Nonlinear signal transfer from mouse rods to bipolar cells and implications for visual sensitivity

Neuron. 2002 May 30;34(5):773-85. doi: 10.1016/s0896-6273(02)00700-6.


We investigated the impact of rod-bipolar signal transfer on visual sensitivity. Two observations indicate that rod-rod bipolar signal transfer is nonlinear. First, responses of rods increased linearly with flash strength, while those of rod bipolars increased supralinearly. Second, fluctuations in the responses of rod bipolars were larger than expected from linear summation of the rod inputs. Rod-OFF bipolar signal transfer did not share this strong nonlinearity. Surprisingly, nonlinear rod-rod bipolar signal transfer eliminated many of the rod's single-photon responses. The impact on sensitivity, however, was more than compensated for by rejection of noise from rods that did not absorb photons. As a consequence, rod bipolars provide a near-optimal readout of rod signals at light levels near visual threshold.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Artifacts*
  • Contrast Sensitivity / physiology
  • Dark Adaptation / physiology
  • Interneurons / cytology
  • Interneurons / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Neural Inhibition / physiology
  • Neural Pathways / cytology
  • Neural Pathways / physiology*
  • Nonlinear Dynamics
  • Photic Stimulation
  • Retinal Rod Photoreceptor Cells / cytology
  • Retinal Rod Photoreceptor Cells / physiology*
  • Sensory Thresholds / physiology*
  • Synapses / physiology
  • Synaptic Transmission / physiology*
  • Vision, Ocular / physiology*
  • Visual Perception / physiology*