Neural coding: Difference between revisions

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Neurons are remarkable among the [[cells (biology)|cells]] of the body in their ability to propagate signals rapidly over large distances. They do this by generating characteristic electrical pulses called [[action potentials]] or, more simply, spikes that can travel down nerve fibers. Sensory neurons change their activities by firing sequences of action potentials in various temporal patterns, with the presence of external sensory stimuli, such as [[light]], [[sound]], [[taste]], [[smell]] and [[touch]]. It is known that information about the stimulus is encoded in this pattern of action potentials and transmitted into and around the brain.

Although action potentials can vary somewhat in [[duration]], [[amplitude]] and [[shape]], they are typically treated as identical stereotyped events in neural coding studies. If the brief duration of an action potential (about 1ms) is ignored, an action potential sequence, or spike train, can be characterized simply by a series of all-or-none point events in time <ref name="Gerstner">Gerstner, W. and Kistler, W. 2002. ''Spiking Neuron Models: Single Neurons, Populations, Plasticity''. Cambridge University Press, Cambridge</ref>. The lengths of interspike intervals ([[ISI]]s) between two successive spikes in a spike train often vary, apparently randomly, both within and across trials <ref name="Stein">Stein, R., Gossen, E. and Jones, K. 2005. Neuronal variability: noise or part of the signal? ''Nature Reviews Neuroscience'' 6:389–397</ref>. The study of neural coding involves measuring and characterizing how stimulus attributes, such as light or sound intensity, or motor actions, such as the direction of an arm movement, are represented by neuron action potentials or spikes. In order to describe and analyze neuronal firing, [[statistical methods]] and methods of [[probability theory]] and stochastic [[point process|point processes]] have been widely applied.

== Encoding and Decoding ==