SCHIZOPHRENIA Factsheet December 2019

What is the ? The basal ganglia is a group of sub-cortical nuclei thought to be involved in motor control and learning. The nuclei comprising the basal ganglia include the caudate, , , the , and the . The caudate and putamen NeuRA (Neuroscience together form the , while the globus pallidus (including the ventral pallidum) and Research Australia) the putamen together form the lenticular nucleus. The striatum is the principal input centre, is one of the largest receiving afferents primarily from the cortex, but also from the substantia nigra, , independent medical and . There are two primary pathways (‘direct’ and ‘indirect’) from and clinical research the striatum through the basal ganglia, which incorporate different components of the basal institutes in Australia and ganglia circuitry, and play different roles in controlling and planning movements and cognition. an international leader in neurological research.

What is the evidence for changes in the basal ganglia? Diseases of the brain and Structural changes nervous system pose the High quality evidence suggests increased in the caudate, bilateral putamen, greatest health, economic and globus pallidus of people with schizophrenia compared to people without schizophrenia and social burden of any disease group because they ('controls'). Lower quality evidence suggests similar findings in childhood-onset schizophrenia. are chronic, debilitating and Moderate quality evidence suggests reduced bilateral grey matter in people have no known cures. with first-episode psychosis, particularly people who have never been medicated, compared to people with schizophrenia, people at high risk of psychosis, and compared to controls. High Medical research is the quality evidence suggests a small effect of greater reductions over time in the left caudate in cornerstone of efforts to people with schizophrenia compared to controls. advance the health and wellbeing of families and the Functional changes community. Our dedicated Moderate quality evidence suggests people with schizophrenia show reduced activity in scientists are focussed on the bilateral and the right putamen during executive functioning tasks. Moderate to transforming their research low quality evidence suggests no functional abnormality in the basal ganglia during cognitive into significant and practical control, long-term and working memory, and language processing tasks. enefits for all patients. Moderate to low quality evidence suggests dopamine receptor occupancy in the While we hope you find striatum of people with schizophrenia varies according to treatment with first or second this information useful, generation antipsychotics. Moderate quality evidence finds unmedicated people with it is always important to schizophrenia have a medium to large increase in choline in the basal ganglia. Moderate discuss any questions to low quality evidence finds no differences in D2/D3 receptor availability in the substantia about schizophrenia or nigra of unmedicated people with schizophrenia compared to controls. There were also no its treatment with your doctor or other health care differences in GABA levels in the striatum of people with schizophrenia. provider. For more information see the technical table

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