Scientists at Kyoto University, Japan, claim that they have formulated a technique that can be used to distinguish between analogue and digital forms of neural coding within the central nervous system. Neural communication occurs via electrical pulses along the axon of a neuron, known as an action potential, a series of which is called a spike train. Neuroscientists have observed that there are two ways in which information can be coded. One is the number of action potentials that occur in a set time frame and the other is the precise timing between action potentials; the first is a form of digital coding and the latter is analogue.
The technique, designed by the team at Kyoto University, involves applying one of two statistical models to spike trains, which are the Empirical Bayes model and Hidden Markov model. Spike trains, which fit the Empirical Bayes model, follow an analogue pattern whereas those fitting the Hidden Markov model show a clear digital pattern.
This method has been used to decode neural signals from several brain areas in long-tailed macaques. It showed how each specific area in the brainsí of the macaques relies on different methods of neural communication. Using this method will hopefully enable neuroscientists to identify the types of coding and signals linked to specific output tasks such as motor control and cognition.
An initiative, which is currently underway in investigating similarities in human and computer processing, is the Human Brain Project. The particular research aims to create a computer model of the human brain. It is believed that by modelling the human mind, computer technology will become more advanced and may even show signs of independent learning. It has also been suggested that engineers will, in the future, be able to replace nerve function following permanent nerve damage, which could bring hope to those living with the loss of movement or sensation in significant areas of the body such as hands and legs.
Sophie Howells
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