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Titolo:
Gaze shifts evoked by electrical stimulation of the superior colliculus inthe head-unrestrained cat. I. Effect of the locus and of the parameters ofthe stimulation
Autore:
Guillaume, A; Pelisson, D;
Indirizzi:
INSERM, U534, F-69500 Bron, France INSERM Bron France F-69500INSERM, U534, F-69500 Bron, France
Titolo Testata:
EUROPEAN JOURNAL OF NEUROSCIENCE
fascicolo: 8, volume: 14, anno: 2001,
pagine: 1331 - 1344
SICI:
0953-816X(200110)14:8<1331:GSEBES>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
SACCADIC EYE-MOVEMENTS; NEURAL-NETWORK MODEL; ALERT CAT; ELICITED SACCADES; RHESUS-MONKEY; OPTIC TECTUM; SYSTEM; MICROSTIMULATION; NEURONS; FIELDS;
Keywords:
eye movement; gaze motor map; saccade; tectum;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
50
Recensione:
Indirizzi per estratti:
Indirizzo: Pelisson, D INSERM, U534, 16 Ave Doyen Lepine, F-69500 Bron, France INSERM16 Ave Doyen Lepine Bron France F-69500 0 Bron, France
Citazione:
A. Guillaume e D. Pelisson, "Gaze shifts evoked by electrical stimulation of the superior colliculus inthe head-unrestrained cat. I. Effect of the locus and of the parameters ofthe stimulation", EUR J NEURO, 14(8), 2001, pp. 1331-1344

Abstract

Several studies have suggested that the pattern of neuronal activity in the superior colliculus (SC) interacts with the well-known topographical coding of saccades (motor map). To further describe this interaction, we recorded gaze saccades evoked by electrical microstimulation of SC deeper layers in the head-unrestrained cat and systematically varied the collicular locus(25 sites) and parameters (intensity, frequency) of the stimulation. Long stimulation trains were used to avoid saccade truncation. We found that thedirection and amplitude of evoked gaze shifts were related to the stimulation locus, describing a gaze shift map. For 18 out of 20 sites the amplitude, but not the direction, also strongly depended on stimulation strength. Indeed, gaze amplitude continuously increased when raising current intensityup to several times the threshold value T (the largest intensity tested was 6 x T), whereas varying pulse frequency from 150 to 750 pulses per second(p.p.s.) revealed an optimal frequency range (300 and 500 p.p.s.) eliciting the largest gaze shifts. Moreover, the intensity effect on amplitude increased in an orderly fashion with the rostro-caudal stimulation locus. Gaze shift amplitude was not related to the number of delivered stimulation pulses. Concerning movement initiation, increasing either intensity or frequency led to an exponential decrease in gaze latency until minimal values near 30 ms were reached, but the number of pulses delivered during the corresponding latency period remained constant within a 300-500 p.p.s. frequency range. These findings indicate that the pattern of collicular discharge evokedby electrical stimulation strongly interacts with the gaze shift map and provide evidence for a summation of collicular activities by downstream premotor neurons.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/01/20 alle ore 04:43:31