“An article published in this week’s issue of PLoS Biology (March 1, 2005) describes Chklovskii’s discovery of strongly preferred patterns of connectivity or scaffolds within the wiring diagram of the rat brain. The patterns are likely to correspond to modules that play an important role in brain function not only in rats, but also in humans.”
I looked online and I don’t believe this article will be generally available until March 15.
Essentially they establish that in a rat visual cortex 17% of synaptic junctions account for almost half the connectivity strength. That means a subset of the connections are heavily preferred signaling pathways. Such preferred pathways could be low-level brain modules.
They are only showing evidence that preferred connections exist. They aren’t saying what causes them or what function such pathways serve.
Update from Razib: Here is the article. Make sure to check “New Research Articles,” many of the best stuff is leaked early and nested within this page. To me, it seems that the modular vs. non-modular debate is going to end up like the Nature vs. Nurture dichotomy, rather than typologically excluded opposites, much of the discussion will (unfortunately) revolve around semantic clarification and emphasis of exposition rather than substance because it seems unlikely that there is an idealized “pure” modularity or non-modularity manifesting itself in mammalian brains.
Posted by fly at 12:49 PM | | TrackBack The invisible Asian
Little Advance Is Seen in Ivies’ Hiring of Minorities and Women.
Here is the full report (PDF) that the article above is based on.
The word “Asian” does not show up once in The New York Times article. It pops up 4 times in the report itself, 3 of them are embedded in charts and one of them is a footnote. There is no mention of Asian Americans in the text.
Doctoral Degree Program Enrollment, 2001 IvyNationalBlack 3.7% 8.9%Hispanic 3.1% 5.3%Asian/Pacific Islander 7.1% 5.1%American Indian/Alaska Native 0.3% 0.6%International Scholars 34.7% 13.1%Women 46.0% 58.2%
60% of graduate students are women! If women have an aversion to pairing up with males with lower educational qualifications, it makes sense that female education correlates negatively with fertility….
Addendum: William asks about the number of women getting education doctorates. The Digest of Education Statistics 2003 is a good source for that sort of information. As a point of fact the slight majority of doctorates in 2003 were awarded to men, while of female doctorates 23% were in Education as opposed to 10% for males. Posted by razib at 11:40 AM | | TrackBack Carl on Language II
Carl Zimmer has posted his follow up on language & evolution. No big surprise, the question is the answer in the end. Though I find Chomsky et al.’s model parsimonious, I have a hunch that it simply explains too little. On the other hand, Pinker et al. might be constructing a rather baroque adaptive cathedral (no spandrels though!), but at least their model offers great opportunies for falsification or confirmation. There are many, perhaps rightly, who dislike the fact that Pinker has a rather outsize reputation because of his public intellectual status, but in the end his ideas will either be stand or fall outside the penumbra of his reputation. This process will occur outside of psycholinguistics as well, in the Synaptic Self Joseph Ledoux explains that nativists favor a “selection” as opposed to an “instruction” model of synaptic connectional structural development. This is a prediction based on a model, and all of Pinker’s public intellectual status will not shield him if his paradigm is found wanting.
Posted by razib at 10:33 AM | | TrackBack