tag:blogger.com,1999:blog-32683882.post116423881822281770..comments2023-07-29T02:58:08.990-05:00Comments on BioMed Notes: Brain wiring patternsUnknownnoreply@blogger.comBlogger2125tag:blogger.com,1999:blog-32683882.post-1164239432271539272006-11-22T18:50:00.000-05:002006-11-22T18:50:00.000-05:00Wrong Random Their null hypothesis network was cre...Wrong Random <BR/><BR/>Their null hypothesis network was created by randomly connecting cells. This produces a <I>normally</I> distributed population of connections with most cells having near the average number of connections. However, biological networks (and other naturally growing networks such as the internet) display a <A HREF="http://www.sciencemag.org/cgi/content/abstract/286/5439/509?ijkey=43a207293fcca22fe0112ea0057c042ee66e1c52&keytype2=tf_ipsecsha" REL="nofollow" TITLE="sciencemag.org">power-law distribution of connections</A> [sciencemag.org] with few, very well connected nodes. A familiar example of power-law distribution is the hub-and-spoke pattern of airline connections whereas a more normal distribution is the interstate highway pattern connecting cities.<BR/><BR/>Their null hypothesis should be tested against this more natural, but still random network. In a <A HREF="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15326338" REL="nofollow" TITLE="nih.gov">Science Note</A> [nih.gov] on a <A HREF="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12399590" REL="nofollow" TITLE="nih.gov">similar paper by Milo et al.</A> [nih.gov],<BR/>Artzy-Randrup and colleagues claim that random networks so constructed have many characteristic patters, such as feed-forward circuits, that are not common to random networks with normally distributed connections.<BR/><BR/>It should be possible to filter the circuits found in the C. elegans central nervous system<BR/>to eliminate those resulting from the power-law alone.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-32683882.post-1164239053292658122006-11-22T18:44:00.000-05:002006-11-22T18:44:00.000-05:00Synthetic BiologySynthesizing circuits should be n...Synthetic Biology<BR/><BR/>Synthesizing circuits should be nicely complementary to analyzing circuits. Wired has an <A HREF="http://www.wired.com/wired/archive/13.01/mit.html" REL="nofollow" TITLE="wired.com">article</A> [wired.com] on a class at MIT that is building small DNA-protein circuits that do things like count (e.g., number of divisions) or blink (on-off).Reuelhttps://www.blogger.com/profile/00375847200584931533noreply@blogger.com