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//genesis - thalchan.g
/**************************************************************************
**
** THALCHAN : channel definition file
**
** By Pratik Mukherjee, Aug. 1991
**
** All units are in SI (Meters Kilograms Seconds Amps). While this
** does result in lots of powers of 10 in the parameters, it prevents
** the chaos of interconversions when relating parameters of different
** units.
**
***************************************************************************/
//========================================================================
// ACTIVE SQUID NA CHANNEL (TABULATED)
// A.L.Hodgkin and A.F.Huxley, J.Physiol(Lond) 117, pp 500-544 (1952)
//========================================================================
// This channel forcibly sets EREST_ACT to -0.045 V to compute V0
function make_Na_squid_tab
float tempvar
if (({exists Na_squid_tab}))
return
end
tempvar = {EREST_ACT}
EREST_ACT = -0.045
create tabchannel Na_squid_tab
setfield Na_squid_tab Ek {ENA_ACT} Gbar {1.2e3*{SOMA_A}} \
Xpower 3.0 Ypower 1.0 Zpower 0.0
setupalpha Na_squid_tab X {0.1e6*(0.025 + {EREST_ACT})} \
-0.1e6 -1.0 {-0.025 - {EREST_ACT}} -0.010 4.0e3 0.0 0.0 \
{0.0 - {EREST_ACT}} 18.0e-3
setupalpha Na_squid_tab Y 70.0 0.0 0.0 {0.0 - {EREST_ACT}} \
20.0e-3 1.0e3 0.0 1.0 {-0.030 - {EREST_ACT}} -10.0e-3
EREST_ACT = tempvar
end
//========================================================================
// SEJNOWSKI CORTICAL FAST NA CHANNEL (TABULATED)
// Lytton & Sejnowski (1991), J. Neurophysiology, in press
//========================================================================
// This channel assumes an EREST_ACT of -0.062 V for published kinetics
function setup_tabchan_bg(chan, table, z, gamma, V0, A0, B0, temp, tmin)
str chan, table
float z, gamma, V0, A0, B0, temp, tmin
float AA, AB, AC, AD, AF, BA, BB, BC, BD, BF
float T = temp + 273.15
int i
str tabB = (table) @ "_B"
AB = 0 /* convert from Borg-Graham to Hodgkin-Huxley format */
BB = 0
AC = 0
BC = 0
AA = A0
BA = B0
AD = (-1.0*V0)
BD = (-1.0*V0)
AF = (-1.0*{R}*T/(z*gamma*{F}))
BF = (-1.0*{R}*T/(-1*z*(1 - gamma)*{F}))
setupalpha {chan} {table} {AA} {AB} {AC} {AD} {AF} {BA} {BB} \
{BC} {BD} {BF}
end
function make_Na_sej_tab
if (({exists Na_sej_tab}))
return
end
create tabchannel Na_sej_tab
setfield Na_sej_tab Ek {ENA} Gbar {1.737e3*{SOMA_A}} Ik 0 Gk 0 \
Xpower 3 Ypower 1 Zpower 0
setup_tabchan_bg Na_sej_tab X 3.3 0.7 {0.0275 + {EREST_ACT}} \
4.2e3 4.2e3 37.0 5.0e-5
setup_tabchan_bg Na_sej_tab Y -3.0 0.27 {0.017 + {EREST_ACT}} \
90.0 90.0 37.0 2.5e-4
end
//----------------------------------------------------------------------------
// ACTIVE SQUID K CHANNEL (TABULATED)
// A.L.Hodgkin and A.F.Huxley, J.Physiol(Lond) 117, pp 500-544 (1952)
//----------------------------------------------------------------------------
function make_K_squid_tab
if (({exists K_squid_tab}))
return
end
create tabchannel K_squid_tab
setfield K_squid_tab Ek {EK} Gbar {360.0*{SOMA_A}} Xpower 4.0 \
Ypower 0.0 Zpower 0.0
setup_tabchan K_squid_tab X {10.0e3*(0.010 + {EREST_ACT})} \
-10.0e3 -1.0 {-10.0e-3 - {EREST_ACT}} -10.0e-3 125.0 0.0 0.0 \
{-1.0*{EREST_ACT}} 80.0e-3
end
//----------------------------------------------------------------------------
// DELAYED RECTIFIER K CURRENT
// McCormick et. al. (1991), Single Neuron Computation, Academic Press
//----------------------------------------------------------------------------
// This channel forcibly sets EREST_ACT to -0.085 V to compute V0
// Kinetics at -0.085 V match published kinetics
function make_K_lgn_hh
float tempvar
if (({exists K_lgn_hh}))
return
end
tempvar = {EREST_ACT}
// McCormick's EREST
EREST_ACT = -0.085
create hh_channel K_lgn_hh
setfield K_lgn_hh Ek {EK} Gbar {180.0*{SOMA_A}} Xpower 4.0 \
Ypower 0.0 X_alpha_FORM {LINOID} X_alpha_A -9.6e4 \
X_alpha_B -5.0e-3 X_alpha_V0 {{EREST_ACT} + 0.040} \
X_beta_FORM {EXPONENTIAL} X_beta_A 1.5e3 X_beta_B -4.0e-2 \
X_beta_V0 {{EREST_ACT} + 0.035}
EREST_ACT = tempvar
end
//----------------------------------------------------------------------------
// DELAYED RECTIFIER K CURRENT (TABULATED)
// McCormick et. al. (1991), Single Neuron Computation, Academic Press
//----------------------------------------------------------------------------
// This channel forcibly sets EREST_ACT to -0.085 V to compute V0
// Kinetics at -0.085 V match published kinetics
function make_K_lgn_tab
float tempvar
if (({exists K_lgn_tab}))
return
end
tempvar = {EREST_ACT}
EREST_ACT = -0.085 // McCormick's EREST
create tabchannel K_lgn_tab
setfield K_lgn_tab Ek {EK} Gbar {180.0*{SOMA_A}} Xpower 4.0 \
Ypower 0.0 Zpower 0.0
setup_tabchan K_lgn_tab X 9.6e4*{{EREST_ACT} + 0.040} -9.6e4 \
-1.0 {-{EREST_ACT} - 0.040} -5.0e-3 1.5e3 0.0 0.0 \
{-{EREST_ACT} - 0.035} 4.0e-2
EREST_ACT = tempvar
end
//========================================================================
// LOW-THRESHOLD CA (T) CHANNEL
// McCormick (1991), Single Neuron Computation, Academic Press
//========================================================================
// This channel forcibly sets EREST_ACT to -0.085 V to compute V0
// Kinetics at -0.085 V match published kinetics
function make_Ca_lgn_hh
float tempvar
if (({exists Ca_lgn_hh}))
return
end
tempvar = {EREST_ACT}
// McCormick's EREST
EREST_ACT = -0.085
create hh_channel Ca_lgn_hh
setfield Ca_lgn_hh Ek {ECA} Gbar {379.1*{SOMA_A}} Xpower 2.0 \
Ypower 1.0 X_alpha_FORM {LINOID} X_alpha_A -7.5e4 \
X_alpha_B -7.5e-3 X_alpha_V0 {{EREST_ACT} + 0.035} \
X_beta_FORM {LINOID} X_beta_A 1.01e4 X_beta_B 4.4e-3 \
X_beta_V0 {{EREST_ACT} + 0.034} Y_alpha_FORM {LINOID} \
Y_alpha_A 344.0 Y_alpha_B 4.45e-3 \
Y_alpha_V0 {{EREST_ACT} + 0.006} Y_beta_FORM {LINOID} \
Y_beta_A -309.3 Y_beta_B -4.0e-3 Y_beta_V0 {EREST_ACT}
EREST_ACT = tempvar
end
//========================================================================
// SEJNOWSKI CA (T) CHANNEL (TABULATED)
// Lytton & Sejnowski (1991), J. Neurophysiology, in press
//========================================================================
// This channel assumes an EREST_ACT of -0.055 V for published kinetics
function make_Ca_sej_tab
if (({exists Ca_sej_tab}))
return
end
create tabchannel Ca_sej_tab
setfield Ca_sej_tab Ek {ECA} Gbar {10.0*{SOMA_A}} Ik 0 Gk 0 Xpower 3 \
Ypower 1 Zpower 0
setup_tabchan_bg Ca_sej_tab X 3.43 0.5 {-0.008 + {EREST_ACT}} \
60.0 60.0 23.0 2.5e-3
setup_tabchan_bg Ca_sej_tab Y -4.24 0.75 {-0.0285 + {EREST_ACT}} \
8.0 8.0 23.0 18.0e-3
end
//========================================================================
// HYPERPOLARIZATION-ACTIVATED K (H) CHANNEL (TABULATED)
// McCormick (1991), Single Neuron Computation, Academic Press
//========================================================================
function setup_Atable3_H(gate, table, xdivs, xmin, xmax)
str gate, table
int xdivs
float xmin, xmax
int i
float x, dx, y
dx = xdivs
dx = (xmax - xmin)/dx
x = xmin
for (i = 0; i <= (xdivs); i = i + 1)
y = 1.0/(({exp {-6.26 - 76.7*x}}) + ({exp {7.13 + 107.9*x}}))
setfield {gate} {table}->table[{i}] {y}
x = x + dx
end
end
function setup_Btable3_H(gate, table, xdivs, xmin, xmax)
str gate, table
int xdivs
float xmin, xmax
int i
float x, dx, y
dx = xdivs
dx = (xmax - xmin)/dx
x = xmin
for (i = 0; i <= (xdivs); i = i + 1)
y = (x + 0.069)/7.1e-3
y = 1.0/(1.0 + ({exp {y}}))
setfield {gate} {table}->table[{i}] {y}
x = x + dx
end
end
/* Sets up a tabchan with special non-hh params, with the non-interp option in
** a table of 3000 entries.
** This version uses parameters for tau and minf instead
** of alpha and beta */
function setup_tabchan_tau_H(chan, table)
str chan, table
str tabA = (table) @ "_A"
str tabB = (table) @ "_B"
call {chan} TABCREATE {table} 49 -0.1 0.05
setup_Atable3_H {chan} {tabA} 49 -0.1 0.05
setup_Btable3_H {chan} {tabB} 49 -0.1 0.05
tweaktau {chan} {table}
setfield {chan} {tabA}->calc_mode 0 {tabB}->calc_mode 0
call {chan} TABFILL {table} 3000 0
end
function make_H_lgn_tab
if (({exists H_lgn_tab}))
return
end
create tabchannel H_lgn_tab
setfield H_lgn_tab Ek {EH} Gbar {360.0*{SOMA_A}} Gk 0 Ik 0 \
Xpower 2 Ypower 0 Zpower 0
setup_tab_tau_H H_lgn_tab X
end
//==========================================================================
// K LEAK CHANNEL
// Pratik Mukherjee
//==========================================================================
// This channel is mainly used to regulate the resting membrane potential
function make_K_leak
if (({exists K_leak}))
return
end
create leakage K_leak
setfield K_leak Ek {EK} activation 0.0 Gk {Gleak} Ik 0.0 \
inject 0.0
end
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