Intact thalamic microstructure in asymptomatic relatives of schizophrenia patients with high genetic loading

Disrupted thalamic connectivity system, which encompasses the deficits in the thalamus and thalamocortical connectivity, is regarded to contribute to the pathophysiology of schizophrenia. Recent reports suggest the possible genetic contribution to the disrupted thalamo-prefrontal connectivity, however, research on elucidating thalamic connectivity system components, specifically the thalamic nuclei, associated with the genetic predisposition to schizophrenia has been limited. Here, we investigated the genetic aspects of thalamic nuclei-specific microstructural integrities in schizophrenia.

A total of 34 asymptomatic relatives of schizophrenia patients with high genetic loading and 33 healthy control subjects underwent diffusion tensor imaging, diffusion kurtosis imaging, and T1-weighted magnetic resonance imaging. The thalamus was segmented via a connectivity-based segmentation method using the region-of-interest masks. The microstructural integrity of each thalamic nucleus, measured by averages of the diffusion kurtosis values, was then compared between the groups.

The volumetric and mean kurtosis values of the thalamic nuclei were intact in asymptomatic relatives of schizophrenia patients with high genetic loading.

Our results revealed that, in the thalamic connectivity system, the genetics may hold different weights of effects on different components, and that more is given on the thalamo-prefrontal connectivity than on the thalamus. Further, the current results may add further evidence to the current literature that thalamic nuclei microstructural abnormalities present in psychosis may have state marker characteristics.