[ExI] The brain learns completely differently than we've assumed since the 20th century

[Dave Sill]

Does this have any implications relating to cryonics? I can't tell.

https://medicalxpress.com/news/2018-03-brain-differently-weve-assumed-20th.html

*The brain is a complex network containing billions of neurons, where each
of these neurons communicates simultaneously with thousands of other via
their synapses (links). However, the neuron actually collects its many
synaptic incoming signals through several extremely long ramified "arms"
only, called dendritic trees.*

*In 1949 Donald Hebb's pioneering work suggested that learning occurs in
the brain by modifying the strength of the synapses, whereas neurons
function as the computational elements in the brain. This has remained the
common assumption until today.*

*Using new theoretical results and experiments on neuronal cultures, a
group of scientists, led by Prof. Ido Kanter, of the Department of Physics
and the Gonda (Goldschmied) Multidisciplinary Brain Research Center at
Bar-Ilan University, has demonstrated that the central assumption for
nearly 70 years that learning occurs only in the synapses is mistaken.*

*In an article published today in the journal Scientific Reports, the
researchers go against conventional wisdom to show that learning is
actually done by several dendrites, similar to the slow learning mechanism
currently attributed to the synapses.*

*"The newly discovered process of learning in the dendrites occurs at a
much faster rate than in the old scenario suggesting that learning occurs
solely in the synapses. In this new dendritic learning process, there are a
few adaptive parameters per neuron, in comparison to thousands of tiny and
sensitive ones in the synaptic learning scenario," said Prof. Kanter, whose
research team includes Shira Sardi, Roni Vardi, Anton Sheinin, Amir
Goldental and Herut Uzan.*

*The newly suggested learning scenario indicates that learning occurs in a
few dendrites that are in much closer proximity to the neuron, as opposed
to the previous notion. "Does it make sense to measure the quality of air
we breathe via many tiny, distant satellite sensors at the elevation of a
skyscraper, or by using one or several sensors in close proximity to the
nose? Similarly, it is more efficient for the neuron to estimate its
incoming signals close to its computational unit, the neuron," says Kanter.
Hebb's theory has been so deeply rooted in the scientific world for 70
years that no one has ever proposed such a different approach. Moreover,
synapses and dendrites are connected to the neuron in a series, so the
exact localized site of the learning process seemed irrelevant.*

*Another important finding of the study is that weak synapses, previously
assumed to be insignificant even though they comprise the majority of our
brain, play an important role in the dynamics of our brain. They induce
oscillations of the learning parameters rather than pushing them to
unrealistic fixed extremes, as suggested in the current synaptic learning
scenario.*

*The new learning scenario occurs in different sites of the brain and
therefore calls for a reevaluation of current treatments for disordered
brain functionality. Hence, the popular phrase "neurons that fire together
wire together", summarizing Donald Hebb's 70-year-old hypothesis, must now
be rephrased. In addition, the learning mechanism is at the basis of recent
advanced machine learning and deep learning achievements. The change in the
learning paradigm opens new horizons for different types of deep learning
algorithms and artificial intelligence based applications imitating our
brain functions, but with advanced features and at a much faster speed.*
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20180323/f1dc1a0a/attachment.html>