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Source localization of sensorimotor gating in schizophrenia: a combined fMRI and EEG study

Projekt: Typer af projekterProjekt

  1. Source localization of sensory gating: a combined EEG and fMRI study in healthy volunteers

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  1. Det Danske ECT/MRI projekt

    Projekt: Typer af projekterProjekt

  • Bak, Nikolaj, Psykiatrisk Center Glostrup, Danmark (Projektdeltager)
  • Birte Yding Glenthøj (Projektleder, organisatorisk)
  • Bob Oranje (Projektleder, faglig)
  • Rostrup, Egill (Projektleder, faglig)
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The ability to successfully inhibit responses to incoming sensory information is an important feature of a healthy individual. Following extensive observation of changes in perceptual awareness in patients with schizophrenia, McGhie and Chapman (1961) postulated that an organism needs an internal mechanism to
select from diverse sensory input the information that is needed to allow it to function efficiently, a process which has come to be termed sensory gating. Patients with schizophrenia show deficits in gating which subsequently
might lead to a state of flooding of higher brain functions (McGhie and Chapman 1961) and, ultimately,to the formation of psychoses (Freedman et al. 1991). In the P50 suppression paradigm, two identical auditory stimuli are presented in close temporal proximity to each other (usually 500 ms), in a conditiontest
paradigm. In healthy subjects, the amplitude of the P50 evoked potential to the first, or conditioning stimulus is larger than the response to the second, or testing stimulus. P50 suppression is a measure of sensory gating Adler et al (1982) found that (unmedicated) patients with schizophrenia exhibited less P50
suppression than healthy control subjects, a finding that has been replicated in numerous subsequent studies (e.g.: Nagamoto et al. 1989). There are relatively few human studies in which the sources of P50 suppression have been investigated. Using source localization in an electrophysiological setting, an initial study resulted in a three source model for sensory gating (Oranje et al. 2006). In the current study we want to validate the results of the initial study, by combining fMRI and EEG technology, which will be done in close collaboration with prof. Henrik Larsson and his research group, located at Glostrup hospital. Since a standard approach to P50 suppression, in which high and low intensity auditory stimuli are used, is not optimal in an fMRI setting (due to the frequent loud noises during MRI assessment), a specially for fMRI settings developed
variant of a P50 paradigm will be used (Oranje 2007). Instead of the low-intensity auditory stimuli, we use mild electrical stimuli, applied to the subjects forearm. These mild electrical stimuli have been used successfully
in our laboratory to assess sensory gating in healthy volunteers (Oranje 2007). The model will first be validated in 20 healthy controls, after which both chronic (N=20) and antipsychotic naïve first-episode patients (N=20) with schizophrenia will be investigated.
FinansieringskildeForskningsråd (Offentlig)
ForskningsprogramGlobaliseringspuljen/PHD skolen samfin. phd/Psyk. Center Glostrup
Beløb525.000,00 Danske Kroner
FinansieringskildePrivat fond (Privat)
Beløb800.000,00 Danske Kroner

ID: 32195253