On 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
    • 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)
    • In the central retina: 36 cones via 150 Bipolars (Cohen&Sterling, 1991,1992)
    • area centralis 154 bipolar synapses - Cohen and Sterling '92
  • Amacrine Cell
    • area centralis 59 amacrine synapses - Cohen and Sterling '92
    • 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
  • On X cat 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 of an on-center X cell to a stationary grating are well described by a gamma distribution function of order 8.0 (stdev 4.2)
    • ISI range [0:50]
    • Mean firing rate for on-center X/Beta:
      • 53 spikes/sec (stdev 13) [range ]- Troy & Robson
      • 49 (17) - Stone and Fukuda
      • 59 (11) - Sato et al. (1976)
  • 3 nS peak conductance (Freed and Nelson, 1994) for a small on beta with ~200 synapses
  • Linear response to stimulus area (Cleland and Enroth-Cugell, 1968)
  • Linear response to stimulus contrast (Troy et al, 1987)
  • Membrane potential is linearly related to spike frequency (Lankheet et al. 1989)
  • Depolarizes up to about 10 mV (Freed and Nelson, 1994)
  • Linear response to light intensity is narrow, hardly more than a log unit of intensity (Creutzfeldt et al, 1970)
  • 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 - dense dendritic arbors (described as bushy)
    • 2623 micrometer2 membrane area,
    • 27 synapses/100 micrometer2
  • 9 degrees - sparse dendritic arbors (described as radiate)
    • 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 Beta and OFF Betas
  • Bipolar synaptic density of Alphas is less than half of that of Betas
  • cell density = 4200 cells/mm2

• 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

• Compartmental Model Characteristics
  • Chris Kier's Models as described in Kier, Buchsbaum, Smith and Sterliing (Preprint)
    • Membrane: membrane resistance in series with a battery Em = -70mV and in parallel with a capacitance, cm
    • Rm (specific membrane resistance): 10 or 50 kW-cm2 (Liipton and Tauck, 1987; Coleman and Miller, 1989; Spruston and Johnston, 1992)
    • Cm (specific membrane capacitance): 1uF-cm2 (Cole, 1968; Brown et al. 1981)
    • Ri (specific cytoplasmic resistance): 200 W-cm (Shelton, 1985; Major et al. 1993, 1994)
    • Synaptic density = 28 synapses/ 100 um2
    • Static model each synapses was a variable conductance in series with a battery (Erev = -10 mV).
    • Conductance was a linear function of the presynaptic voltage and at half maximum was 100 pS.
    • Dynamic model of synapses: quanta of peak conductance ~90 pS and time constant ~2msec released according to a binomial distribution. (corresponds closely to AMPA components of unitary EPSC in cortex (Stern et al, 1992)

• Location

• 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)
  • GABA or Glycine from amacrine (Cohen et al 1994)
  • 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 was a muddled result because 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

Back to list of cells

Back to general retina list

59 visit(s) to this page.