Experimental Brain Research

, Volume 159, Issue 1, pp 99–107

The relationship of saccadic peak velocity to latency: evidence for a new prosaccadic abnormality in schizophrenia

  • Rajeev S. Ramchandran
  • Dara S. Manoach
  • Mariya V. Cherkasova
  • Kristen A. Lindgren
  • Donald C. Goff
  • Jason J. S. Barton
Research Article

DOI: 10.1007/s00221-004-1940-z

Cite this article as:
Ramchandran, R.S., Manoach, D.S., Cherkasova, M.V. et al. Exp Brain Res (2004) 159: 99. doi:10.1007/s00221-004-1940-z
  • 71 Views

Abstract

Antisaccades have not only longer latencies but also lower peak velocities than prosaccades. It is not known whether these latency and velocity differences are related. Studies of non-human primates suggest that prosaccade peak velocity declines as latency from target appearance increases. We examined whether a similar relationship between peak velocity and latency existed in human saccades, whether it accounted for the difference in peak velocity between antisaccades and prosaccades, and whether it was affected by schizophrenia, a condition that affects antisaccade performance. Sixteen control and 21 schizophrenia subjects performed prosaccade and antisaccade trials in the same test session. In both groups antisaccades had lower peak velocities than prosaccades. Latency did not influence the peak velocities of antisaccades in either subject group. At short latencies, the peak velocities of prosaccades were also similar in the two groups. However, while prosaccade peak velocities declined minimally with increasing latency in control subjects, those in the schizophrenia group declined significantly until they reached a value similar to antisaccade peak velocities. We conclude that, in normal subjects, the effect of latency on prosaccade peak velocity is minimal and cannot account for the lower velocity of antisaccades. In schizophrenia, we hypothesize that the latency-related decline in prosaccade peak velocity may reflect either an increased rate of decay of the effect of the transient visual signal at the saccadic goal, or a failure of the continuing presence of the target to sustain neural activity in the saccadic system.

Keywords

SaccadeAntisaccadeSchizophreniaPeak velocityLatencyVisual transient

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Rajeev S. Ramchandran
    • 5
  • Dara S. Manoach
    • 3
    • 4
  • Mariya V. Cherkasova
    • 1
  • Kristen A. Lindgren
    • 1
  • Donald C. Goff
    • 3
  • Jason J. S. Barton
    • 1
    • 2
  1. 1.Department of Neurology, KS 452, Beth Israel Deaconess Medical CenterHarvard Medical SchoolBostonUSA
  2. 2.Department of Ophthalmology, Beth Israel Deaconess Medical CenterHarvard Medical SchoolBostonUSA
  3. 3.Department of Psychiatry, Massachusetts General HospitalHarvard Medical SchoolBostonUSA
  4. 4.Athinoula A. Martinos Center for Biomedical ImagingHarvard Medical SchoolBostonUSA
  5. 5.University of Rochester School of Medicine and DentistyRochesterUSA