I'm not sure whether this is evidence for Bruno's Platonism or it just
shows why it's a common illusion.
Brent
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Nerve cells in the human brain can 'count'
September 21, 2018, University of Bonn
<http://www1.uni-bonn.de/startseite/jsp/index.jsp?lang=en>
Nerve cells in the human brain can 'count'
<https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hires/2018/nervecellsin.jpg>
Professor Florian Mormann from the Department of Epileptology at the
University of Bonn. Credit: © Rolf Müller/UKB-Ukom
How do we know if we're looking at three apples or four? Researchers at
the Universities of Bonn and Tübingen are now one step closer to
answering this question. They were able to demonstrate that some brain
cells fire mainly for quantities of three, others for quantities of four
and others for other quantities. A similar effect can be observed for
digits: In humans, the neurons activated in response to a "2" are, for
instance, different from the neurons activated for a "5." The results
also demonstrate how humans learn to handle number symbols in comparison
to quantities. The study is published online in the journal /Neuron/.
People are born with the ability to count. Shortly after birth, babies
can estimate the number of events and even perform simple calculations.
But what exactly happens in the brain
<https://medicalxpress.com/tags/brain/>? And do we process abstract
numbers differently from concrete quantities? Researchers from the
Department of Epileptology at the University of Bonn and neurobiologists
from the University of Tübingen have investigated these two questions.
They benefited from a special feature of Bonn University Hospital: The
epileptology clinic located there specializes in brain surgery. The
clinic's doctors seek to cure epilepsy patients
<https://medicalxpress.com/tags/epilepsy+patients/> by means of an
operation in which they remove the diseased nerve tissue. In some cases,
they first have to insert electrodes into the patient's brain in order
to ascertain the location of the epileptogenic focus. As a side effect,
researchers can use this to watch patients think.
In the current study, surgeons inserted extremely fine microelectrodes
into the temporal lobes of nine epilepsy patients. "This enabled us to
measure the reaction of individual nerve cells to visual stimuli,"
explains Prof. Dr. Dr. Florian Mormann, head of the Cognitive and
Clinical Neurophysiology group. The scientists showed their subjects a
different number of points on a computer screen—sometimes only one,
sometimes four or even five. "We were able to demonstrate that certain
nerve cells fired primarily in response to very specific quantities,"
explains Esther Kutter, lead author of the study. "For example, some
were activated mainly by three dots, others by one."
Each quantity therefore creates a specific activity pattern in the human
brain. "We have written a classification algorithm that evaluates this
pattern," Mormann explains. "This allowed us to use the arousal state of
the nerve cells to read how many points our respective subject could see."
The scientists also observed an interesting effect: Although the neurons
<https://medicalxpress.com/tags/neurons/> were "set" to a certain
quantity, they also responded to slightly different quantities. A brain
cell set to quantities of three also fired in response to two or four
points, but weaker. With one or five points, however, it could hardly be
activated. Experts call this the "numerical distance effect." Prof. Dr.
Andreas Nieder from the University of Tübingen, co-supervisor of the
study, demonstrated the same phenomenon in experiments on monkeys.
"Numbers are processed in our brains in exactly the same way as in the
brains of monkeys," he says. "This confirms monkeys as an indispensable
model for research into the processing of quantitative information."
How we process digits, i.e. symbols that represent quantities, cannot be
answered with the help of animals. The scientists have now been able to
show for the first time that this works in principle in a similar way as
with quantities: When we see a certain digit, certain brain cells fire.
However, the digit neurons and the quantity neurons are not identical:
The digit "3" excites completely different nerve cells
<https://medicalxpress.com/tags/nerve+cells/> than a quantity of three
points.
Another observation is even more exciting: "The digit neurons also have
a numerical distance effect," says Mormann. "They are also stimulated
not only by the exact digit, but also by its neighbors—but only very
weakly." Nevertheless, this phenomenon shows that we learn digits
differently from simple characters. In a sense, the neurons have learned
that the value of a 3 is only slightly different from a 2 or a
4—otherwise, they would not also respond to these two digits. Digits
therefore seem to be firmly interwoven with a certain idea of quantity.
The researchers hope that their results will also contribute to a better
understanding of dyscalculia, a developmental disorder accompanied,
among other things, by a poorer understanding of quantity.
<https://medicalxpress.com/news/2018-09-nerve-cells-human-brain.html?utm_source=nwletter&utm_medium=email&utm_campaign=daily-nwletter#>
*Explore further:* Nerve cells use brain waves to judge importance
<https://medicalxpress.com/news/2018-08-nerve-cells-brain-importance.html>
*More information:* Esther F. Kutter et al, Single Neurons in the Human
Brain Encode Numbers, /Neuron/ (2018). DOI: 10.1016/j.neuron.2018.08.036
<http://dx.doi.org/10.1016/j.neuron.2018.08.036>
https://medicalxpress.com/news/2018-09-nerve-cells-human-brain.html
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