neurodudes

A forthcoming issue of the journal Neuroscience is devoted to an examination of multidisciplinary approaches to the study of working memory within the field of Cognitive Neuroscience. Although the issue will not be released until late April, a detailed press release is available from the University of Washington at St. Louis.

From the article:

“Multidisciplinary research within cognitive neuroscience has established itself as a promising approach to answering the question of how the mind emerges from the working of the brain” [...] “One of the fields that has gained substantially by successfully combining the theoretical frameworks, methodologies, empirical results and insights of the varied disciplines within cognitive neuroscience, is the study of working memory”

It goes on to describe a “pyramid approach” to multidisciplinary work in this area, which chiefly involves the merging of cognitive psychology, computational science, neuroscience, and cognitive neuropsychiatry.

What gives humans the unique ability to construct novel sentences from the building blocks of language? A recent article in Behavioral and Brain Sciences proposes a “neural blackboard architecture” is capable of just this.

From the article (doi: 10.1017/S0140525X06009022):

“This paper aims to show that neural “blackboard” architectures can provide an adequate theoretical basis for a neural instantiation of combinatorial cognitive structures. [...] We also discuss the similarities between the neural blackboard architecture of sentence structure and neural blackboard architectures of combinatorial structures in visual cognition and visual working memory [...]”

As with all main articles in Behavioral and Brain Sciences, this one is followed by extensive comment and criticism from colleagues, and finally a reply by the authors. This provides a very deep look at the article and the issues surrounding it.

An older, but freely available, version of the article is available here.

“Scans of brain activity, published online in the journal Nature Neuroscience, indicate that the brain can actually get into the ‘right frame of mind’ to store new information and that we perform at our best if the brain is active not only at the moment we get new information but also in the seconds before.
….
Tests showed that the brain’s electrical activity differed after the cue question and before the word was presented and this was linked to whether the subject would remember or forget the word in a later unexpected memory test. If the electrical activity maintained a high level over frontal parts of the scalp just before the word was shown, then it was likely that the subject would remember the word up to 50 minutes later - and after doing a series of other word tests. On the other hand, if the voltage was lower, the subjects were less likely to remember the word.”

(from the press release)

Leun J. Otten, Richard N. A. Henson & Michael D. Rugg. State-related and item-related neural correlates of successful memory encoding. Nature Neuroscience 5, 1339 - 1344 (2002). Published online: 28 October 2002; doi:10.1038/nn967

As you know, here at Neurodudes, we’re always interested in seeing how people are applying results from neuroscience to areas outside of academic neuroscience. Today, I got the following in my inbox:

Special Lecture
BRAIN PLASTICITY IN AGING
Wednesday, February 1, 2006
10:00 am 46-4062
Bonnie Connor, Ph.D., Laila Spina, Psy.D., and Natasha Belfor, Ph.D.
Posit Science Corporation
San Francisco, CA

Leading me to the natural question: What is Posit Science Corp? Well, here is their website. They seem to be a company focused on keeping mental abilities sharp. To that end, they have lead seminars and sell computer programs based on aging research results.

I haven’t looked over their website in detail but they do seem to have a lot of information on the science behind their techniques and Mike Merzenich is their Chief Scientist. (There’s quite a few names you might recognize on their list of advisors and consultants.)

The nice NYT article on the function of sleep follows on a recent NIH-funded Nature insight series.

Some interesting facts from the NYT article:

• Sleep patterns vary greatly. Some bats sleep 20 hours, giraffes get 2 hours. (hmmm… grad students might be evolving toward giraffes…)
• Sleep has recently been found to occur in invertebrates too. Alternatively stated: Sleep is evolutionarily very old.
• Slow wave sleep is also found in fruit flies. (Divergence from fruit flies for us was 600 million years ago.)
• Some people don’t have any REM sleep. Behaviorally, these people are entirely normal, implying that it’s purpose might not be as obvious as one had thought (ie. required for the preservation of new memories, etc.)
• If you put a bunch of ducks in a row, the ones on the inside will sleep more often with both eyes closed. The ones on the outside will sleep with one eye open and it is (always?) the eye facing outward from the huddle. They are able to “sleep” one half of the brain at a time and, apparently, this sleeping with one eye open was lost in higher mammalian evolution. Fascinating.

This article is about efforts by six teams to develop a hippocampal prothesis by monitoring the input/output transformations performed by the hippocampus in slice, and then creating an electronic device to mimic them.

The article quotes noted memory researchers Howard Eichenbaum and Norbert Fortin who seem to approve of the methodology.

Scientific Clearing House: Mind enhancing drugs

Apparently, CX717, an ampakine developed by Cortex Pharmaceuticals, shows some signs of preventing the cognitive impairment brought on by sleep deprivation. The original study in PLoS Biology (news & views) was done with monkeys.

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.

Edge magazine asked people, “What do you believe is true even though you cannot prove it?”

Terrence Sejnowski’s answer was that, “the substrate of really old memories is located not inside cells [or in synaptic strengths], but outside cells, in the extracellular space.”
(more…)

Last summer, I began to make an online mini-bibliography on neocortical synaptic plasticity. It currently contains over 160 citations divided into over 35 cross-linked subtopic listings.
(more…)