The optic nerve leads the nervous impulses from the retina to the brain. The neuron is a cell body with all its processes. From the nucleated cell body extends an axon, which carries impulses away from the cell. Typically several branching dentrites extend from the cell body. These carry impulses towards the cell body.
Synapses are the junction points between neurons.
As the impulses aproaches the presynaptic membrane, it causes the release of a neurochemical transmitter which rapidly diffuses across the confines of the synaptic cleft and approaches the postsynaptic membrane, where it causes a change in its ionic permeability. The resulting flow of ions creates a brief electric potential difference which can be recorded by a microelectrode. The most vulnerable components of any electrochemical system are the electrodes - the interface between the real world and the electronic circuitry which controls the system. The Ion-Selective Ultramicroelectrode senses electronic potential differences at the neural synapses and transmitts the signal to the data processor. The Ultramicroelectrode has an architecture similar to a microchip.