title: Temporal pattern of acoustic imaging noise asymmetrically modulates activation in the auditory cortex.
abstract: This study investigated the hemisphere-specific effects of the temporal pattern of imaging related acoustic noise on auditory cortex activation. Hemodynamic responses (HDRs) to five temporal patterns of imaging noise corresponding to noise generated by unique combinations of imaging volume and effective repetition time (TR), were obtained using a stroboscopic event-related paradigm with extra-long (≥27.5 s) TR to minimize inter-acquisition effects. In addition to confirmation that fMRI responses in auditory cortex do not behave in a linear manner, temporal patterns of imaging noise were found to modulate both the shape and spatial extent of hemodynamic responses, with classically non-auditory areas exhibiting responses to longer duration noise conditions. Hemispheric analysis revealed the right primary auditory cortex to be more sensitive than the left to the presence of imaging related acoustic noise. Right primary auditory cortex responses were significantly larger during all the conditions. This asymmetry of response to imaging related acoustic noise could lead to different baseline activation levels during acquisition schemes using short TR, inducing an observed asymmetry in the responses to an intended acoustic stimulus through limitations of dynamic range, rather than due to differences in neuronal processing of the stimulus. These results emphasize the importance of accounting for the temporal pattern of the acoustic noise when comparing findings across different fMRI studies, especially those involving acoustic stimulation.
authors.affiliation: Department of Electrical & Electronic Engineering, University of Peradeniya, Peradeniya, Sri Lanka; School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA. Electronic address: rdbranaweera@ee.pdn.ac.lk.
authors.forename: Ruwan D
authors.initials: RD
authors.lastname: Ranaweera
authors.affiliation: School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Minseok
authors.initials: M
authors.lastname: Kwon
authors.affiliation: School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Shuowen
authors.initials: S
authors.lastname: Hu
authors.affiliation: School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Gregory G
authors.initials: GG
authors.lastname: Tamer
authors.affiliation: Cornell MRI Facility, Cornell University, Ithaca, NY, USA.
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Luh
authors.affiliation: School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Talavage
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000328:Adult; D016477:Artifacts; D001303:Auditory Cortex / Q000502:physiology*; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D006439:Hemodynamics; D006454:Hemoglobins / Q000737:chemistry; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009622:Noise; D013997:Time Factors; D055815:Young Adult
chemical_list: D006454:Hemoglobins; C100003:deoxyhemoglobin
keywords: Acoustic noise induced hemodynamic response; Asymmetric auditory response; Auditory fMRI; Imaging related acoustic noise; Primary auditory cortex