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.
The ion pump most relevant to the action potential is the sodiumâpotassium pump, which transports three sodium ions out of the cell and two potassium ions in. As a consequence, the concentration of potassium ions K + inside the neuron is roughly 20-fold larger than the outside concentration, whereas the sodium concentration outside is roughly ninefold larger than inside.