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Titolo:
WHAT ARE HUMAN EXPRESS SACCADES
Autore:
KINGSTONE A; KLEIN RM;
Indirizzi:
UNIV CALIF DAVIS,CTR NEUROSCI,1544 NEWTON COURT DAVIS CA 95616 DALHOUSIE UNIV,DEPT PSYCHOL HALIFAX B3H 4J1 NS CANADA
Titolo Testata:
Perception & psychophysics
fascicolo: 2, volume: 54, anno: 1993,
pagine: 260 - 273
SICI:
0031-5117(1993)54:2<260:WAHES>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
SHORT REACTION-TIMES; EYE-MOVEMENTS; VISUAL-ATTENTION; SUPERIOR COLLICULUS; WARNING SIGNALS; FIXATION-POINT; STIMULUS ONSET; LATENCY; MONKEY; OFFSET;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Social Sciences Citation Index
Science Citation Index Expanded
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
A. Kingstone e R.M. Klein, "WHAT ARE HUMAN EXPRESS SACCADES", Perception & psychophysics, 54(2), 1993, pp. 260-273

Abstract

When a fixation point is removed 200 msec prior to target onset (the gap condition), human subjects are said to produce eye movements that have a short latency (80-120 msec), that form the early peak of a bimodal latency distribution, and that have been labeled ''human express saccades'' (see, e.g., Fischer, 1987; Fischer & Breitmeyer, 1987; Fischer & Ramsperger, 1984, 1986). In three experiments, we sought to obtain this express saccade diagnostic pattern in the gap condition. We orthogonally combined target location predictability with the presence versus absence of catch trials (Experiment 1). When target location was fixed and catch trials were not used, we found mostly anticipations. In the remaining conditions, where responses were under stimulus control, bimodality was not frequently observed, and, whether it was or not,latencies were not in the express saccade range. Using random target locations, we then varied stimulus luminance and the mode of stimulus presentation (LEDs vs. oscilloscope) in the gap and overlap (fixation is not removed) conditions (Experiment 2). Bimodality was rarely observed, the gap effect (overlap minus gap reaction time) was additive with luminance, and only the brightest targets elicited saccades in the express range. When fixed locations and no catch trials were combined with latency feedback (Experiment 3), we observed many responses in theexpress saccade range and some evidence for bimodality, but the sudden introduction of catch trials revealed that many early responses werenot under stimulus control. Humans can make stimulus-controlled saccades that are initiated very rapidly (80-120 msec), but unless catch trials or choice reaction time is used, it is not possible to distinguish such saccades from anticipatory responses that are prepared in advance and timed to occur shortly after target onset. Because the express saccade diagnostic pattern is not a characteristic feature of human saccadic performance, we urge investigators to focus their attention on the robust gap effect.

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Documento generato il 03/07/20 alle ore 16:50:47