Eye movement-related brain activity during perceptual and cognitive processing

Abstract

Keywords: eye movements, saccade, smooth pursuit, eye tracking, free viewing, EEG, local field potentials, fMRIFor several decades researchers have been recording electrical brain activity associated with eye movements in attempt to understand their neural mechanisms. However, recent advances in eye-tracking technology have allowed researchers to use eye movements as the means of segmenting the ongoing brain activity into episodes relevant to cognitive processes in scene perception, reading, and visual search. This opened doors to uncovering the active and dynamic neural mechanisms underlying perception, attention and memory in naturalistic conditions. The present eBook contains a representative collection of studies from various fields of visual neuroscience that use this cutting edge approach of combining eye movements and neural activity.The majority of the articles in the eBook combine the measurement of eye movements with the recording of the electroencephalogram (EEG) in human subjects performing various psychological tasks. The most common methodological approach is examination of the EEG activity time-aligned to certain eye movement events, such as the onset of a fixation or a start of a saccadic eye movement (Fischer et al., 2013;Frey et al., 2013;Henderson et al., 2013;Hutzler et al., 2013;Nikolaev et al., 2013;Richards, 2013;Simola et al., 2013). Several works employ the time-frequency and synchrony analysis (Fischer et al., 2013;Hoffman et al., 2013;Ito et al., 2013;.The advantage of simultaneous EEG and eye movement recording is most evident in investigation of perceptual and cognitive processes during free eye movement behavior. Saccades in free viewing are guided by the bottom-up and top-down attentional mechanisms. To study interactions between these mechanisms Fischer et al. (2013) explored the eye fixation-related potentials (EFRP) and EEG power during extended picture viewing. The difference between the mechanisms was reflected in the EFRP components and in the power of the frontal beta-and theta activity. Nakatani and Van Leeuwen (2013) recorded EEG and eye movements during free viewing of the Necker cube. They found that saccades and blinks facilitate perceptual switches. Moreover, the amplitude of alpha activity preceding these eye events predicted whether a blink or a saccade results in the switch. Nikolaev et al. (2013) examined the pre-saccadic EEG activity during free visual exploration of a natural scene in anticipation of a memory test. Their findings illustrate how pre-saccadic activity differentiates encoding of visual information and selection of a target for the next fixation. Simola et al. (2013) investigated attention and emotion processes by analyzing EFRPs in free viewing. They found that emotional processing depends on the overt attentional resources. Ito et al. (2013) observed interaction between low and high frequency components in the local field potentials (LFP) recorded in the visual cortex of monkeys performing voluntary saccades during natural scene viewing. They concl...