Abnormalities of cingulate gyrus neuroanatomy in schizophrenia

Female specific anterior cingulate abnormality and its association with empathic disability in schizophrenia

Evidence suggests that impairments of empathy are present in schizophrenia and that such deficits lead to social dysfunction. However, the relationship between brain morphological abnormalities of the disorder and empathic disabilities has not been fully investigated. As the anterior cingulate cortex (ACC) is one of the critical structures for empathy processing, the pathology of this structure might be a major source of social dysfunction, including interpersonal miscommunication in schizophrenia. In addition, as recent studies suggest that different facets of empathic ability depend on different subdivisions of the ACC, pathology of each subdivision would affect the empathic disability of schizophrenia differentially. Structural MRI data were acquired at 3.0 T from 24 schizophrenic patients and 20 healthy participants, and the volumes of ventral and dorsal ACC were measured and compared between the groups. Subjects' empathic abilities were evaluated using a multidimensional questionnaire, the Interpersonal Reactivity Index (IRI). The relationships of structural abnormalities with empathic disabilities were investigated, by correlating ACC subdivisional volumes with each IRI subscale score. Female schizophrenic patients exhibited volume reductions in the ventral ACC bilaterally and in the left dorsal ACC compared with healthy subjects. Schizophrenic patients performed poorly on fantasy and personal distress subscales of the IRI. Furthermore, volumes of the left dorsal ACC were inversely correlated with personal distress subscale scores within female patients with schizophrenia. These results suggest that pathology of specific ACC subdivisions would have an impact on specific empathic disabilities in schizophrenia, with potential gender specificity.

Reward processing in schizophrenia: a deficit in the representation of value

Patients with schizophrenia demonstrate deficits in motivation and learning that suggest impairment in different aspects of the reward system. In this article, we present the results of 8 converging experiments that address subjective reward experience, the impact of rewards on decision making, and the role of rewards in guiding both rapid and long-term learning. All experiments compared the performance of stably treated outpatients with schizophrenia and demographically matched healthy volunteers. Results to date suggest (1) that patients have surprisingly normal experiences of positive emotion when presented with evocative stimuli, (2) that patients show reduced correlation, compared with controls, between their own subjective valuation of stimuli and action selection, (3) that decision making in patients appears to be compromised by deficits in the ability to fully represent the value of different choices and response options, and (4) that rapid learning on the basis of trial-to-trial feedback is severely impaired whereas more gradual learning may be surprisingly preserved in many paradigms. The overall pattern of findings suggests compromises in the orbital and dorsal prefrontal structures that play a critical role in the ability to represent the value of outcomes and plans. In contrast, patients often (but not always) approach normal performance levels on the slow learning achieved by the integration of reinforcement signals over many trials, thought to be mediated by the basal ganglia.

Cingulate gyrus neuroanatomy in schizophrenia subjects and their non-psychotic siblings

BACKGROUND AND METHODS

In vivo neuroimaging studies have provided evidence of decreases in the gray matter volume of the cingulate gyrus in subjects with schizophrenia as compared to healthy controls. To investigate whether these changes might be related to heritable influences, we used high-resolution magnetic resonance imaging and labeled cortical mantle distance mapping to measure gray matter volume, as well as thickness and the area of the gray/white interface, in the anterior and posterior segments of the cingulate gyrus in 28 subjects with schizophrenia and their non-psychotic siblings, and in 38 healthy control subjects and their siblings.

RESULTS

There was a significant effect of group status on posterior cingulate cortex (PCC) gray matter volume (p=0.02). Subjects with schizophrenia and their non-psychotic siblings showed similar reductions of gray matter volume (approximately 10%) in the PCC compared to healthy control subjects and their siblings. In turn, trend level effects of group status were found for thickness (p=0.08) and surface area (p=0.11) of the PCC. In the combined group of schizophrenia subjects and their siblings, a direct correlation was observed between PCC gray matter volume and negative symptoms. However, the reduction in PCC gray matter volume in schizophrenia subjects and their siblings was proportionate to an overall reduction in whole cerebral volume, i.e., the effect of group on the volume of the PCC became non-significant when cerebral volume was included as a covariate (p=0.4). There was no significant effect of group on anterior cingulate cortex volume, thickness, or area.

CONCLUSIONS

Our findings suggest that decreases in the gray matter volume of the PCC occur in schizophrenia subjects and their siblings. The presence of such decreases in the non-psychotic siblings of schizophrenia subjects suggests that heritable factors may be involved in the development of cortical abnormalities in schizophrenia.

Intrinsic and extrinsic analysis in computational anatomy

We present intrinsic and extrinsic methods for studying anatomical coordinates in order to perform statistical inference on random physiological signals F across clinical populations. In both intrinsic and extrinsic methods, we introduce generalized partition functions of the coordinates, psi(x), x epsilon M, which are used to construct a random field of F on M as statistical model. In the intrinsic analysis, such partition functions are built intrinsically for individual anatomical coordinate based on Courant's theorem on nodal analysis via self-adjoint linear elliptic differential operators. In contrast, the extrinsic method needs only one set of partition functions for a template coordinate system, and then applies to each anatomical coordinate system via diffeomorphic transformation. For illustration, we apply both intrinsic and extrinsic methods to a clinical study: cortical thickness variation of the left cingulate gyrus in schizophrenia. Both methods show that the left cingulate gyrus tends to become thinner in schizophrenia relative to the healthy control population. However, the intrinsic method increases the statistical power.

Combining anatomical manifold information via diffeomorphic metric mappings for studying cortical thinning of the cingulate gyrus in schizophrenia

Spatial normalization is a crucial step in assessing patterns of neuroanatomical structure and function associated with health and disease. Errors that occur during spatial normalization can influence hypothesis testing due to the dimensionalities of mapping algorithms and anatomical manifolds (landmarks, curves, surfaces, volumes) used to drive the mapping algorithms. The primary aim of this paper is to improve statistical inference using multiple anatomical manifolds and large deformation diffeomorphic metric mapping (LDDMM) algorithms. We propose that combining information generated by the various manifolds and algorithms improves the reliability of hypothesis testing. We used this unified approach to assess variation in the thickness of the cingulate gyrus in subjects with schizophrenia and healthy comparison subjects. Three different LDDMM algorithms for mapping landmarks, curves and triangulated meshes were used to transform thickness maps of the cingulate surfaces into an atlas coordinate system. We then tested for group differences by combining the information from the three types of anatomical manifolds and LDDMM mapping algorithms. The unified approach provided reliable statistical results and eliminated ambiguous results due to surface mismatches. Subjects with schizophrenia had non-uniform cortical thinning over the left and right cingulate gyri, especially in the anterior portion, as compared to healthy comparison subjects.