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 axon hillock, because of its configuration of voltage-gated ion channels, is most sensitive to causing APs. EPSPs from dendrites, the soma, the hillock, if they can all push the membrane voltage above threshold together, will ignite a spike. The AP typically runs down the axon towards its synapses.