Low-frequency local field potentials reveal integration of spatial and non-spatial information in prefrontal cortex

The prefrontal cortex (PFC) is critical for various aspects of executive functions, particularly working memory. The debate over whether the dorsal and ventral PFC should be viewed as unitary or heterogeneous in working memory has been ongoing. This study explored the specialization of the posterior dorsal, medial dorsal, and posterior ventral subdivisions of the lateral PFC in two macaque monkeys, focusing on the processing of the location and shape of stimuli during working memory tasks. In contrast to previous studies that focused on spike activity analysis, this article employed local field potential (LFP) power analysis. Results revealed that during the working memory periods, both the dorsal and ventral PFC exhibited significantly higher LFP power for feature stimuli compared to spatial stimuli in the low-frequency bands (∼2-23 Hz). Additionally, the impact of matching versus non-matching stimuli was consistent with repetition suppression in the medial dorsal and posterior ventral regions during the working memory period within the same frequency range. The major modulation of LFP power linked to incorrect decisions made by the monkeys was a sharp reduction in low-frequency LFP power. The similar LFP power patterns in the PFC subdivisions for spatial and feature stimuli throughout the analysis suggested that spatial and non-spatial inputs are integrated by the PFC, revealed by the low-frequency components of the LFP.