Increasing task difficulty facilitates the cerebral compensatory response to total sleep deprivation.
OBJECTIVE
To test the role of task difficulty in the cerebral compensatory response after total sleep deprivation (TSD).


METHODS
Subjects performed a modified version of Baddeley's logical reasoning task while undergoing functional magnetic resonance imaging twice: once after normal sleep and once following 35 hours of TSD. The task was modified to parametrically manipulate task difficulty.


METHODS
Inpatient General Clinical Research Center and outpatient functional magnetic resonance imaging center.


METHODS
16 young adults (7 women; mean age, 27.6 +/- 6.1 years; education, 15.4 +/- 1.8 years) were included in the final analyses.


METHODS
None.


RESULTS
Behaviorally, subjects performed the same after TSD as while well rested. Neuroimaging data revealed a linear increase in cerebral response with a linear increase in task demands in several brain regions after normal sleep. Even stronger linear responses were found after TSD in several brain regions, including bilateral inferior parietal lobes, bilateral temporal cortex, and left inferior and dorsolateral prefrontal cortex.


CONCLUSIONS
Task difficulty facilitates the cerebral compensatory response observed following TSD. Compensation manifests as both new regions that did not show significant responses to task demands in the well-rested condition, as well as stronger responses within regions typically underlying task performance. The possible significance of these 2 types of responses should be explored further, as should the importance of the parietal lobes for cognitive performance after TSD.
Drummond
Sean P A
SP
Department of Psychiatry, University of California San Diego, 92161, USA. drummond@ucsd.edu
Brown
Gregory G
GG
Salamat
Jennifer S
JS
Gillin
J Christian
JC
D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000098:blood supply / Q000503:physiopathology*; D003071:Cognition / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012892:Sleep Deprivation / Q000503:physiopathology*