//genesis

/* FILE INFORMATION
** The 1991 Traub set of voltage and concentration dependent channels
** Implemented as tabchannels by : Dave Beeman
**      R.D.Traub, R. K. S. Wong, R. Miles, and H. Michelson
**	Journal of Neurophysiology, Vol. 66, p. 635 (1991)
**
** This file depends on functions and constants defined in defaults.g
** As it is also intended as an example of the use of the tabchannel
** object to implement concentration dependent channels, it has extensive
** comments.  Note that the original units used in the paper have been
** converted to SI (MKS) units.  Also, we define the ionic equilibrium 
** potentials relative to the resting potential, EREST_ACT.  In the
** paper, this was defined to be zero.  Here, we use -0.060 volts, the
** measured value relative to the outside of the cell.
*/

/* November 1999 update for GENESIS 2.2: Previous versions of this file used
   a combination of a table, tabgate, and vdep_channel to implement the
   Ca-dependent K Channel - K(C).  This new version uses the new tabchannel
   "instant" field, introduced in GENESIS 2.2, to implement an
   "instantaneous" gate for the multiplicative Ca-dependent factor in the
   conductance.   This allows these channels to be used with the fast
   hsolve chanmodes > 1.
*/

// Now updated for Traub et al. J Neurophysiol 2003;89:909-921.

// CONSTANTS
float EREST_ACT = -0.070 /*  cell resting potl */
float ENAP23FRBa = 0.110 + EREST_ACT // 0.05
float EKP23FRBa = -0.025 + EREST_ACT // -0.095
float ECAP23FRBa = 0.195 + EREST_ACT // 0.125
float EARP23FRBa = 0.035 + EREST_ACT // -0.035
float SOMA_A = 3.320e-9       // soma area in square meters

/*
For these channels, the maximum channel conductance (Gbar) has been
calculated using the CA3 soma channel conductance densities and soma
area.  Typically, the functions which create these channels will be used
to create a library of prototype channels.  When the cell reader creates
copies of these channels in various compartments, it will set the actual
value of Gbar by calculating it from the cell parameter file.
*/

//========================================================================
//                Tabchannel gNa-transient, gNa(F) 2005/03
//========================================================================
function make_NaF22
        str chanpath = "NaF22"
        if ({exists NaF22})
            return
        end
        create tabchannel NaF22
        setfield NaF22 \ 
            Ek              0.05 \
            Ik              0  \
            Xpower          3 \
            Ypower          1
        setfield NaF22 \
            Gbar 1875 \
            Gk              0 
        float tab_divs = 741
        float v_min = -0.12
        float v_max = 0.06
        float v, dv, i

        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call NaF22 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            //  tau
            float tau
            v = v * 1000 // v to units of equation
            if (v  < -26.5 )
                tau =  0.025 + 0.14 * { exp { {v  + 26.5} / 10} } 
            else
                tau =  0.02 + 0.145 * { exp { -1 * {v + 26.5} / 10.0} }
            end
            v = v * 0.001 // reset v
            
            // Set correct units of tau
            tau = tau * 0.001

            //  inf
            float inf
            v = v * 1000 // v to units of equation
            inf =  1 / { 1 + {exp { -1*{v + 34.5} / 10}} } 
            v = v * 0.001 // reset v
            

            // alpha and beta
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            setfield NaF22 X_A->table[{i}] {alpha}
            setfield NaF22 X_B->table[{i}] {alpha + beta}
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield NaF22 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Y table for gate h
        float dv = ({v_max} - {v_min})/{tab_divs}
        call NaF22 TABCREATE Y {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // tau
            float tau
            v = v * 1000 // v to units of equation
            tau = 0.15 + 1.15 / { 1 + { exp {{v + 37} / 15} } }
            v = v * 0.001 // reset v
            // Set correct units of tau
            tau = tau * 0.001

            // inf
            float inf
            v = v * 1000 // v to units of equation
            inf = 1 / { 1 + {exp { {v + 62.9} / 10.7}} }
            v = v * 0.001 // reset v
            
            //  alpha and beta
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            setfield NaF22 Y_A->table[{i}] {alpha}
            setfield NaF22 Y_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield NaF22 Y_A->calc_mode 1 Y_B->calc_mode 1
end

//========================================================================
// P23FRB   Tabchannel gNa-persistent (non-inactivating), gNa(P) 2005/03
//========================================================================
function make_NaP22
        str chanpath = "NaP22"
        if ({exists NaP22})
            return
        end
        create tabchannel NaP22
        setfield NaP22 \ 
            Ek              0.05 \
            Ik              0  \
            Xpower          1
        setfield NaP22 \
            Gbar 1 \
            Gk              0 
        float tab_divs = 741
        float v_min = -0.12
        float v_max = 0.06
        float v, dv, i
            
        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call NaP22 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            //  tau
            float tau
            v = v * 1000 // v to units of equation
            if (v < -40 )
                tau =  0.025 + 0.14 * {exp {{ v + 40 }/10}} 
            else
                tau =  0.02 + 0.145 * {exp {-1 * {v + 40}/ 10}}
            end
            v = v * 0.001 // reset v
            // correct units of tau
            tau = tau * 0.001

            // inf
            float inf
            // A = 1, B = -10, Vhalf = -48, in units: Physiological Units
            // A = 1, B = -0.01, Vhalf = -0.048
            inf = 1 / ( {exp {(v + 0.048) / -0.01}} + 1)

            // alpha and beat
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            setfield NaP22 X_A->table[{i}] {alpha}
            setfield NaP22 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield NaP22 X_A->calc_mode 1 X_B->calc_mode 1
end

//========================================================================
//   P23FRB    Tabchannel Anomalous Rectifier, gAR 2005/03
//========================================================================
function make_AR22
        if ({exists AR22})
            return
        end
        create tabchannel AR22
        setfield AR22 \ 
            Ek              -0.035 \
            Ik              0  \
            Xpower          1
        
        setfield AR22 \
            Gbar 2.5 \
            Gk              0 
        float tab_divs = 741
        float v_min = -0.12
        float v_max = 0.06
        float v, dv, i
            
        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call AR22 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // tau
            float tau
            v = v * 1000 // v to units of equation
            tau = 1 /{{exp {-14.6 - {0.086 * v} }} + {exp {-1.87 + {0.07 * v}}}}
            v = v * 0.001 // reset v
            
            // correct units of tau
            tau = tau * 0.001

            // inf
            float inf
                
            // A = 1, B = 5.5, Vhalf = -75, in units: Physiological Units
            // A = 1, B = 0.0055, Vhalf = -0.075
            inf = 1 / ( {exp {(v + 0.075) / 0.0055}} + 1)
        
            //  alpha and beta 
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            setfield AR22 X_A->table[{i}] {alpha}
            setfield AR22 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield AR22 X_A->calc_mode 1 X_B->calc_mode 1
end

//========================================================================
//  P23FRB    Tabchannel gK-delayed rectifier, gK(DR) 2005/03
//========================================================================
function make_KDR22
        if ({exists KDR22})
            return
        end
        create tabchannel KDR22
        setfield KDR22 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          4
        
        setfield KDR22 \
            Gbar 1250 \
            Gk              0 
        float tab_divs = 741
        float v_min = -0.12
        float v_max = 0.06
        float v, dv, i
            
        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call KDR22 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)

            // tau
            float tau
            v = v * 1000 // v to units of equation
            if (v < -10 )
                tau =  0.25 + 4.35 * {exp {{ v + 10 }/10}} 
            else
                tau =  0.25 + 4.35 * {exp {{- v - 10}/ 10}}
            end
            v = v * 0.001 // reset v
            tau = tau * 0.001 // correct units of tau

            //  inf
            float inf
            // A = 1, B = -10, Vhalf = -29.5, in units: Physiological Units
            // A = 1, B = -0.01, Vhalf = -0.0295
            inf = 1 / ( {exp {(v + 0.0295) / -0.01}} + 1)

            
            // alpha and beta 
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            setfield KDR22 X_A->table[{i}] {alpha}
            setfield KDR22 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield KDR22 X_A->calc_mode 1 X_B->calc_mode 1
end

//========================================================================
//   P23FRB       Tabchannel gK-transient, gK(A) 2005/03
//========================================================================
function make_KA22
        if ({exists KA22})
            return
        end
        create tabchannel KA22
        setfield KA22 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          4 \
            Ypower          1
        setfield KA22 \
            Gbar 300 \
            Gk              0 
        float tab_divs = 741
        float v_min = -0.12
        float v_max = 0.06
        float v, dv, i
            
        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call KA22 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // tau
            float tau
            v = v * 1000 // v to units of equation
            tau = 0.185 + 0.5 / {{exp {{ v + 35.8 }/19.7}} + {exp {{-v - 79.7}/12.7}}}
            v = v * 0.001 // reset v
            // correct units of tau
            tau = tau * 0.001

            // inf
            float inf
                
            float A, B, Vhalf
                             

            // ChannelML form of equation: inf which is of form sigmoid, with params:
            // A = 1, B = -8.5, Vhalf = -60, in units: Physiological Units
            // A = 1, B = -0.0085, Vhalf = -0.06
            inf = 1 / ( {exp {(v + 0.06) /-0.0085}} + 1)
        
            // alpha and beta 
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            setfield KA22 X_A->table[{i}] {alpha}
            setfield KA22 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
        setfield KA22 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Y table for gate h
        float dv = ({v_max} - {v_min})/{tab_divs}
        call KA22 TABCREATE Y {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // tau
            float tau
            v = v * 1000 // v to units of equation
            if (v < -63.0 )
                tau =  0.5 / {{exp {{ v + 46 }/5}} + {exp {{ -v - 238 }/37.5}}} 
            else
                tau =  9.5
            end
            v = v * 0.001 // reset v
            // correct units of tau
            tau = tau * 0.001

            // inf
            float inf
                
            // A = 1, B = 6, Vhalf = -78, in units: Physiological Units
            // A = 1, B = 0.006, Vhalf = -0.078
            inf = 1 / ( {exp {(v + 0.078) / 0.006}} + 1)
        
            // alpha and beta
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            setfield KA22 Y_A->table[{i}] {alpha}
            setfield KA22 Y_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield KA22 Y_A->calc_mode 1 Y_B->calc_mode 1
end

//========================================================================
// P23FRB          Tabchannel gK2-slow, gK2 2005/03
//========================================================================
function make_K222
        if ({exists K222})
            return
        end
        create tabchannel K222
        setfield K222 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          1 \
            Ypower          1
        
        setfield K222 \
            Gbar 1 \
            Gk              0 
        float tab_divs = 741
        float v_min = -0.12
        float v_max = 0.06
        float v, dv, i
            
        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call K222 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // tau
            float tau
            v = v * 1000 //  v to units of equat.
            tau = 4.95 + 0.5 / { {exp { {v - 81} / 25.6}} + {exp { {- v - 132} / 18 }}}
            v = v * 0.001 // reset v
            //  correct units of tau
            tau = tau * 0.001

            //  inf
            float inf
            // A = 1, B = -17, Vhalf = -10, in units: Physiological Units
            // A = 1, B = -0.017, Vhalf = -0.01
            inf = 1 / ( {exp {(v + 0.01) / -0.017}} + 1)

            // alpha and beta 
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            setfield K222 X_A->table[{i}] {alpha}
            setfield K222 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield K222 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Y table for gate h
        float dv = ({v_max} - {v_min})/{tab_divs}
        call K222 TABCREATE Y {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            //  tau
            float tau
            v = v * 1000 // v to units of equation
            tau = 60 + 0.5 / {{exp {{ v - 1.33 }/200}} + {exp {{- v - 130}/ 7.1}}}
            v = v * 0.001 // reset v
            // correct units of tau
            tau = tau * 0.001

            // inf
            float inf
            // A = 1, B = 10.6, Vhalf = -58, in units: Physiological Units
            // A = 1, B = 0.0106, half = -0.058
            inf = 1 / ( {exp {(v + 0.058) / 0.0106}} + 1)

            // alpha and beta
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            setfield K222 Y_A->table[{i}] {alpha}
            setfield K222 Y_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield K222 Y_A->calc_mode 1 Y_B->calc_mode 1
end

//========================================================================
// P23FRB    Tabchannel gK-muscarinic receptor supressed, gK(M) 2005/03
//========================================================================
function make_KM22
        if ({exists KM22})
            return
        end
        create tabchannel KM22
        setfield KM22 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          1
        setfield KM22 \
            Gbar 75 \
            Gk              0 
        float tab_divs = 741
        float v_min = -0.12
        float v_max = 0.06
        float v, dv, i
        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call KM22 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)

            // alpha
            float alpha
            // A = 0.02, B = -5, Vhalf = -20, in units: Physiological Units
            // A = 20, B = -0.005, Vhalf = -0.02
            alpha = 20 / ( {exp {(v + 0.02) / -0.005}} + 1)
        
            // beta
            float beta
            // A = 0.01, B = -18, Vhalf = -43, in units: Physiological Units
            // A = 10, B = -0.018, Vhalf = -0.043
            beta = 10 * {exp {(v + 0.043) / -0.018}}
        
            // alpha and beta 
            float tau = 1/(alpha + beta)
            setfield KM22 X_A->table[{i}] {alpha}
            setfield KM22 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
        setfield KM22 X_A->calc_mode 1 X_B->calc_mode 1
end

//========================================================================
//  P23FRB   Tabchannel gCa(L)-low threshold, transient, gCa(L) 2005/03
//========================================================================
function make_CaL22
        if ({exists CaL22})
            return
        end
        create tabchannel CaL22
        setfield CaL22 \ 
            Ek              0.125 \
            Ik              0  \
            Xpower          2 \
            Ypower          1
        
        setfield CaL22 \
            Gbar 1 \
            Gk              0 
        float tab_divs = 741
        float v_min = -0.12
        float v_max = 0.06
        float v, dv, i
        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call CaL22 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            //  tau
            float tau
                
            v = v * 1000 // v to units of equation
            tau = 0.204 + 0.333 / { {exp {{15.8 + v} / 18.2 }} + {exp {{- v - 131} / 16.7}} }
            v = v * 0.001 // reset v
            // correct units of tau
            tau = tau * 0.001

            // inf
            float inf
                
            float A, B, Vhalf
            // A = 1, B = -6.2, Vhalf = -56.0, in units: Physiological Units
            // A = 1, B = -0.0062, Vhalf = -0.056
            inf = 1 / ( {exp {(v + 0.056) / -0.0062}} + 1)
        
            // alpha and beta
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            setfield CaL22 X_A->table[{i}] {alpha}
            setfield CaL22 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield CaL22 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Y table for gate h
        float dv = ({v_max} - {v_min})/{tab_divs}
        call CaL22 TABCREATE Y {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // tau
            float tau
            v = v * 1000 // v to units of equation
            if (v < -81.0 )
                tau =  0.333 * {exp {{ v + 466 } / 66.6}} 
            else
                tau =  9.32 + 0.333 * {exp {{ - v - 21 } / 10.5}}
            end
            v = v * 0.001 // reset v
            // correct units of tau
            tau = tau * 0.001

            // inf
            float inf
            // A = 1, B = 4, Vhalf = -80, in units: Physiological Units
            // A = 1, B = 0.004, Vhalf = -0.08
            inf = 1 / ( {exp {(v + 0.08) / 0.004}} + 1)
        

            // alpha and beta
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            setfield CaL22 Y_A->table[{i}] {alpha}
            setfield CaL22 Y_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield CaL22 Y_A->calc_mode 1 Y_B->calc_mode 1
end

//==========================================================================
// P23FRB    Tabchannel gCaH-high threshold calcium, gCa(L) "long" 2003/05
//==========================================================================
function make_CaH22
        if ({exists CaH22})
            return
        end
        create tabchannel CaH22
        setfield CaH22 \ 
            Ek              0.125 \
            Ik              0  \
            Xpower          2
        
        setfield CaH22 \
            Gbar 5 \
            Gk              0 

        float tab_divs = 741
        float v_min = -0.12
        float v_max = 0.06
        float v, dv, i
        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call CaH22 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // alpha
            float alpha
                
            // A = 1.6, B = -13.888889, Vhalf = 5, in units: Physiological Units
            // A = 1600, B = -0.013888889000000001, Vhalf = 0.005
            alpha = 1600 / ( {exp {(v - 0.005) / -0.013888889000000001}} + 1)
        
            //  beta
            float beta
                
            // A = 0.1, B = -5, Vhalf = -8.9, in units: Physiological Units
            // A = 100, B = -0.005, Vhalf = -0.0089
            if ( {abs {(v + 0.0089)/ -0.005}} < 1e-6)
                beta = 100 * (1 + (v + 0.0089)/-0.005/2)
            else
                beta = 100 * ((v + 0.0089) / -0.005) /(1 - {exp {-1 * (v + 0.0089)/-0.005}})
            end

            //  alpha and beta 
            float tau = 1/(alpha + beta)
            setfield CaH22 X_A->table[{i}] {alpha}
            setfield CaH22 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield CaH22 X_A->calc_mode 1 X_B->calc_mode 1
end

//========================================================================
//   P23FRB   Ca conc, Traub et al. J Neurophysiol 2003;89:909-921.
//========================================================================
/****************************************************************************
Next, we need an element to take the Calcium current calculated by the Ca
channel and convert it to the Ca concentration.  The "Ca_concen" object
solves the equation dC/dt = B*I_Ca - C/tau, and sets Ca = Ca_base + C.  As
it is easy to make mistakes in units when using this Calcium diffusion
equation, the units used here merit some discussion.

With Ca_base = 0, this corresponds to Traub's diffusion equation for
concentration, except that the sign of the current term here is positive, as
GENESIS uses the convention that I_Ca is the current flowing INTO the
compartment through the channel.  In SI units, the concentration is usually
expressed in moles/m^3 (which equals millimoles/liter), and the units of B
are chosen so that B = 1/(ion_charge * Faraday * volume). Current is
expressed in amperes and one Faraday = 96487 coulombs.  However, in this
case, Traub expresses the concentration in arbitrary units, current in
microamps and uses tau = 13.33 msec (50 msec soma, 20 msec dendrites in the
2003 J Neurophys paper).  If we use the same concentration units,
but express current in amperes and tau in seconds, our B constant is then
10^12 times the constant (called "phi") used in the paper.  The actual value
used will typically be determined by the cell reader from the cell
parameter file (will vary inversely with surface area of compartment).  
However, for the prototype channel we will use Traub's
corrected value for the soma.  (An error in the paper gives it as 17,402
rather than 17.402.)  In our units, this will be 17.402e12.

****************************************************************************/
function make_Ca_s22
        if ({exists Ca_s22})
            return
        end
        create Ca_concen Ca_s22
        // params for soma Ca pool 
        setfield Ca_s22 \
            tau                   { 1.0 / 10 }    \
            Ca_base               0
        addfield Ca_s22 addmsg1
        setfield Ca_s22 \
                addmsg1        "../CaH22 . I_Ca Ik"
//        addfield Ca_s22 addmsg2
//        setfield Ca_s22 \
//                addmsg2        "../CaL22 . I_Ca Ik"
end
/*
This Ca_concen element should receive an "I_Ca" message from the calcium
channel, accompanied by the value of the calcium channel current.  As we
will ordinarily use the cell reader to create copies of these prototype
elements in one or more compartments, we need some way to be sure that the
needed messages are established.  Although the cell reader has enough
information to create the messages which link compartments to their channels
and to other adjacent compartments, it must be provided with the information
needed to establish additional messages.  This is done by placing the
message string in a user-defined field of one of the elements which is
involved in the message.  The cell reader recognizes the added field names
"addmsg1", "addmsg2", etc. as indicating that they are to be
evaluated and used to set up messages.  The paths are relative to the
element which contains the message string in its added field.  Thus,
"../Ca_hip_traub91" refers to the sibling element Ca_hip_traub91 and "."
refers to the Ca_hip_conc element itself.
*/

/****************************************************************************/
function make_Ca_d22
        if ({exists Ca_d22})
            return
        end
        create Ca_concen Ca_d22
        // params for dend. Ca pool model
        setfield Ca_d22 \
            tau                   { 1.0 / 50 }    \
            Ca_base               0

        addfield Ca_d22 addmsg1
        setfield Ca_d22 \
                addmsg1        "../CaH22 . I_Ca Ik"
//        addfield Ca_d22 addmsg2
//        setfield Ca_d22 \
//                addmsg2        "../CaL22 . I_Ca Ik"
end
/*
This Ca_concen element should receive an "I_Ca" message from the calcium
channel, accompanied by the value of the calcium channel current.  As we
will ordinarily use the cell reader to create copies of these prototype
elements in one or more compartments, we need some way to be sure that the
needed messages are established.  Although the cell reader has enough
information to create the messages which link compartments to their channels
and to other adjacent compartments, it must be provided with the information
needed to establish additional messages.  This is done by placing the
message string in a user-defined field of one of the elements which is
involved in the message.  The cell reader recognizes the added field names
"addmsg1", "addmsg2", etc. as indicating that they are to be
evaluated and used to set up messages.  The paths are relative to the
element which contains the message string in its added field.  Thus,
"../Ca_hip_traub91" refers to the sibling element Ca_hip_traub91 and "."
refers to the Ca_hip_conc element itself.
*/

//===============================================================================
//  P23FRB Ca-dependent K Channel K(C)
//===============================================================================
/*
The expression for the conductance of the potassium C-current channel has a
typical voltage and time dependent activation gate, where the time dependence
arises from the solution of a differential equation containing the rate
parameters alpha and beta.  It is multiplied by a function of calcium
concentration that is given explicitly rather than being obtained from a
differential equation.  Therefore, we need a way to multiply the activation
by a concentration dependent value which is determined from a lookup table.
This is accomplished by using the Z gate with the new tabchannel "instant"
field, introduced in GENESIS 2.2, to implement an "instantaneous" gate for
the multiplicative Ca-dependent factor in the conductance.
*/
function make_KCs22
        if ({exists KCs22})
            return
        end
        create tabchannel KCs22
        setfield KCs22 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          1 \
            Zpower          1
        setfield KCs22 \
            Gbar 120 \
            Gk              0 
        float tab_divs = 1041
        float v_min = -0.12
        float v_max = 0.14
        float v, dv, i
            
        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call KCs22 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // alpha
            float alpha
            v = v * 1000 // v to units of equation
            if (v < -10 )
                alpha =  {2 / 37.95} * { exp { {{v + 50 } / 11} - {{ v + 53.5} / 27} } } 
            else
                alpha =  2 * {exp { { {-1 * v} - 53.5 } / 27 }}
            end
            v = v * 0.001 // reset v
            //  correct units of alpha
            alpha = alpha * 1000

            
            // beta
            float beta
            v = v * 1000 // v to units of equation
            alpha = alpha * 0.001 // alpha to units of equation
            if (v < -10 )
                beta =  2 * {exp { { {-1 * v} - 53.5 } / 27 }} - alpha 
            else
                beta =  0.0
            end
            v = v * 0.001 // reset v
            alpha = alpha * 1000  // resetting alpha
            // correct units of beta
            beta = beta * 1000

            // alpha and beta
            float tau = 1/(alpha + beta)
            
            setfield KCs22 X_A->table[{i}] {alpha}
            setfield KCs22 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield KCs22 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Ca dependent term (voltage independent)
        float conc_min = 0
        float conc_max = 1000
        float dc = ({conc_max} - {conc_min})/{tab_divs}
        float ca_conc = {conc_min}
        call KCs22 TABCREATE  Z {tab_divs} {conc_min} {conc_max}
        float const_state
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            ca_conc = ca_conc * 0.000001 // ca_conc to units of equation
            if (ca_conc < 0.00025 )
                const_state =  {ca_conc / 0.00025} 
            else
                const_state =  1
            end
            ca_conc = ca_conc * 1000000 //reset  ca_conc
            
            setfield KCs22 Z_A->table[{i}] {0}
            setfield KCs22 Z_B->table[{i}] {const_state}
            ca_conc= ca_conc + dc
        end
        tweaktau KCs22 Z
        
        addfield KCs22 addmsg1
        setfield KCs22 addmsg1  "../Ca_s22  . CONCEN Ca"
end


function make_KCd22
        if ({exists KCd22})
            return
        end
        create tabchannel KCd22
        setfield KCd22 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          1 \
            Zpower          1
        setfield KCd22 \
            Gbar 120 \
            Gk              0 
        float tab_divs = 1041
        float v_min = -0.12
        float v_max = 0.14
        float v, dv, i
            
        // X table for gate m
        float dv = ({v_max} - {v_min})/{tab_divs}
        call KCd22 TABCREATE X {tab_divs} {v_min} {v_max}
        v = {v_min}
        for (i = 0; i <= ({tab_divs}); i = i + 1)

            //  alpha
            float alpha
            v = v * 1000 // v to units of equation
            if (v < -10 )
                alpha =  {2 / 37.95} * { exp { {{v + 50 } / 11} - {{ v + 53.5} / 27} } } 
            else
                alpha =  2 * {exp { { {-1 * v} - 53.5 } / 27 }}
            end
            v = v * 0.001 // reset v
            // correct units of alpha
            alpha = alpha * 1000

            // beta
            float beta
            v = v * 1000 // v to units of equation
            alpha = alpha * 0.001 // alpha to units of equation
            if (v < -10 )
                beta =  2 * {exp { { {-1 * v} - 53.5 } / 27 }} - alpha 
            else
                beta =  0.0
            end
            v = v * 0.001 // reset v
            alpha = alpha * 1000  // resetting alpha
                        
            // correct units of beta
            beta = beta * 1000
            
            //alpha and beta 
            float tau = 1/(alpha + beta)
            
            setfield KCd22 X_A->table[{i}] {alpha}
            setfield KCd22 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield KCd22 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Ca dependent term (voltage independent)
        float conc_min = 0
        float conc_max = 1000
        float dc = ({conc_max} - {conc_min})/{tab_divs}
        float ca_conc = {conc_min}
        call KCd22 TABCREATE  Z {tab_divs} {conc_min} {conc_max}
        float const_state
        for (i = 0; i <= ({tab_divs}); i = i + 1)
            ca_conc = ca_conc * 0.000001 // ca_conc to units of equation
            if (ca_conc < 0.00025 )
                const_state =  {ca_conc / 0.00025} 
            else
                const_state =  1
            end
            ca_conc = ca_conc * 1000000 //reset ca_conc 
            
            setfield KCd22 Z_A->table[{i}] {0}
            setfield KCd22 Z_B->table[{i}] {const_state}
            ca_conc= ca_conc + dc
        end
        tweaktau KCd22 Z
        
        addfield KCd22 addmsg1
        setfield KCd22 addmsg1  "../Ca_d22  . CONCEN Ca"
end


//========================================================================
//              P23FRB  Ca-dependent K AHP Channel,gK(AHP) 
//========================================================================

/* This is a tabchannel which gets the calcium concentration from Ca pool
   in order to calculate the activation of its Z gate.  It is set up much
   like the Ca channel, except that the A and B tables have values which are
   functions of concentration, instead of voltage.
*/


function make_KAHPs22
        if ({exists KAHPs22})
            return
        end
        create tabchannel KAHPs22
        setfield KAHPs22 \ 
            Ek              -0.095 \
            Ik              0  \
            Zpower          1
        
        setfield KAHPs22 \
            Gbar 1 \
            Gk              0 
        float tab_divs = 1041
        // Ca dependent channel 
        float c
        float conc_min = 0
        float conc_max = 1000
        float dc = ({conc_max} - {conc_min})/{tab_divs}
        float ca_conc = {conc_min}
        call KAHPs22 TABCREATE Z {tab_divs} {conc_min} {conc_max}
        for (c = 0; c <= ({tab_divs}); c = c + 1)
                    
            // alpha
            float alpha
            float v
            ca_conc = ca_conc * 0.000001 // ca_conc to units of equation
            if (ca_conc < 0.0001 )
                alpha =  ca_conc/0.01 
            else
                alpha =  0.01
            end
            ca_conc = ca_conc * 1000000 // resetting ca_conc 
            // correct units of alpha
            alpha = alpha * 1000

            // beta
            float beta
            ca_conc = ca_conc * 0.000001 // ca_conc to units of equation
            beta = 0.01
            ca_conc = ca_conc * 1000000 // resetting ca_conc 
            // correct units of beta
            beta = beta * 1000

            // alpha and beta 

            float tau = 1/(alpha + beta)
            setfield KAHPs22 Z_A->table[{c}] {alpha}
            setfield KAHPs22 Z_B->table[{c}] {alpha + beta}
                    ca_conc = ca_conc + dc
        end // end of for (c = 0; c <= ({tab_divs}); c = c + 1)
                
        setfield KAHPs22 Z_conc 1
        setfield KAHPs22 Z_A->calc_mode 1 Z_B->calc_mode 1

        addfield KAHPs22 addmsg1
        setfield KAHPs22  \
                addmsg1        "../Ca_s22 . CONCEN Ca"
end


function make_KAHPd22
        if ({exists KAHPd22})
            return
        end
        create tabchannel KAHPd22
        setfield KAHPd22 \ 
            Ek              -0.095 \
            Ik              0  \
            Zpower          1
        setfield KAHPd22 \
            Gbar 1 \
            Gk              0 
        float tab_divs = 1041

        float c
        float conc_min = 0
        float conc_max = 1000
        float dc = ({conc_max} - {conc_min})/{tab_divs}
        float ca_conc = {conc_min}
        call KAHPd22 TABCREATE Z {tab_divs} {conc_min} {conc_max}
        for (c = 0; c <= ({tab_divs}); c = c + 1)
                    
            // alpha
            float alpha
            ca_conc = ca_conc * 0.000001 // ca_conc to units of equation
            if (ca_conc < 0.0001 )
                alpha =  ca_conc/0.01 
            else
                alpha =  0.01
            end
            ca_conc = ca_conc * 1000000 // reset ca_conc 
            // correct units of alpha
            alpha = alpha * 1000

            // beta
            float beta
            ca_conc = ca_conc * 0.000001 // ca_conc to units of equation
            beta = 0.01
            ca_conc = ca_conc * 1000000 // reset ca_conc 
            // correct units of beta
            beta = beta * 1000

            // alpha and beta
            float tau = 1/(alpha + beta)
            
            setfield KAHPd22 Z_A->table[{c}] {alpha}
            setfield KAHPd22 Z_B->table[{c}] {alpha + beta}
                    ca_conc = ca_conc + dc
        end // end of for (c = 0; c <= ({tab_divs}); c = c + 1)
                
        setfield KAHPd22 Z_conc 1
        setfield KAHPd22 Z_A->calc_mode 1 Z_B->calc_mode 1

        addfield KAHPd22 addmsg1
        setfield KAHPd22  \
                addmsg1        "../Ca_d22 . CONCEN Ca"
end