Abstract:
Recent dose-response sleep restriction studies, in which nightly sleep is curtailed to varying
degrees (e.g., 3-, 5-, 7-hours), have found cumulative, dose-dependent changes in sleepiness,
mood, and reaction time. However, brain activity has typically not been measured, and attentionbased
tests employed tend to be simple (e.g., reaction time). One task addressing the behavioural
and electrophysiological aspects of a specific attention mechanism is the Attentional Blink (AB),
which shows that the report accuracy of a second target (T2) is impaired when it is presented
soon after a first target (Tl). The aim of the present study was to examine behavioural and
electrophysioiogical responses to the AB task to elucidate how sleep restriction impacts
attentional capacity. Thirty-six young-adults spent four consecutive days and nights in a sleep
laboratory where sleep, food, and activity were controlled. Nightly sleep began with a baseline
sleep (8 hours), followed by two nights of sleep restriction (3,5 or 8 hours of sleep), and a
recovery sleep (8 hours). An AB task was administered each day at 11 am. Results from a basic
battery oftests (e.g., sleepiness, mood, reaction time) confirmed the effectiveness of the sleep
restriction manipulation. In terms of the AB, baseline performance was typical (Le., T2 accuracy
impaired when presented soon after Tl); however, no changes in any AB behavioural measures
were observed following sleep restriction for the 3- or 5-hour groups. The only statistically
significant electrophysiological result was a decrease in P300 amplitude (for Tl) from baseline
to the second sleep restriction night for the 3-hour group. Therefore, following a brief, two night
sleep restriction paradigm, brain functioning was impaired for the TI of the AB in the absence of
behavioural deficit. Study limitations and future directions are discussed.
