Auditory P3a and P3b neural generators in schizophrenia: An adaptive sLORETA P300 localization approach

Abstract

The present study investigates the neural substrates underlying cognitive processing in schizophrenia (Sz) patients. To this end, an auditory 3-stimulus oddball paradigm was used to identify P3a and P3b components, elicited by rare-distractor and rare-target tones, respectively. Event-related potentials (ERP) were recorded from 31 Sz patients and 38 healthy controls. The P3a and P3b brain-source generators were identified by time-averaging of low-resolution brain electromagnetic tomography (LORETA) current density images. In contrast with the commonly used fixed window of interest (WOI), we proposed to apply an adaptive WOI, which takes into account subjects' P300 latency variability. Our results showed different P3a and P3b source activation patterns in both groups. P3b sources included frontal, parietal and limbic lobes, whereas P3a response generators were localized over bilateral frontal and superior temporal regions. These areas have been related to the discrimination of auditory stimulus and to the inhibition (P3a) or the initiation (P3b) of motor response in a cognitive task. In addition, differences in source localization between Sz and control groups were observed. Sz patients showed lower P3b source activity in bilateral frontal structures and the cingulate. P3a generators were less widespread for Sz patients than for controls in right superior, medial and middle frontal gyrus. Our findings suggest that target and distractor processing involves distinct attentional subsystems, both being altered in Sz. Hence, the study of neuroelectric brain information can provide further insights to understand cognitive processes and underlying mechanisms in Sz.

Relations between structural and EEG‐based graph metrics in healthy controls and schizophrenia patients

“…It is noteworthy that this filter was only applied to estimate the time window related to the EEG response. Thirdly, the maximum amplitude of the low‐pass filtered evoked wave in the Pz channel was located into a window ranging from 250 to 550 ms from the stimulus onset (Bachiller et al, ). The corresponding sample to the maximum amplitude was used as a central time sample of the response window.…”

Increasing objective cardiometabolic burden associated with attenuations in the P3b event-related potential component in older adults

“…In terms of neural generators, the P1 and N1 predominately relate to activity in visual cortex and ventral temporal areas, whereas the candidate regions contributing to the P3b include frontal, parietal and tempooccipital regions (e.g. Bachiller, et al, 2015;Volpe, et al, 2007) although the exact regions remain a topic of debate. Fawns-Ritchie, et al (2019) reported that frontal and temporal cortical thinning is associated with cardiometabolic burden in a large UK sample; other studies have reported more widespread cortical thinning (Brundel, van den Heuvel, de Bresser, Kappelle, & Biessels;Chen, et al, 2015;Last, et al, 2007;Leritz, et al, 2011;Veit, et al, 2014;Walsh, Shaw, Sachdev, Anstey, & Cherbuin, 2017).…”

Separation of P300 event-related potential using time varying time-lag blind source separation algorithm

“…The group of schizophrenic patients had average age of 33.30 with standard deviation (Std) 9.52. The patients were diagnosed according to DSM-IV [25] and they were receiving a variety of standard neuroleptics medications at the time of recording.…”

“…As far as cognitive impairment is often correlated with modifications in the P300, this wave can be used as a measure to evaluate the various treatments on cognitive functions. In this regard, researchers have suggested the use of P300 as a clinical marker and now a large body of clinical research in the brain function assessment has been devoted to extracting and characterizing the P300 [9].…”