Optogenetic inhibition of rat anterior cingulate cortex impairs the ability to initiate and stay on task

Our prior research has identified neural correlates of cognitive control in the anterior cingulate cortex (ACC), leading us to hypothesize that the ACC is necessary for increasing attention as rats flexibly learn new contingencies during a complex reward-guided decision-making task. Here, we tested this hypothesis by using optogenetics to transiently inhibit the ACC while rats of either sex performed the same two-choice task. ACC inhibition had a profound impact on behavior that extended beyond deficits in attention during learning when expected outcomes were uncertain. We found that ACC inactivation slowed and reduced the number of trials rats initiated, and impaired both their accuracy and their ability to complete sessions. Further, drift-diffusion model analysis suggested that free-choice performance and evidence accumulation (i.e., reduced drift rates) were degraded during initial learning—leading to weaker associations that were more easily overridden in later trial blocks (i.e., stronger bias). Together, these results suggest that in addition to attention-related functions, the ACC contributes to the ability to initiate trials and generally stay on task.Significant StatementAttentional deficits and the ability to stay on task are defining hallmarks of some of the most prevalent and disruptive neuropsychiatric disorders. Here, we use an optogenetic approach and computational modeling to study how within-subject modulation of the anterior cingulate cortex (ACC) impacts the ability of rats to initiate and complete a complex reward-guided decision-making task. We found that on days in which the ACC was inhibited, the ability of rats to initiate and stay on task was impaired, as well as their task accuracy and ability to complete sessions.