Abstract
The hippocampus has been implicated in anxiety, novelty detection, spatial- contextual processing, and hyperactivity. Accordingly, the authors contrasted the role of the dorsal hippocampus (DH) and the basolateral amygdala complex (BLA) in an open field task that presents the onset and termination of a bright light gradient. In the dark, DH rats demonstrated impaired habituation of locomotion behavior and hyperactivity, whereas in bright light their behaviors were normal. DH rats responded differentially to the onset and termination of the light stimulus, which indicates they have normal novelty detection. BLA lesion rats responded normally to bright light. These results demonstrate that a mild fear stimulus, such as bright light, can suppress DH lesion-evoked hyperactivity, and this hyperactivity results from impaired contextual processing.
Publication types
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Comparative Study
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Research Support, N.I.H., Extramural
MeSH terms
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Amygdala / injuries
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Amygdala / physiopathology
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Amygdala / radiation effects
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Analysis of Variance
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Animals
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Behavior, Animal
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Conditioning, Classical / drug effects
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Conditioning, Classical / physiology
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Exploratory Behavior / drug effects
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Exploratory Behavior / physiology
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Fear
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Female
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Freezing Reaction, Cataleptic / drug effects
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Freezing Reaction, Cataleptic / physiology
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Freezing Reaction, Cataleptic / radiation effects
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Hippocampus / drug effects
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Hippocampus / injuries*
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Hippocampus / physiopathology
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Hippocampus / radiation effects*
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Hyperkinesis / chemically induced*
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Hyperkinesis / physiopathology
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Light*
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Locomotion / physiology
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Male
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N-Methylaspartate / toxicity*
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Neurotoxins / toxicity*
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Rats
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Rats, Long-Evans
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Time Factors
Substances
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Neurotoxins
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N-Methylaspartate