The effects of partial sleep deprivation on response inhibition studied by combined functional MRI and EEG

The ability to suppress inadequate responses is an important executive control mechanism in order to meet environmental demands. Such inhibitory actions rely on frontal lobe and anterior cingulate cortex functions, areas that are associated with altered cortical functioning after sleep deprivation. We therefore investigate how the BOLD and neurophysiological responses to an inhibition task change after sleep deprivation (SD). We applied combined fMRI/EEG measurements so far on 13 young healthy subjects before and after partial sleep deprivation. Subjects performed a stop signal task that requires speeded responses to a visual stimulus, but inhibition of responses when an additional acoustic stop signal is given (33% of trials). Latency to the „Stop“ signal was adjusted to maintain a constant error rate of 50%. Correctly performed „Stop“ trials were compared to correct „Go“ trials, and were compared across conditions (SPM 5, random effects analysis). After sleep, successful inhibition elicited robust activation in a task-specific network as published previously. Following SD, right inferior prefrontal activation was enhanced, and additional clusters of activation were detected in further frontal and anterior cingulate structures. In conclusion, loss of sleep leads to recruitment of neural activation in areas that are usually not elicited by this inhibition task. Further analysis of evoked potentials and behavioural data is being performed.