Action selection uncertainty in the test phase of a transitive inference task: Neuronal correlates in monkey premotor cortex.

Cognitively advanced animals are able to dynamically interact with the environment. In this process, action selection could be strongly influenced by the confidence value assigned to single items in the stream of incoming sensory information. A form of dynamic representation of the environment is the organization of learned items in hierarchically ordered series. In a 6-items transitive inference task, when the list A > B > C > D > E > F is finally created, the probability of choosing B in the pair BC is lower than for the pair BE suggesting that the confidence for the value of B is variable and related to the mental representation of all other elements presented/experienced together. This relationship between performance and symbol separation is also know as symbolic distance effect. Previous work has focused on the contribution of sensory information to confidence. We explored how confidence on target value could influence action selection by measuring neuronal activity in the premotor cortex of 2 trained monkeys. We selected neurons with activity modulated by the direction of movement and we analyzed how directionality is influenced by the symbolic distance of items to compare. Our results show that directionality in premotor cortex increases with symbolic distance and uncertainty providing support to the idea that the motor system contributes to perceptual confidence.