Distinct brain systems are involved in subjective minute estimation with eyes open or closed: EEG source analysis study

Abstract

Introduction: Time perception is a fundamental cognitive function, the brain mechanisms of which are not fully understood. Recent electroencephalography (EEG) studies have shown that neural oscillations in specific frequency bands may play a role in this process. In the current study, we sought to investigate how neurophysiological activity of cortical structures relates to subjective time estimations.

Methods: The study sample included 41 healthy volunteers, who were to produce subjective minutes with eyes closed and open by pressing the response button marking the beginning and end of this time interval. High-density EEG was recorded in parallel and the activity of cortical sources within the theta, alpha, and beta frequency bands was analyzed with standardized low-resolution brain electromagnetic tomography.

Results: The results revealed that activity of several cortical structures within the beta-band correlated with the duration of subjective minutes across participants, which highlights the role of the beta-rhythm in supra-second time perception. The sets of involved structures were different depending on eyes being open or closed, while the produced duration did not differ being around 58 s in both conditions. Individual minute correlated with beta power in the left precuneus, left superior parietal lobule, and right superior frontal gyrus (SFG) during eyes-closed sessions, and with that in the caudal anterior cingulate cortex, cuneus, posterior cingulate cortex, parahippocampal gyrus, and right lingual gyrus during the eyes-open condition. Noteworthy, some structures showed tendencies toward opposite correlations between conditions.

Discussion: Taken together, our findings bridge the gap between functional magnetic resonance imaging and EEG time perception studies and suggest reliance on different aspects of subjective experience when judging about time with eyes open or closed.

Keywords: EEG; current source density; duration production task; sLORETA; time perception.

FIGURE 1

Visualization of the experimental paradigm. Participants were to indicate the start and the stop of a subjective minute by pressing the spacebar. First, they were to produce a 1-min interval with open eyes and then with closed eyes. This procedure was repeated one more time resulting in two trials with open eyes and two trials with closed eyes.

FIGURE 2

Significant Spearman correlations (p < 0.05) between right superior frontal gyrus/left superior parietal lobule CSD and subjective minute duration.

FIGURE 3

Significant Spearman correlation (p < 0.05) between left precuneus CSD and subjective minute duration.

FIGURE 4

Brain map with areas showing significant correlations (p (corr.) < 0.05) with subjective minute duration. The top line corresponds to the closed-eyes condition; the bottom line corresponds to the open-eyes condition. Red color indicates areas showing positive correlation, blue color indicates areas showing negative correlation.

FIGURE 5

Significant Spearman correlation (p < 0.05) between left caudal anterior cingulate CSD and subjective minute duration.

FIGURE 6

Significant Spearman correlations (p < 0.05) between left and right cuneus CSD and subjective minute duration.

FIGURE 7

Significant Spearman correlations (p < 0.05) between right/left posterior cingulate and parahippocampal gyri CSD and subjective minute duration.