Behavioral assessment of forgetting in aged rodents and its relationship to peripheral sympathetic function.
Observation of age-related memory deficits in rodents is often dependent on the behavioral task used to assess these changes, rather than being universal to all memories. A review of studies using aversively-motivated multiple trial training paradigms suggests that the apparent acquisition deficits common to older animals may instead be due to a confounding tendency of these animals to behavioral rigidity or perseveration. Data obtained using single trial training paradigms, such as the one-trial passive avoidance task, indicate that young and old rodents can learn tasks with equal facility, that retention in young and old animals is similar at short training-testing intervals, but that retention is impaired in aged animals at longer training-testing intervals. We suggest that the adrenal medulla, a peripheral source of catecholamines, secretes catecholamines that act outside the blood-brain barrier to modulate memory processes. Further, we review evidence suggesting that the ability of the adrenal medulla to respond to the stresses of footshock during aversively-motivated training are impaired in aged rodents, and that this impairment may contribute to the rapid forgetting observed in senescent animals.
Martinez
J L
JL
Department of Psychology, University of California, Berkeley 94720.
Schulteis
G
G
Janak
P H
PH
Weinberger
S B
SB
D000313:Adrenal Medulla / Q000378:metabolism / Q000502:physiology*; D000320:Adrenergic Fibers / Q000378:metabolism / Q000503:physiopathology*; D000375:Aging / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D002395:Catecholamines / Q000378:metabolism / Q000502:physiology; D006801:Humans; D008569:Memory Disorders / Q000378:metabolism / Q000503:physiopathology*; D051381:Rats; D012153:Retention, Psychology
D002395:Catecholamines