MEMORY SCORES IN MIDDLE-AGED RATS PREDICT LATER DEFICITS IN MEMORY, PARADOXICAL SLEEP, AND BLOOD-GLUCOSE REGULATION IN OLD-AGE

Age-related deficits in memory are correlated with deficits in paradox ical sleep and poor glucose tolerance in rats. The present experiment used a longitudinal design to determine whether memory or glucose tole rance in middle-aged rats could predict deficits in memory, sleep, and glucose tolerance in old age. Correlations were obtained between spon taneous alternation scores and glucose tolerance levels in middle age (14 months) and inhibitory avoidance, daytime sleep, and glucose toler ance levels in old age (24 months). Spontaneous alternation scores, bu t not glucose tolerance levels, predicted performance on all 3 behavio ral and biological measures in old age. Measures of functional integri ty, such as memory, may be sensitive predictors of subsequent age-rela ted change in specific cognitive and neurobiological systems.