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.
The influx and outflux of ions (through ion channels during neurotransmission) will make the inside of the target neuron more positive (hence, de-polarized). When this depolarization reaches a point of no return called a threshold, a large electrical signal is generated. This is the action potential.