Fireworks in the primate retina: in vitro photodynamics reveals diverse LGN-projecting ganglion cell types.
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.
Dacey
Dennis M
DM
Department of Biological Structure, University of Washington, Seattle, WA 98175, USA. dmd@u.washington.edu
Peterson
Beth B
BB
Robinson
Farrel R
FR
Gamlin
Paul D
PD
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001370:Axonal Transport / Q000187:drug effects / Q000502:physiology; D001710:Biotin / Q000031:analogs & derivatives*; D003712:Dendrites / Q000502:physiology / Q000648:ultrastructure*; D003911:Dextrans; D004058:Diffusion / Q000187:drug effects; D005829:Geniculate Bodies / Q000166:cytology / Q000502:physiology; D008251:Macaca; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods*; D009924:Organ Culture Techniques; D010775:Photic Stimulation / Q000295:instrumentation / Q000379:methods*; D017966:Pyramidal Cells / Q000166:cytology / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000145:classification / Q000166:cytology* / Q000502:physiology; D012235:Rhodamines; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology
D003911:Dextrans; D012235:Rhodamines; C076397:biotinylated dextran amine; C051311:rhodamine dextran; D001710:Biotin