Abstract
Visually induced gamma–band activity (GBA) has been implicated in several central cognitive functions, in particular perceptual binding, the feedforward routing of attended stimulus information and memory encoding. Several studies have documented that the strength and frequency of GBA are influenced by both subject–intrinsic factors like age, and subject–extrinsic factors such as stimulus contrast. Here, we investigated the relative contributions of previously tested factors, additional factors, and their interactions, in a cohort of 158 subjects recorded with magnetoencephalography (MEG). In agreement with previous studies, we found that gamma strength and gamma peak frequency increase with stimulus contrast and stimulus velocity. Also in confirmation of previous findings, we report that gamma peak frequency declines with subject age. In addition, we found that gamma peak frequency is higher for subjects with thicker occipital cortex, but lower for larger occipital cortices. Also, gamma peak frequency is higher in female than male subjects. Extrinsic factors (stimulus contrast and velocity) and intrinsic factors (age, cortical thickness and sex) together explained 21% of the variance in gamma peak frequency and 20% of the variance in gamma strength. These results can contribute to our understanding of the mechanisms, by which gamma is generated, and the mechanisms, through which it affects the cognitive performance of a given individual subject.
Highlights
Gamma–band activity (30–90Hz) plays a key role in cortical processing (Singer and Gray, 1995; Buzsáki and Wang, 2012; Fries, 2015)
Several studies have documented that the strength and frequency of gamma–band activity (GBA) are influenced by both subject–intrinsic factors like age, and subject–extrinsic factors such as stimulus contrast
In all time–frequency representations (TFRs), it can be seen that GBA increased after stimulus onset (t=0s), up to 400% relative to pre–stimulus baseline levels
Summary
Gamma–band activity (30–90Hz) plays a key role in cortical processing (Singer and Gray, 1995; Buzsáki and Wang, 2012; Fries, 2015). It is enhanced during perception and action (Fries et al, 2002; Wyart and Tallon–Baudry, 2008; Hoogenboom et al, 2010), selective attention (Fries et al, 2001; Bosman et al, 2012; Landau et al, 2015), and successful memory encoding (Howard et al, 2003; Fell et al, 2001). The sources of gamma variability have been studied extensively over the last decade, but Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain
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