Dynamical Systems in Neuroscience:

Electrophysiology of Neurons 49Parameters (Fig. 2.20)Cation currents Eq. 2.11 Eq. 2.12V 1/2 k V max σ C amp C baseI h current 1 I h = ḡ h (V − E h ), E h = −43 mV(opened by hyperpolarization )inactivation −75 −5.5 −75 15 1000 100I h current 2 I h = ḡ h (V − E h ), E h = −1 mVinact. (soma) −82 −9 −75 20 50 10inact. (dendrite) −90 −8.5 −75 20 40 10I h current 3 I h = ḡ h (V − E h ), E h = −21 mVfast inact. (65%) −67 −12 −75 30 50 20slow inact. (35%) −58 −9 −65 30 300 1001. Thalamic relay neurons (McCormick and Pape 1990; Huguenard and McCormick 1992).2. Hippocampal pyramidal neurons in CA1 (Magee 1998).3. Entorhinal cortex Layer II neurons (Dickson et al. 2000).1000slowI hvoltage-gated currentsactivationinactivationI hI K(M)100I K(M)time constant, (ms)10IAI AI K(M)I h IhI AI KI AI NatI NatI NatI KI NatI A1fastI KirI NapI Naplow-threshold-100 -50high-threshold0half-voltage, V 1/2 (mV)Figure 2.21: Summary of current kinetics. Each oval (rectangle) denotes the voltageand temporal scale of activation (inactivation) of a current. Transient currents arerepresented by arrows connecting ovals and rectangles.