Impaired control of an action after supplementary motor area lesion: a case study

The kinematics of the action formed by reaching-grasping an object and plac ing it on a second target was studied in a patient who suffered from an acu te vascular left brain lesion, which affected the Supplementary Motor Area proper (SMA-proper) (Matelli MI Luppino G. Thalamic input to mesial and sup erior area 6 in the macaque monkey. Journal of Comparative Neurology 1996,3 72:59-87, Matelli hi, Luppino G, Fogassi L, Rizzolatti G. Thalamic input to inferior area 6 and area 4 in the macaque monkey. Journal of Comparative N eurology 1989;280:468-488), and in five healthy control subjects. The reach kinematics of the controls war affected by the positions of both the reach ing-grasping and the placing targets (Gentilucci hi, Negrotti A, Gangitano hi, planning an action. Experimental Brain Research 1997,115:116-28). In co ntrast, the reach kinematics of the patient was affected only by the positi on of the reaching-grasping target. By comparing these results with those p reviously found in Parkinson's disease patients executing the same action ( Gentilucci M, Negrotti A. Planning and executing an action in Parkinson's d isease patients. Movement Disorders 1999:1:69-79, Gentilucci M, Negrotti A. The control of an action in Parkinson's disease. Experimental Brain Resear ch 1999;129:269-777), 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 subs trates of parallel processing. Trends in the Neurosciences 1990,13:266-271, Hoover JE, Strick FL. Multiple output channels in the basal ganglia. Natur e 1993;259:819-821) may be involved in the control of actions: SMA-proper a ssembles the sequence of the action, whereas BG updates its parameters and stores them. (C) 2000 Elsevier Science Ltd. All rights reserved.