title: Somatosensory timing deficits in schizophrenia.
abstract: Schizophrenia is often accompanied by disturbances in motor behavior thought to result from abnormalities in the brain's timing mechanisms. Virtually all behavior has a motor component, and proper regulation of motor behavior is often dependent upon accurate registration of somatosensory input. This study uses the steady-state evoked response (SSR) to quantify the accuracy of timing of the neocortical response to rapidly presented tactile somatosensory stimuli in patients with schizophrenia compared to control subjects. We used magnetic evoked fields and source space projection to estimate the time course of equivalent current sources in somatosensory cortex. Wavelet-based time-frequency analysis was used to compute intertrial timing consistency and amplitudes. SSRs in schizophrenic subjects demonstrated decreased performance in both metrics to contralateral 25-Hz tactile stimulation. Previous studies have reported similar abnormalities in the SSR in both auditory and visual domains. The magnetic SSR to tactile stimuli is thought to reflect activation of layer 3 pyramidal cells in primary sensory cortex. Thus, these findings, as in other sensory domains, are suggestive of impaired GABAergic inhibitory interneuronal control of the timing of pyramidal cell activity. This deficit may be intrinsic to neocortex, or might reflect as well impairment of cerebellar and/or thalamic involvement. These findings reinforce the notion that abnormalities in the brain's timing mechanisms are a central component of the schizophrenia syndrome.
authors.affiliation: University of Colorado, School of Medicine, Aurora, CO 80045, United States. peter.teale@ucdenver.edu
authors.forename: Peter
authors.initials: P
authors.lastname: Teale
authors.forename: Bryce
authors.initials: B
authors.lastname: Pasko
authors.forename: Dan
authors.initials: D
authors.lastname: Collins
authors.forename: Donald
authors.initials: D
authors.lastname: Rojas
authors.forename: Martin
authors.initials: M
authors.lastname: Reite
mesh_terms: D000328:Adult; D001931:Brain Mapping; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D010468:Perceptual Disorders / Q000209:etiology*; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000150:complications*; D013998:Time Perception / Q000502:physiology*; D014110:Touch / Q000502:physiology