sodium amytal test: anesthetize one hemisphere and check for language function; dichotic listening test: report more digits heard by dominant half; functional brain imaging: fMRI or PET used to see which half is active when performing a language test speech laterality and handedness sex differences in brain lateralization
A typical neuron has characteristic features: a cell body, dendrites and an axon. The axon projects from the cell body and makes contact with a target cell at the synapse. A neuron is stimulated by signals, chemical and electrical, to initiate an action potential (a rapid and reversible change in membrane potential). In the absence of a signal, the resting potential of the neuron is maintained by the potassium leak channels, which allow the flow of potassium ions out of the cell, resulting in a more negative charge in the cell when compared to outside the cell.
At the axon hillock of a typical neuron, the resting potential is around â70 millivolts (mV) and the threshold potential is around â55 mV. Synaptic inputs to a neuron cause the membrane to depolarize or hyperpolarize; that is, they cause the membrane potential to rise or fall.he course of the action potential can be divided into five parts: the rising phase, the peak phase, the falling phase, the undershoot phase, and the refractory period. During the rising phase the membrane potential depolarizes (becomes more positive). The point at which depolarization stops is called the peak phase.