Retinal ganglion cells responses and activity (Tsai et al 2012, Guo et al 2016)

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Accession:260653
From the abstracts: "Retinal ganglion cells (RGCs), which survive in large numbers following neurodegenerative diseases, could be stimulated with extracellular electric pulses to elicit artificial percepts. How do the RGCs respond to electrical stimulation at the sub-cellular level under different stimulus configurations, and how does this influence the whole-cell response? At the population level, why have experiments yielded conflicting evidence regarding the extent of passing axon activation? We addressed these questions through simulations of morphologically and biophysically detailed computational RGC models on high performance computing clusters. We conducted the analyses on both large-field RGCs and small-field midget RGCs. ...", "... In this study, an existing RGC ionic model was extended by including a hyperpolarization activated non-selective cationic current as well as a T-type calcium current identified in recent experimental findings. Biophysically-defined model parameters were simultaneously optimized against multiple experimental recordings from ON and OFF RGCs. ...
Reference:
1 . Guo T, Tsai D, Morley JW, Suaning GJ, Kameneva T, Lovell NH, Dokos S (2016) Electrical activity of ON and OFF retinal ganglion cells: a modelling study. J Neural Eng 13:025005 [PubMed]
2 . Tsai D, Chen S, Protti DA, Morley JW, Suaning GJ, Lovell NH (2012) Responses of retinal ganglion cells to extracellular electrical stimulation, from single cell to population: model-based analysis. PLoS One 7:e53357 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Synapse; Extracellular;
Brain Region(s)/Organism: Retina;
Cell Type(s): Retina ganglion GLU cell;
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Oscillations; Activity Patterns; Development;
Implementer(s): Tsai, David [d.tsai at unsw.edu.au];
Search NeuronDB for information about:  Retina ganglion GLU cell;
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�	�	�	�	�	z	i	B		���rpo:&����feXJ:87.-�����tsmI$����pXBA/������U='&�����yZ;��������UNITSON}    c_exp = 1 - exp(-dt/tau_c)    q_exp = 1 - exp(-dt/tau_q)    p_exp = 1 - exp(-dt/tau_p)    n_exp = 1 - exp(-dt/tau_n)    h_exp = 1 - exp(-dt/tau_h)    m_exp = 1 - exp(-dt/tau_m): State vars to inifinity    c_inf = a * tau_c    tau_c = 1 / (a + b)    b = 10 * (exp((-1*(v + 38))/18))    a = (-0.3 * (v+13)) / ((exp(-0.1*(v+13))) - 1):CA channel    q_inf = a * tau_q    tau_q = 1 / (a + b)    b = 0.6 / ( 1 + exp(-0.1 *(v+40)))        a = 0.04 * (exp((-1*(v+70))/20))    p_inf = a * tau_p    tau_p = 1 / (a + b)    b = 0.1 * (exp((-1*(v + 30))/10))    a = (-0.006 * (v+90)) / ((exp(-0.1*(v+90))) - 1):K (inactivating)    n_inf = a * tau_n    tau_n = 1 / (a + b)    b = 0.4 * (exp((-1*(v + 50))/80))    a = (-0.02 * (v+40)) / ((exp(-0.1*(v+40))) - 1):K n (non-inactivating, delayed rectifier)    h_inf = a * tau_h    tau_h = 1 / (a + b)    b = 6 / ( 1 + exp(-0.1 *(v+20)))    a = 0.4 * (exp((-1*(v+50))/20)):NA h    m_inf = a * tau_m    tau_m = 1 / (a + b)    b = 20 * (exp((-1*(v+55))/18))    a = (-0.6 * (v+30)) / ((exp(-0.1*(v+30))) - 1):NA m    PROCEDURE evaluate_fct(v(mV)) { LOCAL a,bUNITSOFF}    ENDVERBATIM    return 0;    VERBATIM    c = c + c_exp * (c_inf - c)    q = q + q_exp * (q_inf - q)    p = p + p_exp * (p_inf - p)    n = n + n_exp * (n_inf - n)    h = h + h_exp * (h_inf - h)    m = m + m_exp * (m_inf - m)    evaluate_fct(v)PROCEDURE states() {    : exact when v held constant}    ica = gcabar * c*c*c * (v - eca)    ik = idrk + iak + icak    icak = gkcbar * ((cai / 0.001)/ (1 + (cai / 0.001))) * (v - ek)    iak =  gabar * p*p*p*q * (v - ek)    idrk = gkbar * n*n*n*n * (v - ek)    ina = gnabar * m*m*m*h * (v - ena)    SOLVE statesBREAKPOINT {}    m_exp h_exp n_exp p_exp q_exp c_exp    tau_m tau_h tau_n tau_p tau_q tau_c    m_inf h_inf n_inf p_inf q_inf c_inf    ica    (mA/cm2)    icak   (mA/cm2)    iak    (mA/cm2)    idrk   (mA/cm2)    ik     (mA/cm2)    ina    (mA/cm2)ASSIGNED {}    c = 0.0038    q = 0.2534    p = 0.0862    n = 0.1213    h = 0.8594    m = 0.0345: at -60 mV:    c = 0.0016:    q = 0.4526:    p = 0.0398:    n = 0.0768:    h = 0.9399:    m = 0.0155: single-compartment: The initial values were determined at a resting value of -66.3232 mV in a INITIAL {}    m h n p q c STATE {}    v             (mV)    dt            (ms)    cai     = 0.0001 (mM)    cao     = 1.8 (mM)    eca           (mV)    ek      = -75 (mV)    ena     = 35  (mV)    gkcbar  = 0.00005 (mho/cm2)    gcabar  = 0.002   (mho/cm2)    gabar   = 0.036   (mho/cm2)    gkbar   = 0.012   (mho/cm2)    gnabar  = 0.04    (mho/cm2)PARAMETER {}    (mV) = (millivolt)    (mA) = (milliamp)    (mM) = (millimolar)    (molar) = (1/liter)UNITS {}    RANGE idrk, iak, icak    RANGE m_exp, h_exp, n_exp, p_exp, q_exp, c_exp    RANGE tau_m, tau_h, tau_n, tau_p, tau_q, tau_c    RANGE m_inf, h_inf, n_inf, p_inf, q_inf, c_inf    RANGE gnabar, gkbar, gabar, gcabar, gkcbar    USEION ca READ cai, eca, cao WRITE ica    USEION k READ ek WRITE ik    USEION na READ ena WRITE ina    SUFFIX spikeNEURON {INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}::: must be used with calcium pump mechanism, i.e. capump.mod: by TJ Velte March 17, 1995: Modified from Fohlmeister et al, 1990, Brain Res 510, 343-345:TITLE HH style channels for spiking retinal ganglion cells