White Matter Abnormalities in Schizophrenia and Schizotypal Personality Disorder

Abstract

Prior diffusion tensor imaging (DTI) studies examining schizotypal personality disorder (SPD) and schizophrenia, separately have shown that compared with healthy controls (HCs), patients show frontotemporal white matter (WM) abnormalities. This is the first DTI study to directly compare WM tract coherence with tractography and fractional anisotropy (FA) across the schizophrenia spectrum in a large sample of demographically matched HCs (n = 55), medication-naive SPD patients (n = 49), and unmedicated/never-medicated schizophrenia patients (n = 22) to determine whether (a) frontal-striatal-temporal WM tract abnormalities in schizophrenia are similar to, or distinct from those observed in SPD; and (b) WM tract abnormalities are associated with clinical symptom severity indicating a common underlying pathology across the spectrum. Compared with both the HC and SPD groups, schizophrenia patients showed WM abnormalities, as indexed by lower FA in the temporal lobe (inferior longitudinal fasciculus) and cingulum regions. SPD patients showed lower FA in the corpus callosum genu compared with the HC group, but this regional abnormality was more widespread in schizophrenia patients. Across the schizophrenia spectrum, greater WM disruptions were associated with greater symptom severity. Overall, frontal-striatal-temporal WM dysconnectivity is attenuated in SPD compared with schizophrenia patients and may mitigate the emergence of psychosis.

A disconnection account of subjective empathy impairments in diffuse low-grade glioma patients

“…For both psychopathologies, cognitive empathy impairments have been previously highlighted (Montag et al, 2007;Shamay-Tsoory et al, 2007;Baron-Cohen et al, 2013;Smith et al, 2014) as well as abnormalities of the microstructural organization of the cingulate bundle (Pugliese et al, 2009;Travers et al, 2012;Reis Marques et al, 2014;Lener et al, 2014;Whitford et al, 2014). To the best of our knowledge, no work to date has been planned to directly rely empathy impairments in these pathologies with abnormal DTI parameters in the cingulum.…”

Topographic deficits in alpha-range resting EEG activity and steady state visual evoked responses in schizophrenia

“…Several studies have reported connectivity issues between frontal and occipital cortices (Fornito et al, 2011;Liu et al, 2012;Cheng et al, 2015), including fractional anisotropy deficits of inferior and superior longitudinal fasciculus pathways (Lener et al, 2015;Prasad et al, 2015). Therefore, although from EEG recordings we can only indirectly infer the cortical sources underlying scalp recorded activity, the current findings of decreased alpha resonance in frontal regions may reflect resonance deficits particularly in the frontal cortex, perhaps mediated by thalamo-cortical abnormalities, in addition to dysfunction in connectivity between occipital and frontal cortices preventing alpha oscillations from reaching frontal regions.…”

Genetic and Neuroimaging Features of Personality Disorders: State of the Art

“…Clinically, schizophrenia spectrum disorders are defined as a continuum ranging in severity from schizophrenia and schizotypal personality disorder to prototypical schizophreniarelated personality disorder, and schizophrenia-like symptoms [93,[112][113][114][115]. This might be one of the reasons why schizotypal personality disorder is rarely studied alone.…”

“…Lener et al [114] used the diffusion tensor imaging (DTI) technique to compare the white matter tract coherence across the schizophrenia spectrum. They found that schizophrenia patients showed lower fractional anisotropy in the temporal lobe and cingulum compared with both healthy volunteers and schizotypal personality disorder patients.…”

“…The patients, however, showed lower fractional anisotropy in the corpus callosum genu compared with healthy volunteers. Generally speaking, greater white matter disruptions are associated with more severe symptoms over the schizophrenia spectrum [114].…”