Monitoring/evaluating disease states using functional magnetic resonance imaging

Andrea N Snyder, Purdue University

Abstract

Schizophrenia is a mental disorder that affects approximately 1% of the population. In addition to the well-known psychological symptoms of schizophrenia (SZ), patients also experience several cognitive deficits, many of which appear early in the course of the disease. These cognitive deficits have a significant impact on daily functioning, yet they are not adequately treated by many of the drugs available for schizophrenia (SZ). Two main cognitive deficits in schizophrenia (SZ) are found in visual processing and working memory. To investigate these deficits, a protocol was designed to probe the visual processing streams (both form and motion streams independently) and working memory networks. These tasks were designed using difficulty-matching to correct for differences between the SZ patients and healthy controls in effort, attention, and ability. Ten patients with SZ and ten healthy age- and gender-matched controls were imaged using functional magnetic resonance imaging (fMRI) while performing visual and working memory tasks to elucidate brain activation patterns. Compared with healthy controls, SZ patients had decreased brain activation in the left frontal eye field (L FEF) and anterior cingulate cortex (ACC), and increased activation in the left lingual gyrus during Form tasks. In Working Memory tasks, SZ patients had decreased activity in several frontal areas, including the ACC, L FEF, and L inferior frontal gyrus, as well as in bilateral inferior parietal lobes. Behavioral task performance in SZ patients was directly correlated with brain activation levels in the ACC—as patients performed better on the tasks, brain activation in the ACC increased toward activation levels seen in healthy controls. Further, patients with schizophrenia showed global decreased homogeneity in brain activation patterns for all tasks. This protocol has potential be used to study prodromal phases of SZ to identify risk of development of the disorder in at-risk individuals. In addition, research using this protocol may be useful to evaluate new and existing therapies for their effects on the cognitive aspects of SZ. By using this protocol to research medications to treat these cognitive impairments, we hope to impact the daily lives of patients with SZ.

Degree

Ph.D.

Advisors

Talavage, Purdue University.

Subject Area

Mental health|Biomedical engineering|Medical imaging

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