Subcortical brain region related to social function in schizophrenia Thalamic volume plays key role in neural circuitry

Researchers at the University of Tokyo and their collaborators found that the volume of the brain region called the thalamus, which sends sensory information to the cerebral cortex responsible for higher brain functions, is significantly correlated to cognitive and social functioning of patients with schizophrenia. Using MRI to produce images, they also replicated the findings of previous studies showing that the thalamus of patients with schizophrenia was smaller than that of healthy subjects.

The thalamus is located in an area known as the subcortex, which lies immediately below the cerebral cortex, and plays a pivotal role in the neural circuitry of this subcortical region. Although previous studies found that patients with schizophrenia had a smaller thalamus and those who had a stroke in this region showed impaired social cognition, the relationship between the thalamus and social functions in patients with schizophrenia was unclear.

This is the first study that shows that dysfunction of the neural circuit centered around the thalamus underlies the impairment of social cognitive functions, such as grasping conventional wisdom and understanding context, and social daily skills including counting money and communication, in patients with schizophrenia. The research was led by graduate student Daisuke Koshiyama and Professor Kiyoto Kasai at the Graduate School of Medicine at the University of Tokyo and Associate Professor Ryota Hashimoto at the United Graduate School of Child Development at Osaka University.

These findings may contribute to our understanding of the pathology, and help develop new rehabilitation methods for patients with schizophrenia to acquire social living skills.

"The pathology of schizophrenia remains unclear, and we will continue to investigate the abnormal neural circuit of the disorder," says Kasai.