Archive for the ‘Uncategorized’ Category

Increasing fMRI resolution

Tuesday, January 25th, 2005

Neuroimaging techniques are limited by their spatial and temporal resolution. fMRI has a spatial resolution of about 3-4mm. Now researchers have developed statistical techniques to narrow fMRI resolution down to less than a millimeter, fine enough to see the “orientation columns” in the primary visual cortex (V1), so named because each reacts to lines and edges at a particular orientation.

The research is described in an article in Nature Neuroscience, Decoding the visual and subjective contents of the human brain. The authors conclude their abstract with the observation

Our approach provides a framework for the readout of fine-tuned representations in the human brain and their subjective contents.

Much more of science than people realize is about computers processing massive amounts of data. Theories of the cosmos are basically just computers crunching numbers; the Hubble photos we see are massively computer enhanced. From an information theoretic point of view, it’s highly likely that orders of magnitude of additional useful information can be extracted from even the current generation of fMRI hardware, given the right algorithms. That’s the approach these researchers have taken, highlighting the importance of the field called computational neuroscience.

V1 is the part of the visual cortex at the back of your head which takes the first crack at signals coming in from your eyeballs. It’s just one synapse away from the retina. The interesting thing about this research was not just the ability to look at individual orientation columns, but how this ability was used. Subjects were told to focus on one of two overlapping grids of lines of different orientations. The researchers then used the enhanced scanning technique to verify that the relevant orientation columns were activated. This demonstrates how higher-level, conscious functioning (“attention”) can drive lower-level brain functions—the sort of top-down mechanism that Jeff Hawkins focuses on in On Intelligence.

I do have to object to the headline the NYT came up with for its article about this news: “Improved Scanning Technique Uses Brain as Portal to Thought”.

Now, we just have to hone in on the “God” columns in the temporal lobe, or wherever they are.


Monday, January 24th, 2005

Branch of zoology that studies the behavior of animals in their natural habitats.


Sunday, January 23rd, 2005


Hypnosis and cognitive processing

Saturday, January 22nd, 2005

What can hypnosis teach us about how people’s pre-formed views influence their interpretation of the world?

In This Is Your Brain Under Hypnosis , the New York Times reported on research carried out by Columbia’s Dr. Amir Raz which found that subjects, instructed under hypnosis to ignore the lexical content of colored color words shown to them (the word “red” written in green letters), bypassed the normal conflict between the lexical content (the letters) and their color—the so-called “Stroop effect” (Wikipedia) which causes people to answer slowly when asked the letters’ colors. The abstract is available on PNAS. (An aside: although the researcher emphasizes “conflict reduction”, to me it would seem that the hypnotic suggestion eliminated the entire lexical input mechanism, preventing any conflict from occurring in the first place.)

I have not read the original article. However, the NYT reporting raises some questions. It points out that there are 10 times as many nerve fibers carrying information down as there are carrying it up, concluding that “consciousness” is “top down”:

What you see is not always what you get, because what you see depends on a framework built by experience that stands ready to interpret the raw information – as a flower or a hammer or a face.

But this is wrong. The framework does not “stand ready to interpret the raw information”—it drives the way the raw information is collected. Anyway, I think we already knew that.

The real problems start with its (or the researchers?) claim that the research sheds light both on the mechanism of hypnosis and simultaneously on the process of cognition. It’s like claiming that if I find that I do A and B results, I’ve learned about both A and B. Well I have, but only that A results in B and B results from A.

What would be truly interesting would be to understand the general processes—of which hypnosis is merely a minor one—by which the top-down constructs are built in our brain. Then we might start seeing how people suggest to themselves that God exists.

My favorite part of the article is this quote by Dr. Stephen M. Kosslyn, a neuroscientist at Harvard:

People think that sights, sounds and touch from the outside world constitute reality. But the brain constructs what it perceives based on past experience.

Wow, our nation’s newspaper of record is now reporting on neuroscientists’ theories of reality.


Sunday, January 16th, 2005

To turn inside out or outward. This word was used in a NYT article describing a worm which burrows by “everting” its mouth into a kind of big drill bit.

Numenware turns six months old

Friday, January 14th, 2005

September marks the sixth month of Numenware, with 85 posts in that period, almost exactly one every two days.

I’d like to take this opportunity to convey my warm thanks to all my readers for their interest and comments (and putting up with my occasional idiosyncratic posts about Japanese things—cured sea cucumber entrails, anyone?—and who knows what else).

Alexa regularly ranks us in the top 100,000 most visited sites on the web, and lists us as the most popular site in the Top > Science > Social Sciences > Psychology > Psychology and Religion category. Technorati also has us close to the top 100,000 and rising. We’re averaging more than 500 visitors per day now and over 2,000 unique visitors per month. We’re getting linked to more and more and show up on major blog search sites, including Yahoo!’s new blog-enhanced news search.

What’s popular? At the top of the list recently are posts about Bhutan’s Tiger’s Lair, Stigmata, Pachacuti as Builder, God and the brain in your gut, and Computational models of neurotheology.

Perhaps readers have noticed the new tag-based index available on the index page, hopefully increasing the site’s browsability. This uses a service from a company called TagCloud.

As we move ahead, I want to make Numenware more interesting and incisive, continue frequent posting, tighten up my posts for those whose blog-reading time is limited, and, most importantly, focus more on ideas and hypotheses as a way to make some initial order out of all the raw material available to us in this fascinating and critically important field of neurotheology.

Your support is deeply appreciated.

And no, I don’t know where the mural shown above comes from. Corbis’ description of it is simply “graffiti painting of man vomiting”.

Thursday, January 13th, 2005

As Numenware’s readership grows (thanks!) and its identity grows stronger, it has now moved to its own domain:, obviously. Your existing links and feeds should be redirected transparently.

Really smart people on the meaning of life

Tuesday, January 11th, 2005 is a fascinating site that has videos of interviews with major thinkers—Daniel Dennett (shown), Freeman Dyson, Steven Pinker—on all of our favorite topics, including evolution of religion, consciousness, mystical experience , free will, and death.

For instance, you can listen to Andrew Newberg, whose book Mystical Mind we were unkind to in a recent post, on the topic of why meditate, but I’m sure that’s only one of the interviews you’ll want to listen to.


Friday, January 7th, 2005

Materialist conception of universe. As adjective “hylomorphic”, refers to having material form.


Thursday, January 6th, 2005

Young which are unable to care for themselves, naked, immobile, and/or blind, requiring extended care from their mother; or a species wihch gives birth to such young, such as humans.