Fig. 4.

Example of units with static responses. Each horizontal block is a raster plot of neural activity from a block of 10 trials of the movement indicated on the y-axis. Each row in each block represents a passive movement trial. All rasters are centered on the time onset of the second hold epoch in which the joint was held at the extreme of the range of movement for that block. Yellow periods indicate passive movement in the direction indicated on the vertical axis. Gray periods indicate passive movement in the opposite direction. For example, in the WF block, the joint was flexed during the yellow period, held fully flexed during the following 5-s period (white background) that starts at the solid black line at time 0, and then returned to a neutral position during the gray period. A: C8U1 is an example of a unit with multijoint receptive fields. B: C14U1 had a single-joint receptive field. Both units were recorded in session 2.