Figure 3

Representative eye and hand movement traces performed during the four different tasks. Each panel labeled A, B, C and D consists of two subpanels. The upper subpanel shows the eye movements, the lower subpanel those of the hand. Solid lines: PD patient data, dashed line: control subject data. Panel A: pro-tapping task. At time 0 ms the target for the eyes is displayed at a position of 15 degrees from the central dot. Note that in this situation PD patients are able to initiate a saccade towards the target as fast as controls and that PD patients initiated the hand movement significantly slower (HL), as the release of the finger from the screen (▲) was delayed compared to controls (Δ). This panel also shows that the time between the release of the finger from the screen and the touch of the target was significantly increased in PD patients (▲ to ▼) compared to controls (Δ to ∇). Panel B: dual planning task. PD patients initiated the saccade towards the target dot significantly faster compared to controls. Note that for the PD patient the release of the finger from the screen (▲) was significantly delayed compared to controls (Δ). The example also shows that the time between the release of the finger from the screen and the touch of the target was significantly increased in PD patients (▲ to ▼) compared to controls (Δ to ∇). Panel C: anti-tapping task. The PD patient was significantly faster to initiate an eye movement towards the opposite direction of the displayed dot than the control. The PD patient was able to initiate the hand movement (▲) as fast as controls (Δ). The example also shows that HET was significantly increased in PD patients (▲ to ▼) compared to controls (Δ to ∇). Panel D: spatial memory task. The PD patient initiated a saccade towards the remembered target location about as fast as the control. PD patients were also able to initiate the hand movement (▲) as fast as controls (Δ). The time between the release of the finger from the screen and the touch of the target was significantly increased in PD patients (▲ to ▼) compared to controls (Δ to ∇).