Single Neurons in Anterior Cingulate Cortex Signal the Need to Change Action During Performance of a Stop-change Task that Induces Response Competition

: Several human imaging studies have suggested that anterior cingulate cortex (ACC) is highly active when participants receive competing inputs, and that these signals may be important for influencing the downstream planning of actions. Despite increasing evidence from several neuroimaging studies, no study has examined ACC activity at the level of the single neuron in rodents performing similar tasks. To fill this gap, we recorded from single neurons in ACC while rats performed a stop-change task. We found higher firing on trials with competing inputs (STOP trials), and that firing rates were positively correlated with accuracy and movement speed, suggesting that when ACC was engaged, rats tended to slow down and perform better. Finally, firing was the strongest when STOP trials were preceded by GO trials and was reduced when rats adapted their behavior on trials subsequent to a STOP trial. These data provide the first evidence that activity of single neurons in ACC is elevated when 2 responses are in competition with each other when there is a need to change the course of action to obtain reward.