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. Continue reading

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.

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. Continue reading

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!

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 Continue reading