PERINATAL CHOLINE SUPPLEMENTATION INCREASES THE THRESHOLD FOR CHUNKING IN SPATIAL MEMORY

CHUNKING and perinatal choline supplementation each provide rats with alternative memory processing advantages. Evidence from radial-arm maz e performance of adult (2- to 5-month-old) rats indicates that chunkin g of multiple food types (sunflower seeds, Noyes pellets and rice puff s) emerges for stable, differentiable baiting patterns as a function o f the memory load (6, 12, 18 or 24 maze arms). The number of maze arms appeared to determine both the level of task difficulty at which rats began to implement a chunking strategy as well as when they were unab le to successfully implement such a strategy due to the excess memoria l demands of the task. In comparison to control rats, rats treated per inatally with choline supplementation displayed a horizontal rightward shift of the response function that related level of clustering of li ke-food types to the number of maze arms. These results indicate a hig her threshold for implementing a chunking strategy in rats treated per inatally with choline supplementation, possibly due to a choline-induc ed increase in memory capacity.