MEG responses correlated with the visual perception of velocity change
| Autor: | Kaoru Amano, Shin'ya Nishida, Tsunehiro Takeda |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Adult
Male medicine.medical_specialty Visual perception genetic structures Discrimination threshold Velocity Motion Perception Speed Stimulus (physiology) Audiology RT Developmental psychology Correlation Motion Discrimination Psychological Increment threshold Adaptation Psychological Psychophysics Reaction Time medicine Humans Enhanced sensitivity Adaptation MEG medicine.diagnostic_test Magnetoencephalography Sensory Systems Ophthalmology Amplitude Sensory Thresholds Linear Models Evoked Potentials Visual Psychology |
| Zdroj: | Vision Research. 46:336-345 |
| ISSN: | 0042-6989 |
| Popis: | Magnetoencephalography (MEG) was used to find neural activities, in the human brain, involved in perception of velocity changes in visual motion. We recorded MEG responses evoked by the stimuli whose velocity increased by 40% or 80% of baseline velocities of 1.0, 2.0, 3.0, and 4.0 deg/s. The velocity increment threshold and the manual reaction time (RT) were also measured under similar stimulus conditions. To manipulate observers sensitivity to velocity increments, the MEG responses and the psychophysical performances were measured after adaptation to motion in one direction (adapted condition) or alternating directions (control condition). MEG responses evoked by velocity increments peaked at 200–290 ms (M1), and the M1 amplitudes, especially those obtained for 40% increments, were correlated with the sensitivities, which are the reciprocal of velocity increment thresholds. Furthermore, motion adaptation enhanced sensitivity to velocity increments and increased the M1 amplitudes. These results suggest a close correlation between the perceptual velocity increment and the evoked MEG response. In other words, the results suggest that velocity increments are detectable when there is a constant increment in magnetic neural response. As for latencies, nearly constant value of M1 latency did not quantitatively match a large decrease in manual RT with the increase in the baseline velocity. Motion adaptation reduced neither the peak MEG latency nor the manual RT. � 2005 Elsevier Ltd. All rights reserved. |
| Databáze: | OpenAIRE |
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