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Titolo:
Motion VEPs with simultaneous measurement of perceived velocity
Autore:
Muller, R; Gopfert, E; Breuer, D; Greenlee, MW;
Indirizzi:
Univ Leipzig, Carl Ludwig Inst Physiol, D-04103 Leipzig, Germany Univ Leipzig Leipzig Germany D-04103 t Physiol, D-04103 Leipzig, Germany Univ Freiburg, Dept Neurol, D-7800 Freiburg, Germany Univ Freiburg Freiburg Germany D-7800 t Neurol, D-7800 Freiburg, Germany
Titolo Testata:
DOCUMENTA OPHTHALMOLOGICA
fascicolo: 2, volume: 97, anno: 1999,
pagine: 121 - 134
SICI:
0012-4486(1999)97:2<121:MVWSMO>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
CORTICAL POTENTIALS; EVOKED-POTENTIALS; PATTERN; ADAPTATION; CONTRAST; SPEED; SELECTIVITY; PERCEPTION; FREQUENCY; MOVEMENT;
Keywords:
adaptation; channels; motion-onset VEP; N200 wave; perceived velocity; speed dependence;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
26
Recensione:
Indirizzi per estratti:
Indirizzo: Muller, R Univ Leipzig, Carl Ludwig Inst Physiol, Liebigstr 27, D-04103 Leipzig, Germany Univ Leipzig Liebigstr 27 Leipzig Germany D-04103 pzig, Germany
Citazione:
R. Muller et al., "Motion VEPs with simultaneous measurement of perceived velocity", DOC OPHTHAL, 97(2), 1999, pp. 121-134

Abstract

The dependency of the N200 amplitude of the motion-onset VEP evoked by a parafoveal grating of variable speed (0.25 - 13.5 deg/s, corresponding to 0.5 - 27 Hz) and constant contrast (4%) was studied. Additional measurements were made with parafoveally presented gratings of constant speed (2 deg/s, corresponding to 4 Hz) and a variable contrast (0.5 64%) before and after adaptation to a stationary or drifting grating. In this latter experiment, simultaneous psychophysical measurements were made of the perceived speed. The amplitude of the N200 wave increased with increasing stimulus speed within the slow speed range up to 1.5 deg/s (corresponding to 3 Hz). Adaptationto a stationary grating had no significant effect on the relationship between the N200 amplitude and stimulus contrast. Contrary to this, adaptation to a slowly drifting grating (1 deg/s, corresponding to 2 Hz) or to a rapidly drifting grating (4 deg/s, corresponding to 8 Hz) reduced the N200 amplitude significantly. Adaptation to a stationary grating slightly reduced theperceived speed of subsequently viewed gratings. Adaptation to a slowly drifting grating increased the perceived speed of the subsequently viewed gratings, whereas adaptation to a rapidly drifting grating decreased the perceived speed. The findings can be best explained by a two-channel model of speed perception. While the motion VEP reflects the sum of both channel activities, the psychophysical measures point to the antagonistic encoding of low and high velocities.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/09/20 alle ore 10:42:11