Sensory processing deficits constitute a central feature of schizophrenia. In the visual system, these deficits have typically been investigated using psychophysical and behavioral measures. The findings from many of these studies converge to show that schizophrenia patients, relative to healthy control subjects, have increased susceptibility to visual backward masking (VBM), impaired motion perception and eye tracking deficits. The primary aim of the current application is to apply novel hemodynamic measures of brain activity in parallel with three-dimensional images of the rendered cortical surface to systematically map sensory processing areas in schizophrenia.
Our aim i s to use these maps to visualize the precise location of cortical activity in response to many types of visual stimuli given to one subject. Functionally defining visual processing areas is an important and necessary first step towards gaining a more complete understanding of the neurophysiological and anatomical bases of visual pathway dysfunction in schizophrenia. A secondary aim of the proposed study is to acquire preliminary information regarding dysfunction within the magnocellular (dorsal) visual processing stream in schizophrenia. Dorsal stream dysfunction has been well documented in schizophrenia and increasing evidence suggests that these deficits are due to low-level magnocellular dysfunction. The final study in this application will evaluate magnocellular and parvocellular function in schizophrenia using functional MRI (fMRI). Understanding the integrity of the visual pathways is crucial to understanding high-level visual dysfunction in schizophrenia. Schizophrenia is a devastating disease that significantly impacts the public health system. Understanding the basic brain mechanisms that underlie this disorder is an important and necessary step towards gaining a more complete understanding of the disease and may lead to improved treatment strategies. ? ? ? ?
| Martinez, Antigona; Hillyard, Steven A; Dias, Elisa C et al. (2008) Magnocellular pathway impairment in schizophrenia: evidence from functional magnetic resonance imaging. J Neurosci 28:7492-500 |
