Human pupillary response to ramp changes in light intensity

George K. Hung, Fuchuan Sun

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


The dynamic behavior of the pupillary system was explored using diffent velocity ramp changes in light intensity. Ramp stimuli ranged in velocity from 0.02 to 8.00 log units/s and the responses were recorded from three subjects. For ramp velocity below 0.066 log units/s, the responses were mainly ramps. Above 1.0 log units/s ramp velocity, the responses were mostly steps. In the stimulus velocity range of 0.066 to 1.0 log units/s, the primary responses were step-ramps. The amplitudes of the initial step movement in step-ramp responses were found to be proportional to stimulus ramp velocity. Thus the pupillary system appears either to convert the total energy in a time interval or the rate of change of intensity of the ramp stimulus into a step signal for driving the pupillary plant output.

Original languageEnglish (US)
Pages (from-to)322-331
Number of pages10
JournalExperimental Neurology
Issue number2
StatePublished - May 1988

All Science Journal Classification (ASJC) codes

  • Neurology
  • Developmental Neuroscience


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