Perirhinal cortex involvement in allocentric spatial learning in the rat: Evidence from doubly marked tasks.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Spatial Cognition

Background:

• The medial temporal lobe's cortices are increasingly recognized for mixed object and spatial processing.
• Previous lesion studies suggested perirhinal cortex (Prh) deficits were specific to object learning, not spatial learning.

Purpose of the Study:

• To investigate if perirhinal cortex (Prh) lesions critically impair allocentric spatial learning.
• To determine if prior learning paradigms were sensitive enough to detect such deficits.

Main Methods:

• Rats with Prh lesions and controls were trained on two navigation tasks in a radial maze.
• Tasks involved differentiating between allocentric, egocentric, and S-R/habit strategies for goal location.

Main Results:

• Both lesioned and control rats learned the navigation tasks equally well during training.
• Post-training probe tests revealed Prh-damaged rats predominantly used non-allocentric (egocentric or habit) strategies.
• Control rats showed significantly more allocentric responses than lesioned rats.

Conclusions:

• The perirhinal cortex (Prh) is essential for employing allocentric strategies in spatial navigation.
• Lesion studies may require more sensitive paradigms to fully elucidate the Prh's role in spatial learning.