[Comp-neuro] Review announcement

Sven Abrahamse sabrahamse at gmail.com
Tue Jul 22 15:49:56 CEST 2008


what an amazing discussion this has turned out to be. Way to go guys. I am
sure that everybody simply enjoys this format of things :-)

On Tue, Jul 22, 2008 at 2:57 PM, Ali Minai <minai_ali at yahoo.com> wrote:

>   Nature clearly uses a different "engineering" strategy than humans.
> Classical human engineering is based on control (controlling dynamics,
> controlling noise, controlling quality, etc.) and is primarily
> goal-oriented. Thus, its capabilities are limited by the imaginations of
> those setting the goals. Things like noise, oscillation and combinatorial
> richness interfere with this imagination (such as it is) and are thus seen
> as hazards. Nature's engineering, in contrast, is based on exploitation
> (exploiting oscillations, exploiting noise, exploiting variation, exploiting
> chance combinations, etc.), and its capabilities are limited only by the
> possibilities offered by the phenomena at hand. As this natural engineering
> configures more complex phenomena, the space of possibilities *expands*,
> thus making even more complex phenomena possible. Thus, Nature's engineering
> is open-ended, and things such as noise, variation and combinatorial
> richness are seen as enablers rather than problems. To be fair, human
> engineering has very different purposes than Nature, and its approach is
> well-suited to those purposes, but I think we're starting to build things
> where Nature's way might be the only option. The accompanying loss of
> control is, of course, inevitable.
>
> Ali
>
>
> ---------------------------------------------------------------------
> Ali A. Minai
> Associate Professor
> Associate Head for Electrical Engineering
> Department of Electrical & Computer Engineering
> University of Cincinnati
> Cincinnati, OH 45221-0030
>
> Phone: (513) 556-4783
> Fax: (513) 556-7326
> Email: aminai at ececs.uc.edu
>           minai_ali at yahoo.com
>
> WWW: http://www.ececs.uc.edu/~aminai/
>
> ----------------------------------------------------------------------
>
> --- On *Tue, 7/22/08, jim bower <bower at uthscsa.edu>* wrote:
>
> From: jim bower <bower at uthscsa.edu>
> Subject: Re: [Comp-neuro] Review announcement
> To: "Hans A. Braun" <braun at staff.uni-marburg.de>, "Nathan Urban" <
> nurban at cmu.edu>, comp-neuro-bounces at neuroinf.org, comp-neuro at neuroinf.org
> Date: Tuesday, July 22, 2008, 6:46 AM
>
>
> One other general point about oscillations. Years ago a "neural
> network" engineer from MIT gave a talk at the Snowbird meeting, I think
> the first - in his talk he that, connected at random only 1 percent of networks
> didn't oscillate intrinsically, and he proposed to find those networks as
> they were clearly the only ones that were useful.
>
> Interesting
>  idea but dead wrong. Everything in biology oscillates, in fact
> everything in the natural world does. Engineers fear oscillations because they
> don't know how to control them. The nervous system uses them to its own
> purposes. In fact, my guess is that this is one of the sources of its
> efficiency.
>
> Last point with respect to your car, the quality of the engineer must be based
> on the performance of what it has built. So last last question, does anyone
> know something whose perfomance is more extraordianary then the brain of a fly?
>  Or a slug?
>
> I don't think so
>
> Jim
>
>
> Sent via BlackBerry by AT&T
>
> -----Original Message-----
> From: "Hans A. Braun" <braun at staff.uni-marburg.de>
>
> Date: Tue, 22 Jul 2008 11:32:54
> To: <bower at uthscsa.edu>; Nathan Urban<nurban at cmu.edu>;
> <comp-neuro-bounces at neuroinf.org>; <comp-neuro at neuroinf.org>
> Subject: Re: [Comp-neuro] Review
>  announcement
>
>
> Hi Jim,
>
>
>
> nice to hear from you with an interesting question. Here is a question back:
>
> Who says that the biological coding scheme is optimised in a way as
> engineers would do?
>
>
>
> I have been educated as an engineer. Thereby, I specifically have learnt how
> handle, if it cannot be avoided, such detrimental system properties like
> noise, nonlinearities and time delays because these can lead to
> unpredictable system behavior, including undesired oscillation and chaos –
> what regularly can be seen in all kind of biological systems. If something
> similar would happen in a car or an airplane, the responsible engineer,
> deservedly, would immediately be fired.
>
>
>
> Could it be that the engineer in evolution has used a principally different
> strategy?
>
> What was/is his/her goal?
>
> Who knows or who is interested to find the answer?
>
> - or a more appropriate question
>  ;-) ?
>
>
>
> Coming back to the original "noise" question: During all the years
> as
> experimental physiologist I have got hundreds of hours recordings of impulse
> sequences from different neurons – and all look more or less noisy -
> whatever it means.
>
>
>
> Best wishes
>
> Hans Braun
>
>
>
> PS: if you are interested, here are two references to our work (an actual
> and an earlier paper):
>
>
>
> Finke C, Vollmer J, Postnova S, Braun HA (2008) Propagation effects of
> current and conductance noise in a model neuron with subthreshold
> oscillations. Mathematical Biosciences doi:10.1016/j.mbs.2008.03.007
>
> Braun HA, Wissing H, Schäfer K, Hirsch MC (1994). Oscillation and noise
> determine signal transduction in shark multimodal sensory cells. Nature 367:
> 270-273.
>
>
>
> The first one is a mathematical/computational approach which has very
> recently been published, so far only as online
>  version.
>
> The second reference is to a much earlier experimental paper which
> demonstrates how the evolutionary engineer might have used oscillations and
> noise to achieve a particular sensitivity. This strategy, for whatever
> reasons, was only realized for sensory encoding in some evolutionary very
> old animals like sharks.
>
> Dr. Hans A. Braun, Institute of Physiology, Deutschhausstr. 2, D-35037
> Marburg, Germany.
> Tel: +49 (0)6421-286 23 05, FAX: +49 (0)6421-286 6967, E-mail:
> braun at staff.uni-marburg.de
> URL: http://www.uni-marburg.de/physiology/braun and  http://www.clabs.de
> see also: http://www.BioSim-Network.net <http://www.biosim-network.net/>
>
> ----- Original Message -----
> From: "jim bower" <bower at uthscsa.edu>
> To: "Nathan Urban" <nurban at cmu.edu>;
> <comp-neuro-bounces at neuroinf.org>;
> <comp-neuro at neuroinf.org>
> Sent: Friday, July 18, 2008 3:56 PM
> Subject: Re: [Comp-neuro] Review announcement
>
>
> >
>  Haven't done this in a long time. But who says neurons are noisy?
> >
> > From the point of view of information theory, why isn't the apperance
> of
> noise expected in a highly optimized coding scheme?  And why isn't
> synchrony
> to be avoided as redundency. Engineers avoid it, why shouldn't evolution.
> >
> > Just curious.
> >
> > Jim bower
> > Sent via BlackBerry by AT&T
> >
> > -----Original Message-----
> > From: Nathan Urban <nurban at cmu.edu>
> >
> > Date: Fri, 18 Jul 2008 08:41:22
> > To: <comp-neuro at neuroinf.org>
> > Subject: [Comp-neuro] Review announcement
> >
> >
> > Review announcement
> >
> > This review describes a constructive role for noise in synchronizing
> > populations of neurons and should be of interest to computaional
> > neurosciuentists.
> >
> >
> > Trends Neurosci. 2008 Jul 4. [Epub ahead of print]
> >
>  Reliability, synchrony and noise.
> >     Ermentrout GB, Galán RF, Urban NN.
> >
> > The brain is noisy. Neurons receive tens of thousands of highly
> > fluctuating inputs and generate spike trains that appear highly
> > irregular. Much of this activity is spontaneous - uncoupled to overt
> > stimuli or motor outputs - leading to questions about the functional
> > impact of this noise. Although noise is most often thought of as
> > disrupting patterned activity and interfering with the encoding of
> > stimuli, recent theoretical and experimental work has shown that noise
> > can play a constructive role - leading to increased reliability or
> > regularity of neuronal firing in single neurons and across populations.
> > These results raise fundamental questions about how noise can influence
> > neural function and computation.
> >
> >     PMID: 18603311 [PubMed - as supplied by
>  publisher]
> >
> >
> http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T0V-4SXC918-1&_us
> er=525223&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000026389&_versio
> n=1&_urlVersion=0&_userid=525223&md5=22a86291fe13cd59541d841f692f24a2
> > _______________________________________________
> > Comp-neuro mailing list
> > Comp-neuro at neuroinf.org
> > http://www.neuroinf.org/mailman/listinfo/comp-neuro
> >
>
>
> ----------------------------------------------------------------------------
> ----
>
>
> > _______________________________________________
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> >
>
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-- 
"In God We trust, Everyone else needs to bring data to the table"
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