Decline in visual attention and spatial memory in aged rats

The present study was a longitudinal study of age-related changes in perfor mance of the 5-choice serial reaction time task, a rest of visual attention . Following acquisition of the task, animals were tested on two occasions o n their ability to perform the 5-choice task. In Test 1 (Young: 7 months; A ged: 13-14 months) no age-related effects on baseline performance were reve aled. However, increasing the attentional load of the task revealed an impa irment in choice accuracy by animals of the Aged group. In Test 2 (Young: 1 0-11 months, Aged 23-24 months), animals of the Aged group were significant ly impaired on the baseline schedule of the task compared to the Young grou p. The deficit in accuracy on the task could be improved in the Aged animal s by decreasing the attentional load. The results of the present study sugg est a deficit in attentional function as a result of the aging process, mar kedly similar to that observed following lesions of the basalo-cortical cho linergic system. (C) 2000 Elsevier Science Inc. All rights reserved.