- A biological neural network, in theory, is an assemblage of structures that are able to regulate central nervous system automatisms with efficiency and pin-point accuracy.
- The concept of neural networks was originally coined in order to understand the construction of a neural circuit; it has since evolved to explaining circuitry functionality and interconnectedness with other networks and structures.
- The triple-network model of psychopathology, moreover, is representative of this idea, wherein the salience network (SN) serves as an interface between the frontoparietal network (FPN) and default mode network (DMN), allowing the integration and balance of neural processing with affective processes.

Biological Neural Network

- Experiments conducted by Andreas Bartels and Semir Zeki (2000) found that feelings of love increased activity in the insula and anterior cingulate cortex, as well as in the caudate and putamen. 

- Feelings of love also showed reduced activity in the posterior cingulate and amygdala, as well as the right prefrontal cortex. 


The Love Pathway

-PET images of adult subjects asked to reexperience episodes of happiness showed increased activity in the right posterior cingulate cortex and left insula,  as well as decreased activity in the left anterior cingulate cortex.

The Happiness Pathway

-PET images of adult subjects asked to reexperience episodes of anger showed increased activity in the left anterior cingulate cortex and pons.



Neural Pathway for Anger

-PET images of adult subjects asked to reexperience episodes of sadness showed increased activity in the anterior cingulate cortex, insula, and dorsal pons, as well as decreased activity in the posterior cingulate cortex.

The Sadness Pathway

Not only does the dorsolateral prefrontal cortex activate when one experiences disgust but so does the amygdala, ventromedial PFC, orbitofrontal cortex, insular cortex and the anterior cingulate.

The pathway for social and moral disgust is consistent with core disgust or gastrointestinal discomfort. 



The Disgust Pathway

A neuroscientist conducts a study where participants view images designed to evoke fear. Using fMRI scans, the researcher observes significant activation in the amygdala. Based on this finding, the researcher publishes a paper concluding that the amygdala is the brain's 'fear center.' Based on the contemporary understanding of how the brain processes emotions, evaluate the researcher's conclusion. Why is this conclusion likely an oversimplification?

Interpreting Brain Imaging Research

The limbic system is made up of a number of different structures that are involved in processing both emotion and memory. Three of its most important components include the amygdala, the hippocampus, and the hypothalamus.

Limbic System

Studies investigating different brain regions associated with emotion concluded that there is no singular brain region associated with a specific emotion. Rather, each emotion has different patterns of activation across several different brain regions.

University of Michigan - Ann Arbor

Columbia University

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- Electrical stimulation of the brain, brain lesions, and neural circuitry affect emotion.



Brain circuits for different emotions

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020, April 22). Psychology (2nd ed.). OpenStax. https://openstax.org/books/psychology-2e/pages/1-introduction

OpenStax Psychology (2nd ed.) Textbook

- Papez circuit: the hypothalamus, anterior thalamus, cingulate cortex, hippocampus and fornix

- Limbic model of emotion: this model includes the papez circuit, as well as the amygdala and several other brain regions 

Medial Brain regions involved in emotion

Brain Regions Associated with Emotions

- Brain self-stimulation: the process in which animals work to provide electrical stimulation to certain areas of the brain because it is a rewarding experience.

- Experiments in the 1950's found that rats will readily pull a lever to receive electrical stimulation in the septum

- Brain self-stimulation can also be seen in humans. Patients receiving electrical stimulation in the septum have been known to feel pleasure and warmth. 

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