title: The influence of time awake and circadian rhythm upon performance on a frontal lobe task.
abstract: Previous research has suggested a time-of-day effect for response inhibition on a task known to be dependent on frontal lobe function. We used a forced desynchronisation protocol to separate effects of circadian and sleep homeostat processes on a modified version of this task. Fourteen healthy young adults followed an experimental day length of 28 hr for 18 consecutive "days". There was a significant main effect of wake duration but no circadian component for inhibitory performance on this task. An interaction suggested that performance coinciding with the rising arm of the circadian cycle will vary dependent on the length of prior wakefulness. We suggest that the relationship between homeostatic sleep processes and circadian processes is complex and that their effects on cognitive processes are not easily separated by routine sleep-deprivation or time-of-day studies.
authors.affiliation: School of Psychology, Liverpool John Moores University, Henry Cotton Campus, Liverpool L3 2ET, United Kingdom. y.harrison@ljmu.ac.uk
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Harrison
authors.forename: Kay
authors.initials: K
authors.lastname: Jones
authors.forename: Jim
authors.initials: J
authors.lastname: Waterhouse
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention; D001831:Body Temperature / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009483:Neuropsychological Tests; D017286:Polysomnography / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012892:Sleep Deprivation / Q000503:physiopathology; D013997:Time Factors; D014851:Wakefulness