Reward and adversity processing circuits, their competition and interactions with dopamine and serotonin signaling

TL;DR

This paper proposes a neural circuit model where adversity and reward processing compete, involving specific brain regions and neurotransmitters, to explain decision-making, emotional regulation, and mental dysfunctions.

Contribution

It introduces a novel circuit framework detailing how adversity and reward signals interact via dopamine and serotonin to influence behavior and affect.

Findings

Adversity circuit involves dACC, AI, clOFC, LHb, and VS, predicting harm and risk.

Dopamine reduces adversity circuit activity, decreasing avoidance behaviors.

Serotonin inhibits multiple regions, promoting safety and well-being.

Abstract

We propose that dACC, AI and caudolateral OFC(clOFC) project to lateral habenula (LHb) and D2 loop of ventral striatum (VS), forming a functional adversity processing circuit, directed towards inhibitory avoidance and self-control. This circuit learns what is bad or harmful to us and predicts risks, to stop us from going/moving for bad or suboptimal choices that decrease our well-being and survival chances. Proposed dACC role is to generate a WARNING signal when things are going (or might end) bad or wrong to prevent negative consequences: pain, harm, loss or failure. The AI signals about bad low aversive qualities, which make us sick or cause discomfort. These cortical inputs activate directly and indirectly (via D2 loop of VS) the LHb, which inhibits dopamine and serotonin release (and is reciprocally inhibited by VTA, DRN) to avoid choosing and doing things leading to harm or loss, but also to make us feel worse, down when overstimulated. We propose that dopamine attenuates the output of the adversity processing circuit, thus decreasing inhibitory avoidance and self-control, while serotonin attenuates dACC, AI, clOFC, D1 loop of VS, LHb, amygdala and pain pathway. Thus, by reciprocal inhibition, by causing dopamine and serotonin suppression - and by being suppressed by them, the adversity processing circuit competes with reward processing circuit for control of choice behaviour and affective states. We propose stimulating effect of dopamine and calming inhibitory effect of serotonin on the active avoidance circuit involving amygdala, linked to threat processing, anger, fear, self-defense and violences. We describe causes and roles of dopamine and serotonin signaling, and mental dysfunctions. We add new idea on vACC role in signaling that we are doing well and in inducing serotonin, when we gain/reach safety, comfort, valuable resources, social/biological rewards, affection or goals.