Dysregulation within the Prefronto-Parietal Background-Monitoring Network in Schizophrenia

Abstract

Schizophrenia patients have difficulties in focusing their attention, when distracting information must be ignored. Although it is adaptive in some situations to monitor the background for potentially relevant changes to a certain degree, voluntary attentional processes seem to be more severely disrupted by distracting information in schizophrenia patients compared to healthy controls. Reorienting processes associated with the detection of potentially relevant information outside the current focus of attention have previously shown to activate a bilateral prefronto-parietal network. The aim of the current study was to investigate whether this network is dysregulated in schizophrenia patients using fMRI during the performance in a combined oddball-incongruence task, in which relevant processing must be shielded from distracting irrelevant salient or conflicting information. During the occurrence of both oddballs and incongruence patients exhibited an increased activation of the intraparietal cortex-a saliency sensitive part of the prefronto-parietal network associated with background-monitoring. As this hyperactivation was accompanied by an increased activation in the dopaminergic midbrain, the results of our study link the finding of a hyperactive salience sensitive cortical region to the finding of the hyperdopaminergic state in schizophrenia, supporting the predominant view of psychosis as a

Cortical activation abnormalities in bipolar and schizophrenia patients in a combined oddball–incongruence paradigm

“…Bipolar patients presented enhanced activation in the intraparietal cortex bilaterally compared to healthy controls and schizophrenia patients. In addition, and in line with previous results from Wolter et al [ 19 ], hyperactivation in the right intraparietal cortex of schizophrenia patients compared to healthy controls could be replicated.…”

“…Subjects were trained on the combined oddball–incongruence paradigm (described in [ 4 , 19 ]) prior to being scanned and later performed the task inside a 3 T Siemens TrioTim scanner. First, all participants were instructed to categorize geometric objects by their respective shape or color via a button press as fast and as accurately as possible.…”

“…For instance, Wolter et al . [ 19 ] have shown that in the same combined oddball–incongruence task, schizophrenia patients demonstrated hyperactivity in the intraparietal cortex during the oddball and incongruence task. Furthermore, there are multiple fMRI studies investigating cognitive control processes in schizophrenia or bipolar patients compared to healthy controls.…”

“…In the present study, a combined oddball–incongruence paradigm [ 4 , 19 ] was employed to investigate the potential differences in cognitive control processes of bipolar disorder and schizophrenia patients. By comparing behavioral and fMRI data of both diagnoses and healthy individuals, it was aimed to gain a deeper understanding of the pathophysiology of bipolar disorder and schizophrenia.…”

Testing the expanded continuum hypothesis of schizophrenia and bipolar disorder. Neural and psychological evidence for shared and distinct mechanisms

“…The parietal impairments of this network, instead, could result in abnormalities in higher cognitive processes that can create abnormal perceptions of reality, such as multimodal integration in heteromodal cortices (Andreasen, 1997; Arzy et al, 2006), aberrant saliency of stimuli in the intraparietal cortex (Wolter et al, 2016), and dysfunctional representation and consciousness of self-related concepts (Torrey, 2007). Indeed, inferior parietal and nearby areas also mediate one's intentions together with the feeling of being the agent of the movement (Ffytche and Wible, 2014; Desmurget et al, 2009).…”