title: Lapsing when sleep deprived: neural activation characteristics of resistant and vulnerable individuals.
abstract: Lapses of attention, in the form of delayed responses to salient stimuli, increase in frequency for some but not all persons after sleep deprivation (SD). To identify patterns of task-related brain activation that might explain differences in vulnerability to SD, we performed fMRI on participants during a visual, selective attention task. We analyzed the correct responses in a trial-by-trial fashion to model the effects of response time. Stimulus contrast was varied to modulate perceptual difficulty. Attentional lapses and low-contrast stimuli were independently associated with increased signal in fronto-parietal regions associated with biasing attention. Sleep-deprived vulnerable individuals showed reduced top down fronto-parietal signal across all levels of image contrast and this reduction was particularly significant during lapses. There was concurrent reduction in extrastriate cortex and thalamus activation. Non-vulnerable persons showed a trend towards higher top-down biasing of attention and preserved visual cortex activation during SD lapses. A major contributor to performance degradation in SD appears to be a reduction in top-down biasing of attention that is independent of task difficulty.
authors.affiliation: Cognitive Neuroscience Laboratory, Duke-NUS Graduate Medical School, Singapore 169857, Singapore. mchee@pacific.net.sg
authors.forename: Michael W L
authors.initials: MW
authors.lastname: Chee
authors.forename: Jiat Chow
authors.initials: JC
authors.lastname: Tan
mesh_terms: D001288:Attention / Q000502:physiology*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D011930:Reaction Time; D012892:Sleep Deprivation / Q000503:physiopathology*; D055815:Young Adult