Madrid
Updated:30/05/2022 01:41h
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Guillermina López Bendito (Dominican Republic, 1975) and her team from the UMH-CSIC Institute of Neurosciences in Alicante published a study in the journal ‘Science’ in 2019 that demonstrated, for the first time, that the sense of touch is active in the brain before to be born By touching the whiskers of a mouse embryo with a novel technology, the somatosensory cortex of the rodent’s brain lit up like a lightbulb. But researchers have learned something else. If the animal’s nose is touched, not only the touch area in the cerebral cortex is activated, but also the visual area. The ‘wiring’ is there, but tangled. Each circuit has not yet been assigned its corresponding sense, a job that the brain will not finish until shortly after birth.
The neuroscientist has received an Advanced Grant of excellence from the European Research Council (ERC), endowed with 2.5 million euros, for her ‘Spontsense’ project, which aims to find out how the senses are specialized, what factors are involved and if failures contribute to neurodevelopmental problems such as autism, schizophrenia, or epilepsy. In the future, his work could help find therapies to combat these disorders.
Are we born with ‘mixed’ senses?
-Each sensory circuit, whether it be touch, hearing or sight, has to carry information to the cerebral cortex in a specific way. Everyone must go their own way. Preliminary results from our laboratory seem to indicate that during the development of the embryo these immature circuits do not finish coupling to their modality. That is something that would happen after birth. Clarifying that is the main objective of the project.
-How do they study it?
-We work with transgenic mice that express a fluorescent protein in the cerebral cortex. This protein reflects the activity of neurons. When those regions turn phosphor green, they are active. We approach the embryo’s nose with a microstimulator and by touching its whiskers, which are the equivalent of our fingers, we can see which sensory territories are activated, if only the touch area or some other area.
-Then, how is this ‘wiring’ separated?
-We believe that a very important factor for the circuits to identify with their sensory modality during the first days of life is spontaneous activity, the onset of which has been recorded since mid-gestation and could begin even earlier.
-What does it consist of?
– Right now you have a lot of neurons in your auditory cortex that are firing because you are listening to me. But during embryonic development, when the auditory circuits form, you don’t have that information. The brain simulates the activation of those neurons, because it needs it to form its connections correctly. It communicates to the neurons which circuit they have to use, which are their ‘sisters’… It’s spectacular: it looks like a musical symphony or a wave in the sea. We recorded it with a high resolution machine.
Why is this activity so important?
-The regions in the brain that will be visual, tactile or auditory have different spontaneous activity codes. Our project aims to identify them.
-What will knowing that pattern do for us?
-Imagine that we discover that the activity pattern X of the tactile cortex is the normal one, the one that will produce a tactile sensory map, that each finger activates a corresponding area, etc. Imagine that we always see the same thing, that pattern X. But we receive animal models with a mutation in autism and we no longer see that pattern X but Y. If you know that Y, for example, may be associated with autism, you could predict what is going to happen to happen later.
-What pathologies could be foreseen?
-For a few years, several hospitals in the United Kingdom, Spain and other countries have been recording spontaneous activity in premature or newborn babies. If a rare pattern is identified, it could be predicted whether a child will have a predisposition to autism, schizophrenia, epilepsy or other neurodevelopmental problems.
-Could therapies be developed to correct these ‘factory errors’?
-That is our dream, the next step. We have two lines of research in the laboratory that try to change one circuit for another, adjust it… If pattern X, the correct one, is made up of certain genes, perhaps we could increase those genes in the affected individual to recover it.
-And the brain, why wouldn’t it be well organized from the beginning?
-That pluripotentiality, if it exists, may be an adaptive advantage. If a very strict organization is generated from the beginning, the capacity for reorganization is less. For example, we generate blind mice in the laboratory and in them the visual cortex is reorganized as a tactile one, because they are going to need that sense more.
-What happens to blind people.
-Correct. The brain realizes that it is blind before birth. At least it is so in rodents. You know you’re missing a meaning because some of your spontaneous activity patterns in those circuits have changed.
-This mixture of the senses can be behind synesthesia?
-There is a fairly deep lack of knowledge of what gives rise to synesthesia, but one of the hypotheses is that the sensory circuits have not been separated well. Our preliminary results would support that theory, but of course, generating a rodent with synesthesia to study it is very difficult. But it could be the case, yes.
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