mercy mental network (MMN) will form if some collection of emotional experiences continues to be reproduced and a Teacher mental network (TMN) will form if some theory continues to be used. Sridhar et al. (2024) describe this progression, suggesting, “The VLPFC may regulate emotions by activating the VMPFC. This VMPFC activation may cause a cascade of inhibitory activity in the amygdala and insula, which are involved in emotional reactivity, for example, through projections from VMPFC to local inhibitory interneurons in the amygdala”. Mercy focus and Teacher theories in the vlPFC are causing mental networks to form within the vmPFC, which is then imposing structure upon emotional parts of the mind.

However, Perceiver thought can be used to override (at least temporarily) the default behavior of mental networks in the vmPFC. Tanaka et al. (2023) relate, “Right DLPFC activity and DLPFC-ventromedial prefrontal cortex (VMPFC) functional connectivity were observed when individuals made a social decision that deviated from their default prosocial preferences. Given that the VMPFC is thought to be involved in the representation of subjective value computation”.

Zhao et al. (2021) looked at drug addiction and found that “One session of cTBS over the left vmPFC may modulate drug cue-associated functional connectivity between the vmPFC and ACC in addicted alcohol and cocaine users”. In other words, drug paraphernalia is triggering mental networks of addiction. Disrupting vmPFC activity prevents these mental networks of addiction from functioning. Presumably, the left vmPFC stores TMNs of habit based upon actions of addiction that are being repeated.

Briganti (2024) describes the role played by the vmPFC in making moral decisions. “The vmPFC is [sic] integrates emotional and social information when making moral judgments and evaluates the emotional significance of actions and their outcomes: when individuals face moral dilemmas, the vmPFC helps to weigh the emotional consequences of different choices. On the other hand, the dlPFC is involved in cognitive control and deliberative processes.” This description is consistent with the operation of a mental network that is emotionally imposing some moral structure upon the mind when being triggered. This is different than the role played by the dlPFC.

Cristofori et al. (2024) looked at patients with brain damage and “found that the vmPFC, but not the dlPFC, group assigned lower radicalism scores to statements compared with the parietal and healthy control groups. These findings emphasize the pivotal role of the vmPFC in appropriately evaluating political beliefs and suggest that vmPFC lesions may lead to patients underestimating how radical certain social behaviors are.” In other words, mental networks within the vmPFC allow a person to grasp the full emotional implications of embracing a radical viewpoint. Consistent with this, Rahrig et al. (2024) found that the vmPFC generates emotional responses to radical political views. “Our research suggests that the vmPFC is involved in encoding emotional responses to politically partisan videos, which may in turn shape how partisans collectively interpret such information.”

Gerchen et al. (2023) point out that the vmPFC does not necessarily function logically, noting “higher activation of the right prefrontal cortex when correct logical responses were made. In trials in which logical reasoning was overcome by beliefs, higher activation in the ventromedial prefrontal cortex (vmPFC) was found.” Logic was associated with Perceiver facts in the right prefrontal cortex, while the vmPFC uses emotional pressure to impose the content of mental networks.

Li et al. (2024) also point out this distinction. “Unfairness to self was supported by two separable but interacting neural networks. One was the reflexive and intuitive system, including the AI [anterior insula] and the ventromedial prefrontal cortex (VMPFC), which represented emotional, automatic, and rapid responses to social norm violations. The other was the reflective and deliberate system, involving the dACC, ventrolateral prefrontal cortex (VLPFC), DLPFC, and rostral ACC (RACC), which is typically associated with cognitive control”. Notice that the vmPFC functions reflexively, intuitively, automatically, and emotionally, consistent with the idea of a mental network being triggered and emotionally imposing its structure upon the mind. In contrast, the dACC calculates costs and benefits for Contributor thought, the dlPFC considers facts and sequences, while the vlPFC performs cognitive reappraisal.

Bruns et al. (2025) asked subjects to evaluate whether trait adjectives applied to themselves, close friends, or famous persons. “For uncertainty, we found dmPFC activation. We replicated vmPFC involvement in belief processing and found a common neural correlate for belief and self-belief in the vmPFC”. In other words, the vmPFC stores mental networks that apply to both self and to others, while the dmPFC deals with ambiguous situations where several mental networks might apply.

Chaposhloo et al. (2023) noted that “Strong effective connectivity from vmPFC to the hippocampus has been observed during the elaboration phase of emotionally arousing auto­ biographical memory retrieval”. This is consistent with the suggestion that the mind uses mental networks within the vmPFC to represent personal identity. It also clarifies that mental networks within the vmPFC integrate information provided by other parts of the mind. Nawa & Ando (2020) also point out that the vmPFC integrates information from the rest of the mind, describing “the vmPFC as a major driver of activity within the network, with positive connections to all other nodes but the angular gyrus ROI. This result is in agreement with other studies that have highlighted the involvement of vmPFC in various stages of autobiographical memory processes.”

Nucleus Accumbens (NAcc or Nac) and Dopamine (DA)

The nucleus accumbens is part of the ventral straitum and is associated with Exhorter thought.

Hu et al. (2023) elaborate, “The Nac can be divided into the core-like part and shell-like part. Studies have found that the core-like subdivision receives projections from the mediolateral OFC and prelimbic medial prefrontal cortex (mPFC), and the shell-like subdivision receives projections from the ventral medial prefrontal cortex (vmPFC). Thus, the core is related more to specific emotional memories while the shell is guided by mental networks. Looking at function, “The Nac core-like subdivision is related to appetite controls and responses to aversive motivation, goal-directed behaviour, instrumental learning, and motivation, while the shell-like subdivision is associated with the integration of motivational valence and novelty.” Thus, the core focuses upon specific goals and threats, while the shell places this within the context of some mental network.

The connection from mental networks in the vmPFC to Exhorter thought in the NAcc plays a major role in motivation. Zhou et al. (2022) summarizes, “Human fMRI studies have shown that activity between VMPFC/OFC and VS is highly correlated in resting states or in tasks involving rewards”. (VS is ventral stratium and the ventral striatum contains primarily the nucleus accumbens.)

Whittaker et al. (2018) relate that faulty input from mental networks to the Nac plays a major role in psychiatric disorders. “Interaction of the NAcc with the ventromedial prefrontal cortex (vmPFC) has been shown to be pivotal in regulating responses to reward and emotional symptoms in psychiatric disorders”. Thus, a person is being emotionally driven by an improperly programmed mental network to respond in an irrational manner.

Exhorter thought is associated with dopamine. Billig et al. (2022) “reported reduced hippocampal blood flow when listening to self-selected music experienced as intensely pleasurable, eliciting ‘chills’ and other physiological responses, in comparison to control music selected by other subjects. This reduced response is thought to arise through inhibitory projections from the nucleus accumbens, part of the dopaminergic reward system in which activity increases during chills.” In other words, pleasurable music is activating Exhorter thought and dopamine which is minimizing factual processing, causing a person to focus emotionally the music.

Mental symmetry suggests that Exhorter combines Mercy and Teacher. Consistent with this, Zhou et al. (2022) summarize that “The NAc, VMPFC, and OFC are all important projection areas for dopamine.” Notice that dopamine, which regulates Exhorter thought, is controlling the operation of Exhorter thought, as well as Teacher and Mercy emotional memories and mental networks.

Exhorter thought focuses upon emotional change and motivation. Similarly, Esser et al. (2021) state that “A dopamine-related pathway underlies extinction learning in humans. Dopaminergic enhancement via administration of L-DOPA (vs. Placebo) was associated with reduced retention of differential psychophysiological threat responses at later test, which was mediated by activity in the ventromedial prefrontal cortex that was specific to extinction learning.” Notice that Exhorter thought via dopamine is changing behavior by altering mental networks.

Going the other way, dopamine can also lead to inappropriate responses by mental networks. Hui & Beier (2022) summarize, “Dopamine signaling within the mPFC has been shown to play a role in a variety of neuropsychiatric disorders, such as schizophrenia, post-traumatic stress disorder, and attention deficit hyperactivity disorder”. They add that “DA cells projecting to the mPFC... do not express D2 autoreceptors.” D1 receptors focus upon the primary motivation while D2 receptors involve alternatives. The absence of D2 receptors suggests that mental networks drive the primary motivation rather than alternative choices. (D1 and D2 receptors will be examined further when looking at striosomes.)

MacPherson & Hikida (2019) relate substance abuse with a positive feedback loop involving dopamine, the NAcc, and D1 receptors. “Abused substances often increase the release of dopamine in the NAc, used to signal rewarding stimuli. This increase in NAc dopamine then bidirectionally modulates the activity of NAc neurons, facilitating D1-MSNs via binding at D1 receptors and inhibiting D2-MSNs via binding at D2 receptors, and thus alters the activity in basal ganglia circuits that control learning and behavior.” They also state that “Antipsychotics effective in reducing the positive symptoms of schizophrenia typically act as antagonists at dopamine D2 receptors to decrease D2-signalling.” I am not sure how suppressing D2 minimizes schizophrenic symptoms because schizophrenics have problems with emotional fixations, which implies that one would want to maximize D2. However, there is uncertainty regarding the polarity and exact function of D2 receptors and we will see later that there is new evidence suggesting that D2 functions in the opposite manner within the striosomes. will

Basal Ganglia and Striosomes

Processing by the basal ganglia is separated between a direct path and an indirect path. Graybiel & Matsushima (2020) summarize that “Dopamine released in the striatum increases activity of the pro-kinetic so-called GO D1-expressing direct pathway projection neurons (dSPNs), but that dopamine decreases activity of the anti-kinetic NO-GO D2- expressing indirect pathway projection neurons (iSPNs).” Thus, the classic view is that D1 promotes activity through the direct path, while D2 suppresses activity through the indirect path.

It has also been discovered that the basal ganglia contains striosomes mixed within a matrix, somewhat like plums embedded in a plum pudding. Amemori et al. (2021) explain that “In rodents and primates, the pathways from the striosomes and matrix are clearly independent”. The relationship between striosomes and matrix has been postulated as similar to a critic and actors. In other words, the matrix carries out Contributor plans while the striosomes use Exhorter thought to question and comment on these plans. Graybiel & Matsushita (2023) suggest, “Striosomes are related to internal, cognitive orientation state switches, with or without awareness, that can provide mental templates to orient to what we aim toward, thus learning to evaluate and manifest unitary actions in concordance with the orientations or biases.”

Striosomes are most prominent in the parts of the basal ganglia that are most related to emotions and motivation, indicating a connection with Exhorter thought. Graybiel & Matsushima (2023) explain, “Striosomes are particularly large and prominent in the anterior striatum, especially so in humans, and there they receive inputs especially from components of the limbic system and some association cortex but few, if any, inputs from primary motor and sensory regions... Striosomes are nearly missing from the far lateral part of the striatum, corresponding roughly to the input zone for the primary somatosensory-motor cortex, but are most prominent in the striatal districts that receive inputs from the limbic system–related regions.”

Striosomes can increase dopamine through a positive feedback loop, consistent with the idea of being related to Exhorter thought and motivation. Graybiel & Matsushima (2023) explain, the “striosomal system, a standout feature of the striatum because of its remarkable neurochemical properties, has subdivisions that can directly project to the dopamine-containing neurons of the Snpc [substantia nigra pars compacta], a property that is only to a limited extent, if any, shared with the matrix. SNpc neurons can in turn project back to the striatum, including to striosomes, and can release dopamine, a powerful modulator of neuroplasticity.”

Striosome activity is related to internally generated anxiety while matrix activity is related to externally generated anxiety. Graybiel & Matsushima (2023) explain, “A dichotomy was found between general anxiety disorder and obsessive-compulsive disorder (internally triggered anxiety disorders) associated with striosomes and social anxiety disorder (an externally triggered disorder) associated with the matrix”. In OCD steps are being taken to deal with symptoms but the underlying emotional problem is not being addressed. For instance, one may be checking to see if the stove is off but this does not result in the feeling that the stove is off. Exhorter thought focuses upon internally generated emotional anxiety. Social anxiety disorder, in contrast, attempts to deal with anxiety by altering the way that a person behaves externally in front of others.

Stimulating the striosomes can lead to major changes in emotional behavior. Quoting from Graybiel & Matsushima (2023), “Even small, experimentally induced specific manipulations of striosomes can trigger remarkable state transitions, such as transitions from avoiding to accepting aversive outcomes, from being distressed to being utility oriented, and from being apathetic to engaged, or the reverse behaviors.” This is consistent with the idea that striosomes are being guided by emotional memories and mental networks.

The direct and the indirect paths are both within the matrix and not within the striosomes. (However, we will see later that Lazaradis et al. have discovered a different kind of ‘direct and indirect path’ that exists within the striosomes.) The matrix is associated with action and plans. Graybiel & Matsushima (2023) explain, “The SPNs of the matrix compartment, in about equal numbers, express D1 or D2 dopamine receptors and project directly (direct D1 pathway) or indirectly (indirect D2 pathway) to the motor output nuclei of the basal ganglia. They receive input from the neocortex and thalamus and from various other.” Maracek (2024) clarifies that “Most striosomal MSNs appear to project into the nuclei of the direct pathway, whereas the matrix MSNs are evenly divided between direct and indirect pathway targets.”

The striosomes also have D1 and D2 neurons. D1 projects to DA cells, which presumably enhances the current plan. Quoting from Graybiel & Matsushima (2023), “The SPNs of the striosomes also have D1 and D2 receptor–expressing populations in about equal numbers. The D1 receptor–expressing striosomal SPNs project directly to the dopamine-containing neurons of the Snpc.”

In a new breakthrough, Lazaradis et al. (2024) report that the striosomes have a D1 path to the Snpc as well as a D2 path to the GPe. “Here, we demonstrate that striosomes not only give rise to a direct D1 pathway to the SNpc but also to an indirect pathway originating in D2-expressing striosomal SPNs that target a central, commonly overlooked subdivision of the external globus pallidus (GPe) that itself innervates nigral dopamine-containing neurons.” This is a new D2 path that has not been described before. My feeling is that the globus pallidus is related to Contributor optimization. Thus, personal motivation in the striosomes could drive behavior but they could also lead to a major rethinking of behavior.

Lazaradis et al. (2024) state that in the rat “The striosomal D1 pathway tends to reduce movement and to reduce dopamine release, and the D2 striosomal pathway tends to increase movement and dopamine release—functions opposite to those of the canonical D1 and D2 pathways.” Rats do not have an internal world but rather think by moving through the physical environment. Thus, for a rat rethinking would involve movement and exploration, meaning that the increased movement could be the result of mental rethinking by the rat. This is current research, which means that this confusion cannot be resolved at the moment. Lazardis et al. do state that “The basal ganglia have in place two major direct-indirect systems to exert opposing control over behavior: one targeting motor output nuclei modulating action, and the other, from striosomes, targeting the nigral dopamine-containing neurons that modulate mood state and the motivation to act, and that likely influence the classical direct-indirect circuits.” This distinction is consistent with Contributor planning and action versus Exhorter motivation. This distinction describes concrete thought but animals are only capable of concrete thought.

Summarizing, I have been following research on the striosomes for about thirty years waiting for the confusion to be cleared up, but it never is. However, despite the field remaining in a confused state, the gradually emerging evidence continues to support my hypothesis that Exhorter thought is manipulating mental networks and strong emotions via the nucleus accumbens and imposing goals and mental networks via the striosomes, while Contributor thought is using the matrix to form and implement plans, guided by emotional pressure from Exhorter thought.

Pregenual Anterior Cingulate Cortext (pgACC)

The pregenual anterior cingulate cortex (pgACC or pACC) is a part of the vmPFC that focuses upon emotional issues that have extra significance. The pgACC is connected with the striosomes. Amemori et al. (2021) “found that effective stimulation sites in both pACC and cOFC zones projected preferentially to striosomes in the anterior striatum.” They also found that stimulating these areas in monkeys leads to stressful decision-making. “We performed microstimulation of limbic related cortical regions and the striatum, focusing on the pregenual anterior cingulate cortex (pACC), the caudal orbitofrontal cortex (cOFC), and the caudate nucleus (CN). Microstimulation of localized sites within these regions induced pessimistic decisionmaking by the monkeys, supporting the idea that the focal activation of these regions could induce an anxiety-like state, which subsequently influences decision-making.”

The pgACC as well as the area below it referred to as the subgenual ACC receive input from the amygdala. The sgACC projects to the NAcc, which is related to Exhorter thought. Amemori et al. (2021) clarify, “the pACC, as well as the subgenual anterior cingulate cortex (sACC) and the caudal region of the orbitofrontal cortex (cOFC), are, in particular, limbic cortical regions that have direct inputs from the amygdala. The sACC, just ventral to the pACC, projects strongly to the ventral striatum (VS), prominently to the nucleus accumbens (NAcc). The pACC and cOFC have preferential projections to the striosome compartment in the striatum, especially to the anterior striosomes of the caudate nucleus (CN) and adjoining rostral part of the putamen.”

Klein-Flügge et al. (2022) claim that the pgACC and a region in the oFC are the only areas in the frontal lobes to project to the striosomes. “In primates too, the pgACC is very unusual in having a projection to the striosome; within the frontal cortex, only the pgACC and a pOFC region, on the border with the insula, project to the striosome”. And Grohn et al. (2024) make a similar claim. “The pgACC is unusual in that it is one of only two cortical regions that project strongly to the striosomal compartment of the basal ganglia.” However, the source for both of these claims is a 1995 paper by Eblen and Graybiel. And Graybiel makes a weaker claim in a 2023 paper that also refers back to the 1995 paper. “Striosomes are particularly large and prominent in the anterior striatum, especially so in humans, and there they receive inputs especially from components of the limbic system and some association cortex but few, if any, inputs from primary motor and sensory regions.” Graybiel & Matsushima also add that “This list is almost certainly incomplete.” (p. 367).” Other papers mention that determining the precise connections of the striosomes is rather difficult, but I suggest that making a definitive claim about connectivity based in a 1995 paper when writing in 2023 or 2024 is sloppy. However, one can still conclude that the pgACC projects strongly to the striosomes.

Looking now at activity, Klein-Flügge et al. (2022) quote others as stating that human pgACC activity relates to personal monitoring. “In humans, the pgACC carries signals consistent with the monitoring of one’s own performance over both shorter and more extended time frames. For example, Wittmann and colleagues reported that pgACC activity reflected the feedback human participants received about their performance levels on a variety of arbitrary games, and it predicted the influence that the feedback would have on the participants’ estimations of their ability levels. One recent hypothesis is that this type of self-awareness may be altered in mood and anxiety disorders known to implicate the pgACC.” This goes beyond emotional value guiding Contributor thought to personal significance and personal well-being.

A 2020 paper by Amemori et al., which includes Ann Graybiel as an author, found that “Local microstimulation of a small part of the pregenual anterior cingulate cortex (pACC) was found to increase avoidance decisions in a cost-benefit decision-making task (Ap-Av task) in which differing amounts of ‘good’ and ‘bad’ options were given simultaneously.” The authors backed up this behavioral evidence with solid neurological evidence, “After identifying these sites, we injected viral tracers carrying constructs allowing subsequent track-tracing post-mortem. For each site identified behaviorally as increasing avoidance choices, we found strong fiber projections to the caudate nucleus and anterior striatum with large parts of these targeting striosomes subsequently identified by serial-section immunohistochemistry.” Thus, one can definitely conclude that the pgACC handles emotionally potent values and projects to striosomes. In the words of the authors, “These findings outline circuits leading from pACC/cOFC to striosomes and causally modulating decision-making under emotional conflict.”

Grohn et al. (2024) found that pgACC activity is related to task engagement in monkeys. “When animals were strongly engaged in any task and unlikely to disengage, then a broad region of increased activity spanning several areas, but which was especially prominent in pgACC, was found. Activity was weakest on trials when the animals’ task engagement levels collapsed and the monkeys disengaged. The effects were apparent even when we controlled for RT [reaction time] suggesting that pgACC activity was related to task disengagement”. They also report that “In humans, coupling between pgACC activity and striatal activity has been linked to disinhibition of effortful choices; first, it was more prominent when the costs of a course of action were high but it was still pursued and second it was more prominent in individuals who were inclined to pursue such courses of action. Individual variation in pgACC activity has also been reported to covary with how influenced each person is by the prospect of future reward despite the need to engage in a sequence of decisions”. In other words, pgACC activity reflects personal commitment. This goes beyond pursuing some goal in an objective manner to personally committing to pursuing this goal despite the cost. Obviously, personally committing to some goal may induce anxiety because the stakes are high.

Looking at this cognitively, the Contributor person tends to use technical thought to pursue some emotional goal in an objective manner. Evidence indicates that this type of behavior does not involve the pgACC and does not use the striosomes. Instead, it involves the direct and indirect paths of the matrix. The pgACC and striosomes get involved when making a personal commitment, or when recognizing that one is dealing with a high-stakes, stressful situation where choices can have a personal impact.

Weigand et al. (2022) looked at the effect of ketamine upon depression. “A growing body of evidence suggests that the pgACC is also a key locus of action for ketamine, a promising Glu-modulating drug with a rapid antidepressant effect.” More generally, they “highlight increased pgACC activity prior to treatment as a reliable biomarker of clinical response to a variety of antidepressant treatments, including pharmacotherapy, sleep deprivation, and repetitive transcranial magnetic stimulation (rTMS).” They conclude, “Based on these findings, the pgACC is currently the best supported candidate for a general neuroimaging biomarker for antidepressant response. Similarly, with regard to ketamine it was shown that pgACC activity during emotional and cognitive tasks predicted antidepressant response to ketamine”. Stated cognitively, depression implies that I feel that my personal state is unpleasant. If psychiatric treatment is to be effective, then a patient must be personally committed to being helped. This brings to mind the joke: “How many psychiatrists does it take to change a light bulb? Only one, but the light bulb really has to want to change.” The pgACC appears to be responsible for generating this ‘really wanting to change’.

Related to this, Jüllig et al. (2024) describe a relationship between low self-esteem, depression, and the pgACC. They “conclude that low self-esteem in MDD patients is linked to a task-induced deactivation dysfunction of the pgACC. Our findings suggest that a previously described possible subtype of MDD with pgACC and ventral striatal overactivations during reward processing is clinically characterized by low self-esteem.” In other words, depression generally involves avoiding thinking about self because this is unpleasant. However, there is a subset of depression in which patients personally commit to a low self-esteem. The authors quote an earlier paper (Wagner et al., 2013) that “found enhanced pgACC activity while healthy participants read negative statements, for example, ‘I consider myself to be a loser,’ compared to positive or neutral self-referential statements. pgACC activity also correlated positively with the endorsement of the negative self-descriptions as an indicator of low trait self-esteem.” Looking at this cognitively, Teacher thought can come up with an overgeneralization such as ‘I am unlovable’ or ‘I am worthless’, causing the pgACC to focus upon this overgeneralization, leading to a stable low self-esteem in which Teacher thought feels good about Mercy thought feeling miserable.

Summarizing more generally, the pgACC is a specific area within the vmPFC. Mental symmetry suggests that mental networks are stored within the vmPFC. Mental symmetry also defines self as the mental networks that repeatedly come to mind. If pgACC activity is related to personal commitment, then this adds a dimension of choice to self. One can choose to define self physically based upon input from the insula. One can choose to identify with the TMN of some name, slogan, or theory (including some self-destructive theory such as ‘I am worthless’). Or one can choose to identify with some set of experiential MMNs.

Looking at this now from the perspective of Contributor thought, serotonin appears to be related to Contributor thought. 5HT1A receptors appear to enhance normal Contributor functioning while 5HT2A receptors enhance Contributor creativity and openness. This was discussed in the 2019 paper. Striosomes are related to 5HT2A receptors. Graybiel & Matsushima (2023) report, “A remarkably extensive set of substances with psychotropic effects via biogenic amines and other agents have concentrated expression in the striosomal system such as 5HT2A receptors, activated by hallucinogens such as LSD”. Thus, there is a relationship between striosomes, 5HT2A, and LSD.

Lewis et al. (2020) looked at cortical thickness and various measures of mystical experience. They “used four in this study: experience of unity (example item: “I experienced past, present, and future as a oneness”), spiritual experience (example item: “I experienced a kind of awe”), blissful state (example item: “I enjoyed boundless pleasure”), and insightfulness (example item: “I gained clarity into connections that puzzled me before”)”. ‘Experience of unity’ describes the Teacher overgeneralization of cosmic oneness; awe is the feeling that one is a small aspect of something as much larger in Teacher thought; ‘blissful state’ describes identifying in Mercy thought with ultimate unity in Teacher thought; and ‘insightfulness’ is the feeling of having a Teacher understanding that brings unity to current complexity. Lewis et al. “found rostral anterior cingulate thickness specifically predicted all four sub-scales of Unity, Spiritual Experience, Blissful State, and Insightfulness, whereas the caudal anterior and posterior cingulate did not.” Rostral anterior cingulate is another term for pgAcc. The authors focused upon this area “Due to high expression of serotonin 2A receptors (5HT-2Ar) in the cingulate cortex, and its prior associations with psilocybin”. Thus, there is a connection between the pgAcc, 5HT2A, LSD, and mystical experience. (Psilocybin behaves like LSD.) This also provides evidence that both personal MMNs and universal TMNs involve the pgACC.

The 2019 paper on neurology also mentioned that the cognitive effect of 5HT2A is highly dependent upon the context. “The main hypothesis of this article is that the therapeutic action of psychedelics is fundamentally reliant on context – both in the psychological and environmental sense. It is argued that neglect of context could render a psychedelic experience not only clinically ineffective but also potentially harmful – accounting, in part, for the negative stigma that still shackles these drugs” (Carhart-Harris, 2018).

Putting this all together, Contributor thought is normally guided by some objective bottom line that does not involve the pgACC or the striosomes. However, Contributor thought can also let go and be driven emotionally by the pgACC and the striosomes. This is risky because it activates highly emotional mental networks. If emotional processing combines Teacher overgeneralization with Mercy identification, then this opening up of Contributor thought can lead to a mystical experience. But a ‘bad LSD trip’ will happen if Contributor thought opens up to unpleasant mental networks. However, Contributor thought is actually opening up to the aspect of thought that involves personal commitment, which mysticism abuses by personally identifying with a Teacher overgeneralization of cosmic unity. Thus, the long-term solution is to program this region with a meta-theory in Teacher thought combined with Platonic forms in Mercy thought and then commit personally to these universal elements that actually apply to human existence, as opposed to mysticism which ‘transcends’ human existence.

Speaking of personal commitment, I have had several conversations with individuals who practice mysticism and I have found that no amount of logic or reasoning is able to deter them from their personal commitment to the practice and centrality of mysticism. They are deeply committed to the exaltation of personal and universal insanity. And I have found that having a PhD actually makes a person more susceptible to such global insanity, because a PhD emphasizes locally rational thinking.

Turning briefly to another monamine, mental symmetry suggests that Facilitator thought is related to Noradrenaline (NA) which is generated primarily by the locus coeruleus. Recent evidence backs up this suggestion. Parades-Rodriguez et al. (2020) note that in Parkinson’s disease, “One of the first areas undergoing degeneration is the locus coeruleus (LC). Despite being a tiny nucleus, the LC shows an enormous projecting network, influencing the activity of nuclei all over the brain.” Facilitator thought balances the functioning of the entire mind, consistent with a nucleus that influences global brain activity. Parades-Rodriguez et al. add, “In early PD, subtle cognitive deficits include difficulty in executing functioning, particularly cognitive flexibility, which is the capacity to update and redirect attention when the environmental or homeostatic conditions change. Flexibility in cognitive processing is an essential function of prefrontal cortex and it has been proposed that loss of prefrontal noradrenergic input may contribute to this prodromal cognitive deficit.” Facilitator thought thinks in an analog manner, continually redirecting attention and exhibiting cognitive flexibility in response to environmental changes.

Tosserams et al. (2023) describe the blending function of Facilitator thought. “We propose that the noradrenergic locus coeruleus plays an important role in modulating PD symptom severity and expression, by regulating arousal and by mediating network-level functional integration across the brain. The ability of the locus coeruleus to facilitate dynamic ‘cross-talk’ between distinct, otherwise largely segregated brain regions may facilitate the necessary cerebral compensation for gait impairments in PD.” This describes Facilitator thought, which attempts to bring consensus by blending and averaging disparate points of view. More specifically, “Increased activity of the locus coeruleus (i.e., turning up the volume) increases the strength of functional interactions between brain regions that are otherwise largely segregated.” Tosserams et al. also describe the adjusting and fine tuning of Facilitator thought. “The concept of fine-tuning one’s arousal level to optimizing one’s ability to compensate for gait impairments in PD is tightly connected to the functions of the locus coeruleus.”

Conclusion

Recent neurological evidence continues to support the detailed mapping of mental symmetry onto neurology that was done in the 2019 paper, adding a number of details and clarifications. The cutting edge of neurology is always in a state of flux, but this uncertainty continues to resolve itself in a manner that remains consistent with the personality traits that were discovered by my brother Lane Friesen and myself back in the 1980s. I recently presented a summary of the neurological evidence for mental symmetry to an academic audience, and this essay on current neurology was prompted by the research that I did when preparing for that talk. One of the audience members suggested that I should focus upon the neurology and drop what he referred to as the non-scientific idea of cognitive styles and personality traits. My response was that my ‘non-scientific method’ of studying cognitive styles and personality traits generated all of the evidence that neurology has been confirming for the last forty years. Going further, I observed that what the audience members typically regarded as scientific thought was using mathematical, technical reasoning to extrapolate from limited evidence, often based upon a few, often dated, academic papers. Such a ‘scientific’ methodology may be appropriate when making incremental advances within some field, but it is not appropriate when attempting to come up with a general theory that bridges many fields, and those who work within academia continually complain about the fragmented, isolated thinking that pervades academic specializations.

Stated more generally, the ultimate bottom line of science should be to gain an understanding of how things work. Instead, most science has degraded into policing a methodology of studying how things work in a ‘scientific manner’, while ignoring and rejecting theories that explain how things work if these theories were developed in an insufficiently rigorous manner. Stated more simply, science has changed from studying how the natural world works to policing how scientists work.