Dataset Information

Dynamics of neurobehavioral performance variability under forced desynchrony: evidence of state instability.

ABSTRACT:

Study objectives

The state instability hypothesis posits that increasing sleep drive brings about escalating state instability in attention, making neurobehavioral performance increasingly variable. This hypothesis predicts that performance variability is a function of prior wake, circadian phase, and time on task. These predictions have been supported when wakefulness is beyond the habitual wake period. Our study aimed to test these predictions within the habitual wake period.

Design

A 12-calendar-day 28-h forced desynchrony protocol consisting of 7 repetitions of a 28-h sleep/wake cycle, with two-thirds time awake and one-third time in bed. Each wake period included 7 equally spaced 1-h testing sessions.

Setting

A time-isolation sleep laboratory.

Participants

Thirteen young healthy males.

Interventions

Wake periods during the protocol were 4 h delayed each 28-h "day" relative to the circadian system, such that they were distributed across the whole circadian cycle. This allowed performance testing at different combinations of prior wake of a habitual length (i.e., < 18 h) and circadian phase.

Measurements and results

Performance variability was indexed by standard deviation of response times within a 10-min psychomotor vigilance task. We found that response times became more variable with increasing wakefulness and towards circadian nadir, i.e., when sleep drive was increasing. These changes in response time variability were however not dependent on time on task, which is likely due to the modest level of sleep drive in our study.

Conclusions

The state instability hypothesis, as an explanation for the responsiveness of neurobehavioral performance to increasing sleep drive, is supported during the habitual wake period.

SUBMITTER: Zhou X

PROVIDER: S-EPMC3001796 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature

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Publications

Dynamics of neurobehavioral performance variability under forced desynchrony: evidence of state instability.

Zhou Xuan X Ferguson Sally A SA Matthews Raymond W RW Sargent Charli C Darwent David D Kennaway David J DJ Roach Gregory D GD

Sleep 20110101 1

<h4>Study objectives</h4>The state instability hypothesis posits that increasing sleep drive brings about escalating state instability in attention, making neurobehavioral performance increasingly variable. This hypothesis predicts that performance variability is a function of prior wake, circadian phase, and time on task. These predictions have been supported when wakefulness is beyond the habitual wake period. Our study aimed to test these predictions within the habitual wake period.<h4>Design ...[more]

PMID: 21203373

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Project description:Spatiotemporal dynamics of EEG/MEG (electro-/magneto-encephalogram) have typically been investigated by applying time-frequency decomposition and examining amplitude-amplitude, phase-phase, or phase-amplitude associations between combinations of frequency bands and scalp sites, primarily to identify neural correlates of behaviors and traits. Instead, we directly extracted global EEG spatiotemporal dynamics as trajectories of k-dimensional state vectors (k = the number of estimated current sources) to investigate potential global rules governing neural dynamics. We chose timescale-dependent measures of trajectory instability (approximately the 2nd temporal derivative) and speed (approximately the 1st temporal derivative) as state variables, that succinctly characterized trajectory forms. We compared trajectories across posterior, central, anterior, and lateral scalp regions as the current sources under those regions may serve distinct functions. We recorded EEG while participants rested with their eyes closed (likely engaged in spontaneous thoughts) to investigate intrinsic neural dynamics. Some potential global rules emerged. Time-averaged trajectory instability from all five regions tightly converged (with their variability minimized) at the level of generating nearly unconstrained but slightly conservative turns (~100° on average) on the timescale of ~25 ms, suggesting that spectral-amplitude profiles are globally adjusted to maintain this convergence. Further, within-frequency and cross-frequency phase relations appear to be independently coordinated to reduce average trajectory speed and increase the variability in trajectory speed and instability in a relatively timescale-invariant manner, and to make trajectories less oscillatory. Future research may investigate the functional relevance of these intrinsic global-dynamics rules by examining how they adjust to various sensory environments and task demands or remain invariant. The current results also provide macroscopic constraints for quantitative modeling of neural dynamics as the timescale dependencies of trajectory instability and speed are relatable to oscillatory dynamics.

Dataset Information

Dynamics of neurobehavioral performance variability under forced desynchrony: evidence of state instability.

Study objectives

Design

Setting

Participants

Interventions

Measurements and results

Conclusions

Publications

Dynamics of neurobehavioral performance variability under forced desynchrony: evidence of state instability.

Similar Datasets

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