کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4035609 | 1263537 | 2005 | 13 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Human cortical responses to contrast modulations of visual noise Human cortical responses to contrast modulations of visual noise](/preview/png/4035609.png)
We studied visual evoked potentials (VEPs) elicited by second-order contrast modulations of binary dynamic noise and first-order luminance modulations. Using a 3-point Laplacian operator centred on Oz, we found that contrast modulations of both low and higher spatial frequencies elicited a negative component whose latency was about 200 ms. The latency of this component was significantly longer than that of the early Laplacian components to first-order luminance modulations. These findings could be due to slower first-stage linear filters and additional processing stages of the second-order pathway. The topographical analysis of scalp recorded VEPs to central and half-field stimulation has suggested that the responses to second-order patterns are likely to be generated by neuronal structures within the primary visual cortex which may have inputs from extrastriate neurons via feedback connections.
Journal: Vision Research - Volume 45, Issue 17, August 2005, Pages 2218–2230