Article

Superior temporal gyrus spectral abnormalities in schizophrenia.

Department of Psychology, Beckman Institute Biomedical Imaging Center, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Psychophysiology (Impact Factor: 3.18). 08/2008; 45(5):812-24. DOI: 10.1111/j.1469-8986.2008.00682.x
Source: PubMed

ABSTRACT Considerable evidence indicates early auditory stimulus processing abnormalities in schizophrenia, but the mechanisms are unclear. The present study examined oscillatory phenomena during a paired-click paradigm in the superior temporal gyrus (STG) as a possible core problem. The primary question addressed is whether first click and/or second click group differences in the time-domain evoked response in patients with schizophrenia are due to (1) group differences in the magnitude of poststimulus oscillatory activity, (2) group differences in poststimulus phase-locking, and/or (3) group differences in the magnitude of ongoing background oscillatory activity. Dense-array magnetoencephalography from 45 controls and 45 patients with schizophrenia produced left- and right-hemisphere STG 50- and 100-ms time-frequency evoked, phase-locking, and total power measures. Whereas first click 100-ms evoked theta and alpha abnormalities were observed bilaterally, evoked low beta-band differences were specific to the left hemisphere. Compared to controls, patients with schizophrenia showed more low-frequency phase variability, and the decreased 100-ms S1 evoked response observed in patients was best predicted by the STG phase-locking measure.

0 Bookmarks
 · 
125 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Symptoms of schizophrenia are related to deficits in self-monitoring function, which may be a consequence of irregularity in aspects of the default mode network (DMN). Schizophrenia can also be characterized by a functional abnormality of the brain activity that is reflected in the resting state. Oscillatory analysis provides an important understanding of resting brain activity. However, conventional methods using electroencephalography are restricted because of low spatial resolution, despite their excellent temporal resolution.The aim of this study was to investigate resting brain oscillation and the default mode network based on a source space in various frequency bands such as theta, alpha, beta, and gamma using magnetoencephalography. In addition, we investigated whether these resting and DMN activities could distinguish schizophrenia patients from normal controls. To do this, the power spectral density of each frequency band at rest was imaged and compared on a spatially normalized brain template in 20 patients and 20 controls.
    BMC Neuroscience 09/2014; 15(1):104. · 2.85 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Evoked and induced event-related neural oscillations have recently been proposed as a key mechanism supporting higher-order cognition. Cognitive decay and abnormal electromagnetic sensory gating reliably distinguish schizophrenia (SZ) patients and healthy individuals, demonstrated in chronic (CHR) and first-admission (FA) patients. Not yet determined is whether altered event-related modulation of oscillatory activity is manifested at early stages of SZ, thus reflects and perhaps embodies the development of psychopathology, and provides a mechanism for the gating deficit. The present study compared behavioral and functional brain measures in CHR and FA samples. Cognitive test performance (MATRICS Consortium Cognitive Battery, MCCB), neuromagnetic event-related fields (M50 gating ratio), and oscillatory dynamics (evoked and induced modulation of 8-12Hz alpha) during a paired-click task were assessed in 35 CHR and 31 FA patients meeting the criteria for ICD-10 diagnoses of schizophrenia as well as 28 healthy comparison subjects (HC). Both patient groups displayed poorer cognitive performance, higher M50 ratio (poorer sensory gating), and less induced modulation of alpha activity than did HC. Induced alpha power decrease in bilateral posterior regions varied with M50 ratio in HC but not SZ, whereas orbitofrontal alpha power decrease was related to M50 ratio in SZ but not HC. Results suggest disruption of oscillatory dynamics at early stages of illness, which may contribute to deficient information sampling, memory updating, and higher cognitive functioning.
    Schizophrenia Research 06/2014; · 4.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background Understanding how cerebral regions are synchronized when hearing illusions might help to explain some of the mechanisms of hallucination in psychiatric disorders. EEG theta coherence in response to the octave illusion in healthy volunteers might be used for this purpose. Methods Right-handed healthy volunteers were invited to hear silence, normal and reversed sequences of the octave illusion. Results After hearing both normal and reversed sequences of the octave illusion, 11 people reported hearing the high tone in the left ear (RL) and 18 in the right (RR). The task-related power change in the right frontal and temporal areas and the task-related coherence difference in the right medial frontal and temporal areas were significantly increased in the RR group compared to the RL group. Conclusion When processing the octave illusion, the right ear predominance was linked to a higher reactivity in the right frontal and right temporal areas in healthy right-handers.
    Translational Neuroscience. 03/2014; 5(1):25-34.

Full-text (2 Sources)

Download
56 Downloads
Available from
May 27, 2014