Resting-state BOLD oscillation frequency predicts vigilance task performance at both normal and high environmental temperatures

Abstract

Hyperthermia may impair vigilance functions and lead to slower reaction times (RTs) in the psychomotor vigilance task (PVT) and possibly disturbing cerebral hemodynamic rhythms. To test these hypotheses, we acquired the resting-state BOLD and cerebral blood flow (CBF) data, as well as PVTRTs from 15 participants in two simulated environmental thermal conditions (50 °C/25 °C). We adopted a data-driven method, frequency component analysis, to quantify the mean frequency of the BOLD series of each voxel. Across-subject correlation analysis was employed to detect the brain areas whose BOLD oscillation frequency was correlated with the RTs. Significant changes of BOLD frequency and CBF within these areas were compared between hyperthermia and normothermia conditions. Spatial correlations between BOLD frequency and CBF were calculated within different brain areas for each subject under both thermal conditions. Results showed that, under both thermal conditions, the RTs correlated with the BOLD frequency positively in the default mode network (DMN) and negatively in the sensorimotor network (SMN). The increase of BOLD frequency in the thalamus and ventral medial prefrontal cortex was correlated with the increase of RTs in hyperthermia compared with normothermia. Hyperthermia decreased BOLD frequency and CBF in the SMN, while it increased CBF in the thalamus and posterior cingulate. In both thermal conditions, the spatial distribution of CBF negatively correlated with the spatial distribution of BOLD oscillation frequency in most cortical areas, especially in cingulate cortices, precuneus, and primary visual cortex. These results suggest that hyperthermia might deteriorate task performance by interfering with the resting-state CBF, and with BOLD rhythms. The overlapping of the thermoregulatory and vigilance functions in the SMN and DMN might underlie the neural mechanisms of the cognitive-behavioral impairments induced by hyperthermia.

Loss of frontal regulator of vigilance during sleep inertia: A simultaneous EEG‐fMRI study

“…Decreased activities of the three networks were observed upon awakening, especially the DMN (t (42) = 2.787, p = .003), suggesting deficient vigilance during sleep inertia. This linkage of diminished vigilance and reduced spontaneous activity of the DMN has also been reported in previous studies (Dai et al, 2015;Song et al, 2017). Furthermore, lower BOLD activity in the DMN indicated reduced vigilance and worse performance (Gui et al, 2015).…”

Resting-state brain activity predicts selective attention deficits during hyperthermia exposure

“…Participants: The data of resting-state BOLD-fMRI were collected together with the data of 3 D arterial spin labeling (ASL) in our previous study [24]. Twenty healthy young male students (23.4 ± 1.8 years, aging from 21 to 26 years) were recruited.…”

“…However, there has been no unified protocol for the study of human physiological and psychological alterations in high temperature environment. Therefore, the experiment procedure used in this study, as well as our other studies [14,16,24,32,33], was designed according to the protocols from the previous studies [25][26][27][28][29][30][31], especially, those studies on brain cognition during hyperthermia [30,31,34]. The experiment was performed 5:00 p.m.$8:00 p.m. Each participant underwent the experiment at the same time of day for each thermal condition.…”

“…Physiological parameters measuring: Using the same approach as our previous studies [14,24,32], in the environmental chamber we measured the physiological parameters intermittently once every 5 min using a portable multi-parameter monitor (PM-9000, Mindray Co., Ltd), including rectal temperature, heart rate, respiration rate and blood pressure in this study. Due to unavailability of the monitor equipment in the MRI room, physiological parameters, including rectal temperature, blood pressure, were not measured during scanning.…”

“…After preprocessing, data from 5 participants in the previous pool of 20 were discarded due to discomfort report or under the exclusion criteria with displacement greater than 1.5 mm or rotation greater than 1.5 . The data of totally 25 participants (the remaining 15 participants of previously recruited [24] and the newly recruited 10 participants) were involved into following analysis.…”