Schizophrenia: Describe the symptoms of the disorder and how those symptoms are related to the brain structures
Schizophrenia is a chronic mental disorder that affects how a person thinks, feels, and acts. People living with Schizophrenia interpret reality abnormally. When active, Schizophrenia causes hallucinations, delusions, disorganized thoughts and speech, lack of motivation, among other behavioral changes that can impair daily functioning. While there is no cure for Schizophrenia, treatment options, including medications and therapies, effectively control and manage the symptoms.
A series of studies have established a correlation between structural alterations of the brain with symptoms in Schizophrenia. Using some of the most advanced brain imaging like Tomography and functional MRI, doctors and researchers have been able to establish specific links between behavioral symptoms of Schizophrenia and brain anatomy. Brain scans of people living with Schizophrenia have shown various structural abnormalities in the portions of the corpus callosum and fibers that contain nerves responsible for neural communication between the right and the left hemispheres of the brain.
Researchers found that certain abnormalities in the corpus callosum are consistent with certain symptoms. For instance, Patients with similar features in one part of the corpus callous displayed unusual and disorganized behavior. In some patients, abnormalities in another part of the corpus callosum were associated with disorganized thoughts and speech and other symptoms such as loss of memory and lack of emotions. In other patients, the abnormalities were linked to delusions and hallucinations.
On average, brains with Schizophrenia appear to be structurally different. One major consistent finding is the reductions in grey matter volume (GMV) of the brain’s frontal, temporal, medial, limbic regions. The gray matter part of the brain contains neuronal cell bodies involved in muscle control, sensory perception like hearing and emotions, auditory information processing, short-term memory, and decision-making. Neuroimaging studies also show evidence linking structural abnormalities and reductions in the white matter with first episodes and chronic symptoms.
Brains with Schizophrenia also show major neurochemical differences when compared to a normal brain. The brain uses neurochemicals known as neurotransmitters to communicate with other parts of the brain and the nervous system. Neurotransmitters are essential to all brain functions, including memory, learning, movements, and reasoning. Disrupted neural connectivity impairs communication between brain regions resulting in cognitive changes.
Brain imaging has linked abnormalities in the Auditory Cortex with vulnerability to hallucinations in Schizophrenia. Studies regarding the origins of auditory hallucinations in Schizophrenia have been linked to structural abnormalities in the brain’s auditory cortex, particularly during the pre-onset phase of the disorder.
Strik, W., Stegmayer, K., Walther, S., and Dierks, T., 2017. Systems neuroscience of psychosis: mapping schizophrenia symptoms onto brain systems. Neuropsychobiology, 75(3), pp.100-116.
Sun, Y., Chen, Y., Collinson, S.L., Bezerianos, A., and Sim, K., 2017. Reduced hemispheric asymmetry of brain anatomical networks is linked to Schizophrenia: a connectome study. Cerebral cortex, 27(1), pp.602-615.
Zhang, W., Du Lei, S.K.K., Ivleva, E.I., Eum, S., Yao, L., Tamminga, C.A., Clementz, B.A., Keshavan, M.S., Pearlson, G.D., Gershon, E.S. and Bishop, J.R., 2020. Brain gray matter network organization in psychotic disorders. Neuropsychopharmacology, 45(4), p.666.
