Preliminary fMRI findings in experimentally sleep-restricted adolescents engaged in a working memory task

Abstract

Here we report preliminary findings from a small-sample functional magnetic resonance imaging (fMRI) study of healthy adolescents who completed a working memory task in the context of a chronic sleep restriction experiment. Findings were consistent with those previously obtained on acutely sleep-deprived adults. Our data suggest that, when asked to maintain attention and burdened by chronic sleep restriction, the adolescent brain responds via compensatory mechanisms that accentuate the typical activation patterns of attention-relevant brain regions. Specifically, it appeared that regions that are normally active during an attention-demanding working memory task in the well-rested brain became even more active to maintain performance after chronic sleep restriction. In contrast, regions in which activity is normally suppressed during such a task in the well-rested brain showed even greater suppression to maintain performance after chronic sleep restriction. Although limited by the small sample, study results provide important evidence of feasibility, as well as guidance for future research into the functional neurological effects of chronic sleep restriction in general, the effects of sleep restriction in children and adolescents, and the neuroscience of attention and its disorders in children.

Figure 1

Accuracy and reaction time were comparable across sleep conditions on the 0-back and 2-back tasks (p > .10). SR = Sleep Restriction, HD = Healthy Sleep Duration.

Figure 2

Composite activation/deactivation maps, showing contrast of 2-back task with 0-back task in each experimental sleep condition. Warm colors (orange to yellow) reflect voxels that are more active during 2-back than the control task, with a threshold of T > 3; Cool colors (blue) reflect relative deactivation during 2-back, T < -3. Slices shown are at -19, -15, -11, -3, +9, +11, +13, +15, +23, +37, +43, and +45 mm.

Figure 3

Histograms reflecting results of the bootstrap resampling procedure across experimental sleep conditions. The panel on the left illustrates the greater activation in the task positive ROI during the Sleep Restriction (SR) condition than during the Healthy Sleep Duration (HD) condition. The panel on the right illustrates the greater deactivation in the task negative ROI during the SR condition than during the HD condition.