Disrupted thalamic resting-state functional networks in schizophrenia

https://www.frontiersin.org/articles/10.3389/fnbeh.2015.00045/full

Modern studies have provided evidence of thalamic abnormalities in patients with schizophrenia. Recent neuroscience research has been looking more in-depth at these thalamic abnormalities and their effects on the cognitive and behavioral aspects of schizophrenia. Lei Wang, et al. studied the deterioration of thalamic nuclei and its correlation to the decline of a schizophrenic patient's cortical network. Another study by Hsiao-Lan Sharon Wang, et al. looks at thalamic resting-state networks (RSNs) in patients with schizophrenia. They aimed to challenge the "disconnectivity model" of schizophrenia, which hypothesizes that schizophrenia is a disease characterized by disconnectivity of the neuronal circuits that connect different cortical areas in healthy patients, which gives rise to the cognitive and behavioral symptoms of schizophrenia.

This study focuses on the resting-state networks (RSNs) of the thalamus, which "typically characterize a corresponding set of significantly coherent brain areas with respect to low-frequency BOLD signals during resting state." Observing this metric via resting-state fMRI allowed the researchers to understand whether or not connectivity differences between the thalamus and various other cortical regions are responsible for the characteristics found in schizophrenics. To study this, researchers recruited 72 schizophrenic patients and 74 control patients,  all of whom underwent resting-state fMRIs. A seed-region approach to focus on specific cortical regions was used in analyzing the fMRI imaging. Upon image and statistical analysis, researchers found reduced thalamus-based functional connectivity with the bilateral superior frontal gyrus, anterior cingulate cortex, inferior parietal lobe, and cerebellum in patients with schizophrenia, and increased thalamus-based functional connectivity with the bilateral precentral gyrus, dorsal medial frontal gyrus, middle occipital gyrus, and lingual gyrus. These findings of hyper- and hypo-connectivity in schizophrenic patients challenges the disconnectivity model, and indirectly supports the hypothesis that the RSNs of  the thalamus play a role in the characteristics of schizophrenia. 

This study as well as the study done by Lei Wang, et al. goes to show how much there is to discover in the field of neuroscience, even if it pertains to just one disease. The discovery of the role of the thalamus in schizophrenia was one step that opened the door to countless other research discoveries.