title: Differential Effects of Lowered Arousal on Covert and Overt Shifts of Attention.
abstract: Based on previous studies demonstrating detrimental effects of reduced alertness on attentional orienting our study seeks to examine covert and overt attentional orienting in different arousal states. We hypothesized an attentional asymmetry with increasing reaction times to stimuli presented to the left visual field in a state of maximally reduced arousal. Eleven healthy participants underwent sleep deprivation and were examined repeatedly every 4 hr over 28 hr in total with two tasks measuring covert and overt orienting of attention. Contrary to our hypothesis, a reduction of arousal did not induce any asymmetry of overt orienting. Even in participants with profound and significant attentional asymmetries in covert orienting no substantial reaction time differences between left- and right-sided targets in the overt orienting task could be observed. This result is not in agreement with assumptions of a tight coupling of covert and overt attentional processes. In conclusion, we found differential effects of lowered arousal induced by sleep deprivation on covert and overt orienting of attention. This pattern of results points to a neuronal non-overlap of brain structures subserving these functions and a differential influence of the norepinephrine system on these modes of spatial attention.
authors.affiliation: 1RWTH Aachen University,Department of Neurology,Section Neuropsychology,Aachen.
authors.forename: Bruno
authors.initials: B
authors.lastname: Fimm
authors.affiliation: 1RWTH Aachen University,Department of Neurology,Section Neuropsychology,Aachen.
authors.forename: Klaus
authors.initials: K
authors.lastname: Willmes
authors.affiliation: 2RWTH Aachen University,Institute of Psychology,Aachen.
authors.forename: Will
authors.initials: W
authors.lastname: Spijkers
mesh_terms: D000328:Adult; D001143:Arousal; D001288:Attention; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance; D011930:Reaction Time; D012892:Sleep Deprivation / Q000523:psychology
keywords: Arousal; Attention; Norepinephrine; Reaction time; Sensory neglect; Sleep deprivation