// Reinoud Maex 20 June 2007
// The AMPA and GABAA channels are copied from De Schutter & Bower
// Purkinje cell model, modified by Sergio Solinas et al. (EJN 2006).
// The NMDA channel is copied from the Maex & De Schutter (J Neurophysiol 1998)
// granule cell model.
// Hence this script merges the files Purk_syn37dC.g and Gran_synchan.g
//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.
*/
include ../L5P37C/L5P_const+axon+syn.g
// 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
/*********************************************************************
** The synaptic conductance equations
*********************************************************************/
function make_GABAA_channels
/* 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
// SS We use 37 degrees here since it's not specified in the article
// RM This does not make sense because then the somatic GABA is slower than the dendritic;
// changed to 37 to 23
setfield GABA3 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
// 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}}}
echo GABAAs soma gmax {GB_GABAs}
end // make_GABAA_channels
function make_AMPA_channels
/* 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 AMPA}))
create synchan AMPA
end
setfield AMPA Ek {E_AMPA} \
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}
setfield AMPA gmax {G_par_syn}
/* synchronously firing channel removed, was for climbing fibre synapses on PC */
end // make_AMPA_channels
function make_NMDA_channels
/* NMDA channel made by CP */
/* From Gabbiani et al.(model) 1994, based on Jahr and Stevens */
float Q10_synapse = 3.0
//[Mg] in mM
float CMg = 1.2
// per mM
float eta = 0.2801
// per V
float gamma = 62
float offset = - 0.01
echo eta = {eta}
eta = eta * {exp {- gamma * offset}}
echo new eta = {eta}
if (!({exists NMDA}))
create synchan2 NMDA
end
setfield NMDA Ek {E_NMDA} tau2 {3e-3 / Q10_synapse} \
tau1 {40e-3 / Q10_synapse} \
gmax {G_NMDA}
// use the following value for synaptic activation when TEST.g is run
// gmax {4.0 * G_NMDA}
if (! {exists NMDA/Mg_BLOCK})
create Mg_block NMDA/Mg_BLOCK
end
setfield NMDA/Mg_BLOCK CMg {CMg} \
KMg_A {1/eta} \ \\ *({exp {EREST_ACT*gamma}})} \
KMg_B {1.0/gamma}
end // make_NMDA_channels
function make_GABAB_channels
/* GABA_B channel, using a dual exponential function with time constants of 80
** and 40 msec as in Suarez, Koch and Douglas 1995 (J. Neurosci. 15,
** 6700-1719; cat visual cortex).
** A more detailed model can be found in Otis, De Koninck and Mody 1993
** (J. Physiol. 463, 391-407; rat hippocampal slices; this model uses 4th
** power exponential activation and dual exponential inactivation).
** See also Benardo 1994 (J. Physiol. 476.2, 203-215; slice rat neocortex)
** and Connors, Malenka and Silva 1988 (J. Physiol. 406, 443-468; slice
** rat and cat visual cortex.
*/
float Q10_synapse = 3.0
if (!({exists GABAB}))
create synchan2 GABAB
end
setfield GABAB Ek {E_GABAB} tau1 {0.080 / Q10_synapse} \
tau2 {0.040 / Q10_synapse} \
gmax {G_GABAB} frequency 0.0
end // make_GABAB_channels
function make_L5P_synchans
echo making Purkinje synapse library...
/* The conductance equations in this library are general and not
** specific to the Purkinje celxl */
// Make library protoptypes *****
if ({!{exists /library}})
create neutral /library
disable /library
end
ce /library
if ({!{exists L5P}})
create neutral L5P
end
ce L5P
make_GABAA_channels
make_AMPA_channels
make_NMDA_channels
make_GABAB_channels
end // make_L5P_synchans
make_L5P_synchans