The frontal lobe contains most of the dopamine-sensitive neurons in the cerebral cortex. The dopamine system is associated with reward, attention, short-term memory tasks, planning, and motivation. Dopamine tends to limit and select sensory information arriving from the thalamus to the forebrain.
Na + concentration is lowered, indicating that Na + in-flux is responsible for the rising phase of the action po-tential. Their data also suggested that the falling phaseof the action potential was caused by a later increase inK+ permeability.
Phase 1 of the myocyte action potential occurs with the inactivation of the fast Na+ channels. The transient net outward current causing the small downward deflection of the action potential is due to the movement of K + and Cl â ions, carried by the Ito1 and I to2 currents, respectively.