History of Illicit Stimulant Use Is Not Associated with Long-Lasting Changes in Learning of Fine Motor Skills in Humans

Figure 1

Experimental apparatus for the visuomotor tracking task. (a) Subjects were instructed to match their index finger metacarpophalangeal (MCP) joint angle with a moving target displayed on a computer screen. The target moved across the screen while making unpredictable upward and downward movements. Abduction of the finger moved the feedback line downward while adduction moved the feedback line upward. The maximum MCP joint angle movement was ±10° from neutral. (b) Medial-lateral movement of the index finger was recorded with a potentiometer. The axis of rotation of the potentiometer was positioned over the MCP joint. Muscle activity was also recorded from the first dorsal interosseous muscle using surface EMG.

(a)

(b)