title: Full-field electroretinogram response to increment and decrement stimuli.
abstract: OBJECTIVE
  The d-wave is typically elicited after the termination of an increment flash, but a decrement flash provides an alternative, and perhaps more appropriate, stimulus to elicit the d-wave. Here, we investigated the affects of stimulus polarity on the electroretinogram (ERG) response.
  
  
  METHODS
  ERG responses elicited to increment and decrement flashes of varying intensity and duration from different background levels were measured from human participants to assess the b-wave and d-wave responses as a function of adaptation level and flash polarity. Response amplitudes were measured using standard metrics for waveform analysis.
  
  
  RESULTS
  The amplitude of the b-wave is larger than the d-wave regardless of flash polarity when using different background levels which maximized the dynamic range of the two waveforms. However, when response amplitudes are measured from a common background, the d-wave elicited with decrement flash was larger than the b-wave elicited by an increment flash. This trend was evident across a range of background levels. The b-wave and d-wave become separate entities when flash duration reaches approximately 50 ms. Rapid-on and rapid-off sawtooth stimuli were also tested against increment and decrement step stimuli that were matched in mean luminance. These two stimulus types produced different amplitude b-wave and d-wave responses, suggesting asymmetric effects of the two stimulus types on the retinal response.
  
  
  CONCLUSIONS
  We conclude that the response properties of the b-wave and d-wave are influenced by the duration, polarity and waveform of the stimulus, as well as the background from which the stimuli arise.
authors: Department of Psychological and Brain Sciences, 317 Life Sciences Bldg., University of Louisville, Louisville, KY, USA.
authors: Eric
authors: E
authors: Vukmanic
authors: Kate
authors: K
authors: Godwin
authors: Pan
authors: P
authors: Shi
authors: Alan
authors: A
authors: Hughes
authors: Paul
authors: P
authors: DeMarco
mesh_terms: D000221:Adaptation, Ocular / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D004596:Electroretinography; D006801:Humans; D010775:Photic Stimulation; D012160:Retina / Q000502:physiology*