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Study reveals that the brain hides information from us to prevent mistakes

By 10 de July de 2008November 18th, 2020No Comments
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 10.07.2008

Study reveals that the brain hides information from us to prevent mistakes

When we notice a mosquito alight on our forearm, we direct our gaze in order to find its exact position and quickly try to swat it or brush it away to prevent it bite us. This apparently simple, instantaneous reaction is the result of a mental process that is much more complex than it may seem. It requires the brain to align the tactile sensation on the skin with spatial information about our surroundings and our posture. For the first time, a study done by the Cognitive Neuroscience Research Group (GRNC), attached to the Barcelona Science Park, has shown how this process unfolds over time, examining the conflicts posed by the coexistence of differing spatial maps in the brain. GRNC researchers Salvador Soto-Faraco (ICREA research professor) and Elena Azañón conducted the study forthcoming in the 22 July issue of the journal Current Biology, available online on 10th July (doi:10.1016/j.cub.2008.06.045).


“The main finding of the study is that it has enabled us to confirm that tactile sensations are initially located unconsciously in anatomical coordinates, but they reach our awareness only when the brain has formed an image of their origin in the spatial coordinates, external to the body,” explained Salvador Soto-Faraco. The coexistence of different spatial reference frames in the brain has been known for some time. So has the fact that confusions between them may result in some cases, such as when we invert the usual anatomical position of some body parts (e.g. when crossing our arms over the body midline). “The brain sorts out problems of this kind rapidly, in a matter of tenths of a second. To do so, however, it has to integrate information arriving in formats that are quite disparate”, Sotoa-Faraco added. “Our research has helped us understand how this process works and how the brain manages spatial realignment when faced with conflict”, he concluded.

In order to determine how long it takes for the brain to realign these conflicting spatial reference frames, the GRNC researchers devised a specific methodology that enabled indirect measurement of the location of a tactile sensation on the skin. To do this, they measured response times to a brief flash (produced with an LED light emitting diode) appearing near one of the observer’s hands. The researchers then compared the reaction times to the flash when it had appeared near a hand that had previously received a tactile stimulus, versus when the flash had appeared near the opposite hand.

In the main study, the participants (a group of 32 university students) were asked to cross their arms so that their right hand lay in their left-hand visual field and vice versa. The purpose of this procedure was to ensure that the actual external position of the hands was in conflict with their anatomical location.

“The study’s results have allowed us to deepen our understanding of how tactile information is located, suggesting that our brain avoids confusions among the various spatial reference frames by keeping the initial part of the process below the threshold of awareness”, explained Soto-Faraco. “Put simply, it could be said that this system of spatial transformation works much as when we hastily jot down some rough notes and later copy them out into final form, discard the original draft,” he concluded.