Effects of entorhinal cortex lesions on sensory integration and spatial learning.
BACKGROUND
The entorhinal cortex provides sensory information to the hippocampus for memory and learning. Damage to the entorhinal cortex is common in patients who experience traumatic brain injury, stroke, and Alzheimer's disease. Entorhinal damage is assumed to interfere with sensory integration; however, substantive knowledge of behavioral patterns is lacking.


OBJECTIVE
To describe specific behavioral deficits associated with entorhinal cortex injury related to special senses identification, sensory integration, and spatial learning.


METHODS
Adult male rats received bilateral entorhinal cortex damage (n = 19) or sham surgery (n = 11) with a subset randomized to participate in special senses identification, exploration, and sensory integration testing. Spatial learning was examined using a water maze.


RESULTS
Lesion and control animals were similar in special senses identification testing. Sensory integration was markedly impaired in lesion animals over 3 days for all integration tasks; however, travel deficit persisted for 4 days. By day 5 sensory integration ability was equal. Lesion animals were significantly impaired across all days of spatial learning for swim time (p = .0001) and directional heading error (p = .03). Control animals exposed to sensory testing demonstrated significantly more efficient learning (p = .005) on swim days 2 and 3 versus control animals not exposed to sensory testing.


CONCLUSIONS
Early and prolonged behavioral changes are evident following entorhinal cortex damage including sensory integration deficits and persistent spatial learning impairment.
Davis
A E
AE
University of Michigan School of Nursing, Ann Arbor 48109, USA.
Gimenez
A M
AM
Therrien
B
B
D000544:Alzheimer Disease / Q000150:complications; D000818:Animals; D001930:Brain Injuries / Q000150:complications; D004195:Disease Models, Animal; D018728:Entorhinal Cortex / Q000293:injuries* / Q000503:physiopathology*; D007858:Learning / Q000502:physiology*; D008297:Male; D009483:Neuropsychological Tests; D010465:Perception / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013028:Space Perception / Q000502:physiology*; D013037:Spatial Behavior / Q000502:physiology*; D020521:Stroke / Q000150:complications; D013997:Time Factors