ABSTRACT
Neurons encode information by virtue of two properties. Firstly, the frequency with which a sensory neuron fires conveys information about the duration of a stimulus, its intensity and how the intensity changes over time. In the same way, motor neuron firing rate encodes the timing and force of contraction of a discrete population of muscle fibers. Secondly, the address of an afferent neuron, that is, how it is connected via its inputs and outputs, encodes the spatial location of a stimulus, and the qualitative nature of the stimulus or modality. The firing patterns of either single neurons or clusters of neurons in living animals in response to physiological stimuli are obtained by extracellular recording. Neuron activity will cause currents to flow between the two electrodes. These currents are amplified and fed to a cathode ray oscilloscope (CRO) or to the analog-to-digital port of a computer running software to capture, store and analyse such data.
