Research
Print page Print page
Switch language
The Capital Region of Denmark - a part of Copenhagen University Hospital
Published

Effects of dopaminergic treatment on functional cortico-cortical connectivity in Parkinson's disease

Research output: Contribution to journalJournal articleResearchpeer-review

  1. Sensory defunctionalization induced by 8% topical capsaicin treatment in a model of ultraviolet-B-induced cutaneous hyperalgesia

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. Influence of visual feedback, hand dominance and sex on individuated finger movements

    Research output: Contribution to journalJournal articleResearchpeer-review

  3. Improved assessment of outcomes following transient global cerebral ischemia in mice

    Research output: Contribution to journalJournal articleResearchpeer-review

  4. Cue integration and the perception of action in intentional binding

    Research output: Contribution to journalJournal articleResearchpeer-review

View graph of relations

Interactions between dorsal premotor cortex (PMd) and primary motor cortex (M1) and interhemispheric inhibition (IHI) between M1 are impaired in Parkinson's disease (PD). We used dual-site transcranial magnetic stimulation to compare effects of first-time levodopa application with chronic dopaminergic therapy on these interactions in PD. Twelve untreated PD patients were studied before and after their first-ever intake of levodopa. The effects of chronic dopaminergic medication were evaluated in 11 patients who had received regular dopaminergic medication for approximately 3 years. Nine of these patients were also measured after overnight withdrawal of medication. For IHI, conditioning stimuli (CS) were applied to left M1 followed by test stimuli (TS) over right M1 and vice versa in separate blocks at interstimulus intervals (ISI) of 6-10 ms. Next, CS were applied to left PMd at subthreshold intensity followed by TS over left M1 at ISIs of 4 and 6 ms. Results were compared to 17 age- and gender-matched controls. In de novo PD patients, levodopa reduced left-to-right IHI, but did not alter PMd-M1 connectivity. In contrast, inhibitory PMd-M1 connectivity was present in early disease patients under chronic dopaminergic stimulation, but not in de novo PD patients at low stimulus intensities at an ISI of 4 ms. First-time exposure to levodopa exerts different effects on cortico-cortical pathways than chronic dopaminergic stimulation in PD, suggesting a change in the responsiveness of cortico-cortical circuits during the course of PD.

Original languageEnglish
JournalExperimental Brain Research
Volume233
Issue number1
Pages (from-to)329-37
Number of pages9
ISSN0014-4819
DOIs
Publication statusPublished - Jan 2015

ID: 44859565