Learn More
INTRODUCTION The failure of integrative brain function is a fundamental characteristic of schizophrenia. Synchronous Gamma (40 Hz) activity, proposed as a candidate mechanism underlying the integration ("binding") of distributed brain activities, may provide a direct window into schizophrenic disintegration. METHODS 40 schizophrenia and 40(More)
Widespread synchronous oscillatory activity, particularly in the gamma ('40 Hz') band, has been postulated to exist in the brain as a mechanism underlying binding. A new method of examining phase synchronicity across multiple electrode sites in specific EEG frequency bands as a function of time was employed, in a conventional cognitive ERP paradigm in 40(More)
OBJECTIVES Gamma ('40 Hz') rhythms may play a role in the integration of sensory processing activity. Impaired temporal integration may be a key feature of the associated disturbances in schizophrenia. This is the first study to examine the time course of Gamma activity induced in response to stimuli in this disorder. METHODS Gamma activity induced in(More)
OBJECTIVE To determine whether a relationship existed across trials between evoked gamma and reaction time in a conventional cognitive ERP paradigm. METHODS Auditory oddball data in 40 normal subjects was examined. A moving Welch window and short time FFT were employed to elucidate the time course of gamma (29 to 45 Hz) activity in each single-trial(More)
Examination of the single trials which are traditionally averaged to form late-component ERPs reveals a number of different sub-types of response. This study introduces an automated and robust approach to objectively classify these ERP sub-types. Auditory oddball ERP (target tones) data were examined in 25 normal subjects. Globally optimal vector(More)
OBJECTIVE There has been consistent evidence for a lower incidence and milder course of schizophrenia in women, yet there have been very few investigations of sex differences in brain function in this disorder. This study used a new high-temporal-resolution measure of functional brain connectivity to test the prediction that female patients would show(More)
The influence of the level of prestimulus alpha phase synchronicity on the N100 component and reaction time (RT) was examined, in target auditory oddball data from 25 normal subjects. Alpha phase synchronicity is a new measure consisting (for a given stimulus presentation) of the angular or circular variance of the alpha phase at stimulus onset across the(More)
Analysis of the relationship between prestimulus EEG alpha phase and the subsequent ERP has proved difficult because of the non-Euclidean nature of phase measurements. In this study, we employed a conventional P3 templating method of single-trial analysis to identify the P3 component in target auditory oddball data from 25 normals. As in previous studies,(More)
OBJECTIVES Frontal and lateralized schizophrenia disturbances were examined in terms of arousal-modulated changes in 40 Hz Gamma activity. METHODS Forty patients with schizophrenia and 40 age- and gender-matched controls were studied in a conventional auditory ERP oddball paradigm. We investigated sub-averaged Gamma activity based upon a simultaneous(More)
We dispute McCarthy and Wood's (1985) claim that some form of scaling should be applied routinely to ERP data before determining differences in scalp distributions between conditions (or groups). Their simulation study involved assumptions about the nature of the variability within each condition, most significantly that the standard deviations are(More)