Time dynamics of stimulus- and event-related gamma band activity: contrast-VEPs and the visual P300 in man

Phase/amplitude reset and theta–gamma interaction in the human medial temporal lobe during a continuous word recognition memory task

“…In theory, ERP components can result from either a stimulus-evoked increase in EEG power or from increased phase clustering of ongoing oscillatory EEG activity, i.e., a stimulus-related concentration of phases (e.g., Basar et al, 1984;Demiralp et al, 1998;Yordanova and Kolev, 1998;Sannita et al, 2001;Penny et al, 2002;Shah et al, 2004;Duzel et al, in press;Gruber et al, 2005). Stimulus-evoked power changes are thought to correspond to the event-related activation of a neural assembly distinct from ongoing background dynamics that are present in each trial and, after averaging, produce the ERP.…”

Occipital gamma response to auditory stimulation in patients with schizophrenia

“…Gamma synchrony is suggested to be a central building block within frameworks regarding mechanism for the integration or binding of brain functions across diverse networks, providing a temporal coherence to perception and actions (Basar et al, 1980(Basar et al, , 2010aKaiser et al, 2004;Sannita et al, 2001;Singer and Gray, 1995;Tallon-Baudry et al, 1997;Varela et al, 2001). Therefore, most studies related to schizophrenia focus on disturbances in gamma oscillations, particularly on reduced gamma synchrony or the magnitude of evoked gamma responses in schizophrenia (Haenschel et al, 2007;Haig et al, 2000;Herrmann and Demiralp, 2005;Lee et al, 2003;Schnitzler and Gross, 2005;Spencer et al, 2003Spencer et al, , 2004.…”

Are oscillatory brain responses generally reduced in schizophrenia during long sustained attentional processing?

“…The electrophysiological findings suggest abnormal temporal integration of brain networks as a core disturbance in schizophrenia (Andreasen et al, 1999;Lee et al, 2003), especially as reflected by functional gamma activity (BasarEroglu et al, 2007;Gallinat et al, 2004;Haig et al, 2000;Herrmann and Demiralp, 2005;Spencer et al, 2003Spencer et al, , 2004. These processes may reflect deficits in the neural mechanism underlying the integration or binding of brain functions across diverse networks that provide a temporal coherence to perceptions and actions Haig et al, 2000;Herrmann and Demiralp, 2005;Kaiser et al, 2004;Sannita et al, 2001;Singer and Gray, 1995;Tallon-Baudry et al, 1996;Varela et al, 2001). Consonant with the cognitive dysmetria model of schizophrenia not only are decreased frequency magnitude but also decreased phase synchrony observed, which appear to index binding errors in the integration of cognitive activities across variegated brain regions (Haig et al, 2000;Lee et al, 2003;van der Stelt and Belger, 2007).…”