Attentional dynamics during free picture viewing: Evidence from oculomotor behavior and electrocortical activity

Abstract

Most empirical evidence on attentional control is based on brief presentations of rather abstract stimuli. Results revealed indications for a dynamic interplay between bottom-up and top-down attentional mechanisms. Here we used a more naturalistic task to examine temporal signatures of attentional mechanisms on fine and coarse time scales. Subjects had to inspect digitized copies of 60 paintings, each shown for 40 s. We simultaneously measured oculomotor behavior and electrophysiological correlates of brain activity to compare early and late intervals (1) of inspection time of each picture (picture viewing) and (2) of the full experiment (time on task). For picture viewing, we found an increase in fixation duration and a decrease of saccadic amplitude while these parameters did not change with time on task. Furthermore, early in picture viewing we observed higher spatial and temporal similarity of gaze behavior. Analyzing electrical brain activity revealed changes in three components (C1, N1 and P2) of the eye fixation-related potential (EFRP); during picture viewing; no variation was obtained for the power in the frontal beta- and in the theta activity. Time on task analyses demonstrated no effects on the EFRP amplitudes but an increase of power in the frontal theta and beta band activity. Thus, behavioral and electrophysiological measures similarly show characteristic changes during picture viewing, indicating a shifting balance of its underlying (bottom-up and top-down) attentional mechanisms. Time on task also modulated top-down attention but probably represents a different attentional mechanism.

Early Visual Foraging in Relationship to Familial Risk for Autism and Hyperactivity/Inattention

“…For example, when freely exploring new visual scenes, participants make shorter fixations and longer saccades during the first few seconds, covering the whole visual scene. However, as participants continue to look, their fixations gradually become longer and their saccades shorter (Pannasch et al, 2008;Fischer et al, 2013) This suggests that the optimum visual information strategy relies on an initial exploratory phase, where a new scene/environment is mapped to discover potential interesting sights. This is then followed by information exploitation, where chosen locations (sources of information) are repeatedly investigated (Krebs, Kacelnik & Taylor, 1978).…”

A Tomada de Decisão (Bio)ética: Estudo Preliminar Utilizando o Mobile Eye Tracking

“…Its usage in health sciences however is still not routine. In any case, it is worth mentioning a study which used -simultaneously -the Mobile Eye Tracking and electroencephalogram (EEG) during free observation of scenes; focus activities were observed along with theta and beta waves, adjustment of focus and saccadic movements were correlated with activated cortical areas 18,19 .…”

“…Nikolaev and collaborators thereby revised the most recent research findings about the use of EyeTracking 17 . Based on experiments with primates (humans and no humans) the correlation between emotions, point of fixation and saccadic movements 18,19 , which occur involuntarily in the oculomotor system, has been established. Such movements help to interpret scenes or background images captured by the eyes.…”

Eye movement-related brain activity during perceptual and cognitive processing

“…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;.…”

“…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.…”