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ON‐OFF amacrine cells in cat retina
Author(s) -
Freed Michael A.,
Pflug Renate,
Kolb Helga,
Nelson Ralph
Publication year - 1996
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19960115)364:3<556::aid-cne12>3.0.co;2-n
Subject(s) - inner plexiform layer , amacrine cell , receptive field , retina , biology , axon , neuroscience , lucifer yellow , postsynaptic potential , excitatory postsynaptic potential , biophysics , anatomy , microbiology and biotechnology , intracellular , gap junction , inhibitory postsynaptic potential , biochemistry , receptor
We studied the morphology, photic responses, and synaptic connections of ON‐OFF amacrine cells in the cat retina by penetrating them with intracellular electrodes, staining them with horseradish peroxidase, and examining them with the electron microscope. In a sample of seven cells, we found two different morphological types: the A19, which ramifies narrowly in stratum 2 (sublamina a ) of the inner plexiform layer, and the A22, which ramifies mostly in stratum 4 (sublamina b ) but extends some dendrites to sublamina a . Both of these cell types have axon‐like processes that extend >800 μm from the conventional dendritic arbor. ON‐OFF amacrine cells in our sample had receptive fields (1.7 ± 0.3 mm diameter) that were broader than their dendritic arbors (425 ± 35 μm diameter) and that extended over the region of axon‐like processes. In addition, we found many features in common with ON‐OFF amacrine cells in poikilotherm vertebrates: a broad receptive field without surround antagonism, two sizes of spike‐like events, narrow dynamic range (1 log unit intensity), and excitatory postsynaptic potentials at light on and light off. Two A19 amacrine cells were examined in the electron microscope: most synaptic inputs (93 and 76%, respectively) to either cell were from amacrine cells, with minor inputs from cone bipolar cells. Synaptic outputs were to bipolar, amacrine, and ganglion cells, including the OFF‐α cell. © 1996 Wiley‐Liss, Inc.