Neuroscience 2002 Abstract
| Presentation Number: | 657.3 |
|---|---|
| Abstract Title: | Second-order motion detection in humans: A magnetoencephalography and functional MRI study. |
| Authors: |
Sofue, A.*1
; Kaneoke, Y.1
; Kakigi, R.1
1Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan |
| Primary Theme and Topics |
Sensory Systems - Vision -- Extrastriate visual cortex: Motion and depth |
| Session: |
657. Visual cortex: motion II Poster |
| Presentation Time: | Wednesday, November 6, 2002 10:00 AM-11:00 AM |
| Location: | Hall A2-B3 F-55 |
| Keywords: | VISUAL MOTION, MAGNETOENCEPHALOGRAPHY, second order, FUNCTIONAL MRI |
Humans detect motions of images defined not only by luminance difference (first-order) but images segregated by the second-order characteristics such as texture, contrast, and so on. There have been few electrophysiological studies addressed on the mechanism underlying the second-order motion detection. First, we measured the magnetoencephalographic (MEG) response to the second-order motion defined by the sinusoidally modulated dots speeds but there was no obvious responses detected whereas the responses to the first-order sinusoidal grating at the same speed (2.6 deg/s) were found peaking at about 310 ms. Second, we measured the MEG responses to the apparent motions of the square areas. The areas were defined by the three characteristics: difference in the dots speeds (second-order apparent motion; SA), luminance of the dots (first-order; FA), and dots speeds and luminance (mixed; MA). For all the stimuli, MEG latencies decreased and the amplitudes increased as the motion distance increased. The latencies for SA were about 100 ms longer than those for FA. The latencies for MA were in the middle but close to FA. The amplitudes for SA were the smallest and those for MA were the second. The functional MRI study using the same motion stimuli revealed that both first- and second-order motions activated mainly the primary visual cortex and MT+. Our study showed that the distinct difference in the human cortical response to the second-order motion compared to the first-order motion though the similar cortical areas seem to be involved. Furthermore, the response properties for MA suggest the interaction at early neural processes for both motions.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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