Schizophrenia: neural architecture, brain regional differences, and changes with age

Thesis

Schizophrenia is a heterogeneous and life-altering disorder. Although a multitude of research has been published on schizophrenia since its first iteration as dementia praecox, there is still much to be learned about this disease. Neuroscientific research has revealed important findings on brain changes; some of these have become consistent with the disease, such as the decrease in whole-brain gray matter and the enlargement of the ventricles. However, other findings remain controversial, including the posited increase in neuron density. New techniques are being implemented every day to study these changes, including the use of diffusion tensor imaging. A novel application of this method in the gray matter in the current study reveals increased diffusivity in schizophrenia, potentially implicating decreased tissue integrity and a loss of neuropil. Relationships with asymmetry are also explored in conjunction with altered neurodevelopment. An examination of the microstructure literature using meta-analysis suggests that overall there is an increase in density in schizophrenia. This provides support for a neurodevelopmental origin of schizophrenia, and has implications for the reduced neuropil hypothesis; additionally, a finding of decreased inhibitory neurons in schizophrenia provides support for the theory of dysfunctional inhibitory cortical circuits. A focus on the microstructure in the inferior parietal lobule, a neglected region in schizophrenia research, reveals a difference in structure in schizophrenia, as well as important relationships with age that support a progressive course to the disease. The effect of clinical variables such as medication and length of illness were examined in each of these studies, and these relationships provide important insight into the progression of the disease, as well as the nature of the impairment in those who have schizophrenia. The various techniques used in this project combine to create a picture of profound and comprehensive alterations in brain structure at both the macro- and micro-scale.

Authors: Bakhshi, K

• Publication date: 2013
• Type of award: MSc by Research
• Level of award: Masters
• Awarding institution: Oxford University, UK
• Language: English
• Keywords: DTI; schizophrenia; neuropathology; neuroscience; microstructure; changes with age; neuroanatomy
• Subjects: Neuroscience; Neuropathology; Neuroanatomy; Schizophrenia