TITLE pnas :Transient sodium current in the pyram soma NEURON { SUFFIX pnas USEION na READ ena WRITE ina RANGE gna, ina, qna } UNITS { (mV) = (millivolt) (mA) = (milliamp) PI = (pi) (1) FARADAY = 96485.309 (coul/mole) } INDEPENDENT {t FROM 0 TO 1 WITH 100 (ms)} PARAMETER { celsius=37 (degC) gna=1e-3 (mho/cm2) } ASSIGNED { ina (mA/cm2) v (mV) ena (mV) diam (um) } STATE { ma mb ha hb qna } BREAKPOINT { SOLVE nastate METHOD sparse ina = gna*ma*ma*ma*ha*(v-ena) } INITIAL { ma=m_inf(v) ha=h_inf(v) mb=1-ma hb=1-ha qna = 0 ina = gna*ma*ma*ma*ha*(v-ena) } LOCAL a1, a2, b1, b2 KINETIC nastate { a1 = m_a(v) a2 = m_b(v) b1 = h_a(v) b2 = h_b(v) ~ mb <-> ma (a1, a2) ~ hb <-> ha (b1, b2) CONSERVE ma + mb = 1 CONSERVE ha + hb = 1 COMPARTMENT diam*diam*PI/4 { qna } ~ qna << (-ina*PI*diam*(1e4)/FARADAY) } FUNCTION m_a(v(mV)) { TABLE FROM -150 TO 150 WITH 301 m_a=0.8*(17.2-v-60)/(exp((17.2-v-60)/4)-1) } FUNCTION m_b(v(mV)) { TABLE FROM -150 TO 150 WITH 301 m_b=0.7*(v-42.2+60)/(exp((v-42.2+60)/5)-1) } FUNCTION h_a(v(mV)) { TABLE FROM -150 TO 150 WITH 301 : h_a = 0.32*exp((42-v-60+10)/18) h_a = 0.32*exp((42-v-60+5)/18) } FUNCTION h_b(v(mV)) { TABLE FROM -150 TO 150 WITH 301 : h_b = 10/(1+exp((42-v-60+10)/5)) h_b = 10/(1+exp((42-v-60+5)/5)) } FUNCTION m_inf(v(mV)) { m_inf = m_a(v)/(m_a(v)+m_b(v)) } FUNCTION h_inf(v(mV)) { h_inf = h_a(v)/(h_a(v)+h_b(v)) }