Localized abnormalities in the cingulum bundle in patients with schizophrenia: A Diffusion Tensor tractography study

Abstract

The cingulum bundle (CB) connects gray matter structures of the limbic system and as such has been implicated in the etiology of schizophrenia. There is growing evidence to suggest that the CB is actually comprised of a conglomeration of discrete sub-connections. The present study aimed to use Diffusion Tensor tractography to subdivide the CB into its constituent sub-connections, and to investigate the structural integrity of these sub-connections in patients with schizophrenia and matched healthy controls. Diffusion Tensor Imaging scans were acquired from 24 patients diagnosed with chronic schizophrenia and 26 matched healthy controls. Deterministic tractography was used in conjunction with FreeSurfer-based regions-of-interest to subdivide the CB into 5 sub-connections (I1 to I5). The patients with schizophrenia exhibited subnormal levels of FA in two cingulum sub-connections, specifically the fibers connecting the rostral and caudal anterior cingulate gyrus (I1) and the fibers connecting the isthmus of the cingulate with the parahippocampal cortex (I4). Furthermore, while FA in the I1 sub-connection was correlated with the severity of patients' positive symptoms (specifically hallucinations and delusions), FA in the I4 sub-connection was correlated with the severity of patients' negative symptoms (specifically affective flattening and anhedonia/asociality). These results support the notion that the CB is a conglomeration of structurally interconnected yet functionally distinct sub-connections, of which only a subset are abnormal in patients with schizophrenia. Furthermore, while acknowledging the fact that the present study only investigated the CB, these results suggest that the positive and negative symptoms of schizophrenia may have distinct neurobiological underpinnings.

Cingulum bundle integrity associated with delusions of control in schizophrenia: Preliminary evidence from diffusion-tensor tractography

“…This result is also consistent with the results of a recent study by Whitford et al (2014) who identified a significant negative correlation between patients’ score on the global Delusions scale of the SAPS and their FA in a sub-component of the cingulum bundle . The cingulum bundle connects the cingulate gyrus with several cerebral regions, including the premotor, prefrontal and parietal cortices, thalamus and hippocampus (Pandya et al, 1981).…”

Interaction of language, auditory and memory brain networks in auditory verbal hallucinations

“…Similarly, Hubl et al (2004) demonstrated reduced anisotropy in the cingulate bundle in patients without AVH compared to patients who had experienced AVH, but this was restricted to the left hemisphere. In contrast, Whitford et al (2014) found a negative correlation of FA values in Subsection 4.1 of the right cingulum with the hallucination subscale of SAPS. This subsection of the cingulum projects into the rostral anterior cingulate gyrus and the caudal anterior cingulate gyrus.…”

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.…”