Abstract
The nucleus accumbens (NAc) helps govern motivation to pursue reward. Two distinct sets of NAc projection neurons—expressing dopamine D1 vs. D2 receptors—are thought to promote and suppress motivated behaviors, respectively. However, support for this conceptual framework is limited: in particular, the spiking patterns of these distinct cell types during motivated behavior have been largely unknown. Using optogenetic tagging, we recorded the spiking of identified D1+ and D2+ neurons in the NAc core as unrestrained rats performed an operant task in which motivation to initiate work tracks recent reward rate. D1+ neurons preferentially increased firing as rats initiated trials and fired more when reward expectation was higher. By contrast, D2+ cells preferentially increased firing later in the trial, especially in response to reward delivery—a finding not anticipated from current theoretical models. Our results provide new evidence for the specific contribution of NAc D1+ cells to self-initiated approach behavior and will spur updated models of how D2+ cells contribute to learning.
T.W. Faust, A. Mohebi, J.D. Berke. Reward expectation and receipt differentially modulate the spiking of accumbens D1+ and D2+ neurons. Current Biology, 2025-03. [LINK]
Speaker: Yuanpei Mi
Time: 9:00 am, 2025/07/07
Location: CIBR A622
