title: Towards neural correlates of auditory stimulus processing: a simultaneous auditory evoked potentials and functional magnetic resonance study using an odd-ball paradigm.
abstract: BACKGROUND
  The neural underpinnings of auditory information processing have often been investigated using the odd-ball paradigm, in which infrequent sounds (deviants) are presented within a regular train of frequent stimuli (standards). Traditionally, this paradigm has been applied using either high temporal resolution (EEG) or high spatial resolution (fMRI, PET). However, used separately, these techniques cannot provide information on both the location and time course of particular neural processes. The goal of this study was to investigate the neural correlates of auditory processes with a fine spatio-temporal resolution. A simultaneous auditory evoked potentials (AEP) and functional magnetic resonance imaging (fMRI) technique (AEP-fMRI), together with an odd-ball paradigm, were used.
  
  
  METHODS
  Six healthy volunteers, aged 20-35 years, participated in an odd-ball simultaneous AEP-fMRI experiment. AEP in response to acoustic stimuli were used to model bioelectric intracerebral generators, and electrophysiological results were integrated with fMRI data.
  
  
  RESULTS
  fMRI activation evoked by standard stimuli was found to occur mainly in the primary auditory cortex. Activity in these regions overlapped with intracerebral bioelectric sources (dipoles) of the N1 component. Dipoles of the N1/P2 complex in response to standard stimuli were also found in the auditory pathway between the thalamus and the auditory cortex. Deviant stimuli induced fMRI activity in the anterior cingulate gyrus, insula, and parietal lobes.
  
  
  CONCLUSIONS
  The present study showed that neural processes evoked by standard stimuli occur predominantly in subcortical and cortical structures of the auditory pathway. Deviants activate areas non-specific for auditory information processing.
authors.affiliation: World Hearing Center, Institute of Physiology and Pathology of Hearing, Warsaw/Kajetany, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Milner
authors.affiliation: World Hearing Center, Institute of Physiology and Pathology of Hearing, Warsaw/Kajetany, Poland.
authors.forename: Mateusz
authors.initials: M
authors.lastname: Rusiniak
authors.affiliation: World Hearing Center, Institute of Physiology and Pathology of Hearing, Warsaw/Kajetany, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Lewandowska
authors.affiliation: World Hearing Center, Institute of Physiology and Pathology of Hearing, Warsaw/Kajetany, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Wolak
authors.affiliation: World Hearing Center, Institute of Physiology and Pathology of Hearing, Warsaw/Kajetany, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Ganc
authors.affiliation: Nuclear and Medical Electronics Division, Institute of Radioelectronics, Warsaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Piątkowska-Janko
authors.affiliation: Nuclear and Medical Electronics Division, Institute of Radioelectronics, Warsaw, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Bogorodzki
authors.affiliation: World Hearing Center, Institute of Physiology and Pathology of Hearing, Warsaw/Kajetany, Poland.
authors.forename: Henryk
authors.initials: H
authors.lastname: Skarżyński
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male