Fronto-parietal and cingulo-opercular network integrity and cognition in health and schizophrenia

Abstract

Growing evidence suggests that coordinated activity within specific functional brain networks supports cognitive ability, and that abnormalities in brain connectivity may underlie cognitive deficits observed in neuropsychiatric diseases, such as schizophrenia. Two functional networks, the fronto-parietal network (FPN) and cingulo-opercular network (CON), are hypothesized to support top-down control of executive functioning, and have therefore emerged as potential drivers of cognitive impairment in disease-states. Graph theoretic analyses of functional connectivity data can characterize network topology, allowing the relationships between cognitive ability and network integrity to be examined. In the current study we applied graph analysis to pseudo-resting state data in 54 healthy subjects and 46 schizophrenia patients, and measured overall cognitive ability as the shared variance in performance from tasks of episodic memory, verbal memory, processing speed, goal maintenance, and visual integration. We found that, across all participants, cognitive ability was significantly positively associated with the local and global efficiency of the whole brain, FPN, and CON, but not with the efficiency of a comparison network, the auditory network. Additionally, the participation coefficient of the right anterior insula, a major hub within the CON, significantly predicted cognition, and this relationship was independent of CON global efficiency. Surprisingly, we did not observe strong evidence for group differences in any of our network metrics. These data suggest that functionally efficient task control networks support better cognitive ability in both health and schizophrenia, and that the right anterior insula may be a particularly important hub for successful cognitive performance across both health and disease.

Neuroimaging tests for clinical psychiatry: Are we there yet?

“…20 Individual differences in network efficiency covaried with cognitive function, with the cortical and the subcortical networks making statistically independent contributions. These findings replicate observations made in 2 separate smaller samples 21,22 and were presaged by similar findings from independent researchers.…”

“…1,32 For example, Drysdale and colleagues 10 replicated the anxietyinsomnia-related depression biotype in patients with diagnoses of generalized anxiety disorder. The studies by Sheffield and colleagues [20][21][22] found the same psychosis-related connectivity patterns, irrespective of whether the patient's formal diagnosis was schizophrenia, schizoaffective disorder, or a bipolar mood disorder. Mary Phillips' research group reports that, in patients with bipolar depression, emotional dysregulation is associated with disturbed connectivity in the limbic circuitry implicated in negative mood states; 9 high sensation-seeking youth exhibit frontostriatal connectivity alterations across diagnoses.…”

Cingulo-opercular Network Efficiency Mediates the Association Between Psychotic-like Experiences and Cognitive Ability in the General Population

“…Global efficiency also appears to be a predictive measure, as global efficiency of the whole brain graph has been shown to be decreased in individuals with subclinical psychotic experiences (26), as well as in schizophrenia (27), and correlates with positive symptoms (28) and IQ (29). Although some studies have shown increased whole brain global efficiency in the context of psychosis (30, 31), previous work from our group looking at specific functional networks (CON and FPN) – taking into account the connectivity of only the nodes within that network -- have revealed associations between reduced global efficiency of these specific networks and decreased cognitive ability (32). Therefore, based on these studies, as well as consistently observed abnormalities in DMN connectivity in psychotic disorders (e.g.…”

“…This hypothesis was based on previous literature showing that greater PLEs (2, 7) and lower network efficiency (32) are associated with lower cognitive ability – associations we hoped to replicate and extend to the general population, in order to test the psychosis continuum model. Additionally, we hypothesized that efficiency of these networks would mediate the relationship between psychosis and cognitive ability, suggesting a shared mechanism between these two phenotypes.…”

Cortical contributions to impaired contour integration in schizophrenia

“…It should be noted that the lack of greater activation for the CON versus SCZ group is unlikely to be an artifact, as greater activation in CON than SCZ was seen during working and relational memory paradigms that were completed during the same scanning session (Ragland et al, in Press; Sheffield et al, 2015). However, a fuller exploration of the effects of higher level visual processing on JOVI performance was precluded by the lack of sufficient data for analysis of activity in bilateral IFG pars triangularis and parietal angular gyrus, as described in Footnote 1.…”