title: Cortical response variation with different sound pressure levels: a combined event-related potentials and FMRI study.
abstract: BACKGROUND
  Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) provides high spatial and temporal resolution. In this study we combined EEG and fMRI to investigate the structures involved in the processing of different sound pressure levels (SPLs).
  
  
  METHODS
  EEG data were recorded simultaneously with fMRI from 16 healthy volunteers using MR compatible devices at 3 T. Tones with different SPLs were delivered to the volunteers and the N1/P2 amplitudes were included as covariates in the fMRI data analysis in order to compare the structures activated with high and low SPLs. Analysis of variance (ANOVA) and ROI analysis were also performed. Additionally, source localisation analysis was performed on the EEG data.
  
  
  RESULTS
  The integration of averaged ERP parameters into the fMRI analysis showed an extended map of areas exhibiting covariation with the BOLD signal related to the auditory stimuli. The ANOVA and ROI analyses also revealed additional brain areas other than the primary auditory cortex (PAC) which were active with the auditory stimulation at different SPLs. The source localisation analyses showed additional sources apart from the PAC which were active with the high SPLs.
  
  
  CONCLUSIONS
  The PAC and the insula play an important role in the processing of different SPLs. In the fMRI analysis, additional activation was found in the anterior cingulate cortex, opercular and orbito-frontal cortices with high SPLs. A strong response of the visual cortex was also found with the high SPLs, suggesting the presence of cross-modal effects.
authors.affiliation: Institute of Neuroscience and Medicine 4, INM 4, Forschungszentrum Jülich, Jülich, Germany; Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany; JARA - BRAIN - Translational Medicine, RWTH Aachen University, Aachen, Germany.
authors.forename: Irene
authors.initials: I
authors.lastname: Neuner
authors.affiliation: Centre of Social Psychiatry, Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry, Zurich, Switzerland.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Kawohl
authors.affiliation: Institute of Neuroscience and Medicine 4, INM 4, Forschungszentrum Jülich, Jülich, Germany; Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany.
authors.forename: Jorge
authors.initials: J
authors.lastname: Arrubla
authors.affiliation: Institute of Neuroscience and Medicine 4, INM 4, Forschungszentrum Jülich, Jülich, Germany.
authors.forename: Tracy
authors.initials: T
authors.lastname: Warbrick
authors.affiliation: Centre of Social Psychiatry, Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry, Zurich, Switzerland.
authors.forename: Konrad
authors.initials: K
authors.lastname: Hitz
authors.affiliation: Centre of Social Psychiatry, Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry, Zurich, Switzerland.
authors.forename: Christine
authors.initials: C
authors.lastname: Wyss
authors.affiliation: Institute of Neuroscience and Medicine 4, INM 4, Forschungszentrum Jülich, Jülich, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Boers
authors.affiliation: Institute of Neuroscience and Medicine 4, INM 4, Forschungszentrum Jülich, Jülich, Germany; JARA - BRAIN - Translational Medicine, RWTH Aachen University, Aachen, Germany; Department of Neurology, RWTH Aachen University, Aachen, Germany.
authors.forename: N Jon
authors.initials: NJ
authors.lastname: Shah
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000704:Analysis of Variance; D001307:Auditory Perception; D001931:Brain Mapping / Q000379:methods*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008032:Limbic System / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male