OBJECTIVE: To compare fMRI activation during two visual stimulation paradigms in Parkinson disease (PD) subjects with chronic visual hallucinations vs PD patients who had never hallucinated. METHODS: Twelve pairs of PD subjects, matched for age, PD duration, and dopaminergic drug exposure duration, participated in this study. The authors examined group differences in activation during stroboscopic (flashing) vs no visual stimulation and kinematic (apparent motion) vs stationary visual stimulation. RESULTS: During stroboscopic stimulation, non-hallucinating PD subjects showed significantly greater activation in the parietal lobe and cingulate gyrus compared to hallucinating PD subjects. In contrast, the hallucinating subjects showed significantly greater activation in the inferior frontal gyrus and the caudate nucleus. During kinematic stimulation, non-hallucinating PD subjects showed significantly greater activation in area V5/MT, parietal lobe, and cingulate gyrus compared to hallucinating PD subjects. Hallucinating PD subjects showed significantly greater activation in the superior frontal gyrus. CONCLUSIONS: PD patients with chronic visual hallucinations respond to visual stimuli with greater frontal and subcortical activation and less visual cortical activation than non-hallucinating PD subjects. Shifting visual circuitry from posterior to anterior regions associated primarily with attention processes suggests altered network organization may play a role in the pathophysiology of visual hallucinations in PD.
OBJECTIVE: To compare fMRI activation during two visual stimulation paradigms in Parkinson disease (PD) subjects with chronic visual hallucinations vs PDpatients who had never hallucinated. METHODS: Twelve pairs of PD subjects, matched for age, PD duration, and dopaminergic drug exposure duration, participated in this study. The authors examined group differences in activation during stroboscopic (flashing) vs no visual stimulation and kinematic (apparent motion) vs stationary visual stimulation. RESULTS: During stroboscopic stimulation, non-hallucinating PD subjects showed significantly greater activation in the parietal lobe and cingulate gyrus compared to hallucinating PD subjects. In contrast, the hallucinating subjects showed significantly greater activation in the inferior frontal gyrus and the caudate nucleus. During kinematic stimulation, non-hallucinating PD subjects showed significantly greater activation in area V5/MT, parietal lobe, and cingulate gyrus compared to hallucinating PD subjects. Hallucinating PD subjects showed significantly greater activation in the superior frontal gyrus. CONCLUSIONS:PDpatients with chronic visual hallucinations respond to visual stimuli with greater frontal and subcortical activation and less visual cortical activation than non-hallucinating PD subjects. Shifting visual circuitry from posterior to anterior regions associated primarily with attention processes suggests altered network organization may play a role in the pathophysiology of visual hallucinations in PD.
Authors: Maiya R Geddes; Yanmei Tie; John D E Gabrieli; Scott M McGinnis; Alexandra J Golby; Susan Whitfield-Gabrieli Journal: Cortex Date: 2015-11-05 Impact factor: 4.027
Authors: James M Shine; Glenda M Halliday; Moran Gilat; Elie Matar; Samuel J Bolitho; Maria Carlos; Sharon L Naismith; Simon J G Lewis Journal: Hum Brain Mapp Date: 2013-06-13 Impact factor: 5.038
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Authors: Judith M Ford; Vanessa A Palzes; Brian J Roach; Steven G Potkin; Theo G M van Erp; Jessica A Turner; Bryon A Mueller; Vincent D Calhoun; Jim Voyvodic; Aysenil Belger; Juan Bustillo; Jatin G Vaidya; Adrian Preda; Sarah C McEwen; Daniel H Mathalon Journal: Schizophr Bull Date: 2014-03-11 Impact factor: 9.306