The Differential Weights of Motivational and Task Performance Measures on Medial and Lateral Frontal Neural Activity

Behavioral adaptations are triggered by different constraints given by rules, and are informed by outcomes, or motivational changes. Neural activity in multiple frontal areas is modulated during behavioral adaptations, but the source of these modula-tions and the nature of the mechanisms involved are unclear. Here we tested how different variables related to changes in task performance and to behavioral adaptation impact the amplitude of event-related local field potentials (LFPs) in the lat-eral prefrontal and midcingulate cortex of male rhesus macaques. We found that the behavioral task used induced consis-tently different types of performance modulation: in relation to task difficulty (imposed by the experimental setup), to successes and errors, and to the time spent in the task. Difficulty had a significant effect on monkeys' accuracy and reaction times. Interestingly, there is also a strong interaction between difficulty and trial success on the reaction times variation. However, LFP modulations were mostly related to reaction times, touch position, feedback valence and time-in-session, with little, if any, effect of difficulty. Hence, difficulty modulated performance but not LFP activity. This suggests that, in our ex-perimental design, execution, regulation, and motivation-related factors are the main factors influencing medial and lateral frontal activity.

Automated summary

Behavioral adaptations are influenced by different constraints and outcomes, however, the mechanisms behind these adaptations in neural activity are unclear. This study investigated the impact of task performance and behavioral adaptation on local field potentials (LFPs) in the prefrontal and midcingulate cortex of rhesus macaques. The results showed that task difficulty had a significant effect on accuracy and reaction times, while LFP modulations were mainly related to reaction times, touch position, feedback valence, and time-in-session. This suggests that execution, regulation, and motivation-related factors play a major role in frontal activity.