title: Human flicker electroretinography using different temporal modulations at mesopic and photopic luminance levels.
abstract: BACKGROUND
  Electroretinographic measurement instruments allow the variation of several stimulation parameters enabling to study a wide range of retinal processes. The purpose of the present study was to measure human flicker electroretinograms (ERGs) varying temporal modulation, temporal frequency and mean luminance in the photopic and higher mesopic ranges where the change from cone to rod dominance occurs.
  
  
  METHODS
  Fourteen healthy subjects (mean age = 31 ± 6) participated in this study. ERG recordings were performed with the RetiPort system (Roland Consult, Germany). The stimuli were ON and OFF sawtooth waves, square wave and sine wave. The temporal frequencies were 4 and 8 Hz. The mean luminance varied from 1 to 60 cd/m(2).
  
  
  RESULTS
  The results confirmed the possibility to distinguish between rod- and cone-dominated retinal responses when using the flicker ERG at different temporal frequencies and luminances. We have also evaluated the responses at luminance levels at which the transition between rod- and cone-dominated responses occurs. This transition between rod- and cone-dominated flicker ERG responses is indicated by a significant change in the response characteristics between 4 and 8 cd/m(2) (between 200 and 400 phot Td).
  
  
  CONCLUSIONS
  The findings on the transition between rod- and cone-dominated ERGs along with the demonstration of ERG responses to different temporal flicker modulations might be informative for the electrophysiologists when setting up the stimulus at mesopic and photopic luminance levels.
authors: Neuroscience and Behavior, University of São Paulo, São Paulo, SP, Brazil, nagybal@gmail.com.
authors: Balázs Vince
authors: BV
authors: Nagy
authors: Mirella Telles Salgueiro
authors: MT
authors: Barboni
authors: Cristiane Maria Gomes
authors: CM
authors: Martins
authors: Marcelo Fernandes
authors: MF
authors: da Costa
authors: Jan
authors: J
authors: Kremers
authors: Dora Fix
authors: DF
authors: Ventura
mesh_terms: D000328:Adult; D055253:Color Vision / Q000502:physiology*; D004596:Electroretinography; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D055255:Mesopic Vision / Q000502:physiology*; D010775:Photic Stimulation; D012160:Retina / Q000502:physiology*