Modelization of the brain
Since some time I am interested in modelling
the brain through some self-organized critical model.
One first attempt was a model developped with Enrique Miranda
who works now in Argentina as described in the
paper published in Physica A, Vol. 175, 339-344 (1991)
Recently we made a more successful model with
Lucilla de Arcangelis
and Carla Perrone
in which neurons reinforce their synapses each time they fire
while the not used synapses weaken constantly. If a synapse
is too weak it disappears (= is "pruned"). Note that this rule does not
correspond to Hebb's rule. We measure the time dependent electrical
signal of a network made out of such neurons and excited always
at one given input. Interestingly we obtain a signal which has
a power spectrum following a power law with an exponent 0.8 which
fully agrees with electroencephalograms and other neural signals
like the pace maker of the heart or the human gait. In the figure
you see above an EEG and below two of out time series. We submitted
these results in a
paper to Physical Review Letters.