Off Anatomical Beta/Physiological X Ganglion Cell

The Beta classification is largely an anatomical distinction for a cat ganglion cell. It is commonly linked with the physiologically classified X cat ganglion cell (Boycott & Wassle, 1974)

• Postsynaptic connections (Input)
  • Bipolar Cell
    • McGuire, Stevens and Sterling (1986) within 2 degrees of center

      Input Synapses

      Presynaptic Cell	Cell #?		Cell #?
      Cone Bipolar CBa2/cb1	12	34%	23	59%
      Cone Bipolar CBa1/cb2	23	66%	16	41%
      Cone Bipolar Total	35		39

    • Kolb and Nelson, '93 at 1.5 mm (~ 5 degrees)
      • 4 bipolars (2 cb1, 2 cb2)
      • 152 bipolar ribbon synapses (38% of all synaptic input)
    • NOT the blue bipolar: It looks like this cell does not receive input from the blue cones. (Cleland & Levick, 1974 as cited by Cohen and Sterling, 1991)
  • Amacrine Cell
    • Kolb and Nelson, '93 at 1.5 mm (~ 5 degrees)

      Input Synapses

      Presynaptic Cell	Synapses	% of non-AII	% of Am	% of Ttl
      Cone Bipolars Total	152			38%
      Amacrine non-AII in IPL-A	196	94%	77%	48%
      Amacrine non-AII in IPL-B	8	4%	3%	2%
      Amacrine non-AII non-IPL	5	2%	2%	1%
      Amacrine non-AII	209	100%	82%	51%
      Amacrine AII	47		18%	12%
      Amacrine Total	256		100%	62%
      Total	408			100%

      • A2, A3, A8
      • AII Amacrines via chemical synapses from 3-5 AII's
      • A13 synapse onto the apical dendrite as the dendrite entered sublamina b of the IPL and on top of the cell body.
      • Unidentified Amacrines synapse onto the base and side of the cell body.
    • 5-6 AII Amacrines via 6-8 cone bipolars
  • No coupling with other Ganglion Cells via electrical synapses Vaney, 1991 cited in Vaney, 1994

• Presynaptic connections (Output)
  • No coupling with other Ganglion Cells via electrical synapses Vaney, 1991 cited in Vaney, 1994
  • Lateral Geniculate Nucleus

• Function
  • An Off X ganglion cell (Boycott & Wassle, 1974)
  • " Steady discharges of X and Y retinal ganglion cells of cat under photopic illuminance" Troy & Robson (1992):
    • The interspike interval histograms of the steady-state response to a stationary grating are well described by a gamma distribution function of order 3.1 (stdev 2.4).
    • ISI range 0:140
    • Mean firing rate for the Off-center X/Beta:
      • 18 spikes/sec (stdev 13) [range]- Troy & Robson
      • 39 (16) - Stone and Fukuda
  • Beta/X axonal conductance velocity is slower than Alpha/Y axonal conductance velocity - Cleland, Dubin and Levick, W. R. (1971) & Stone and Hoffmann '71

• Morphology(Sterling Lab)
  • 1 degree
    • 2623 micrometer2 membrane area,
    • 27 synapses/100 micrometer2
  • 9 degrees
    • 836 micrometer2 membrane area,
    • 28 synapses/100 micrometer2
  • Dendritic fields: ~20 micrometers to ~200 micrometers in diameter
  • Max field is about 4 mm.
  • Synaptic density is virtually the same for On Betaand off beta
  • Bipolar synaptic density of Alphas is less than half of that of Betas
  • cell density = 4200 cells/mm2
  • Kolb and Nelson, 1993: 1.5 mm (~ 5 degrees)
    • Dendrites branched in "distal third" or s1 of sublamina a of the IPL
    • Soma: 17 x 30 um
    • Dendritic spread: 62 um
    • Single Apical dendrite leaves the soma and branches first at the sublamina a/b border in the IPL
    • The daughter branches continue to bifurcatethrough the depth of sublamina a of the IPL
    • A2, A3, A8 and A13 contacted the primary and secondary dendrites
    • Some of the dendrites actually extended slightly into the INL

• Array characteristics
  • "From central to peripheral retina beta dendritic fields increase about 10-fold in diameter (20-200 um), reaching assymptote at about 4mm (Fig. 5B; Figure 8 in Boycott and Wassle, 1974)." Kier, Buchsbaum and Sterling '95
  • -> area:

• Compartmental Model Characteristics

• Location
  Kolb and Nelson, 1993: 1.5 mm (~ 5 degrees)
  • Dendrites in sublamina A of the IPL
  • A2, A3, A8 and A13 contacted the primary and secondary dendrites
  • cb2 contacted the Off-Beta/X on dendites close to the soma (~S2)
  • cb1 contacted the Off-Beta/X on dendites further from the soma (~S1)
  • Soma in the GCL
  • Synapse types

  • Synapse Receptors

  • Neurotransmitters
    • Glycine - Strychnine (an antagonist of glycine) reduces both the center and surround response of the Beta/X cell, but the surround more. (Kirby, 1979)
    • GABA - On- and Off-Beta/X cells are not directly affected by a large intravenous dose of GABA, though On- and Off- Alpha/Y cells are affected. (Kirby and Enroth-Cugell, 1976 as cited by Kirby, 1979) However, bicuculline (GABA blocker) excites/disinhibits some Off Beta/X response to Quisqualate and AMPA which suggests an GABAergic amacrine input. (Boos, Muller and Wassle, 1990)
    • Increased spiking at spontaneous and stimulated (Boos, Muller and Wassle, 1990)
      • glutamate (GLU)
      • Asparate (ASP)
      • Kainate (KA) - more effective than ASP and GLU at lower concentrations (more effective on X-cells than Y-cells)
      • Quisqualate (QQ) and AMPA - looks like (directly or indirectly) QQ excites, but it also appears to excite inhibitory neurons presynaptic to the ganglion cells
      • NMDA excites

  • Immunoreactivity

  • Nomenclature
    • The Beta classification is largely an anatomical distinction for a cat ganglion cell. It is commonly linked with the physiologically classified X cat ganglion cell (Boycott & Wassle, 1974)
    • X-type and Y-type have also been refered to as brisk (firing) cells or brisk-sustained and brisk-transient. (i.e. Bolz, Wassle and Thier, 1984).
    • Class II - i.e. Berson, Pu and Famiglietti '96 ARVO

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  © 1995 Lance Hahn (lance@retina.anatomy.upenn.edu)