Pursuit and saccadic tracking exhibit a similar dependence on movement preparation time

Wilsaan M. Joiner, Mark Shelhamer

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Data from previous human and primate studies on saccadic and smooth pursuit eye movements suggest that there are shared internal inputs (for example, perception, attention, expectation, and memory) for the initiation of the two types of movements. Additional reports examining the effect of preparation time on movement responses have shown that when ample time is allowed subjects usually generate long-latency "reactive" responses. When the time allowed to prepare a movement is short, however, subjects respond with reduced latency and often anticipate the stimulus ("predictive" response). Based on these findings, we believe that the shared internal inputs at early stages of movement preparation may result in saccade and pursuit eye movements demonstrating the same dependence on preparation time despite acting through different neural pathways further downstream. Previously we demonstrated a behavioral "phase transition" when normal subjects tracked alternating targets with saccades. When preparation time was long (low-frequency pacing) subjects made reactive saccades (latency ∼180 ms). As preparation time monotonically decreased (pacing frequency increased), there was an abrupt transition to a predictive response (latency <100 ms). In the present study we show that a similar transition exists in smooth pursuit tracking and that the point of transition between the two behaviors is the same for both systems. In other words, the same behavior (reactive versus predictive) is selected when pursuit and saccade tracking are tested under the same time constraints. This provides further evidence that the two types of movements are different motor outcomes of a common decision process.

Original languageEnglish (US)
Pages (from-to)572-586
Number of pages15
JournalExperimental Brain Research
Issue number4
StatePublished - Sep 2006


  • Motor response
  • Prediction
  • Preparation time
  • Pursuit
  • Saccade

ASJC Scopus subject areas

  • Neuroscience(all)


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