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Animal models for evaluation of age‐related changes in behaviour
Author(s) -
Schulze Gert,
Coper Helmut,
Jänicke Bernhard
Publication year - 1988
Publication title -
drug development research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.582
H-Index - 60
eISSN - 1098-2299
pISSN - 0272-4391
DOI - 10.1002/ddr.430140331
Subject(s) - reinforcement , psychology , conditioning , developmental psychology , cognition , audiology , physiology , zoology , statistics , neuroscience , medicine , biology , mathematics , social psychology
A larger degree of deterioration of the centrally controlled physiological, motor, and cognitive functions is characteristic of an organism's aging process. This restricted adaptation can be monitored on various organizational and functional levels. Mazes permit registration of cognitive performance in controlled motivation such as memory, spatial orientation, ability to learn, and speed of learning. The total running time is a composite parameter determined by a number of time‐dependent and time‐independent factors. With time‐dependent factors, age‐related differences remain after five repetitions, even when slight effects of training are evident. In most time‐independent factors, age‐related differences can be nearly eliminated by training. An example of the method “testing the limits” is to measure compensative responses under 10% normobaric hypoxia over a period of several days. Young as well as old rats reacted with the same reduction in feed intake and spontaneous activity. Adaptation to normal levels concerning motility and food consumption is accomplished less effectively and more slowly by the old rats than by the young ones. There were no differences between age groups in comparing the blood gas values of O 2 , CO 2 , and pH values. If the animals have to learn an operant conditioning schedule (fixed ratio/differential reinforcement of low rates), there are age‐related divergences of performance. Under hypoxic conditions, 27‐month‐old animals need twice as long to reach the test criterion in the “fixed ratio” as 4‐ and 20‐month‐old rats. Only the young and middle‐aged groups accomplished the task called “differential reinforcement of low rates”.