The medial prefrontal cortex is required for prospective navigation in spatial sequential memory

Abstract

Goal-directed spatial navigation depends not only on the retrieval of past experiences but also on the prospective representation of future paths. The medial prefrontal cortex (mPFC) is well-established as a critical region for executive functions, particularly in supporting goal-directed behavior and prospective information processing. Although recent electrophysiological recordings show that mPFC neuronal ensembles exhibit predictive codes for future movement directions, a clear behavioral demonstration of whether this region is causally required for prospective navigation remains to be determined. To address this question, we developed a novel spatial sequential memory task using a modified water maze, in which the escape platform moved along a circular path by a constant angle and direction across trials within each day. Using this paradigm, functional dissociation within the prefrontal cortex was investigated by targeting bilateral excitotoxic lesions to two distinct subregions: the mPFC and the anterior cingulate cortex (ACC). Our results demonstrated that mPFC lesions, but not ACC lesions, selectively disrupted the ability to predict and navigate toward the subsequent escape platform location. Furthermore, this behavioral deficit, characterized by disorganized search patterns, occurred without impairment of retrospective navigation to the previously visited location. These findings suggest that the mPFC is essential for prospective spatial navigation, integrating sequential rules with spatial information to generate future trajectories.