The role of the agranular insular cortex in working memory for food reward value and allocentric space in rats.
The present experiment examined the effects of quinolinic acid (125 mM) lesions of the agranular insular area on working memory for food reward value and working memory for spatial locations. In both tasks a go/no-go procedure was used. Working memory for food reward value was assessed using a delayed conditional discrimination in which either a 20% or 45% sugar content cereal was associated with a reinforcement and the other cereal was not. In the spatial locations task, rats were allowed to enter 12 arms in a radial maze for a food reinforcement. Of the 12 arm presentations, three or four arms were presented for a second time in a session which did not contain a reinforcement. The number of trials between the 1st and 2nd presentation of an arm ranged from 0 to 6 (lags). Working memory was assessed by the latency to enter an arm during the 2nd presentation. In the food reward value task, agranular insular lesions produced memory deficits in a delay-dependent manner. In contrast, agranular insular lesions did not impair working memory for spatial locations. These results add to accumulating evidence suggesting that different types of working memory are distributed across separate prefrontal subregions.
Ragozzino
M E
ME
Department of Psychology, University of Utah, Salt Lake City 84112, USA.
Kesner
R P
RP
D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology*; D001931:Brain Mapping; D008297:Male; D018782:Maze Learning / Q000502:physiology; D011939:Mental Recall / Q000502:physiology*; D009042:Motivation; D009949:Orientation / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D011930:Reaction Time / Q000502:physiology; D012153:Retention, Psychology / Q000502:physiology*; D013652:Taste Threshold / Q000502:physiology