Neural activity in the anterior cingulate cortex is required for effort-based decision making

Adaptive decision making requires the evaluation of cost-benefit tradeoffs to guide action selection. Effort-based decision making involves weighing predicted gains against effort costs and is disrupted in several neuropsychiatric disorders. The ACC is postulated to control effort-base choice via its role in encoding the value of overcoming effort costs in rodent effort-based decision making assays. However, temporally precise methods of manipulating neural activity have rarely been applied to effort-based decision making. We developed and validated a mouse version of the barrier T-maze, and used optogenetics to inhibit ACC excitatory neurons at specific times during this task. Bilateral inhibition of ACC rapidly and reversibly impaired preference to exert greater effort for a larger reward when a less rewarded, low effort alternative was available. Equalizing effort for potential choice options led mice to choose the high reward arm of the maze regardless of whether the ACC was inhibited or not. The mechanics of choice behavior were altered during trials where the ACC was inhibited, but there were no effects on overall mobility or tendency to exert effort in an unrelated assay. These findings establish causality between ACC neural activity during a choice trial and effortful action selection during cost-benefit decision making. SIGNIFICANCE STATEMENT Disturbances in evaluating effort-based costs during decision making occur in depression, schizophrenia, addiction and Parkinson’s disease. Precisely resolving the function of prefrontal brain regions in mediating these processes will reveal key loci of dysfunction and potential therapeutic intervention in these disorders.