Areas V1 and V2 show microsaccade‐related 3–4‐Hz covariation in gamma power and frequency. (16th December 2015)

• Record Type: Journal Article
• Authors: Lowet, E.; Roberts, M. J.; Bosman, C. A.; Fries, P.; De Weerd, P.
• Editors: Foxe, John
• Is Part Of: European journal of neuroscience. Volume 43:Number 10(2016:May)
• Page Start: 1286
• Page End: 1296
• Publication Date: 2015-12-16
• Subjects: electrophysiology -- gamma‐band response -- monkey -- saccade -- visual system; Nervous system -- Periodicals; 612.8
• DOI: 10.1111/ejn.13126
• Languages: English
• ISSNs: 0953-816X

Abstract

Abstract: Neuronal gamma‐band synchronization (25–80 Hz) in visual cortex appears sustained and stable during prolonged visual stimulation when investigated with conventional averages across trials. However, recent studies in macaque visual cortex have used single‐trial analyses to show that both power and frequency of gamma oscillations exhibit substantial moment‐by‐moment variation. This has raised the question of whether these apparently random variations might limit the functional role of gamma‐band synchronization for neural processing. Here, we studied the moment‐by‐moment variation in gamma oscillation power and frequency, as well as inter‐areal gamma synchronization, by simultaneously recording local field potentials in V1 and V2 of two macaque monkeys. We additionally analyzed electrocorticographic V1 data from a third monkey. Our analyses confirm that gamma‐band synchronization is not stationary and sustained but undergoes moment‐by‐moment variations in power and frequency. However, those variations are neither random and nor a possible obstacle to neural communication. Instead, the gamma power and frequency variations are highly structured, shared between areas and shaped by a microsaccade‐related 3–4‐Hz theta rhythm. Our findings provide experimental support for the suggestion that cross‐frequency coupling might structure and facilitate the information flow between brain regions. Abstract : Visual cortical V1 and V2 gamma‐band oscillations undergo moment‐by‐moment variations in power and frequency. However, they are structured and shaped by a microsaccade‐related 3‐4‐Hz theta rhythm coordinated between V1 and V2. This supports the suggestion that cross‐frequency coupling might structure and coordinate neural activity within and between brain regions.