Fireworks in the primate retina: in vitro photodynamics reveals diverse LGN-projecting ganglion cell types

Neuron. 2003 Jan 9;37(1):15-27. doi: 10.1016/s0896-6273(02)01143-1.


Diverse cell types and parallel pathways are characteristic of the vertebrate nervous system, yet it remains a challenge to define the basic components of most neural structures. We describe a process termed retrograde photodynamics that allowed us to rapidly make the link between morphology, physiology, and connectivity for ganglion cells in the macaque retina that project to the lateral geniculate nucleus (LGN). Rhodamine dextran injected into the LGN was transported retrogradely and sequestered within the cytoplasm of ganglion cell bodies. Exposure of the retina to light in vitro liberated the tracer and allowed it to diffuse throughout the dendrites, revealing the cell's complete morphology. Eight previously unknown LGN-projecting cell types were identified. Cells could also be targeted in vitro for intracellular recording and physiological analysis. The photodynamic process was also observed in pyramidal cells in a rat neocortical slice.

Publication types

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

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Axonal Transport / drug effects
  • Axonal Transport / physiology
  • Biotin / analogs & derivatives*
  • Dendrites / physiology
  • Dendrites / ultrastructure*
  • Dextrans*
  • Diffusion / drug effects
  • Geniculate Bodies / cytology
  • Geniculate Bodies / physiology
  • Macaca
  • Microscopy, Fluorescence / instrumentation
  • Microscopy, Fluorescence / methods*
  • Organ Culture Techniques
  • Photic Stimulation / instrumentation
  • Photic Stimulation / methods*
  • Pyramidal Cells / cytology
  • Pyramidal Cells / physiology
  • Rats
  • Rats, Sprague-Dawley
  • Reaction Time / drug effects
  • Reaction Time / physiology
  • Retinal Ganglion Cells / classification
  • Retinal Ganglion Cells / cytology*
  • Retinal Ganglion Cells / physiology
  • Rhodamines*
  • Visual Cortex / cytology
  • Visual Cortex / physiology
  • Visual Pathways / cytology
  • Visual Pathways / physiology


  • Dextrans
  • Rhodamines
  • biotinylated dextran amine
  • rhodamine dextran
  • Biotin