When is the perirhinal cortex necessary for the performance of spatial memory tasks?

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurobiology of Memory

Background:

• The perirhinal cortex and hippocampus are anatomically linked, suggesting coordinated memory functions.
• Spatial memory tasks are known to be dependent on hippocampal function.

Purpose of the Study:

• To review the relative roles of the perirhinal cortex and hippocampus in spatial memory.
• To examine inconsistencies in lesion data regarding perirhinal cortex involvement in spatial memory.

Main Methods:

• Review of published lesion studies on perirhinal cortex and hippocampal function in spatial memory.
• Analysis of electrophysiological data on the effects of perirhinal cortex lesions on hippocampal activity.
• Examination of potential reasons for inconsistencies in lesion data.

Main Results:

• Lesion data for the perirhinal cortex in spatial memory tasks yield mixed results, with some studies showing deficits and others not.
• When observed, perirhinal cortex lesions cause transient and less severe spatial memory deficits compared to hippocampal lesions.
• Electrophysiological data suggest perirhinal cortex lesions can alter hippocampal neuronal activity.

Conclusions:

• The perirhinal cortex appears to have a supporting, rather than primary, role in hippocampal-dependent spatial memory.
• Parallel cortical pathways provide sensory information to the hippocampus, offering alternative routes when the perirhinal cortex is damaged.
• Perirhinal damage may impair spatial memory specifically when tasks rely on ambiguous distal cues with overlapping visual features.