title: Effect of fMRI acoustic noise on non-auditory working memory task: comparison between continuous and pulsed sound emitting EPI.
abstract: Conventional blood oxygenation level-dependent (BOLD) based functional magnetic resonance imaging (fMRI) is accompanied by substantial acoustic gradient noise. This noise can influence the performance as well as neuronal activations. Conventional fMRI typically has a pulsed noise component, which is a particularly efficient auditory stimulus. We investigated whether the elimination of this pulsed noise component in a recent modification of continuous-sound fMRI modifies neuronal activations in a cognitively demanding non-auditory working memory task. Sixteen normal subjects performed a letter variant n-back task. Brain activity and psychomotor performance was examined during fMRI with continuous-sound fMRI and conventional fMRI. We found greater BOLD responses in bilateral medial frontal gyrus, left middle frontal gyrus, left middle temporal gyrus, left hippocampus, right superior frontal gyrus, right precuneus and right cingulate gyrus with continuous-sound compared to conventional fMRI. Conversely, BOLD responses were greater in bilateral cingulate gyrus, left middle and superior frontal gyrus and right lingual gyrus with conventional compared to continuous-sound fMRI. There were no differences in psychomotor performance between both scanning protocols. Although behavioral performance was not affected, acoustic gradient noise interferes with neuronal activations in non-auditory cognitive tasks and represents a putative systematic confound.
authors.affiliation: Institute of Neuroradiology, Department of Medical Radiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. shaller@uhbs.ch
authors.forename: Sven
authors.initials: S
authors.lastname: Haller
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Bartsch
authors.forename: Ernst W
authors.initials: EW
authors.lastname: Radue
authors.forename: Markus
authors.initials: M
authors.lastname: Klarhöfer
authors.forename: Erich
authors.initials: E
authors.lastname: Seifritz
authors.forename: Klaus
authors.initials: K
authors.lastname: Scheffler
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D016477:Artifacts; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006309:Hearing / Q000502:physiology; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008568:Memory / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013269:Stochastic Processes