Visual-tracking neurons in area MST are activated during anticipatory pursuit eye movements

Here, I report that rhesus monkeys are able to generate anticipatory smooth pursuit eye movements in the transient absence of a moving target, if this target moves periodically. The eye velocity before target reappearance was significantly larger if the target trajectory was predictable compared with the control condition consisting of unpredictable target trajectory. Parallel to the registration of the eye movements, single-unit activity was recorded from neurons in the middle superior temporal (MST) area of the two monkeys. The neuronal activity of visual-tracking neurons resembled the observed eye movements, i.e. these neurons increased their activity earlier if the movement of the target was predictable compared with the unpredictable control. These results provide further evidence for the existence of extra-retinal signals in the activity of visual-tracking neurons located in area MST.