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Titolo:
THRESHOLDS OF ELECTRICALLY-INDUCED DEFENSE REACTION OF THE RAT - SHORT-TERM AND LONG-TERM ADAPTATION MECHANISMS
Autore:
SUDRE ECM; SUDRE M; DEBARROS MR; SUDRE GN; SCHENBERG LC;
Indirizzi:
UNIV BIRMINGHAM,SCH MED,DEPT PHYSIOL BIRMINGHAM B15 2TT W MIDLANDS ENGLAND UNIV BIRMINGHAM,SCH MED,DEPT PHYSIOL BIRMINGHAM B15 2TT W MIDLANDS ENGLAND FED UNIV ESPIRITO SANTO,CTR BIOMED,DEPT PHYSIOL SCI VITORIA ES BRAZIL
Titolo Testata:
Behavioural brain research
fascicolo: 1-2, volume: 58, anno: 1993,
pagine: 141 - 154
SICI:
0166-4328(1993)58:1-2<141:TOEDRO>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Soggetto:
MIDBRAIN PERIAQUEDUCTAL GRAY; AMINO-ACID MICROINJECTION; SUPERIOR COLLICULUS; EFFERENT PROJECTIONS; NERVOUS-SYSTEM; NEURONS; CALCIUM; STIMULATION; CAT; ORGANIZATION;
Keywords:
DEFENSE REACTION; FEAR; FLIGHT BEHAVIOR; FREEZING BEHAVIOR; PERIAQUEDUCTAL GRAY; SUPERIOR COLLICULUS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
77
Recensione:
Indirizzi per estratti:
Citazione:
E.C.M. Sudre et al., "THRESHOLDS OF ELECTRICALLY-INDUCED DEFENSE REACTION OF THE RAT - SHORT-TERM AND LONG-TERM ADAPTATION MECHANISMS", Behavioural brain research, 58(1-2), 1993, pp. 141-154

Abstract

The thresholds electrically induced defence reaction of the rat were studied through the logistic fitting of the response output. When stepwise increasing stimuli were applied at the dorsal midbrain, hierarchically organized mean thresholds, spaced 10 muA apart, were observed for immobility, running and jumping defensive behaviours. The parallel threshold functions of these responses, ranked in the above order, denote that they have distinct output probabilities when induced with sequential stepwise increasing stimuli. In contrast, when single daily stimuli were given in a random order, virtually superimposed threshold functions were obtained for these defensive behaviours. In this case, since the same output probabilities would be expected for immobility, running and jumping behaviours, the defence system seems to operate in astate of maximum entropy. The above data suggest that the dorsal midbrain, including the deep collicular layers and the periaqueductal gray, may encode hierarchical or non-hierarchical defensive patterns which, respectively, mimic either the attentive behaviour of the prey watching the approaching predator or its chaotic behaviour when cornered bya sudden attack. On the other hand, whereas quite stable thresholds were observed for the somatic defensive responses when 5 stimulation sessions were repeated over 15 days, the defecation and micturition output underwent a marked and progressive lessening. Since these autonomicresponses have long been considered as reliable indexes of fear, their attenuation throughout the repeated sessions could express the rat adaptation to fear by the recurrence of the aversive experience. Taken together, these data suggest that while short-term neuronal adaptationcould be responsible for the hierarchical threshold structure of the short interval stepwise stimulation, long-term neuronal adaptation could underlie the selective decrease of defecation and micturition responses over repeated sessions of intracranial stimulation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 23/09/20 alle ore 12:23:09