//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 /* hippocampal cell resting potl */
float ENAP5IBa = 0.11 + EREST_ACT // 0.05
float EKP5IBa = -0.025 + EREST_ACT // -0.095
float ECAP5IBa = 0.195 + EREST_ACT // 0.125
float EARP5IBa = 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_NaF6
        if ({exists NaF6})
            return
        end
        
        create tabchannel NaF6
            

        setfield NaF6 \ 
            Ek              0.05 \
            Ik              0  \
            Xpower          3 \
            Ypower          1
        
        setfield NaF6 \
            Gbar 1875 \
            Gk              0 

        float tab_divs = 741
        float v_min = -0.12

        float v_max = 0.06

        float v, dv, i
            
        // Creating table for gate m, using name X for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call NaF6 TABCREATE X {tab_divs} {v_min} {v_max}
                
        v = {v_min}

            

        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // Looking at rate: tau
                

            float tau
            v = v * 1000 // temporarily set v to units of equation...
            if ({v - 3.5} < -30 )
                tau =  0.025 + 0.14 * { exp { {{v - 3.5} + 30} / 10} } 
            else
                tau =  0.02 + 0.145 * { exp { -1 * {{v - 3.5} + 30} / 10.0} }
            end
            v = v * 0.001 // reset v
            
            // Set correct units of tau
            tau = tau * 0.001
            // inf
                

            float inf
            v = v * 1000 // temporarily set v to units of equation...
            inf =  1 / { 1 + {exp { { -1 * {v - 3.5} - 38} / 10}} } 
            v = v * 0.001 // reset v
            

            // Working out the "real" alpha and beta expressions from the tau and inf
            
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            
            setfield NaF6 X_A->table[{i}] {alpha}
            setfield NaF6 X_B->table[{i}] {alpha + beta}

                
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield NaF6 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Creating table for gate h, using name Y for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call NaF6 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 // temporarily set 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
            // Looking at rate: inf
                

            float inf
            v = v * 1000 // temporarily set v to units of equation...
            inf = 1 / { 1 + {exp {{ v + 62.9 } / 10.7}} }
            v = v * 0.001 // reset v
            

            // Working out the "real" alpha and beta expressions from the tau and inf
            
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            
            setfield NaF6 Y_A->table[{i}] {alpha}
            setfield NaF6 Y_B->table[{i}] {alpha + beta}

                
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield NaF6 Y_A->calc_mode 1 Y_B->calc_mode 1
                    


end

//========================================================================
//        Tabchannel gNa-persistent (non-inactivating), gNa(P) 2005/03
//========================================================================
function make_NaP6
        if ({exists NaP6})
            return
        end
        
        create tabchannel NaP6
            

        setfield NaP6 \ 
            Ek              0.05 \
            Ik              0  \
            Xpower          1
        
        setfield NaP6 \
            Gbar 1 \
            Gk              0 

        float tab_divs = 741
        float v_min = -0.12

        float v_max = 0.06

        float v, dv, i
            
        // Creating table for gate m, using name X for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call NaP6 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 // temporarily set 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
            
            // Set correct units of tau
            tau = tau * 0.001
            // inf
            float inf
            float A, B, Vhalf
                             
            inf = 1 / ( {exp {(v +0.048) / -0.01}} + 1)

            // alpha & beta 
            
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            setfield NaP6 X_A->table[{i}] {alpha}
            setfield NaP6 X_B->table[{i}] {alpha + beta}
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield NaP6 X_A->calc_mode 1 X_B->calc_mode 1
                    


end

//========================================================================
//        Tabchannel Anomalous Rectifier, gAR 2005/03
//========================================================================
function make_AR6
        if ({exists AR6})
            return
        end
        
        create tabchannel AR6
            

        setfield AR6 \ 
            Ek              -0.035 \
            Ik              0  \
            Xpower          1
        
        setfield AR6 \
            Gbar 2.5 \
            Gk              0 

        float tab_divs = 741
        float v_min = -0.12

        float v_max = 0.06

        float v, dv, i
            
        // Creating table for gate m, using name X for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call AR6 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 // temporarily set 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
            inf = 1 / ( {exp {(v + 0.075) / 0.0055}} + 1)
        
            // alpha &beta 
            
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau

            setfield AR6 X_A->table[{i}] {alpha}
            setfield AR6 X_B->table[{i}] {alpha + beta}
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield AR6 X_A->calc_mode 1 X_B->calc_mode 1
end

//========================================================================
//                Tabchannel gK-delayed rectifier, gK(DR) 2005/03
//========================================================================
function make_KDR6
        if ({exists KDR6})
            return
        end
        
        create tabchannel KDR6
            

        setfield KDR6 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          4
        
        setfield KDR6 \
            Gbar 1250 \
            Gk              0 

        
        float tab_divs = 741
        float v_min = -0.12

        float v_max = 0.06

        float v, dv, i
            
        // Creating table for gate m, using name X for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call KDR6 TABCREATE X {tab_divs} {v_min} {v_max}
                
        v = {v_min}

            

        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // Looking at rate: tau
                

            float tau
            v = v * 1000 // temporarily set 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
            
            // correct units of tau
            tau = tau * 0.001
            

            // inf
            float inf
            inf = 1 / ( {exp {(v + 0.0295) / -0.01}} + 1)

            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            
            setfield KDR6 X_A->table[{i}] {alpha}
            setfield KDR6 X_B->table[{i}] {alpha + beta}
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield KDR6 X_A->calc_mode 1 X_B->calc_mode 1
end

//========================================================================
//                Tabchannel gK-transient, gK(A) 2005/03
//========================================================================
function make_KA6
        if ({exists KA6})
            return
        end
        
        create tabchannel KA6

        setfield KA6 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          4 \
            Ypower          1
        
        setfield KA6 \
            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 KA6 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 // temporarily set 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
            // A = 1, B = -8.5, Vhalf = -60, in p.u. 
            // A = 1  B = -0.0085 Vhalf = -0.06 in SI
            inf = 1 / ( {exp {(v + 0.05) / -0.0085}} + 1)
        

            // alpha and beta
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            setfield KA6 X_A->table[{i}] {alpha}
            setfield KA6 X_B->table[{i}] {alpha + beta}
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield KA6 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Creating table for gate h, using name Y for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call KA6 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 // temporarily set v to units of equation...
            if (v < -63.0 )
                tau =  2.6 * 0.5 / {{exp {{ v + 46 }/5}} + {exp {{ -v - 238 }/37.5}}} 
            else
                tau =  2.6 * 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 KA6 Y_A->table[{i}] {alpha}
            setfield KA6 Y_B->table[{i}] {alpha + beta}
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield KA6 Y_A->calc_mode 1 Y_B->calc_mode 1
end


//========================================================================
//                Tabchannel gK2-slow, gK2 2005/03
//========================================================================
function make_K26
        if ({exists K26})
            return
        end
        
        create tabchannel K26
        setfield K26 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          1 \
            Ypower          1
        
        setfield K26 \
            Gbar 1 \
            Gk              0 

        float tab_divs = 741
        float v_min = -0.12

        float v_max = 0.06

        float v, dv, i
            
        // Creating table for gate m, using name X for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call K26 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 // temporarily set v to units of equation...
            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 p.u. 
            // A = 1  B = -0.017 Vhalf = -0.01 in SI

            inf = 1 / ( {exp {(v + 0.01) / -0.017}} + 1)

            // alpha and beta
            
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            setfield K26 X_A->table[{i}] {alpha}
            setfield K26 X_B->table[{i}] {alpha + beta}
                
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield K26 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Creating table for gate h, using name Y for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call K26 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 // temporarily set 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 p.u.
            // A = 1  B = 0.0106  Vhalf = -0.058 in SI
            inf = 1 / ( {exp {(v + 0.058 ) / 0.0106}} + 1)
        
            // alpha and beta
            
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            setfield K26 Y_A->table[{i}] {alpha}
            setfield K26 Y_B->table[{i}] {alpha + beta}
                
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield K26 Y_A->calc_mode 1 Y_B->calc_mode 1
end

//========================================================================
//           Tabchannel gK-muscarinic receptor supressed, gK(M) 2005/03
//========================================================================
function make_KM6
        if ({exists KM6})
            return
        end
        
        create tabchannel KM6
        setfield KM6 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          1
        
        setfield KM6 \
            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 KM6 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 p.u.
            // A = 20 B = -0.005 Vhalf = -0.02 in SI

            alpha = 20 / ( {exp {(v + 0.02) / -0.005}} + 1)
        
            // beta
                

            float beta
                
            // A = 0.01, B = -18,   Vhalf = -43, in p.u.
            // A = 10    B = -0.018 Vhalf = -0.043 in SI
            beta = 10 * {exp {(v + 0.043) / -0.018}}
        
            //  tables

            float tau = 1/(alpha + beta)
            
            setfield KM6 X_A->table[{i}] {alpha}
            setfield KM6 X_B->table[{i}] {alpha + beta}
                    
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield KM6 X_A->calc_mode 1 X_B->calc_mode 1
end

//========================================================================
//          Tabchannel gCa(L)-low threshold, transient, gCa(L) 2005/03
//========================================================================
function make_CaL6
        if ({exists CaL6})
            return
        end
        
        create tabchannel CaL6
            

        setfield CaL6 \ 
            Ek              0.125 \
            Ik              0  \
            Xpower          2 \
            Ypower          1
        
        setfield CaL6 \
            Gbar 1 \
            Gk              0 

        float tab_divs = 741
        float v_min = -0.12

        float v_max = 0.06

        float v, dv, i
            
        // Creating table for gate m, using name X for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call CaL6 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 // temporarily set 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
            // A = 1, B = -6.2, Vhalf = -56.0, in physiological unit
            inf = 1 / ( {exp {(v + 0.056) / -0.0062}} + 1)
        
            // alpha and beta 
            
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            
            setfield CaL6 X_A->table[{i}] {alpha}
            setfield CaL6 X_B->table[{i}] {alpha + beta}
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield CaL6 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Creating table for gate h, using name Y for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call CaL6 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 // temporarily set 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
            inf = 1 / ( {exp {(v + 0.08) / 0.004}} + 1)

            // alpha and beta
            float alpha
            float beta
            alpha = inf / tau   
            beta = (1- inf)/tau
            
            
            setfield CaL6 Y_A->table[{i}] {alpha}
            setfield CaL6 Y_B->table[{i}] {alpha + beta}
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield CaL6 Y_A->calc_mode 1 Y_B->calc_mode 1
end

//==========================================================================
//            Tabchannel gCaH-high threshold calcium, gCa(L) "long" 2003/05
//==========================================================================
function make_CaH6
        if ({exists CaH6})
            return
        end
        
        create tabchannel CaH6
            

        setfield CaH6 \ 
            Ek              0.125 \
            Ik              0  \
            Xpower          2
        
        setfield CaH6 \
            Gbar 5 \
            Gk              0 

        float tab_divs = 741
        float v_min = -0.12

        float v_max = 0.06

        float v, dv, i
            
        // Creating table for gate m, using name X for it here

        float dv = ({v_max} - {v_min})/{tab_divs}
            
        call CaH6 TABCREATE X {tab_divs} {v_min} {v_max}
                
        v = {v_min}

            

        for (i = 0; i <= ({tab_divs}); i = i + 1)
            
            // Looking at rate: alpha
                

            float alpha

            // A = 1.6, B = -13.888889, Vhalf = 5, in physiological units
            alpha = 1600 / ( {exp {(v - 0.005) / -0.013888889000000001}} + 1)
        
            // beta
                

            float beta
            // A = 0.1, B = -5, Vhalf = -8.9, in units: Physiological Units
            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 CaH6 X_A->table[{i}] {alpha}
            setfield CaH6 X_B->table[{i}] {alpha + beta}
                    
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield CaH6 X_A->calc_mode 1 X_B->calc_mode 1
end

//========================================================================
//             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_s6
        if ({exists Ca_s6})
            return
        end
        create Ca_concen Ca_s6
        // params for a pool model in soma
        setfield Ca_s6 \
            tau                   { 1.0 / 10 }    \
            Ca_base               0

        addfield Ca_s6 addmsg1
        setfield Ca_s6 \
                addmsg1        "../CaH6 . I_Ca Ik"
        addfield Ca_s6 addmsg2
        setfield Ca_s6 \
                addmsg2        "../CaL6 . 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_d6
        if ({exists Ca_d6})
            return
        end
        create Ca_concen Ca_d6
        // par. for a pool model

        setfield Ca_d6 \
            tau                   { 1.0 / 75 }    \
            Ca_base               0

        addfield Ca_d6 addmsg1
        setfield Ca_d6 \
                addmsg1        "../CaH6 . I_Ca Ik"
        addfield Ca_d6 addmsg2
        setfield Ca_d6 \
                addmsg2        "../CaL6 . I_Ca Ik"
             
end


function make_Ca_db6

        if ({exists Ca_db6})
            return
        end

        create Ca_concen Ca_db6

        setfield Ca_db6 \
            tau                   { 1.0 / 20 }    \
            Ca_base               0

        addfield Ca_db6 addmsg1
        setfield Ca_db6 \
                addmsg1        "../CaH6 . I_Ca Ik"
        addfield Ca_db6 addmsg2
        setfield Ca_db6 \
                addmsg2        "../CaL6 . I_Ca Ik"
             
end


//===============================================================================
//  Ca-dependent K Channel - K(C) - (vdep_channel with table and tabgate)2005/03
//===============================================================================
/*
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_KCs6
        if ({exists KCs6})
            return
        end
        
        create tabchannel KCs6

        setfield KCs6 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          1 \
            Zpower          1
            
        
        setfield KCs6 \
            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 KCs6 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 // temporarily set 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 // temporarily set v to units of equation...
            
            // Equation depends on alpha, so converting it...
            alpha = alpha * 0.001

            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 to populate the tables

            float tau = 1/(alpha + beta)
            
            setfield KCs6 X_A->table[{i}] {alpha}
            setfield KCs6 X_B->table[{i}] {alpha + beta}
            v = v + dv

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield KCs6 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // Adding voltage independent concentration term
        
        float conc_min = 0
        float conc_max = 1000

        float dc = ({conc_max} - {conc_min})/{tab_divs}

        float ca_conc = {conc_min}
        
        call KCs6 TABCREATE  Z {tab_divs} {conc_min} {conc_max}
        
        float const_state

        for (i = 0; i <= ({tab_divs}); i = i + 1)
                
            // Equation is in different set of units...
            ca_conc = ca_conc * 0.000001
            if (ca_conc < 0.00025 )
                const_state =  {ca_conc / 0.00025} 
            else
                const_state =  1
            end
            // Converting back...
            ca_conc = ca_conc * 1000000
            
            setfield KCs6 Z_A->table[{i}] {0}
            setfield KCs6 Z_B->table[{i}] {const_state}

            ca_conc= ca_conc + dc
        end
             
        tweaktau KCs6 Z
        
        addfield KCs6 addmsg1
        setfield KCs6 addmsg1  "../Ca_s6  . CONCEN Ca"
end


function make_KCd6
        if ({exists KCd6})
            return
        end
        create tabchannel KCd6
        setfield KCd6 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          1 \
            Zpower          1
        setfield KCd6 \
            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 KCd6 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 // temporarily set 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 // temporarily set v to units of equation
            alpha = alpha * 0.001 // and set 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 KCd6 X_A->table[{i}] {alpha}
            setfield KCd6 X_B->table[{i}] {alpha + beta}
            v = v + dv
        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)
            
        setfield KCd6 X_A->calc_mode 1 X_B->calc_mode 1
        // Adding voltage independent concentration term
        
        float conc_min = 0
        float conc_max = 1000
        float dc = ({conc_max} - {conc_min})/{tab_divs}
        float ca_conc = {conc_min}
        call KCd6 TABCREATE  Z {tab_divs} {conc_min} {conc_max}
        float const_state
        for (i = 0; i <= ({tab_divs}); i = i + 1)
                
            // Equation is in different set of units...
            ca_conc = ca_conc * 0.000001

            if (ca_conc < 0.00025 )
                const_state =  {ca_conc / 0.00025} 
            else
                const_state =  1
            end
            // Converting back...
            ca_conc = ca_conc * 1000000
            
            setfield KCd6 Z_A->table[{i}] {0}
            setfield KCd6 Z_B->table[{i}] {const_state}
            ca_conc= ca_conc + dc
        end
             
        tweaktau KCd6 Z
        addfield KCd6 addmsg1
        setfield KCd6 addmsg1  "../Ca_d6  . CONCEN Ca"
end

function make_KCdb6
        if ({exists KCdb6})
            return
        end
        create tabchannel KCdb6

        setfield KCdb6 \ 
            Ek              -0.095 \
            Ik              0  \
            Xpower          1 \
            Zpower          1
        
        setfield KCdb6 \
            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 KCdb6 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 // temporarily set 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 // temporarily set v to units of equation...
            alpha = alpha * 0.001  //and set alpha too

            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 KCdb6 X_A->table[{i}] {alpha}
            setfield KCdb6 X_B->table[{i}] {alpha + beta}
            v = v + dv                    

        end // end of for (i = 0; i <= ({tab_divs}); i = i + 1)

        setfield KCdb6 X_A->calc_mode 1 X_B->calc_mode 1
                    
        // now voltage independent concentration term
        
        float conc_min = 0
        float conc_max = 1000
        float dc = ({conc_max} - {conc_min})/{tab_divs}
        float ca_conc = {conc_min}
        call KCdb6 TABCREATE  Z {tab_divs} {conc_min} {conc_max}
        float const_state

        for (i = 0; i <= ({tab_divs}); i = i + 1)
                
            // Equation is in different set of units...
            ca_conc = ca_conc * 0.000001

            if (ca_conc < 0.00025 )
                const_state =  {ca_conc / 0.00025} 
            else
                const_state =  1
            end
                
            // Converting back...
            ca_conc = ca_conc * 1000000
            
            setfield KCdb6 Z_A->table[{i}] {0}
            setfield KCdb6 Z_B->table[{i}] {const_state}
            
            ca_conc= ca_conc + dc
        end
        tweaktau KCdb6 Z
        
        addfield KCdb6 addmsg1
        setfield KCdb6 addmsg1  "../Ca_db6  . CONCEN Ca"
end


//========================================================================
//             Tabulated Ca-dependent K AHP Channel,gK(AHP) 2003/05
//========================================================================

/* This is a tabchannel which gets the calcium concentration from Ca_hip_conc
   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_KAHPs6
        if ({exists KAHPs6})
            return
        end
        create tabchannel KAHPs6
        setfield KAHPs6 \ 
            Ek              -0.095 \
            Ik              0  \
            Zpower          1
        
        setfield KAHPs6 \
            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 KAHPs6 TABCREATE Z {tab_divs} {conc_min} {conc_max}

        for (c = 0; c <= ({tab_divs}); c = c + 1)
            //alpha
            float alpha
            float v    
            v = v * 1000 // temporarily set v to units of equation...
            ca_conc = ca_conc * 0.000001 //  set Ca conc to units of equation 

            if (ca_conc < 0.0001 )
                alpha =  ca_conc/0.01 
            else
                alpha =  0.01
            end
            v = v * 0.001 // reset v
            ca_conc = ca_conc * 1000000 // resetting ca_conc 
            
            // Set correct units of alpha
            alpha = alpha * 1000
            
            // beta
            float beta
            v = v * 1000 // temporarily set v to units of equation...
            ca_conc = ca_conc * 0.000001 //  set Ca conc to units of equation
            beta = 0.001
            v = v * 0.001 // reset v
            ca_conc = ca_conc * 1000000 // resetting ca_conc 
            
            // correct units of beta
            beta = beta * 1000

            // alpha and beta 

            float tau = 1/(alpha + beta)
            
            setfield KAHPs6 Z_A->table[{c}] {alpha}
            setfield KAHPs6 Z_B->table[{c}] {alpha + beta}
                    ca_conc = ca_conc + dc
                
        end // end of for (c = 0; c <= ({tab_divs}); c = c + 1)
        setfield KAHPs6 Z_conc 1
        setfield KAHPs6 Z_A->calc_mode 1 Z_B->calc_mode 1

        addfield KAHPs6 addmsg1
        setfield KAHPs6  \
                addmsg1        "../Ca_s6 . CONCEN Ca"
end


function make_KAHPd6
        if ({exists KAHPd6})
            return
        end
        create tabchannel KAHPd6
        setfield KAHPd6 \ 
            Ek              -0.095 \
            Ik              0  \
            Zpower          1
        
        setfield KAHPd6 \
            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 KAHPd6 TABCREATE Z {tab_divs} {conc_min} {conc_max}

        for (c = 0; c <= ({tab_divs}); c = c + 1)
                    
            // alpha
            float alpha
            float v    
                        
            v = v * 1000 // temporarily set v to units of equation...
            ca_conc = ca_conc * 0.000001 // set ca_conc to  units of equation...
            if (ca_conc < 0.0001 )
                alpha =  ca_conc/0.01 
            else
                alpha =  0.01
            end
            v = v * 0.001 // reset v
            ca_conc = ca_conc * 1000000 // resetting ca_conc 
            
            // Set correct units of alpha
            alpha = alpha * 1000
            
            // beta

            float beta
            v = v * 1000 // temporarily set v to units of equation...
            ca_conc = ca_conc * 0.000001 // set ca_conc to  units of equation...
            beta = 0.001
            v = v * 0.001 // reset v
            ca_conc = ca_conc * 1000000 // resetting ca_conc 
            
            // correct units of beta
            beta = beta * 1000

            //alpha & beata

            float tau = 1/(alpha + beta)
            
            setfield KAHPd6 Z_A->table[{c}] {alpha}
            setfield KAHPd6 Z_B->table[{c}] {alpha + beta}
                    ca_conc = ca_conc + dc
                
        end // end of for (c = 0; c <= ({tab_divs}); c = c + 1)
                
        setfield KAHPd6 Z_conc 1
        setfield KAHPd6 Z_A->calc_mode 1 Z_B->calc_mode 1

        addfield KAHPd6 addmsg1
        setfield KAHPd6  \
                addmsg1        "../Ca_d6 . CONCEN Ca"
end


function make_KAHPdb6
        if ({exists KAHPdb6})
            return
        end
        create tabchannel KAHPdb6
        setfield KAHPdb6 \ 
            Ek              -0.095 \
            Ik              0  \
            Zpower          1
        
        setfield KAHPdb6 \
            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 KAHPdb6 TABCREATE Z {tab_divs} {conc_min} {conc_max}
            
        for (c = 0; c <= ({tab_divs}); c = c + 1)
            //  alpha
            float alpha
            float v    
                        
            v = v * 1000 // temporarily set v to units of equation...
            ca_conc = ca_conc * 0.000001 //set ca_conc to units of equation...
            if (ca_conc < 0.0001 )
                alpha =  ca_conc/0.01 
            else
                alpha =  0.01
            end
            v = v * 0.001 // reset v
            ca_conc = ca_conc * 1000000 // resetting ca_conc 
            
            // correct units of alpha
            alpha = alpha * 1000

            
            //  beta
            float beta

            v = v * 1000 // temporarily set v to units of equation...
            ca_conc = ca_conc * 0.000001 //set ca_cnonc to to units of equation...
            beta = 0.001
            v = v * 0.001 // reset v
            ca_conc = ca_conc * 1000000 // resetting ca_conc 
            
            // correct units of beta
            beta = beta * 1000

            // alpha and beta
            float tau = 1/(alpha + beta)
            
            setfield KAHPdb6 Z_A->table[{c}] {alpha}
            setfield KAHPdb6 Z_B->table[{c}] {alpha + beta}
                    ca_conc = ca_conc + dc
                
        end // end of for (c = 0; c <= ({tab_divs}); c = c + 1)
                
        setfield KAHPdb6 Z_conc 1
        setfield KAHPdb6 Z_A->calc_mode 1 Z_B->calc_mode 1

        addfield KAHPdb6 addmsg1
        setfield KAHPdb6  \
                addmsg1        "../Ca_db6 . CONCEN Ca"
end