Brain activation during ideomotor praxis: imitation and movements executed by verbal command
- 1Cognitive Neuroscience, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- 2Radiology, Teikyo University Hospital, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8606, Japan
- 3Institute of Brain and Blood Vessels, 366 Ohtamachi, Isesaki, Gunma 372-0006, Japan
- Correspondence to: Professor M Sugishita Institute of Brain and Blood Vessels, 366 Ohtamachi, Isesaki, Gunma 372-0006, Japan;
- Received 27 September 2003
- Accepted 18 April 2004
- Revised 14 April 2004
Background: Ideomotor apraxia is a disorder of both imitation movements and movements executed by verbal command. Lesion studies have identified the left parietal lobe as the neural correlate for ideomotor praxis (IP), although there are opposing views.
Objectives: To localise the neural substrates for IP using functional magnetic resonance imaging. Brain regions activated by both imitation and verbal command movements were tested against a simple self paced movement.
Methods: Twenty two young, right handed, healthy subjects were examined. Functional and anatomical data were acquired. The experiment comprised three motor conditions (imitation, movements executed by verbal command, and finger bending/unbending) and a rest condition. All motor tasks were performed using the left hand. Eighteen drawings of left hand postures were presented for the imitation condition. Identical postures were instructed verbally for the verbal command condition. The finger bending/unbending movement was self paced. Blood oxygenation level dependent (BOLD) signal increases were compared during two kinds of IP (imitation and verbal command movements) and during finger bending/unbending movements.
Results: The depth of the posterior part of the left intraparietal sulcus and bilateral precunei were activated during both imitation and verbal command movements. The difference in BOLD signal between imitation and verbal command movements was localised in the dorsal and ventral occipital areas. BOLD signal differences for movements executed by verbal command against imitation were observed in the superior temporal areas.
Conclusions: The depth of the posterior part of the left intraparietal sulcus and bilateral precunei are the neural substrates for IP.
- BOLD, blood oxygenation dependent
- EPI, echo planar imaging
- fMRI, functional magnetic resonance imaging
- FB/UM, finger bending/unbending movement
- FOV, field of view
- I, imitation
- MNI, Montreal Neurological Institute
- MRI, magnetic resonance imaging
- PET, positron emission tomography
- SPM, statistical parametric mapping
- VC, verbal command
Competing interests: none declared