title: Rhythm-specific modulation of the sensorimotor network in drug-naive patients with Parkinson's disease by levodopa.
abstract: Brain activity during rest is characterized by slow (0.01-0.1 Hz) fluctuations of blood oxygenation level-dependent functional magnetic resonance imaging signals. These fluctuations are organized as functional connectivity networks called resting-state networks, anatomically corresponding to specific neuronal circuits. As Parkinson's disease is mainly characterized by a dysfunction of the sensorimotor pathways, which can be influenced by levodopa administration, the present study investigated the functional connectivity changes within the sensorimotor resting-state network in drug-naïve patients with Parkinson's disease after acute levodopa administration. Using a double-blind placebo-controlled design, resting-state functional magnetic resonance imaging was carried out in 20 drug-naïve patients with Parkinson's disease, immediately before and 60 min after, oral administration of either levodopa or placebo. Control resting-state functional magnetic resonance imaging data were recorded in 18 age- and sex-matched healthy volunteers. Independent component analysis was performed to extract resting-state network maps and associated time-course spectral features. At the anatomical level, levodopa enhanced the sensorimotor network functional connectivity in the supplementary motor area, a region where drug-naïve patients with Parkinson's disease exhibited reduced signal fluctuations compared with untreated patients. At the spectral frequency level, levodopa stimulated these fluctuations in a selective frequency band of the sensorimotor network. The reported effects induced by levodopa on sensorimotor network topological and spectral features confirm that the sensorimotor system is a target of acute levodopa administration in drug-naïve patients with Parkinson's disease. Moreover, while the regional changes in supplementary motor area reflect the functional improvement in motor function, the rhythm-specific modulation induced by the dopamine precursor discloses a novel aspect of pharmacological stimulation in Parkinson's disease, adding further insight to the comprehension of levodopa action.
authors: Department of Neuroscience, University of Naples 'Federico II', Via S. Pansini 5, 80131 Naples, Italy. fabrizio.esposito@unina.it
authors: Fabrizio
authors: F
authors: Esposito
authors: Alessandro
authors: A
authors: Tessitore
authors: Alfonso
authors: A
authors: Giordano
authors: Rosita
authors: R
authors: De Micco
authors: Antonella
authors: A
authors: Paccone
authors: Renta
authors: R
authors: Conforti
authors: Giuseppe
authors: G
authors: Pignataro
authors: Lucio
authors: L
authors: Annunziato
authors: Gioacchino
authors: G
authors: Tedeschi
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D001921:Brain / Q000187:drug effects*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000187:drug effects*; D010300:Parkinson Disease / Q000188:drug therapy*; D012146:Rest
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa