RT Journal Article
SR Electronic
T1 Human visual gamma for color stimuli: When LGN drive is equalized, red is not special
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.11.22.469550
DO 10.1101/2021.11.22.469550
A1 Benjamin Johannes Stauch
A1 Alina Peter
A1 Isabelle Ehrlich
A1 Zora Nolte
A1 Pascal Fries
YR 2021
UL http://biorxiv.org/content/early/2021/11/22/2021.11.22.469550.abstract
AB Strong gamma-band oscillations in primate early visual cortex can be induced by spatially homogeneous, high-contrast stimuli, such as color surfaces. Compared to other hues, particularly strong gamma oscillations have been reported for red stimuli. However, precortical color processing and the resultant strength of input to V1 has often not been fully controlled for. This leaves the possibility that stronger responses to some hues were due to differences in V1 input strength. We presented stimuli that had equal luminance and color contrast levels in a color coordinate system based on color responses of the lateral geniculate nucleus, the main input source for area V1. With these stimuli, we recorded magnetoencephalography in 30 human subjects. We found narrowband color-induced gamma oscillations in early visual cortex, which, contrary to previous reports, did not differ between red and green stimuli of equal L-M cone contrast. Notably, blue stimuli with contrast exclusively on the S-cone axis induced very weak gamma responses, as well as smaller event-related fields and poorer change detection performance. The strength of human color gamma responses could be well explained by the strength of thalamic input induced by each hue and does not show a clear red bias when this input strength is properly equalized.Competing Interest StatementP.F. has a patent on thin-film electrodes (US20170181707A1) and is beneficiary of a respective license contract on thin-film electrodes with Blackrock Microsystems LLC (Salt Lake City, UT). P.F. is member of the Scientific Technical Advisory Board of CorTec GmbH (Freiburg, Germany), and managing director of Brain Science GmbH (Frankfurt am Main, Germany). The authors declare no further competing interests.