Cognitive Mapping and Spatial Navigation in Patients with Anterior Temporal Lobectomy

The purpose of this paper is to examine questions about the role of the hippocampal formation in spatial cognition and spatial navigation. Specifically, Study 1 and Study 2 show that patients with unilateral language nondominant anterior temporal lobectomy (ATL) show impairments on tasks assessing cognitive mapping. Study 3 shows that the ability of these patients to navigate a virtual environment (VE) by means of cognitive maps is disrupted. Study 4 shows that, under normal circumstances, healthy adults have a choice of at least two spatial navigation strategies (navigation by means of heading vectors, or navigation by means of cognitive mapping), and that they will likely choose the optimal strategy for task solution. Study 5 suggests that patients with unilateral language nondominant ATL are able to successfully navigate by means of heading vectors. The data from these studies are generally consistent with predictions derived from cognitive mapping theory (O'Keefe & Nadel, 1978). The data are also consistent with other empirical and theoretical work in pointing to the hippocampal formation of the language nondominant hemisphere as the neural substrate of a cognitive mapping system.