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Light modulates oscillatory alpha activity in the occipital cortex of totally visually blind individuals with intact non-visual photoreception
- Publication Year :
- 2017
- Publisher :
- Cold Spring Harbor Laboratory, 2017.
-
Abstract
- The discovery of intrinsically photosensitive retinal ganglion cells (ipRGCs) marked a major shift in our understanding of how light is processed by the mammalian brain. These ipRGCs influence multiple functions not directly related to vision such as the synchronization of circadian rhythmicity, pupil constriction, the regulation of alertness and sleep, as well as the modulation of cognition. More recently, it was demonstrated that ipRGCs may also contribute to basic visual functions. The impact of ipRGCs on visual functions, independently of image forming photoreceptors, remains however difficult to isolate, particularly in humans. We previously showed that exposure to intense monochromatic blue light (465nm) induced awareness of light in a forced choice task in three rare totally visually blind individuals without detectable rod and cone function, but who retained non-visual responses to light, very likely via ipRGCs. The neural foundation of such light awareness in the absence of conscious vision is unknown, however. In this study, we characterized the brain activity of these three rare participants using electroencephalography (EEG), and demonstrate that unconsciously perceived light triggers an early and reliable transient desynchronization (i.e. decreased power) of the alpha EEG rhythm (8-14 Hz) over the occipital cortex. These results provide compelling insight into how ipRGC may contribute to transient changes in ongoing brain activity. They suggest that occipital alpha rhythm synchrony, which is typically linked to the visual system, is modulated by ipRGCs photoreception; a process that may contribute to the awareness of light in those blind individuals.
- Subjects :
- 0303 health sciences
genetic structures
medicine.diagnostic_test
Brain activity and meditation
Intrinsically photosensitive retinal ganglion cells
Cognition
Electroencephalography
Biology
03 medical and health sciences
Alertness
0302 clinical medicine
medicine.anatomical_structure
Rhythm
Cortex (anatomy)
medicine
Circadian rhythm
Neuroscience
030217 neurology & neurosurgery
030304 developmental biology
Subjects
Details
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....593adc1270c2dc35ffe92363a07ce1ee