neurodudes

Myomancy is my blog on research into ADHD, dyslexia and autism. Its aim is to take the scientific research and make it accessible for parents, sufferers and educators. My background is in computers but my interest in nueroscience comes from a lifetime of trying to understand how my dyslexic brain was different from everyone else. This interest grew into a hobby and it now threatens to become semi-professional involvement following my successful dyslexia treatment and the lauch on Myomancy.

Chris Tregenza

Jeff Hawkins has just sent out an email to the Redwood Neuroscience Institute mailing list announcing that it’s moving to UC Berkeley and changing its name to the Redwood Center for Theoretical Neuroscience. It will be directed by Bruno Olshausen. Jeff also mentions that he will now be working full-time on his brain-theory-inspired AI projects at Numenta.

Full letter after the jump.

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The Aug 4 issue of Neuron has an interesting article (news & views) on fMRI of the ventral (”what”/perception) and dorsal (”where”/motor) visual pathways.

Subjects in the fMRI were either shown images of objects alone or hands grasping these objects. Reliably, the object-only stimuli activated the contralateral ventral visual pathway. In the case of grasping stimuli where the hand was presented in the opposite visual hemifield from the object, contralateral activation of the dorsal and ventral visual pathways was seen. When subjects were asked to focus their attention on either object or grasping hand, activation was pronounced in the ventral or dorsal visual streams, respectively.

Most importantly, the study affirms that there really isn’t a single fundamental visual representation in the brain — the representation used to recognize an object is not the same as the representation used to pick up that object. Because of the different functions of these tasks, this probably doesn’t sound too surprising but, to me, it is surprising! What we consciously see is neurally separate from what our motor system is “seeing” and the break between the two pathways happens quite early in visual processing.

Like the mirror neuron work, this provides further evidence in the “seeing is believing/doing” vein. As the author of the news and views summary points out, this work

remind[s] us once more that (ultimately) the brain did not evolve to enable us to think; it evolved to enable us to act.

Lastly, this type of idea is the basis of Rodolfo Llinas’s elegant book i of the vortex, which I’ve been reading recently. So far, it’s great and I recommend it highly!

Hi guys,

First of all, congratulations for this great blog that even allows the readers to publish stuff. My name is David and I am a Ph.D student at the Max Planck Institute for molecular genetics in Berlin, Germany. I just wanted to share with you a paper from Dr. Donoghue, one of the founders of Cyberkinetics and an expert in the field of computer-brain interfaces, which provides very useful analysis and insights on these devices. Anyone interested on the field, should take a look at it. Lots of interesting material!

http://donoghue.neuro.brown.edu/pubs/2003-SerruyaDonoghue-Chap3-preprint.pdf [Design Principles of a Neuromotor Prosthetic Device]

I [Eric Thomson] have started a new blog for discussion of Hille’s classic Ion Channels of Excitable Membranes:

http://neurochannels.blogspot.com

Participate, tell your friends, get the book.

[From Neville: Just a note for the guest posters. It's fine to promote neuroscience-related materials (well, nothing overtly commercial... unless it's *really* cool). Still, if you're making a guest post -- something which we encourage and have directions on how to do on the right sidebar of the screen -- please put your name in the post. If you feel so inclined, it also wouldn't hurt to put in a few sentences about where you're from and your relation to the field -- ie. grad student, postdoc, industry, prof, regular guy or girl interested in brain stuff, etc. Thanks!]

NEUROSCIENCE: Preventing Alzheimer’s: A Lifelong Commitment? — Marx 309 (5736): 864 — Science

Some quotes of interest:

For example, a 1997 study of 642 elderly people, conducted by Denis Evans of Rush Presbyterian-St. Luke’s Medical Center in Chicago and his colleagues, found that each year of education reduces a person’s risk of Alzheimer’s disease by 17%.

[...]

As in other studies, Snowdon and his colleagues found that high education levels seem to protect against Alzheimer’s disease. The researchers originally thought that this supported the idea that more education leads to a higher cognitive reserve. But analysis of biographical essays the sisters had written when they entered the convent, usually in their early 20s, pointed in a different direction. The early writings, Snowdon says, were an even better predictor of who would get Alzheimer’s disease than education level. “Those who had the lowest linguistic skills at age 22 had a very high risk of Alzheimer’s,” Snowdon says. Indeed, most of the cases occurred in the nuns whose essays put them in the bottom third on the linguistic ability scale.

[...]

A few years ago, Arthur Kramer of the University of Illinois, Urbana-Champaign (UIUC), and his colleagues performed a meta-analysis of 18 trials involving adults between the ages of 55 and 80 that explored the effects of physical exercise on performance of various cognitive tasks. They concluded that the answer to the question, “Does aerobic exercise enhance cognition?” was an “unequivocal yes.”

[...]

As reported in the April issue of the American Journal of Epidemiology, study members who engaged in four or more physical activities, which could be anything from gardening to jogging or biking, had about half the risk of dementia as that of participants who engaged in one or none. The effect was primarily seen, however, in persons who did not carry a gene variant called ApoE4 that’s known to increase Alzheimer’s risk. In the ApoE4-endowed population at least, genetics seems to trump activity.

[...]

Another possibility is that exercise turns up production of proteins that stimulate neuronal growth. About 10 years ago, Carl Cotman’s team at UC Irvine, found that the brains of rats who ran voluntarily on a wheel show increases in one such factor, BDNF (for brain-derived neurotrophic factor). The increase was particularly strong in the hippocampus, an area involved in learning and memory that’s hard-hit by Alzheimer’s disease.

The NYT has a nice summary of a recent Cell paper, where investigators from the Karolinska Institute used a wonderfully innovative technique to determine the age of many cells, including neurons from visual cortex and the cerebellum.

The general idea is this: Up until 1963, above ground nuclear weapons testing was allowed, dispersing radioactive carbon (14C) into the atmosphere. This “tagged” carbon was integrated into all plants and animals at that time and, since 1963, at an exponentially decreasing amount. Thus, calibrated with pine tree trunk rings (which are produced every year), the scientists are able to judge the age of cells by seeing how much of the genomic DNA of the cell contains 14C. Genomic DNA is created during cell division and, as the authors show, it appears not to be regenerated since preserved cell specimens from different years show the characteristic exponential decay of 14C post-1963.

The neat finding is that several neurons, from cortex and cerebellum, are very old… in 50-60 year old cadavers, neurons were found that were just as old or nearly just as old as the cadavers. So, even if there is neurogenesis occuring, it is now almost certain that some of our neurons are with us throughout life.

The NYT has an article on student life at Columbia called The Adderall Advantage.

Relevant quote:

But interviews and e-mail exchanges with two dozen Columbia students suggest that the prevailing ethos is that Adderall, the drug of choice these days, is a legitimate and even hip way to get through the rigors of a hectic academic and social life. “The culture here actually encourages people to use stimulants,” said Barak Ben-Ezer, a computer science and economics major who prefers Red Bull, a caffeinated beverage, and cigarettes over prescription drugs.

And on addiction:

Designer stimulants like Adderall are far less dangerous than cocaine or methamphetamines. According to the Shire Pharmaceuticals Group, which makes Adderall, medical research has found it has no potential for addiction.