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Title: FMRI Study of Effects of Sleep Deprivation on Attentional Capacity
Keywords: fMRI, sleep deprivation, capacity, attention, visual, PPA
Issue Date: 11-Oct-2012
Citation: KONG DANYANG (2012-10-11). FMRI Study of Effects of Sleep Deprivation on Attentional Capacity. ScholarBank@NUS Repository.
Abstract: While our brain is extremely sophisticated at processing incoming information, it is generally safe to posit that all processing stages, from sensory processing to high level cognitive control functions and decision making, are capacity limited. These limitations show state related alterations an example of which is sleep deprivation (SD). Previous studies investigating deficits in various cognitive domains have found sleep deprivation to attenuate task-related parietal and extrastriate visual activation, suggesting a reduction of processing capacity in this state. However, how different aspects of attentional capacity limitation are worsened following sleep deprivation has not well characterized. Using functional brain imaging coupled with a variety of behavioral tasks, my work shows the exacerbation of visual processing limitations at multiple sites (visual areas as well as attentional control regions) in the processing stages following sleep deprivation. I first evaluated directly the SD-induced change in visual processing capacity by employing Lavie?s perceptual load theory of attention as a framework. Repetition suppression in parahippocampal place areas (PPA) was used to indicate processing of unattended scenes while participants attended to faces embedded in face-scene pictures. Attenuated repetition suppression effect following sleep deprivation indicated a reduction in total visual processing capacity following sleep deprivation. Using rapid serial visual presentation (RSVP) paradigm of houses presented at various presentation frequencies, I next showed that temporal processing limitation was exacerbated following sleep deprivation, evidenced by worsened performance and reduced activation across multiple cortical areas. Particularly, the temporal processing in higher visual areas, in this case the parahippocampal place area, were more severely affected by sleep deprivation, showing greater sensitivity to slower presentation rates. Selective attention itself as a resource allocator is also capacity limited and impairment in this function leads to performance decrement. The remainder of the dissertation focused on how sleep deprivation adversely impairs sub components of selective attention, namely target enhancement and distractor suppression. Participants attended to, passively viewed or ignored house images in superimposed face-house pictures. MR signal enhancement or suppression in PPA was evaluated relative to passive viewing. Following sleep deprivation, selective attention as a resource allocator only preserved its ability to enhance target processing, while the ability to suppress distractor was significantly impaired. This research demonstrates that sleep deprivation exacerbates limitations at multiple processing stages, resulting in poor behavioral performance and slower responses.
Appears in Collections:Ph.D Theses (Open)

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