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Titolo:
DISINHIBITION OF THE SUPERIOR COLLICULUS RESTORES ORIENTING TO VISUAL-STIMULI IN THE HEMIANOPIC FIELD OF THE CAT
Autore:
CIARAMITARO VM; TODD WE; ROSENQUIST AC;
Indirizzi:
UNIV PENN,DEPT NEUROSCI,215 STEMMLER HALL,36TH ST & HAMILTON WALK PHILADELPHIA PA 19104 UNIV PENN,DEPT NEUROSCI PHILADELPHIA PA 19104
Titolo Testata:
Journal of comparative neurology
fascicolo: 4, volume: 387, anno: 1997,
pagine: 568 - 587
SICI:
0021-9967(1997)387:4<568:DOTSCR>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
SACCADIC EYE-MOVEMENTS; NIGRA PARS RETICULATA; LATERAL SUPRASYLVIAN CORTEX; INTERMEDIATE GRAY LAYER; GABA-RELATED SUBSTANCES; ALERT RHESUS-MONKEY; HORSERADISH-PEROXIDASE; ELECTRICAL-STIMULATION; NIGROTECTAL PROJECTION; HEAD MOVEMENTS;
Keywords:
CORTICAL LESION; GAMMA-AMINOBUTYRIC; NEGLECT; SENSORIMOTOR INTEGRATION; VISUAL ORIENTING;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
117
Recensione:
Indirizzi per estratti:
Citazione:
V.M. Ciaramitaro et al., "DISINHIBITION OF THE SUPERIOR COLLICULUS RESTORES ORIENTING TO VISUAL-STIMULI IN THE HEMIANOPIC FIELD OF THE CAT", Journal of comparative neurology, 387(4), 1997, pp. 568-587

Abstract

Following unilateral removal of all known visual cortical areas, a cat is rendered hemianopic in the contralateral visual field. Visual orientation can be restored to the blind hemifield by transection of the commissure of the superior colliculus or by destruction of the superior colliculus (SC) or the substantia nigra pars reticulata (SNpr) contralateral to the cortical lesion. It is hypothesized that a mechanism mediating recovery is disinhibition of the SC ipsilateral to the cortical lesion. The ipsilateral nigrotectal projection exerts a robust inhibitory tone onto cells in the SC. However, ibotenic acid destruction of SNpr neurons, which should decrease inhibition onto the SC, does notresult in recovery. The failure of ipsilateral SNpr lesions to produce recovery puts into question the validity of SC disinhibition as a mechanism of recovery. We directly tested the disinhibition hypothesis by reversibly disinhibiting the SC ipsilateral to a visual cortical lesion with a gamma-aminobutyric acid (GABA)(A) antagonist, bicuculline methiodide. In accordance with the hypothesis, transient disinhibition of the SC restored visual orienting for several hours in three of eight animals. Recovery was not a volume or pH effect and was distinct from the release of irrepressible motor effects (i.e., approach and avoidance behaviors) seen within the first hour after injection. Thus, in the absence of all visual cortical areas unilaterally, disinhibition ofthe SC can transiently restore the ability of the cat to orient to visual stimuli in the previously ''blind'' hemifield. J. Comp. Neurol. 387:568-587, 1997. (C) 1997 Wiley-Liss, Inc.

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Documento generato il 09/07/20 alle ore 20:53:43