Human visual cortex responds to invisible chromatic flicker

Yi Jiang, Ke Zhou, Sheng He

Research output: Contribution to journalArticlepeer-review

96 Scopus citations


When two isoluminant colors alternate at frequencies of 25 Hz or higher, observers perceive only one fused color. Chromatic flicker beyond the fusion frequency induces flicker adaptation in human observers and stimulates monkey V1 neurons. Here we use functional magnetic resonance imaging (fMRI) to show that many human visual cortical areas, with the exception of VO, can distinguish between fused chromatic flicker and its matched nonflickering control. This result supports the existence of significant intracortical temporal filtering of high-frequency chromatic information. The result also suggests that a considerable difference in cortical activation in many visual cortical areas does not necessarily lead to different conscious experiences.

Original languageEnglish (US)
Pages (from-to)657-662
Number of pages6
JournalNature neuroscience
Issue number5
StatePublished - May 2007

Bibliographical note

Funding Information:
We thank F. Fang for technical assistance, D. MacLeod for comments on an early version of the manuscript, and P. Costello and R. Shannon for their help with the manuscript. This research was supported by the James S. McDonnell foundation, the US National Institutes of Health (EY-015261-01), the 973 program (2005CB522800) and the Knowledge Innovation Project of the Chinese Academy of Sciences. The 3T scanner at the University of Minnesota is supported by Biotechnology Research Resource (BTRR) grant P41 008079 and by the Mental Illness and Neuroscience Discovery (MIND) Institute.


Dive into the research topics of 'Human visual cortex responds to invisible chromatic flicker'. Together they form a unique fingerprint.

Cite this