title: Adaptation of naturally paced saccades.
abstract: In the natural environment, humans make saccades almost continuously. In many eye movement experiments, however, observers are required to fixate for unnaturally long periods of time. The resulting long and monotonous experimental sessions can become especially problematic when collecting data in a clinical setting, where time can be scarce and subjects easily fatigued. With this in mind, we tested whether the well-studied motor learning process of saccade adaptation could be induced with a dramatically shortened intertrial interval. Observers made saccades to targets that stepped left or right either ∼250 ms or ∼1,600 ms after the saccade landed. In experiment I, we tested baseline saccade parameters to four different target amplitudes (5°, 10°, 15°, and 20°) in the two timing settings. In experiments II and III, we adapted 10° saccades via 2° intrasaccadic steps either backwards or forwards, respectively. Seven subjects performed eight separate adaptation sessions (2 intertrial timings × 2 adaptation direction × 2 session trial lengths). Adaptation proceeded remarkably similarly in both timing conditions across the multiple sessions. In the faster-paced sessions, robust adaptation was achieved in under 2 min, demonstrating the efficacy of our approach to streamlining saccade adaptation experiments. Although saccade amplitudes were similar between conditions, the faster-paced condition unexpectedly resulted in significantly higher peak velocities in all subjects. This surprising finding demonstrates that the stereotyped "main sequence" relationship between saccade amplitude and peak velocity is not as fixed as originally thought.
authors.affiliation: PhD Program in Behavioral and Cognitive Neuroscience, The Graduate Center at City University of New York, New York, New York; Department of Biology, The City College of New York, New York, New York; and michaelgr87@gmail.com.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gray
authors.affiliation: Department of Biology, The City College of New York, New York, New York; and.
authors.forename: Annabelle
authors.initials: A
authors.lastname: Blangero
authors.affiliation: Department of Biology, The City College of New York, New York, New York; and Laboratory of Sensorimotor Research, National Eye institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: James P
authors.initials: JP
authors.lastname: Herman
authors.affiliation: Department of Biology, The City College of New York, New York, New York; and.
authors.forename: Josh
authors.initials: J
authors.lastname: Wallman
authors.affiliation: Department of Biology, The City College of New York, New York, New York; and.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Harwood
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D012438:Saccades / Q000502:physiology*; D013647:Task Performance and Analysis; D055815:Young Adult
keywords: main sequence; motor learning; saccade adaptation; speed-accuracy trade-off