The prefrontal cortex encodes task-identity information and flexibly adjusts its sensory processes as a function of...

The prefrontal cortex (PFC) plays a key role in selecting, maintaining, and representing sensory information, and in its integration with our current internal goals and expectations, implementing such cognitive processes as executive functions, attention, decision-making, and working memory. Performing computation over all of these functional cognitive processes and dynamically shifting from one to the other based on task demands requires a complex functional organization and a high degree of coding flexibility. The PFC cells show a non-linear mixed selectivity characterized by specific tuning for multiple task- and behavior-related parameters. This non-linear mixed selectivity is thought to allow for a high-dimensional representation of information. Here, we asked if the PFC is mainly involved in the specific task-parameters representation, or if it additionally holds a higher-order representation for task-identity. We thus trained two macaques to perform three different tasks: A memory guided saccade task and two detection tasks involving different attention mechanisms. Multi-unit activity was recorded in the frontal eye field, bilaterally, while the monkeys performed these three tasks in the same session. Using demixed Principal Component Analysis, we found a two-dimensional neural state that characterized each of these tasks. The lower dimensional representations of the activity recorded during the performance of the two attentional tasks were more similar to each other than to the memory-guided saccade task. Furthermore, we report that task and spatial information are non-linearly mixed, a signature of a high-dimensional neural representation. Overall, this indicates that PFC encodes task-identity information and flexibly adjusts its sensory processes as a function of the specific ongoing task.