Date of Award

Spring 2009

Project Type


Program or Major


Degree Name

Master of Arts

First Advisor

Jill McGaughy


The role of acetylcholine in the medial prefrontal cortex (mPFC) in working memory was investigated in aged rats. Subjects with cholinergic lesions of the prelimbic portion of the mPFC (pACh-lx) or a sham lesion of the same region were trained on an odor delayed non-match to sample paradigm. The effects of prefrontal cholinergic depletion and aging were assessed in task variations that manipulated mnemonic demand and stimulus novelty.

pACh-lx animals were impaired relative to sham-lx animals at memory for familiar stimuli over delays. This global impairment was not dependent on the length of the delay, suggesting that aged pACh-lx animals were impaired at a non-mnemonic component of the working memory task. Aged animals' accuracy was also impaired during sessions with novel sample stimuli, indicating a novel encoding impairment due to age-related cholinergic depletion in the entorhinal cortex.