Structural and Functional Cerebral Correlates of Memory in Parkinson Disease

Lucas Jimenez, O. 1 , Ibarretxe Bilbao, N. 1 , Diez Cirarda, M. 1 , Peña, J. 1 , Cabrera, A. 2 & Ojeda, N. 1

1 Department of Methods and Experimental Psychology, Faculty of Psychology and Education, University of Deusto, Bilbao, Spain
2 OSATEK. MR Unit Hospital of Galdakao, Galdakao, Spain

Introduction:
Neuroimaging studies have increased our understanding of Parkinson Disease (PD). The goal of this study was to combine functional magnetic resonance (fMRI) with diffusion tensor imaging (DTI) to better understand the neural mechanisms that underlie verbal memory (VM) dysfunction in PD.

Methods:
Thirty-three non-demented PD patients participated in this study. Memory was assessed with a codification fMRI paradigm. DTI and fMRI were acquired on a Philips Achieva 3T. FA values were calculated after running TBSS as implemented in FSL. Pearson´s Correlation Coefficient was used to investigate the correlation between structure and function.

Results:
Activation values while performing the memory task in left orbitofrontal inferior showed a positive correlation with FA values of callosal body (r=.365, p=.034), left (r=.353, p=.041) and right (r=.398, p=.020) inferior longitudinal fasciculus, right fronto-occipital (r=.345, p=.046), left optic radiation (r=.372, p=.030) and left (r=.448, p=.008) and right (r=.419, p=.014) corticospinal tract. Activation values in right amygdala correlated with FA of left corticospinal tract (r=.437, p=.010). There was a negative correlation between activation in right medial temporal lobe and FA of right uncinate fasciculus (r=-.417, p=.014).

Conclusions:
These results suggest that stronger activation values in several brain areas are associated with higher integrity in WM tracts. The present data represent a first step toward an integration of functional and structural MRI in the investigation of memory in PD.