Adaptation and habituation to an open field and responses to various stressful events in animals with neonatal lesions in the amygdala or ventral hippocampus

• Published in: Brain research Vol. 918; no. 1; pp. 153 - 165
• Main Authors: Daenen, E.W.P.M, Van der Heyden, J.A, Kruse, C.G, Wolterink, G, Van Ree, J.M
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 09.11.2001; Amsterdam Elsevier; New York, NY
• Subjects: Adaptation, Biological - physiology; Adult and adolescent clinical studies; Aging - physiology; Amygdala; Amygdala - growth & development; Amygdala - injuries; Amygdala - physiopathology; Animal model; Animals; Behavior, Animal - physiology; Biological and medical sciences; Brain Injuries - physiopathology; Disease Models, Animal; Electric Stimulation - adverse effects; Environment, Controlled; Female; Fever - physiopathology; Habituation, Psychophysiologic - physiology; Hippocampus - growth & development; Hippocampus - injuries; Hippocampus - physiopathology; Ibotenic acid; Male; Medical sciences; Motor Activity - physiology; Neonatal lesion; Nerve Degeneration - physiopathology; Nervous System Malformations - physiopathology; Neurodevelopment; Pregnancy; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychoses; Rats; Rats, Wistar; Schizophrenia; Stress, Physiological - physiopathology; Vocalization, Animal - physiology; Disorders of the nervous system; Animal model; Ibotenic acid; Amygdala; Neurodevelopment; Schizophrenia; Neonatal lesion; Rat; Rodentia; Central nervous system; Basal ganglion; Stress; Habituation; Psychosis; Vertebrata; Mammalia; Newborn animal; Development; Lesion; Hippocampus; Brain (vertebrata); Adaptation
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/S0006-8993(01)02987-0

A rat model of neurodevelopmental psychopathological disorders, designed to determine neurodevelopmental deficits following damage to the brain early in life, was used to investigate behavioural changes in adaptation and habituation to an open field and responses to different kinds of stressful events. Animals with bilateral ibotenic acid lesions in the amygdala or ventral hippocampus on day 7 or 21 of life were compared to sham-operated animals. According to the model it was assumed that behavioural changes in animals lesioned on day 7, but not in animals lesioned on day 21 of life, were caused by maldevelopment of one or more structures connected to the damaged area. Animals lesioned in the amygdala or ventral hippocampus on day 7, but not animals lesioned in these structures on day 21 of life, displayed decreased (within-session) adaptation and (between-session) habituation to the open field and a decrease in immobility in the forced swim test, whereas only animals lesioned in the amygdala displayed enhanced general activity. These results were indicative of neurodevelopmental deficits. No changes in stress-induced hyperthermia were found, while animals lesioned in the amygdala both on day 7 or 21 of life exhibited decreased conditioned ultrasonic vocalizations. These latter results suggest that the amygdala is implicated in the conditioned stress-induced response. The contribution of the present findings to the animal model of neurodevelopmental disorders like schizophrenia and possible brain structures and neurotransmitter systems involved in the neurodevelopmental deficits are discussed.