Bipolar cells

Bipolar cells are a type of neuron found in the retina of the human eye. They are located between photoreceptors (rod cells and cone cells) and ganglion cells. They act, directly or indirectly, to transmit signals from the photoreceptors to the ganglion cells.

  • Bipolar cells are connected to rod and cone cells by synapses. These cells are located within the retina between these photoreceptors and ganglion cells.
  • There are around 12 types of bipolar cells that function as integrating centres. Each type acts directly or indirectly, as a conduit from a photoreceptor to ganglion cells and each carries a different parsing of its output. So, each type of bipolar cell that contacts a given rod or cone transmits a different analysis and interpretation of information extracted from its output.
  • The output of bipolar cells onto ganglion cells includes both the direct response of the bipolar cell to signals derived from phototransduction but also responses to those signals received indirectly from information and actions provided by amacrine cells.
  • We might imagine a type of bipolar cell that connects directly from a cone to a ganglion cell and simply compares signals on the basis of what is known of their wavelength. The ganglion cell uses the information to determine whether a certain point is a scene is red or green.
  • Not all bipolar cells synapse directly with a single ganglion cell. Some channel information that is sampled by different sets of ganglion cells. Others terminate elsewhere within the complex lattices of interconnections within the retina enabling them to carry packets of information to an array of different locations and cell types.