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Advanced Neurology The anterior cingulate cortex in social empathy

plays an important role in perceiving social fear as well as both the observation and the experience of overlapping
receiving and encoding social cues. emotions [48-50] . Similarly, the subtype ACC neurons can be
activated by observational fear and classical fear [40,51] . More
4. Neuronal types associated with empathy than 50% of the neurons that are activated by observational
in the anterior cingulate cortex fear have mirror image properties, that is, they can be
[48]
Considering the versatility of the ACC and the universality activated by both observational fear and pain . Only
of its connections with various brain regions, the neural a very small proportion of this group of neurons can
mechanisms underlying empathy need to be further be activated by both nociceptive and conditioned fear
studied from the perspective of specific neurons. The responses at the same time. The peaks of neurons have
previous studies have only focused on the functional been shown to correspond to different conditions. In an
connections between brain regions, neglecting the algorithmic analysis of the peaks of neurons in the ACC
classification of neurons. Here, two types of neurons after pain and observational fear tests, the alternative pain
that mediate empathy in the ACC are discussed: Mirror induced by observational fear did have the same code as
neurons and somatostatin (SST) neurons (Table 1). As the pain experience [52,53] , but with an asymmetry of coding
for whether there are other types of neurons that mediate overlap, where neurons encoding ShockObs signals also
empathy, more in-depth research is needed. encoded signals for pain, whereas neurons encoding pain
signals did not necessarily encode signals for ShockObs .
[48]
4.1. Mirror neurons in empathy The alternative activation of mirror neurons, which can
The ACC has proven to be important not only in the also elicit pain behaviors, is explained through the results.
generation and processing of painful, negative emotions, The difference in the peak of mirror neurons under
but also in recognizing and perceiving the painful states different signal stimuli provides greater selectivity in the
in others. It has been speculated that the ACC might activation of downstream neurons. These experimental
be the intersection for processing both empathic and results suggest that mirror neurons may be the biological
painful emotions [46,47] . With the advancement of single- basis for the overlap of the ACC in processing painful
cell resolution techniques, a class of emotional mirrors emotions and emotional empathy functions. Some
has been identified within the ACC in A24 extending experiments have even observed mirror neuron properties
toward M2 and A32 . According to several studies, in ACC-basolateral nucleus of amygdala (BLA) neural
[19]
the specific types of ACC neurons are responsive to pathway, with previously pain-activated neurons being

Table 1. Specific neurons and neural circuits associated with empathy
Neurons and Empathic Methods and mechanisms References
neural circuits behaviors
Mirror neurons Pain empathy A mirror neuron system located in A24b. [48,54,55]
Fear empathy
SST+neurons Fear empathy Associated with the recognition of emotional states [46,58]
Reducing inhibitory synaptic transmission in Nrxn3-dependent
SST neurons enhances alternative fear responses
ACC-NAc pathway Pain empathy A neural circuit from the ACC to the NAc that mediates the rapid [36,65,66]
transfer of pain sensitivity and analgesia.
A familiar social environment is important for pain empathy
ACC-BLA pathway Fear empathy ACC neurons rapidly alter basal firing rates during social fear [44,45,71]
transmission
ACC input dominates the BLA encoding of social cues and
subsequent behaviors
ACC-MDL pathway Fear empathy The optogenetic activation of the ACC to MDL reduces freezing [22,77]
behavior
The destruction of ACC-MDL projection neurons delays the onset
of the alternative behavior
ACC internal Fear empathy Abnormal connections of interneurons induce severe deficits in [46,94]
microcircuits social functioning
SST + neurons in the ACC in the social transfer of fear
A24b: Area 24b/cingulate cortex 1; ACC: Anterior cingulate cortex; BLA: Basolateral nucleus of amygdala; MDL: Mediodorsal thalamic nucleus;
NAc: Nucleus accumbens, Nrxn3: Neurexin 3; SST: Somatostatin

Volume 2 Issue 1 (2023) 5 https://doi.org/10.36922/an.281