Reduced Resting-State Connectivity in the Precuneus is correlated with Apathy in Patients with Schizophrenia

Abstract

A diagnosis of schizophrenia is associated with a heterogeneous psychopathology including positive and negative symptoms. The disconnection hypothesis, an early pathophysiological framework conceptualizes the diversity of symptoms as a result of disconnections in neural networks. in line with this hypothesis, previous neuroimaging studies of patients with schizophrenia reported alterations within the default mode network (DMN), the most prominent network at rest. The aim of the present study was to investigate the functional connectivity during rest in patients with schizophrenia and with healthy individuals and explore whether observed functional alterations are related to the psychopathology of patients. Therefore, functional magnetic resonance images at rest were recorded of 35 patients with schizophrenia and 41 healthy individuals. Independent component analysis (ICA) was used to extract resting state networks. comparing icA results between groups indicated alterations only within the network of the DMN. More explicitly, reduced connectivity in the precuneus was observed in patients with schizophrenia compared to healthy controls. connectivity in this area was negatively correlated with the severity of negative symptoms, more specifically with the domain of apathy. Taken together, the current results provide further evidence for a role DMN alterations might play in schizophrenia and especially in negative symptoms such as apathy.

Spindle-Shaped Neurons in the Human Posteromedial (Precuneus) Cortex

“…That is, primates have evolved cognitive mechanisms to understand and analyze complex social interactions ( Freiwald, 2020 ). Among the multiple cellular components with an intrinsic connectivity and functional networks in the human cerebral cortex (see further discussion in van den Heuvel et al, 2015 ), some large-scale circuits have been studied for their roles in resting state, attention and task-related activity or cognitive functions ( Ng et al, 2016 ; Deming and Koenigs, 2020 ; Forlim et al, 2020 ; Kolb and Whishaw, 2021 ). High signal coherence within these networks makes the sub-components functionally coupled along varied timeframes ( Ng et al, 2016 and references therein), such as in the DMN, which comprises the PC ( Cavanna and Trimble, 2006 ) and the posterior cingulate cortex, the medial prefrontal cortex, and the bilateral intraparietal cortex/angular gyrus; in the “salience network” (SN), including the bilateral anterior insula and the dorsal ACC; and, in the “executive control network” (ECN) including the “frontoparietal network” (FPN) composed of bilateral middle frontal gyri and supramarginal gyri/inferior parietal lobe ( Hidalgo-Lopez et al, 2021 and references therein), the intraparietal sulcus, and dorsal prefrontal cortex ( Ptak, 2012 ; Deming and Koenigs, 2020 ).…”

“…The protein encoded by the gene DISC1 (disrupted in schizophrenia) had an evolutionary change in the line leading to humans, is related to neuronal migration and dendritic branching, and is preferentially expressed by VENs ( Allman et al, 2010 ; Cauda et al, 2014 ; see the GWAS atlas at https://atlas.ctglab.nl for current data on current DISC1 associations). In addition, reduced resting-state connectivity in the PC was correlated with apathy in patients with schizophrenia ( Forlim et al, 2020 ). Apathy is a motivational disorder incurring reduced or loss of goal-directed behavior, goal-directed cognitive processes, and emotion ( Forlim et al, 2020 ).…”

“…In addition, reduced resting-state connectivity in the PC was correlated with apathy in patients with schizophrenia ( Forlim et al, 2020 ). Apathy is a motivational disorder incurring reduced or loss of goal-directed behavior, goal-directed cognitive processes, and emotion ( Forlim et al, 2020 ). In this regard, the PC connectivity was correlated with the severity of these symptoms and with alterations in the subjective experience of a continuous sense of the self, regarded as dysfunctional interactions between relevant brain regions ( Forlim et al, 2020 ).…”

Hypoconnectivity networks in schizophrenia patients: a voxelwise meta-analysis of rs-fMRI

“…Connectivity intensity in this area is negatively correlated with the severity of negative symptoms, more speci cally with the apathy domain (Forlim et al, 2020). Gangadin et al (2021) also demonstrated a reduction in the connectivity of the hypocampal-mesencephal-striate network in patients with schizophrenia.…”

Structural and Functional Default Mode Network Connectivity and Antipsychotic Treatment Response in Medication-Naïve First Episode Psychosis Patients

“…The DMN has also been identified as relevant for a number of clinical variables including symptom severity, 20 long-term clinical outcomes, 21 and response to antipsychotic treatment. 22 , 23 Importantly, baseline functional connectivity of the DMN was found to be the single most positive predictor for subsequent response to antipsychotic treatment in an assessment of five key functional brain networks in early illness schizophrenia patients.…”