Investigating the Relationship between White Matter Connectivity and Motivational Circuits in Subjects with Deficit Schizophrenia: A Diffusion Tensor Imaging (DTI) Study.

Giulia M Giordano,Pasquale Pezzella,Anna Prinster,Andrea Perrottelli,Andrea Soricelli,Michele Fabrazzo,Silvana Galderisi,Mario Quarantelli,Luigi Giuliani,Paola Bucci

doi:10.3390/jcm11010061

Abstract

Deficit schizophrenia is a subtype of schizophrenia presenting primary and enduring negative symptoms (NS). Although one of the most updated hypotheses indicates a relationship between NS and impaired motivation, only a few studies have investigated abnormalities of motivational circuits in subjects with deficit schizophrenia (DS). Our aim was to investigate structural connectivity within motivational circuits in DS. We analyzed diffusion tensor imaging (DTI) data from 46 subjects with schizophrenia (SCZ) and 35 healthy controls (HCs). SCZ were classified as DS (n = 9) and non-deficit (NDS) (n = 37) using the Schedule for Deficit Syndrome. The connectivity index (CI) and the Fractional Anisotropy (FA) of the connections between selected brain areas involved in motivational circuits were examined. DS, as compared with NDS and HCs, showed increased CI between the right amygdala and dorsal anterior insular cortex and increased FA of the pathway connecting the left nucleus accumbens with the posterior insular cortex. Our results support previous evidence of distinct neurobiological alterations underlying different clinical subtypes of schizophrenia. DS, as compared with NDS and HCs, may present an altered pruning process (consistent with the hyperconnectivity) in cerebral regions involved in updating the stimulus value to guide goal-directed behavior.

Highlights

Negative symptoms represent a core aspect of schizophrenia, with a negative impact on the functioning of people suffering from this disorder
Primary and persistent negative symptoms characterize a subtype of schizophrenia, named deficit schizophrenia, which is associated with a greater impairment of general cognitive functions and poorer treatment response and outcome, in comparison with non-deficit schizophrenia [21,22,23,24,25,26,27,28,29,30]
In light of the above observations, our study aimed to fill the gap in the previous literature, investigating, in subjects with deficit schizophrenia, the presence of abnormalities within motivational circuits. To this aim, using a bilateral probabilistic approach on diffusion tensor imaging (DTI) data, the present study examined differences between subjects with deficit schizophrenia, subjects with non-deficit schizophrenia and healthy controls in white matter (WM) connections between major brain regions involved in motivational pathways

Summary

Introduction

Negative symptoms represent a core aspect of schizophrenia, with a negative impact on the functioning of people suffering from this disorder To date, they remain an unmet therapeutic need, since no effective treatment is available for these symptoms, when they are primary to the disorder [1,2,3,4,5,6,7,8,9,10,11,12,13,14]. According to the current conceptualization provided by the Consensus Conference of the National Institute of Mental Health—Measurement and Treatment Research to Improve Cognition in Schizophrenia (NIMH-MATRICS), the negative symptom construct includes five individual symptoms, namely avolition, anhedonia, asociality, blunted affect and alogia [15]. Primary and persistent negative symptoms characterize a subtype of schizophrenia, named deficit schizophrenia, which is associated with a greater impairment of general cognitive functions and poorer treatment response and outcome, in comparison with non-deficit schizophrenia [21,22,23,24,25,26,27,28,29,30]

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Results