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Titolo:
Functional adaptation of reactive saccades in humans: a PET study
Autore:
Desmurget, M; Pelisson, D; Grethe, JS; Alexander, GE; Urquizar, C; Prablanc, C; Grafton, ST;
Indirizzi:
Emory Univ, Dept Radiol, Atlanta, GA 30322 USA Emory Univ Atlanta GA USA 30322 Univ, Dept Radiol, Atlanta, GA 30322 USA Emory Univ, PET Imaging Ctr, Atlanta, GA 30322 USA Emory Univ Atlanta GA USA 30322 v, PET Imaging Ctr, Atlanta, GA 30322 USA Emory Univ, Dept Neurol, Atlanta, GA 30322 USA Emory Univ Atlanta GA USA 30322 Univ, Dept Neurol, Atlanta, GA 30322 USA INSERM, U534, F-69500 Bron, France INSERM Bron France F-69500INSERM, U534, F-69500 Bron, France
Titolo Testata:
EXPERIMENTAL BRAIN RESEARCH
fascicolo: 2, volume: 132, anno: 2000,
pagine: 243 - 259
SICI:
0014-4819(200005)132:2<243:FAORSI>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
VISUALLY-GUIDED SACCADES; FRONTAL EYE-FIELD; POSITRON EMISSION TOMOGRAPHY; CAUDAL FASTIGIAL NUCLEUS; SHORT-TERM ADAPTATION; AUTOMATED IMAGE REGISTRATION; MONKEY SUPERIOR COLLICULUS; CEREBELLAR VERMIS; OCULOMOTOR VERMIS; CORTICAL CONTROL;
Keywords:
saccadic adaptation; saccade; adaptation; PET; cerebellum; FEF; colliculus;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
95
Recensione:
Indirizzi per estratti:
Indirizzo: Grafton, ST Dartmouth Coll, Ctr Cognit Neurosci, 6162 Moore Hall, Hanover,NH 03755 USA Dartmouth Coll 6162 Moore Hall Hanover NH USA 03755 03755 USA
Citazione:
M. Desmurget et al., "Functional adaptation of reactive saccades in humans: a PET study", EXP BRAIN R, 132(2), 2000, pp. 243-259

Abstract

It is known that the saccadic system shows adaptive changes when the command sent to the extraocular muscles is inappropriate. Despite an abundance of supportive psychophysical investigations, the neurophysiological substrate of this process is still debated. The present study addresses this issue using (H2O)-O-15 positron emission tomography (PET). We contrasted three conditions in which healthy human subjects were required to perform saccadic eye movements toward peripheral visual targets. Two conditions involved a modification of the target location during the course of the initial saccade, when there is suppression of visual perception. In the RAND condition, intra-saccadic target displacement was random from trial-to-trial, precludingany systematic modification of the primary saccade amplitude. In the ADAPTcondition, intra-saccadic target displacement was uniform, causing adaptive modification of the primary saccade amplitude. In the third condition (stationary, STAT), the target remained at the same location during the entiretrial. Difference images reflecting regional cerebral-blood-flow changes attributable to the process of saccadic adaptation (ADAPT minus RAND; ADAPT minus STAT) showed a selective activation in the oculomotor cerebellar vermis (OCV; lobules VI and VII). This finding is consistent with neurophysiological studies in monkeys. Additional analyses indicated that the cerebellaractivation was not related to kinematic factors, and that the absence of significant activation within the frontal eye fields (FEF) or the superior colliculus (SC) did not represent a false negative inference. Besides the contribution of the OCV to saccadic adaptation, we also observed, in the RANDcondition, that the saccade amplitude was significantly larger when the previous trial involved a forward jump than when the previous trial involved a backward jump. This observation indicates that saccade accuracy is constantly monitored on a trial-to-trial basis. Behavioral measurements and PET observations (RAND minus STAT) suggest that this single-trial control of saccade amplitude may be functionally distinct from the process of saccadic adaptation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/04/20 alle ore 08:23:40