TITLE A Slow A-type Potassium current COMMENT Used in Role of a Striatal Slowly Inactivating Potassion Current in Short-term Facilitation of Corticostriatal Inputs" A computer Simulation Study" (Mahon et al. 2000) Implemented by Kevin M. Biddell kevin.biddell@gmail.com 7/13/06 NOTE: 1S=1mho Neuron wants the units in mhos not millisiemens, please note the conversion! ENDCOMMENT UNITS { (mA) = (milliamp) (mV) = (millivolt) } NEURON { SUFFIX KAsm USEION k WRITE ik RANGE gkasmbar, gkasm, minf, hinf, mtau, htau } INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)} PARAMETER { ek = -85 (mV) gkasmbar= 0.00032 (mho/cm2) :0.32mS Etemp = 22 : Delord correspondence 11/15/06 and fitting Vsm = -25.6 ksm = 13.3 Vsh = -78.8 ksh = -10.4 tom = 131.4 Vtm = -37.4 ktm = 27.3 Vth = -38.2 kth = 28 hint = 0.46 : Delord correspondence 11/15/06 = 0.2968 } STATE { m h } ASSIGNED { v (mV) ik (mA/cm2) celsius (degC) minf hinf mtau htau gkasm } BREAKPOINT { SOLVE states METHOD cnexp gkasm = gkasmbar*m*h ik = gkasm*(v - ek) } UNITSOFF INITIAL { rates(v) m= minf h= hint } DERIVATIVE states { :Computes states variable m at the current v and dt. rates(v) m' = ( minf - m ) / mtau h' = (hinf - h ) / htau } PROCEDURE rates(v) { :Computes rate and other constants at current v. Call once from HOC to initialize inf at resting v. LOCAL q10, tadj q10 = 2.5 tadj=q10^((celsius-Etemp)/10) minf=1/(1+exp(-(v-Vsm)/ksm)) hinf=1/(1+exp(-(v-Vsh)/ksh)) mtau=tom/(exp(-(v-Vtm)/ktm)+exp((v-Vtm)/ktm))/tadj htau=(1790+2930*exp(-((v-Vth)/kth)^2)*((v-Vth)/kth))/tadj } UNITSON