The effect on gross locomotor activity of irrelevant stimuli, prior exposure to these stimuli and two dosages of amphetamine were assessed on rats with lesions in the dorsal hippocampus. These animals were significantly more active post-operatively than sham-lesioned subjects. Prior exposure to the irrelevant stimuli increased post-operative differentiation between stimuli, whereas the introduction of amphetamine had the reverse effect. Changes in locomotor activity occurred at lower dosages of amphetamine than in previous studies, suggesting that the irrelevant stimuli have an arousal effect which acts additively with amphetamine and hippocampal impairment.
Get full access to this article
View all access options for this article.
References
1.
BerlyneD. E.The reward value of light increment under supranormal and subnormal arousal. Canadian Journal of Psychology, 1969, 23, 11–23.
2.
CampbellB. A.BallantineP.LynchG.Hippocampal control of behavioral arousal: Duration of lesion effects and possible interaction with recovery after frontal cortical damage. Experimental Neurology, 1971, 33, 159–170.
3.
ColeS. O.Experimental effects of amphetamine. Psychological Bulletin, 1967, 68, 81–90.
4.
DouglasR. J.PribramK. H.Learning and limbic lesions. Neuropsychologia, 1966, 4, 197–200.
HendricksonC. W.KimbleR. J.KimbleD. P.Hippocampal lesions and the orienting response. Journal of Comparative and Physiological Psychology, 1969, 67, 220–227.
7.
HirshR.Lack of variability or perseveration: Describing the effect of the hippocampal ablation. Physiology and Behavior, 1970, 5, 1249–1254.
8.
KimbleD. P.Hippocampus and internal inhibition. Psychological Bulletin, 1968, 70, 285–295.
9.
PeacockL. J.WilliamsM.An ultrasonic device for recording activity. American Journal of Psychology, 1962, 75, 648.
10.
PihlR. O.GreenbergI.Effect of amphetamine on activity level of rats with lesions in the hippocampus. Proceedings, 77th Annual Convention of the American Psychological Association, 1969, 4, 798–848.
