Neuromagnetic evidence of broader auditory cortical tuning in schizophrenia

Abstract

Deficits in basic auditory perception have been described in schizophrenia. Previous electrophysiological imaging research has documented a structure-function disassociation in the auditory system and altered tonotopic mapping in schizophrenia. The present study examined auditory cortical tuning in patients with schizophrenia.Eighteen patients with schizophrenia and 15 comparison subjects were recorded in a magnetoencephalographic (MEG) experiment of auditory tuning. Auditory cortical tuning at 1 kHz was examined by delivering 1 kHz pure tones in conjunction with pure tones at 5 frequencies surrounding and including 1 kHz. Source reconstruction data were examined for evidence of frequency specificity for the M100 component.There was a significant broadening of tuning in the schizophrenia group evident for the source amplitude of the M100. The frequently reported reduction in anterior-posterior source asymmetry for individuals with schizophrenia was replicated in this experiment. No relationships between symptom severity ratings and MEG measures were observed.This finding suggests that the frequency specificity of the M100 auditory evoked field is disturbed in schizophrenia, and may help explain the relatively poor behavioral performance of schizophrenia patients on simple frequency discrimination tasks. KeywordsMagnetoencephalography; Evoked Potentials; Auditory Cortex; Mental Illness; N100; M100 Corresponding Author: Donald C. Rojas, Ph.D. Box C268−68 CPH Rm 2J10 4200 E. 9th Avenue Denver, CO 80262 Phone: (303) 315 −8624 FAX: (303) 315−5641 email: Don.Rojas@uchsc.edu. Contributors D.C.R designed the study, performed the statistical analysis and wrote the manuscript. E.S. contributed data analyses and preliminary statistical analyses. P.D.T. contributed to the design of the experiment and selection of data analytic strategies and M.L.R. had substantial input on clinical aspects of the design, including selection and implementation of schizophrenia diagnostic and clinical measures appearing in the paper. All authors have contributed to and approved the final manuscript.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Conflict of InterestAll authors declare that they have no conflicts of interest with respect to this manuscript. NIH Public Access IntroductionThe M100 auditory evoked field has been reported to show anomalous anterior-posteior source location asymmetry in actively psychotic patients with paranoid schizophrenia. In normal adults, the neuroanatomical source of the M100 component is further anterior in the right hemisphere (Baumann et al., 1991). We and ...

Preliminary evidence for reduced auditory lateral suppression in schizophrenia

“…The finding that lateral suppression of auditory ERPs is reduced in SZ is consistent with previous studies showing less suppression of auditory responses in SZ after repeated clicks or tones (Boutros et al, 2004; Clementz et al, 1998; Olincy and Martin, 2005; Rojas et al, 2007), and studies showing reduced suppression of responses to self-produced speech in auditory cortex of those with SZ (Ford and Mathalon, 2005; Ford et al, 2001). However, the current study is among the first to our knowledge (also see Rojas et al, 2007) showing that lateral suppression in particular is impaired in SZ, which is an important finding because lateral suppression is likely to be a neurophysiological capability that is vital for more precise coding of auditory features (Chen and Jen, 2000; Wang et al, 2002).…”

“…However, the current study is among the first to our knowledge (also see Rojas et al, 2007) showing that lateral suppression in particular is impaired in SZ, which is an important finding because lateral suppression is likely to be a neurophysiological capability that is vital for more precise coding of auditory features (Chen and Jen, 2000; Wang et al, 2002). The finding of impaired P2 lateral suppression in particular could be related to the fact that P2 is particularly involved in processing spectral information in healthy individuals (Shahin et al, 2005; Shahin et al, 2007; Snyder et al, 2006; Snyder et al, 2009).…”

“…Many previous studies showed less reduction of auditory responses when tones and clicks are repeated in SZ, relatives of those with SZ, and in bipolar disorder (Boutros et al, 2004; Clementz et al, 1998; Olincy and Martin, 2005; Rojas et al, 2007). However, these prior studies have not separately measured lateral and recurrent suppression because the repeated stimuli have been identical in frequency content.…”

“…However, these prior studies have not separately measured lateral and recurrent suppression because the repeated stimuli have been identical in frequency content. One magnetoencephalography (MEG) study did show that alternation of tones with different frequencies resulted in less suppression of the N1 response in SZ (Rojas et al, 2007), consistent with a lateral suppression deficit.…”

“…Previous studies using this type of paradigm reported lateral and recurrent suppression of the N1 response, an index of auditory sensory memory and pitch processing (Lu et al, 1992; Näätänen & Winkler, 1999; Pantev et al, 1989) that we expect to show suppression deficits in lateral suppression (cf. Rojas et al, 2007). However, it is also possible other components such as P2 will show suppression deficits in SZ because prior MEG studies only reported findings for N1, but the P2 is an index of spectral processing and therefore might also reflect frequency-dependent suppression (Shahin et al, 2005; Shahin et al, 2007; Snyder et al, 2006; Snyder et al, 2009).…”