Acute Exercise Modulates Feature-selective Responses in Human Cortex

Abstract

An organism's current behavioral state influences ongoing brain activity. Nonhuman mammalian and invertebrate brains exhibit large increases in the gain of feature-selective neural responses in sensory cortex during locomotion, suggesting that the visual system becomes more sensitive when actively exploring the environment. This raises the possibility that human vision is also more sensitive during active movement. To investigate this possibility, we used an inverted encoding model technique to estimate feature-selective neural response profiles from EEG data acquired from participants performing an orientation discrimination task. Participants (n = 18) fixated at the center of a flickering (15 Hz) circular grating presented at one of nine different orientations and monitored for a brief shift in orientation that occurred on every trial. Participants completed the task while seated on a stationary exercise bike at rest and during low- and high-intensity cycling. We found evidence for inverted-U effects; such that the peak of the reconstructed feature-selective tuning profiles was highest during low-intensity exercise compared with those estimated during rest and high-intensity exercise. When modeled, these effects were driven by changes in the gain of the tuning curve and in the profile bandwidth during low-intensity exercise relative to rest. Thus, despite profound differences in visual pathways across species, these data show that sensitivity in human visual cortex is also enhanced during locomotive behavior. Our results reveal the nature of exercise-induced gain on feature-selective coding in human sensory cortex and provide valuable evidence linking the neural mechanisms of behavior state across species.

Taking off the training wheels: Measuring auditory P3 during outdoor cycling using an active wet EEG system

“…For the same reasons we don't believe that the modulations in the N1 and P2 we observed are due to increases in noise due to movement, respiration or perspiration, given the slow speed of biking and the very similar noise levels compared to studies of indoor biking. We believe that any effects of acute exercise on brain processing would require a much higher intensity of biking Outdoor Cycling and Auditory P300 29 (see Pontifex & Hillman, 2007;Yagi, Coburn, Estes, & Arruda, 1999;Grego et al, 2004;Bullock et al, 2017). In follow up research we plan to push individuals to faster biking paces and investigate changes in acute behavioural effects, ERP measurement ability, and measured noise in the data.…”

Tonic and transient oscillatory brain activity during acute exercise

“…exercise by means of EEG event-related brain potentials (ERPs) as a way to pinpoint the brain correlates of (task relevant) stimulus processing under physical effort [13] [14][15] [16][17] [18]. Here, we take a step further by analysing power spectral changes time-locked to the (task) stimulus instead of ERPs.…”

“…[8][9][10][11][12][13][14] parametric paired t-test maps comparing the averaged spectral power across subjects over time (x-axes) and frequency (y-axes) during moderate-to-high intensity and light intensity exercise in standard trials. The enclosed areas denote significant clusters of channels and time with p < 0.025.…”

Dual process coding of recalled locations in human oscillatory brain activity

“…The parameters of these channel response estimates can then be used to quantify the spatially selective response. This method was initially applied to fMRI data (Brouwer & Heeger, 2009Ester, Sprague, & Serences, 2015;Naselaris, Kay, Nishimoto, & Gallant, 2011;Serences & Saproo, 2012) and has been recently applied to EEG recorded at the scalp (Bullock, Elliott, Serences, & Giesbrecht, 2017;Foster et al, 2016Foster et al, , 2017Garcia, Srinivasan, & Serences, 2013;Samaha et al, 2016).…”