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A study led by the Consejo Superior de Investigaciones Científicas (CSIC) has determined that different neurons in the tactile system variables to encode the same stimulus. These results, published this week in the journal Neuron, mark a further step in understanding the dialogue between the thalamus and the cerebral cortex involved in the
perception of the environment.

The purpose of the study on the system of touch Vibrissae (whiskers) of mice, was to determine the nature of the information encoded tactile neurons in the ventral posterior half nucleus of the thalamus (VPM). This region is the cortex that sends the main messages about touch mediated by Vibrissae. As the researcher Miguel Maravall CSIC, one of the directors of the study, we demonstrated that each neuron is encoding a different type of information, which implies a source richer, more flexible, allowing the bark to convey a message much more complex. "

Work revalued tradition of scientific knowledge in this field, which is inclined to think that all VPM neurons responded similarly to a stimulus, so that your message is duplicated so that it becomes stronger in the cortex.

"It has been found, despite what was thought until now, that different neurons encode different variables to the same stimulus, but have in common a prominent temporal acuity, such that fluctuations may report very rapid and brief, about one thousandth of a second, in the movement of Vibrissae "affects the CSIC researcher.

The study was conducted at the Institute of Neurosciences (Joint CSIC and Universidad Miguel Hernández), headquartered in San Juan de Alicante, in collaboration with the Faculty of Life Sciences, University of Manchester the Italian Institute of Technology.

To try to deduce what is the code used by neurons, were responses to complex stimuli in the Vibrissae in anesthetized rats, from the technique known as inverse correlation.

"The results indicate that the VPM nucleus of the thalamus contains a distributed representation of movement Vibrissae, in which different neurons participate equally in the coding of the stimulus but each conveys a different type of information on different variables, eg The position of the whisker, the rapidity of motion or if it is accelerating or slowing, "describes Maravall.

Control the stimulus is applied can somehow deduce that the message conveyed by the neurons until the crust is the result of the codification of that stimulus. CSIC researcher illustrates this: "The main goal of these studies is to get a 'dictionary' that allows us to decipher what the symbols used by neurons to encode and, secondly, what is the meaning or the concept that is associated with those electrical impulses. "

The system of touch Vibrissae or whiskers of mice using basic principles of brain organization generalizable to other species. This expert system is crucial to touch these animals, which are mainly nocturnal and depend on their Vibrissae to assess the location and identity of objects. "Ultimately, understanding the system of Vibrissae promises to help us understand how we perceive ourselves the world," concludes Maravall.