//genesis - Purkinje cell M9 genesis2.1 script
/* Copyright E. De Schutter (Caltech and BBF-UIA) */
/**********************************************************************
** Sets of synapse objects developed for rat cerebellum Purkinje
** E. De Schutter, Caltech, 1991-1992
**********************************************************************/
/* Reference:
** E. De Schutter and J.M. Bower: An active membrane model of the
** cerebellar Purkinje cell: II. Simulation of synaptic responses.
** Journal of Neurophysiology 71: 401-419 (1994).
** http://bbf-www.uia.ac.be/TNB/TNB_pub7.html
** Consult this reference for sources of experimental data.
*/
// CONSTANTS
/* should be defined by calling routine (all correctly scaled):
** E_non_NMDA
** E_GABA, G_GABA */
// factor Q10 of 1.5: Regehr et al. J. Neuroscience 1996 16(18):5661-5671
float Q10 = 1.5
function Calc_tau(Q10,T1,T2,tau1)
return {tau1 / { Q10**{{T2 -T1}/10}}}
end
float temp = 37 // Celsius degrees
float Q12_non_NMDA = 1.68 // for 10 1.4
// correctio for low input resistance
float Rin_corr = 1
int include_Purk_syn
if ( !{include_Purk_syn} )
include_Purk_syn = 1
/*********************************************************************
** The synaptic conductance equations
*********************************************************************/
function make_Purkinje_syns
echo making Purkinje synapse library...
/* The conductance equations in this library are general and not
** specific to the Purkinje celxl */
/* GABA channel, made by SS */
/* Reference: current clamp data from
** Pouzat C. and Hestrin S. J. Neuroscince 1997
** V_drive 60 mV, I_syn 20 pA -> G_peak = 333 pS
** (that is 35.3 pA at 37 C which should be recorded in voltage clamp)
** T_rise: 2.6 +- 0.5 ms, Thalf-width = 16.7 +- 2.7 ms
** room temperature: we assume 23 Celsius degrees
** Found T_on = 1.65 ms and T_off = 9.3 ms by hand (MATLAB)
** Found with c++ program /bbf/milaan/sergio/Work/C++/Rise2Tau/rise2tau:
** Found T_on = 2.1 ms and T_off = 15.3 ms by hand (c++) */
float PC_GABAA_factor = 5.8
// Stell & Stell1 channels: average conpartment surface 4.020627647e-11 m2
float PC_GABAA_gmax = {333e-12 / 4.020627647e-11 * PC_GABAA_factor}
// Stell3 channels: average conpartment surface 2.247033843e-10 m2
float PC_GABAAm_gmax = {333e-12 / 2.49670427e-10 * PC_GABAA_factor}
// Stell4 channels: somatic surface m2
float PC_GABAAs_gmax = {3.5e-9 / 2.789857497e-09 }
float PC_GABAA_t_on = 1.65e-3
float PC_GABAA_t_off = 9.3e-3
/* Synaptic channel for Stellate connections */
if (!({exists GABA}))
create synchan GABA
end
setfield GABA Ek {E_GABA} \
tau1 {Calc_tau {Q10} 23 {temp} {PC_GABAA_t_on}} \
tau2 {Calc_tau {Q10} 23 {temp} {PC_GABAA_t_off}} \
gmax {G_GABA} frequency {0.0}
/* Synaptic channel for Basket connections on PC main dendrite */
if (!({exists GABA2}))
create synchan GABA2
end
setfield GABA2 Ek {E_GABA} \
tau1 {Calc_tau {Q10} 23 {temp} {PC_GABAA_t_on}} \
tau2 {Calc_tau {Q10} 23 {temp} {PC_GABAA_t_off}} \
gmax {G_GABA} frequency {0.0}
/* Synaptic channel for Basket connections PC soma */
if (!({exists GABA3}))
create synchan GABA3
end
setfield GABA3 Ek {E_GABA} \
tau1 {Calc_tau {Q10} 37 {temp} {PC_GABAA_t_on}} \ // We use 37 degrees here since it's not specified in the article
tau2 {Calc_tau {Q10} 37 {temp} {PC_GABAA_t_off}} \
gmax {G_GABA} frequency {0.0}
// set the right GABAA density value to get gmax from Hausser M. and Clark B. A. Neuron 1997
G_GABA = {{PC_GABAA_gmax} * {Q10**{{{temp} - 23}/10}}}
echo GABAA gmax {G_GABA}
G_GABAm = {{PC_GABAAm_gmax} * {Q10**{{{temp} - 23}/10}}}
echo GABAA2 gmax {GB_GABA}
G_GABAs = {{PC_GABAAs_gmax} * {Q10**{{{temp} - 37}/10}}} // We use 37 degrees here since it's not specified in the article
echo GABAAs soma gmax {GB_GABAs}
/* non-NMDA channel, made by SS */
/* Reference: Barbour B. 2002 (personal communication)
** room temp: 32 C
** somatic EPSC peak = 8.4 +- 7.1 pA
** (that is 10.2 pA at 37 C which should be recorded in voltage clamp)
** the driving force at the excitatory synapse is 70 mV
** during Voltage clamp at -70 mV
** thus the peak conductance G_par_syn = 120 pS
** t_on = 1.0 +- 0.7 ms
** the low-pass filtering effect of the large PC dendritic tree
** could slow down the fast rise EPSC fase. Since the effect of single vescicle release
** is kown to have an almost instantaneous effect on PSC we use a faster t_on
** t_on = 0.7 ms
** t_off = 11.1 +- 5.7 ms
** t_off is long and it light be due to the glutammate spillover
** activating the extrasynaptic AMPA receptors
** We use t_off = 1.2 ms */
/* Modified by SS 30/04/2002
** We need to be able to set the AMPA receptor strength
** indipendently on previous settings
** since when the AMPA receptor is placed on the spine head
** it's scaled by its surface here we devide the gmax by the surface */
float dia = 0.54e-6
float surf = dia*dia*{PI}
//- here we can keep control of the Gmax since the readcell
// will add the spines (*rand_spines) without modify them
float PC_AMPA_factor = 9
float PC_AMPA_gmax = {120e-12/surf * PC_AMPA_factor}
float PC_AMPA_t_on = 0.7e-3
float PC_AMPA_t_off = 1.2e-3
/* asynchronously firing channel */
if (!({exists non_NMDA}))
create synchan non_NMDA
end
setfield non_NMDA Ek {E_non_NMDA} \
tau1 {Calc_tau {Q10} 32 {temp} {PC_AMPA_t_on}} \
tau2 {Calc_tau {Q10} 32 {temp} {PC_AMPA_t_off}} \
frequency {0.0}
G_par_syn = {{PC_AMPA_gmax} * {Q10**{{{temp} - 32}/10}} }
echo AMPA gmax = {G_par_syn}
/* synchronously firing channel */
if (!({exists non_NMDA2}))
create synchan non_NMDA2
end
setfield non_NMDA2 Ek {E_non_NMDA} tau1 {0.50e-3} tau2 {1.20e-3}
end
end