Tarnow preprint on moving memory structure

Tarnow analyzes some data on short/mid-term memory recall (up to 10 minutes) to show support for a model in which there is a finite “buffer” storing recent events, indexed by time, which is searched by starting at the present time and going back in time.


Neuroscientists protest Dalai Lama at SfN

Looks like some SfN members are not happy with the Dalai Lama’s proposed lecture at the upcoming annual SfN meeting, according to an article in Nature. I can’t say I agree with the critics:

Some of the critics believe that the Dalai Lama’s lecture should be ruled out because of his status as a political and religious figure. “One of the reasons for inviting him is that he has views on controlling negative emotions, which is a legitimate area for neuroscience research in the future,” says Robert Desimone, director of the McGovern Institute for Brain Research at the Massachusetts Institute of Technology. But “the SfN needs to distance itself as much as it can from the Dalai Lama and his beliefs”, adds Desimone, who opposes the lecture but has not yet signed the petition.

Um, OK, but what’s the point of having a series of “neuroscience and society” lectures if we’re not going to be talking with religious, political, and other non-neuroscience areas? Even those who have signed the petition don’t seem to have very compelling reasons:

[…] they insist that their concerns are purely scientific. Yi Rao a neuroscientist at Northwestern University in Chicago, Illinois, helped to draft the petition, which says that the science of meditation is “a subject with hyperbolic claims, limited research and compromised scientific rigour”.

Regardless of what you think about meditation and any neural impact it may or may not have, this seems at little preemptive. Stopping dialogue is never necessary when trying to debunk bad science — dialogue, if anything, helps! Unless the Dalai Lama is persuading people to do bad science (and it certainly didn’t seem that way during his symposium at MIT on neuroscience), these scientists need to be a little more accepting. How cool would it be if President Bush — or any major political/religious leader, for that matter — cared enough about a scientific subject to actually come to a professional society’s annual meeting?

Tom Wolfe's neuroscience idolatry

From it opening invocation describing the behavior of amygdalectomized cats (an allegory for the novel’s primary theme involving modern college life), Tom Wolfe’s newest novel, I am Charlotte Simmons, reads like a paen to modern neuroscience. I normally would not post this kind of stuff but I have been thinking that Wolfe’s novel is part of a larger phenomenon — the popularization and dissemination of neuroscience to a wider audience than ever before. For example, in the last few years, it is my impression that there have been many more articles in the NYT about neuroscience. I don’t recall seeing neuroscience-related articles there on such a frequent basis before.

Back to the topic on hand. I was especially eager to read Wolfe’s novel because he wrote it after visiting and observing students at a few colleges. Of note, he spent the most time (I think a whole year) at Stanford — my senior year there. His previous short story collection (Hooking Up), written right after his time at Stanford in 2001, does an excellent job of capturing snippets of college life, as any recent Stanford graduate can probably tell just from the title’s clever use of a popular new (well, relatively) phrase. Also, strangely enough, President Bush has repeatedly been seen reading Charlotte Simmons. With all the important world matters to read up on, why this book of college life? Between this fact and the Stanford connection, I decided to check the book out myself.

Here’s an excerpt from Charlotte talking to another student:

This class in neuroscience? It’s the most exciting subject in the world. It’s like in the future it’s going to be the key to just about everything

Ah, I agree entirely! Anyways, if you’re looking for a good read that includes some neuroscience idolatry, some crazy fraternity parties, and is recommended by none other than the President of the United States, Wolfe’s your man.

Dopamine D_3 agonist leads to compulsive gambling, hedonism

11 patients taking dopamine agonists for Parkinson’s developed compulsive gambling, sometimes accompanied with hypersexuality. A retrospective study of one clinic found that 1.5% of 529 patients taking pramipexole developed compulsive gambling. Pramipexole is a D_3 agonist. D_3 receptors are located in the limbic system.

The article is short and the case studies are interesting. Interestingly, many of the patients profiled recognized a change in their behavior and thought it was abnormal for them to be obsessed with gambling, and told their neurologist.

M. Leann Dodd, MD; Kevin J. Klos, MD; James H. Bower, MD; Yonas E. Geda, MD; Keith A. Josephs, MST, MD; J. Eric Ahlskog, PhD, MD. Pathological Gambling Caused by Drugs Used to Treat Parkinson Disease. Arch Neurol. 2005;62

Somatic mosaicism in neuronal precursor cells mediated by jumping genes

This research suggests that neuronal variety within a single person may be partly due to “jumping genes” which change their position from cell to cell.

<a href="http://www.livescience.com/humanbiology/050615_jumping_genes.html&quot;

Alysson R. Muotri, Vi T. Chu, Maria C. N. Marchetto, Wei Deng, John V. Moran and Fred H. Gage. Somatic mosaicism in neuronal precursor cells mediated by L1 retrotransposition p903. Nature 435, 903-910 (16 June 2005). doi: 10.1038/nature03663

News and Views

Object-responsive, abstract, neurons in medial-temporal lobe

A fascinating study finds neurons which respond selectively to certain individuals or landmarks in varied representations. For example, one unit responded to “various pictures of the actress Halle Berry – as well as drawings of her and her name written down”. Another one responded both to pictures of the Sydney Opera House and also to the letter string “Sydney Opera”.

For most of the responsive units, the experimenters could only find a single concept which the unit responded to. The authors don’t feel that the units are “grandmother cells”, but rather, they think they just didn’t test for the other things that the cells would have responded to. Still, this argues strongly for pretty sparse coding.

R. Quian Quiroga, L. Reddy, G. Kreiman, C. Koch, I. Fried. Invariant visual representation by single neurons in the human brain. Nature 435, 1102-1107 (23 Jun 2005) Letters to Editor.

Pop sci article

More on romantic love study

You may have heard about the fMRI study about early-stage, intense romantic love. I recommend checking out this short CogNews excerpt from LiveScience article about it.

Arthur Aron, Helen Fisher, Debra J. Mashek, Greg Strong, Haifang Li, and Lucy L. Brown. Reward, Motivation, and Emotion Systems Associated With Early-Stage Intense Romantic Love. J Neurophysiol 94: 327-337, 2005. First published doi:10.1152/jn.00838.2004

Attentional effects of FEF

(from January)

Tirin Moore and Katherine Armstrong have showed that stimulating the frontal eye fields (FEF) can cause neurons in V4 to become more responsive to stimuli. It was known that stimulating FEF can cause saccades, but this shows that even if you stimulate too weakly to cause a saccade, you still enhance the responsiveness of V4 neurons which target the visual location corresponding to your FEF stimulation.

An earlier behavioral study has already shown that weak FEF stimulation can improve visual performance for the corresponding visual location.

Tirin Moore, Katherine M. Armstrong.
Selective gating of visual signals by microstimulation of frontal cortex.Nature 421, 370-373 (23 Jan 2003) Letters to Editor.

Press release