Summary: The study reveals the mechanism of the nucleus accumbens for the mediation of reward and aversion.
Source: chinese academy of sciences
Seeking rewards and avoiding threats are essential for survival. The pursuit of pleasurable things triggers the release of dopamine in the brain, which causes people to feel pleasure.
In contrast, people subconsciously avoid unpleasant sensations such as hunger, nausea, and pain in order to avoid risk and greatly reduce the risk of harm.
Previous studies have proven that the nucleus accumbens (NAc) area of the brain plays an important role in the regulation of drug reward, eating, social interaction, pain, and instrumental learning.
Recently, a research group led by Professor Zhu Yingjie from Shenzhen Institute of Advanced Technology (SIAT) of Chinese Academy of Sciences (CAS) revealed the mechanism of NAc in mediating positive and negative motivational valence.
The study was published in Nature Communication.
The researchers designed a series of experiments to elucidate this mechanism. They found two subsets of neurons in the NAc: NAcBLA (BLA, basolateral amygdala) neurons and NAcPVT (PVT, paraventricular thalamic).
NAcBLA neurons receive BLA inputs and project to VTAGABA (VTA, ventral tegmental area) neurons and LHGlue (LH, lateral hypothalamus) to control reward-seeking behavior. NAcPVT input neurons receive PVT inputs and project to LHGABA neurons to promote aversion.
These results provide an input-output connectivity framework for understanding the role of NAc subcircuits in mediating reward and aversion.
“Our findings have solved a long-standing puzzle as to why distinct glutamatergic inputs into the NAc produce opposite motivational valence and underscore the importance of input-output connectivity when dissecting NAc circuitry,” Professor Zhu said.
The traditional view is that the NAc is the brain’s reward center and that input from other brain regions to the NAc carries reward information.
“This work raises an important question, why activating input from the PVT and activating input from other brain regions to the NAc produce completely different behaviors,” commented Professor Chen Xiaoke. from Stanford University.
“The results of this work provide the neural circuitry basis for the projection of BLA-NAc and PVT-NAc glutamate in the regulation of reward and aversive behavior, highlighting the importance of different inputs from NAc neurons and sub- sets of these neurons in the limbic system into dopamine,” said Professor Liu Xing of Fudan University.
About this neuroscience research news
Original research: Free access.
“Processing of reward and aversion by input-defined parallel nucleus accumbens circuits in mice” by Kuikui Zhou et al. Nature Communication
Processing of reward and aversion by input-defined parallel nucleus accumbens circuits in mice
The nucleus accumbens (NAc) is essential in mediating reward seeking and is also involved in the processing of negative emotions, but the cellular and circuit mechanisms underlying these opposing behaviors remain elusive.
Here, using the recently developed AAV1-mediated anterograde transsynaptic labeling technique in mice, we show that NAc neurons receive inputs from the basolateral amygdala (NAcBLA) promote positive reinforcement via disinhibition of dopaminergic neurons in the ventral tegmental area (VTA).
In contrast, NAc neurons receiving paraventricular thalamic inputs (NAcPVT) innervate GABAergic neurons in the lateral hypothalamus (LH) and mediate aversion.
Silence synaptic output from NAcBLA neurons alter reward-seeking behavior, while silencing the NAcPVT or NAcPVT→The LH pathway suppresses the aversive symptoms of opiate withdrawal.
Our results elucidate the specific afferent circuit architecture of the NAc in the control of reward and aversion.