The relationship between neuronal activity and psychophysical judgments is central to understanding the brain mechanisms responsible for perceptual decisions. The ventral premotor cortex is known to be involved in representing different components of the decision-making process. In this cortical area, however, neither the neuronal ability to discriminate nor the trial-to-trial relationship between neuronal activity and behavior have been studied during visual decision-making. We recorded from single neurons while monkeys reported a decision based on the comparison of the orientation of two lines shown sequentially and separated by a delay. Analyses based on signal detection theory provided both the behavioral and neuronal sensitivities (d') and the coherence between behavioral and neuronal choices. To determine the temporal evolution of neuronal sensitivity and of coherence, the optimal size and position of the encoding windows were assessed. For a subset of neurons from the premotor ventral cortex, neuronal sensitivity was close to behavioral sensitivity and the trial-to-trial coherence between the neuronal and behavioral choices was close to 100%. By comparing these results with those obtained in a motor control task we ruled out the possibility of this activity being explained by the motor component of the task. These results suggest that activity in the ventral premotor cortex explains behavioral performance and predicts trial-to-trial subject choices.
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