Passive visual stimulation induces fatigue or improvement depending on cognitive load

Abstract

Theories of mental fatigue disagree on whether performance decrement is caused by motivational or functional alterations. We tested the assumption that keeping neural networks active for an extensive period of time entrains consequences at the subjective, objective and neurophysiological level – the defining characteristics of fatigue – when confounds such as motivation, boredom and level of skill are controlled. We reveal that passive visual stimulation affects visual gamma activity and the performance of a subsequent task when carried out in the same portion of visual space. This outcome was influenced by participants’ level of arousal, manipulated through variations in the difficulty of concurrent auditory tasks. Thus, repeated stimulation of neural networks leads to their altered functional performance and this mechanism seems to play a role in the development of mental fatigue.

Decoding visual fatigue in a visual search task selectively manipulated via myopia-correcting lenses

“…Concerning higher-level effects of visual fatigue, recent studies (Csathó et al, 2012 ; Cao et al, 2014 ; Rodrigues et al, 2022 ) utilized a visual attention task to characterize the decline in cognitive performance showing significant adverse effects of fatigue on task performance, particularly when the perceptual load of the target stimuli was high. This phenomenon also relates to the so-called cognitive fatigue—a mental exhaustion that can affect task performance and subjective affective evaluation (Bess and Hornsby, 2014 ; Karshikoff et al, 2017 ; Ioannucci et al, 2020 ; Guillemin et al, 2021 ). Given that visual fatigue therefore has a much wider-reaching impact on visual and cognitive processing, an investigation of the brain networks triggered by this type of fatigue will be an important, further step in a deeper understanding of this process.…”