July 4, 2008

Google TechTalk on personal genomics

Personal genomics is just starting and this talk gives a preview of what one of the first companies is doing to bring this to market, though the field is starting to heat up with some competition.

Surprising facts from the video:

  1. 23andme co-founder Anne Wojcicki is married to Google co-found Sergei Brin
  2. Data portability is already available. According to the video, users can download the raw data from the 580,000 SNP array and do whatever they want with it.
  3. The SNP array is 580,000 SNPs! Wow. I assumed that the number of genetic features was on the order of 100-1000, giving a rough haplotype.
  4. Sharing/Web 2.0 features: The real power is 23andwe, an effort to data mine and leverage the power of a large database with many people’s genetic information. The founders mention that they want to contribute back to science and healthcare by surveying their customers behaviors and medical issues to uncover further correlations with genes. Like Facebook, the service becomes more valuable and more informative as the network grows.

Description of the talk from Google:

The 23andMe Personal Genome Service offers customers a glimpse at their own DNA sequence, a 750-megabyte string that functions as the operating system for a human being. Common variations in this code can influence the structure and function of the associated wetware in predictable ways. Some of these variations and their effects on traits such as athletic talent, pain sensitivity and avoidance of errors will be discussed in reference to three well-documented examples.


Aging faculty and the decline of liberalism in universities

On Campus, the 1960s Begin to Fade as Liberal Professors Retire - NYTimes.com

Although the shift away from liberalism amongst faculty is interesting, this graphic caught my attention:

Should we take this to mean that there should be more faculty jobs as the avg age increases? (Or is this negated by the fact that people are living longer and working longer?)


June 10, 2008

Plant neuroscience

Plants Found to Show Preferences for Their Relatives - NYTimes.com

Two amazing things here:

  1. Plants missing photosynthetic enzymes of their own that migrate directionally toward “victim” plants. This behavior has an uncanny resemblance to axon guidance. Make sure to view the time-lapse video in the NYT article. Here’s an image from the PSU website:

  2. Plants capable of identifying kin and “being nice” to kin while going into a competitive mode of root growth with non-kin. Amazing.

It refreshing to see this kind of interesting behavior without any neurons involved. It makes me think (realize) that the idea of a neuron or a neural system has many components and there might not be any good reason to assume that a single cell must have all of those properties or none of them. Something like a neuron-like cell that’s not a neuron in the classical sense. Anyone know of other examples?


May 27, 2008

Evaluating different 3D fluorescence microscopy techniques

Saw this on the Confocal list… Several times in the last few years I and others in the lab have debated the advantages and disadvantages of different fluorescence microscopy techniques. As many of you know, fluorescence microscopy is becoming increasingly important for many cool neuroscience techniques. But equally important in knowing how to properly image fluorescence.

Here’s a really thorough 2007 article from J. Microscopy that does a nice job of comparing wide-field/deconvolution, spinning disk confocal, and laser scanning confocal microscopy. Punchline is after the jump. Read on »


May 21, 2008

Hyperthymestic syndrome: Perfect automatic memory

Fascinating. The first case of a person with virtually perfect autobiographic memory. In the interview, she says that she runs her entire life through her head every day. Perhaps the difference isn’t in memory capacity but rather the automatic (unconscious) practicing of all past sensory experience.

NPR interview with patient, John Gabrieli and Larry Cahill.

Link to paper
. Abstract:

This report describes AJ, a woman whose remembering dominates her life. Her memory is “nonstop, uncontrollable, and automatic.” AJ spends an excessive amount of time recalling her personal past with considerable accuracy and reliability. If given a date, she can tell you what she was doing and what day of the week it fell on. She differs from other cases of superior memory who use practiced mnemonics to remember vast amounts of personally irrelevant information. We propose the name hyperthymestic syndrome, from the Greek word thymesis meaning remembering, and that AJ is the first reported case.


May 13, 2008

PBS: Not so neuroscience-savvy

Salon has an interesting piece condemning a recent PBS show purportedly on Alzheimer’s treatment but really more of a sketchy informercial. The program concerns a neurologist with tenuous ties to UC Irvine who advocates SPECT (single photon emission computed tomograpy, a technique which, similar to PET, uses a radiotracer) and some unfounded preventative treatments for Alzheimer’s. The neurologist Bill Amen has appeared on many big-name media outlets including CNN, the Today Show, and Fox News (and the real sign of media success — Oprah) although his approach to Alzheimer’s detection and treatment is lacking in scientific credibility:

“SPECT scans are not sufficiently sensitive or specific to be useful in the diagnosis of A.D.,” neurologist Michael Greicius , who runs the Stanford University memory clinic, and has a special interest in the use of functional brain imaging in the diagnosis of A.D., tells me. “The PBS airing of Amen’s program provides a stamp of scientific validity to work which has no scientific validity.”

Continued pontification on neuroethics issues after the jump. Read on »


May 9, 2008

Quantitative biology database

BioNumbers - The Database of Useful Biological Numbers

Here’s a neat new website. It’s a repository of quantitative information on biological things (eg. organisms, biomolecules, etc.) Some stuff I found while glancing through:

Number of mRNA/cell in E. coli: 138

Volume occupied by all RNA in E. coli: 6%

Average gene length in mammals: 16.6kb

Average gene length in nematode C. elegans:  4 kb

Mutation rate per genome per replication in humans: 0.16 mutation/genome/replication

Average time between blinks in humans: 2.8 sec

Amount of photons necessary to excite a cone in humans: 100

Citations are included for most numbers too. The database seems a little sparse on neuroscience topics, so go over and contribute some numbers!


May 5, 2008

The truth about TTX!

If the Fish Liver Can’t Kill, Is It Really a Delicacy? [NYT, login]

Amazing. It looks like TTX (tetrodotoxin, a potent voltage-gated sodium channel blocker well-known to electrophysiologists) is not made by the pufferfish (which I had always assumed), rather it is from the bacteria/food consumed by the fish.

Decades earlier, another Japanese scientist had identified fugu’s poison as tetrodotoxin, a neurotoxin that leaves victims mentally aware while they suffer paralysis and, in the worst cases, die of heart failure or suffocation. There is no known antidote.

Researchers surmised that fugu probably got the toxin by eating other animals that carried tetrodotoxin-laden bacteria, developing immunity over time — though scientists then did not rule out the possibility that fugu produced the toxin on its own.

By this year, Mr. Noguchi had tested more than 7,000 fugu in seven prefectures in Japan that had been given only feed free of the tetrodotoxin-laden bacteria. Not one was poisonous.

“When it wasn’t known where fugu’s poison came from, the mystery made for better conversation,” Mr. Noguchi said. “So, in effect, we took the romance out of fugu.”

Aside from the interesting science, it appears there is also a small Japanese “industry” (de-ttx? detox?) seriously affected by TTX-free fugu. More after the jump Read on »


Neurotechnology conference in Boston this week

Full agenda is available here. Speakers are mostly a mix of neurotech CEOs and VCs (and Rep. Patrick Kennedy).

I’ve heard that there are no more free passes for students. (sadly) If anyone attends and would be willing to write-up something about the conference, please let me know and I’d be glad to put it on neurodudes.

READ MORE: Conferences

April 29, 2008

Control of mental activities by internal models in the cerebellum

The great Masao Ito, originator of one of the classic theories of cerebellar function, has published a new theory in the recent issue of Nature Neuroscience regarding how the cerebellum may be involved in control of cognition.

The basic idea is that while the cerebellum has evolutionarily had a role of refining motor commands for the purpose of controlling the skeleton, in the human the cerebellum is capable of refining commands from frontal cortex to “control” internal representations of the outside world. Ito uses the increasingly popular language of control theory to describe the effect that the cerebellum may have on different parts of the brain.

From the abstract:

The intricate neuronal circuitry of the cerebellum is thought to encode internal models that reproduce the dynamic properties of body parts. These models are essential for controlling the movement of these body parts: they allow the brain to precisely control the movement without the need for sensory feedback. It is thought that the cerebellum might also encode internal models that reproduce the essential properties of mental representations in the cerebral cortex. This hypothesis suggests a possible mechanism by which intuition and implicit thought might function and explains some of the symptoms that are exhibited by psychiatric patients. This article examines the conceptual bases and experimental evidence for this hypothesis.