Yuwei, Right, bidirectional connections are *not *a norm or random in nature.
On Mon, Aug 3, 2015 at 11:01 AM, Yuwei Cui <[email protected]> wrote: > Hi Chandan, > > Thanks for sharing this interesting article. There are a number of papers > reporting high probability of bidirectional connections in the cortex. But > this "high-probability" is relative to a null hypothesis that assume > independent random connections among pairs of neurons. If you look at the > absolute numbers, it is still safe to say that the majority of the > connections are unidirectional. I am not surprised that connections in the > cortex is more organized than a random network, but we cannot conclude from > this paper that bidirectional connection is the general principle in the > cortex. > > -- > Yuwei Cui > > Research Engineer, Numenta Inc. > > LinkedIn: https://www.linkedin.com/pub/yuwei-cui/1b/400/866 > > On Mon, Aug 3, 2015 at 10:49 AM, Chandan Maruthi < > [email protected]> wrote: > >> Pascal, >> You are right , synaptic connections are unidirectional, however there >> seems to be a high probability of bidirectional connections. at different >> distances >> >> Found an interesting article on synaptic connections . >> http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1054880/ >> >> >> >> >> On Sun, Aug 2, 2015 at 2:44 AM, Pascal Weinberger < >> [email protected]> wrote: >> >>> Well that's how it is in biology as well... >>> Despite of gap-junctions all synapses are one directional. >>> This is also logically sensical, as one feature can predict another >>> while the other does not necessarily mean the first one is present. You >>> want to learn these connections separately. >>> >>> On a high level you may draw the analogy that 'Car' implies 'seat'; but >>> 'seat' does not necessarily (or with the same strength) imply 'car'... >>> On Aug 2, 2015 4:26 AM, "Chandan Maruthi" <[email protected]> >>> wrote: >>> >>>> Is a Nupic synaptic connection 2 way? Or is it one way by default and >>>> has to explicitly be trained to learn a new connection back. >>>> >>>> >>>> So cell a on column a1 connected to cell b on column b1 does not >>>> automatically mean activation of b will result in prediction of a right? >>>> >>>> I see why it is so, but it seems inefficient , doesn't it? >>>> >>>> >>>> >>>> -- >>>> Regards >>>> Chandan Maruthi >>>> >>>> >>>> >> >> >> -- >> Regards >> Chandan Maruthi >> >> > -- Regards Chandan Maruthi
