title: Depression in Parkinson's disease: convergence from voxel-based morphometry and functional magnetic resonance imaging in the limbic thalamus.
abstract: Depression is the most frequent psychiatric disorder in Parkinson's disease (PD). Although evidence suggests that depression in PD is related to the degenerative process that underlies the disease, further studies are necessary to better understand the neural basis of depression in this population of patients. In order to investigate neuronal alterations underlying the depression in PD, we studied thirty-six patients with idiopathic PD. Twenty of these patients had the diagnosis of major depression disorder and sixteen did not. The two groups were matched for PD motor severity according to Unified Parkinson Disease Rating Scale (UPDRS). First we conducted a functional magnetic resonance imaging (fMRI) using an event-related parametric emotional perception paradigm with test retest design. Our results showed decreased activation in the left mediodorsal (MD) thalamus and in medial prefrontal cortex in PD patients with depression compared to those without depression. Based upon these results and the increased neuron count in MD thalamus found in previous studies, we conducted a region of interest (ROI) guided voxel-based morphometry (VBM) study comparing the thalamic volume. Our results showed an increased volume in mediodorsal thalamic nuclei bilaterally. Converging morphological changes and functional emotional processing in mediodorsal thalamus highlight the importance of limbic thalamus in PD depression. In addition this data supports the link between neurodegenerative alterations and mood regulation.
authors.affiliation: NIF, LIM-44, Department of Radiology, University of São Paulo, São Paulo, Brazil. lim@usp.br
authors.forename: Ellison Fernando
authors.initials: EF
authors.lastname: Cardoso
authors.forename: Fernanda Martins
authors.initials: FM
authors.lastname: Maia
authors.forename: Felipe
authors.initials: F
authors.lastname: Fregni
authors.forename: Martin Luis
authors.initials: ML
authors.lastname: Myczkowski
authors.forename: Luciano M
authors.initials: LM
authors.lastname: Melo
authors.forename: João R
authors.initials: JR
authors.lastname: Sato
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Marcolin
authors.forename: Sergio P
authors.initials: SP
authors.lastname: Rigonatti
authors.forename: Antonio Cesário
authors.initials: AC
authors.lastname: Cruz
authors.forename: Egberto Reis
authors.initials: ER
authors.lastname: Barbosa
authors.forename: Edson
authors.initials: E
authors.lastname: Amaro
mesh_terms: D003863:Depression / Q000175:diagnosis* / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008032:Limbic System / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications* / Q000175:diagnosis*; D013788:Thalamus / Q000473:pathology*