Research Unit 5159

Short Summary: My lab is focused on understanding the function of the anterior cingulate cortex (ACC) and how it is modulated by dopamine (DA). While most theories of the ACC are cognitive in nature, we believe the ACC is most closely involved with the monitoring and regulation of autonomic state (Seamans & Floresco 2022). This talk will focus on studies involving our ‘3-valence’ task, which seeks to evoke different autonomic/emotional responses in rats by presenting tones paired with either a rewarding outcome (food pellet), an aversive outcome (footshock), or a null outcome (no outcome) in separate blocks of trials. Tetrode recordings revealed that ensembles of ACC neurons entered unique activity-state patterns at the start of each trial block that remained in place throughout the entirety of the block, even during periods when cues and outcomes were absent. We also observed that kinematically identical behaviors were represented differently depending on the block in which they were performed. This meant that the way information was represented by ACC neurons depended on the valence of the block (or the internal state it evoked). Optically-based neurochemical measurements revealed that the tones and outcomes evoked clear DA responses that did not differ according to the valence of the block. Furthermore, we were unable to find any evidence of signed reward-prediction errors (RPEs), that are typically observed in striatum. Instead, we believe ACC DA is more of a general salience signal whose function is to separate ensemble representations (Durstewitz & Seamans 2008). This function may be manifest differently in each subregion of frontal cortex, such that in the dorsolateral prefrontal cortex, DA may separate representations according to cognitive task demands, whereas in ACC, it may separate representations according to the valence of the prevailing internal state.