Neuroanatomic correlates of distance and direction processing during cognitive map retrieval
Article [Version of Record]
Abstract(s)
Navigating toward a goal and mentally comparing distances and directions to landmarks
are processes requiring reading information off the memorized representation of the
environment, that is, the cognitive map. Brain structures in the medial temporal lobe,
in particular, are known to be involved in the learning, storage, and retrieval of cognitive
map information, which is generally assumed to be in allocentric form, whereby pure
spatial relations (i.e., distance and direction) connect locations with each other. The
authors recorded functional magnetic resonance imaging activity, while participants were
submitted to a variant of a neuropsychological test (the Cognitive Map Reading Test;
CMRT) originally developed to evaluate the performance of brain-lesioned patients and in
which participants have to compare distances and directions in their mental map of their
hometown. Our main results indicated posterior parahippocampal, but not hippocampal,
activity, consistent with a task involving spatial memory of places learned a long time
ago; left parietal and left frontal activity, consistent with the distributed processing of
navigational representations; and, unexpectedly, cerebellar activity, possibly related to
the role of the cerebellum in the processing of (here, imaginary) self-motion cues. In
addition, direction, but not distance, comparisons elicited significant activation in the
posterior parahippocampal gyrus.