A neural correlate of visual discomfort from flicker

Abstract

The theory of "visual stress" holds that visual discomfort results from overactivation of the visual cortex. Despite general acceptance, there is a paucity of empirical data that confirm this relationship, particularly for discomfort from visual flicker. We examined the association between neural response and visual discomfort using flickering light of different temporal frequencies that separately targeted the magnocellular, parvocellular, and koniocellular post-receptoral pathways. Given prior work that has shown larger cortical responses to flickering light in people with migraine, we examined 10 headache free people and 10 migraineurs with visual aura. The stimulus was a uniform field, 50 degrees in diameter, that modulated with high-contrast flicker between 1.625 and 30 Hz. We asked subjects to rate their visual discomfort while we recorded steady state visually evoked potentials (ssVEP) from primary visual cortex. The peak temporal sensitivity ssVEP amplitude varied by post-receptoral pathway, and was consistent with the known properties of these visual channels. Notably, there was a direct, linear relationship between the amplitude of neural response to a stimulus and the degree of visual discomfort it evoked. No substantive differences between the migraine and control groups was found. These data link increased visual cortical activation with the experience of visual discomfort.

Influence of spatial frequency in visual stimuli for cVEP-based BCIs: evaluation of performance and user experience

“…In the BB-CBbased conditions (C002-C128), the stimulus was only illuminated on 50% of the surface with squares of different sizes. Hence, this trend regarding ocular irritation was consistent with previous literature (Gembler et al, 2020;Ladouce et al, 2022;Martinez-Cagigal et al, 2023), and it could be attributed to an increased activation of the LMS (luminance) postreceptoral pathway (Gentile and Aguirre, 2020). Consequently, this effect may contribute to the lower comfort levels observed for C001, and it should be considered for situations in which a user has to control the application for an extended period of time.…”

Visual Discomfort and Variations in Chromaticity in Art and Nature

“…Discomfort arises when the luminance content of a stimulus deviates consistently from that expected in natural scenes. Uncomfortable stimuli also evoke large metabolic and electrophysiological responses (Huang et al, 2003(Huang et al, , 2011O'Hare, 2016;Le et al, 2017;Haigh et al, 2018Haigh et al, , 2019Gentile and Aguirre, 2020;Lindquist et al, 2021). The discomfort is theorized to serve as a homeostatic signal to avoid stimuli that are computationally and therefore metabolically demanding (Wilkins and Hibbard, 2014).…”

“…In computational models of the cortex, uncomfortable images have been shown to give rise to a response that is less sparse than for other images (Hibbard and O'Hare, 2015). Images that are uncomfortable usually evoke a large cortical hemodynamic response, measured using fMRI (Huang et al, 2003(Huang et al, , 2011 or near infrared spectroscopy (Haigh et al, 2013a(Haigh et al, , 2015Le et al, 2017), and a large electrical response measured in terms of steady state visual evoked potential (O'Hare, 2016;Haigh et al, 2019;Gentile and Aguirre, 2020;Lindquist et al, 2021) or alpha suppression (Haigh et al, 2018). Taken together, converging evidence suggests that specific deviations from the luminance profile typically found in natural scenes causes visual stress and can be associated with increased cortical activity.…”

The physiology of deterrence: Flicker vertigo and its application in avian management

“…This suggests that light stimuli exert influence not only on the eyes but also on the brain. Flickering stimuli are associated with large amplitude neural responses within the visual cortex (Gentile and Aguirre 2020); more precisely, the source of discomfort is transient abnormal synchronized activity of brain cells (Wilkins et al 2010). Photosensitive epilepsy has been documented not only in humans but also in baboons, dogs, and poultry, indicating a lack of species specificity (Corcoran et al 1979; Batini et al 2004; Da Silva and Leal 2017; Szabó and Fischer 2021).…”