Excitation-Inhibition Balance of Prefrontal Neurons During the Execution of a Path-Planning Task

The balance between excitation and inhibition in the cortex is thought to play a crucial role in the processing of information by neurons in the network. We hypothesize that the excitation-inhibition balance contributes to flexible behavioral planning in the lateral prefrontal cortex (lPFC). In this study, we analyzed the temporal development of the relative activities of inhibitory interneurons (INs) against excitatory pyramidal neurons (PNs) showing significant directional selectivity of cursor-movement at each step of the execution period in the lPFC of monkeys while they were engaged in a path-planning task. During the preparatory period, INs transiently made a greater relative contribution before enhanced cursor-movement selectivity. In contrast, no relative increase in IN activity was observed before the corresponding enhanced selectivity during the execution period. These observations suggest that the excitation-inhibition balance may contribute to planning and execution in different ways in the lPFC network.