Linguistics Research Today is a free monthly online journal that collates and summarizes the latest research about Linguistics, including details on human language, phonetics, syntax, phonology.

Fronto-striatal deficit in Parkinson's disease during semantic event sequencing.

Tinaz S, Schendan HE, Stern CE

Center for Memory and Brain, Boston University, Boston, MA 02215, USA.

Studies of Parkinson's disease (PD) suggest that cognitive deficits accompany the classically recognized motor symptoms, and that these cognitive deficits may result from damage to frontal-basal ganglia circuits. PD patients are impaired on ordering events and action components into coherent sequences. In this study, we examined early-stage, nondemented, medicated PD subjects and matched control subjects during a semantic event sequencing task using functional MRI (fMRI). The task required subjects to examine four pictures of meaningful events, determine the correct temporal relationship between each picture, and re-order the pictures into a coherent sequence. There were two main findings. First, we found abnormal activation within the prefrontal cortex (PFC) and the "default" network in the PD group. Distinct areas of the PFC showed both hypoactivation and hyperactivation, whereas the "default" network showed reduced levels of resting activation in PD. Secondly, we observed left caudate hyperactivation in the PD group. The findings are discussed in relationship to how more activation may be compensatory, but does not necessarily mean efficient and correlated brain function.

Published 15 February 2008 in Neurobiol Aging, 29(3): 397-407.
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