Researcher: Carolien Toxopeus, MSc (MD-PhD student)

Other supervisors: Nico Leenders, MD, PhD, Bauke de Jong, MD, PhD

Thesis defense: 2012

The main aim of this thesis was to investigate the organization of basic components of movement constituted by initiation, inhibition and gradual modulation of movement, focused on the role of the basal ganglia (BG) and interconnected circuitry in healthy subjects and patients with Parkinson’s disease (PD). Given this thesis’ main theme, PD patients are of particular interest since progressive changes in BG functionality are a key feature in these patients, causing a range of different motor symptoms linked to problems with movement initiation and inhibition. By employing a set of specific hand movement tasks focused on initiation, inhibition and gradual movement modulation in combination with several techniques (EMG, fMRI and an MR-compatible joystick for wrist movements), we linked the cerebral organization of these basic motor components to movement parameters at the behavioral level in both healthy subjects and patients with Parkinson’s disease (PD).

References

• Toxopeus CM1, de Jong BM, Valsan G, Conway BA, Leenders KL, Maurits NM. Direction of movement is encoded in the human primary motor cortex. PLoS One. 2011;6(11):e27838. PMID: 22110768.
  
• Toxopeus CM1, de Jong BM, Valsan G, Conway BA, van der Hoeven JH, Leenders KL, Maurits NM. Impairment of gradual muscle adjustment during wrist circumduction in Parkinson’s disease. PLoS One. 2011;6(9):e24572. PMID: 21912704.
• Toxopeus CM1, Maurits NM, Valsan G, Conway BA, Leenders KL, de Jong BM. Cerebral activations related to ballistic, stepwise interrupted and gradually modulated movements in Parkinson patients. PLoS One. 2012;7(7):e41042. PMID: 22911738.