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Impaired control of an action after supplementary motor area lesion: a case study
M Gentilucci1, L Bertolani, F Benuzzi
1Istituto di Fisiologia Umana, Università di Parma, via Volturno 39, 43100, Parma, Italy. gentiluc@ipruniv.cce.unipr.it
Abstract:
The kinematics of the action formed by reaching-grasping an object and placing it on a second target was studied in a patient who suffered from an acute vascular left brain lesion, which affected the Supplementary Motor Area proper (SMA-proper) (Matelli M, Luppino G. Thalamic input to mesial and superior area 6 in the macaque monkey. Journal of Comparative Neurology 1996;372:59-87, Matelli M, Luppino G, Fogassi L, Rizzolatti G. Thalamic input to inferior area 6 and area 4 in the macaque monkey. Journal of Comparative Neurology 1989;280:468-488), and in five healthy control subjects. The reach kinematics of the controls was affected by the positions of both the reaching-grasping and the placing targets (Gentilucci M, Negrotti A, Gangitano M. Planning an action. Experimental Brain Research 1997;115:116-28). In contrast, the reach kinematics of the patient was affected only by the position of the reaching-grasping target. By comparing these results with those previously found in Parkinson's disease patients executing the same action (Gentilucci M, Negrotti A. Planning and executing an action in Parkinson's disease patients. Movement Disorders 1999;1:69-79, Gentilucci M, Negrotti A. The control of an action in Parkinson's disease. Experimental Brain Research 1999;129:269-277), we suggest that the anatomical "motor" circuit formed by SMA-proper (see above), Basal Ganglia (BG) and Thalamus (Alexander GE, Crutcher MD. Functional architecture of basal ganglia circuits: neural substrates of parallel processing. Trends in the Neurosciences 1990;13:266-271, Hoover JE, Strick PL. Multiple output channels in the basal ganglia. Nature 1993;259:819-821) may be involved in the control of actions: SMA-proper assembles the sequence of the action, whereas BG updates its parameters and stores them.
Insights
This study investigated action control after brain injury. A patient with Supplementary Motor Area proper damage showed altered reach planning compared to controls, suggesting its role in action sequencing.
Area of Science:
- Neuroscience
- Motor Control
- Neurorehabilitation
Background:
- The Supplementary Motor Area proper (SMA-proper) is implicated in motor control.
- Understanding the role of SMA-proper in action planning is crucial for neurorehabilitation.
Purpose of the Study:
- To investigate the role of SMA-proper in the kinematics of a sequential action (reaching-grasping and placing).
- To compare motor control deficits in a patient with SMA-proper lesion to healthy controls and Parkinson's disease patients.
Main Methods:
- Kinematic analysis of reaching-grasping and placing actions.
- Comparison of a patient with acute vascular left brain lesion affecting SMA-proper against five healthy controls.
- Literature comparison with Parkinson's disease patients performing the same task.
Main Results:
- Healthy controls' reach kinematics were influenced by both target locations.
- The patient with SMA-proper lesion had reach kinematics affected only by the initial target location.
- This contrasts with findings in Parkinson's disease, where basal ganglia dysfunction impacts action control.
Conclusions:
- The SMA-proper, Basal Ganglia (BG), and Thalamus form a motor circuit for action control.
- SMA-proper appears critical for assembling action sequences.
- BG likely updates and stores action parameters.