Form and Function of on-off Amacrine Cells in the Amphibian Retina

Robert F. Miller, Nathan P. Staff, Toby J. Velte
2006 Journal of Neurophysiology  
Miller, Robert F., Nathan P. Staff, and Toby J. Velte. Form and function of ON-OFF amacrine cells in the amphibian retina. amacrine cells were studied with whole cell recording techniques and intracellular staining methods using intact retina-eyecup preparations of the tiger salamander (Ambystoma tigrinum) and the mudpuppy (Necturus maculosus). Morphological characterization of these cells included three-dimensional reconstruction methods based on serial optical sections obtained with a
more » ... microscope. Some cells had their detailed morphology digitized with a computer-assisted tracing system and converted to compartmental models for computer simulations. The dendrites of ON-OFF amacrine cells have spines and numerous varicosities. Physiological recordings confirmed that ON-OFF amacrine cells generate both large-and small-amplitude impulses attributed, respectively, to somatic and dendritic generation sites. Using a multichannel model for impulse generation, computer simulations were carried out to evaluate how impulses are likely to propagate throughout these structures. We conclude that the ON-OFF amacrine cell is organized with multifocal dendritic impulse generating sites and that both dendritic and somatic impulse activity contribute to the functional repertoire of these interneurons: locally generated dendritic impulses can provide regional activation, while somatic impulse activity results in rapid activation of the entire dendritic tree.
doi:10.1152/jn.00090.2005 pmid:16481463 fatcat:yqwqznpcvff3po7bngecib6sme