(warning: if you’re not too interested in neuroscience, ignore bohemian scientist for the next week! check here for a good discussion of halloween-eerr-reformation day, and here for answers of high profile academics on the question “is there a purpose?” (courtesy of millinerd).
throughout the next week, watch for updates here on the society for neuroscience meeting in san diego… mainly on the following topics:
sensory encoding (see especially the barrels satellite meeting, thursday-friday)
motor control, satellite conference on friday, assorted posters throughout the week
sensorimotor integration (a few poster sessions and a symposium)
computational systems issues (throughout the week)
and, of course, a good amount of extracurricular work…e.g. all are welcome here:
the center for ethics in science and technology, based out of ucsd, has declared this week “neuroethics week.” each day, a high-profile speaker and expert panel discuss a subfield relevant to neuroscience and ethics. monday, hank greely, a law prof at stanford, gave a keynote lecture “A Revolution in Neuroscience: Challenges for Society.” below are some notes from the lecture… read at your own risk! (disclaimer: these don’t necessarily reflect the views of bosci).
if these are issues you’re interested in, come to a coffee hour i’m co-hosting this saturday afternoon; feel free to email me for details.
ethical issues in neuroscience research
as many as 40% of participants in research fMRI scans (typically undergrads) have some abnormality. what should the researcher do?
identification of anonymous research subjects (a problem similar to those in genetics)
dual use problems. similar to biological warfare today, or nuclear physics of fifty years ago. e.g. monkey stimulation of thalamus can keep people awake. this could be used by our military, or others.
the neuroscience of ethics
the trolley problem: flipping a switch to kill five instead of 20 people, throwing someone in the way to kill just one person instead of 20 people (researchers like josh greene).
by extension, neuroeconomics and advertising
ethical, legal, social implications of neuro applications
prediction. discrimination for insurance. examples:
similar to the genetics diagnosis problem (e.g. huntington’s disease); amyloid plaques (indirectly visible by PET or MRI) to compute likelihood of dementia onset (long-term studies are underway).
schizophrenia
psychopaths, greater likelihood in crime (1-2% in general population, 30-70% of incarcerated population)
mind-reading.
currently, we can read whether someone is looking at a face or a house (fusiform face area).
we can detect the feeling of pain by fMRI (useful for law and insurance purposes), and could examine the pain associated with lethal injection.
lie detection. so far, 12 peer-reviewed papers. two companies are doing it: no-lie mri, based in san diego. the relevant research found 80% accuracy. much of this is funded by the intelligence community (darpa, cia, homeland security).
competence, consciousness, and responsibility
when a crime is committed, to what extent is he culpable. put differently, is there free will?
is an elderly person in a capable state to sign a will?
vegetative states. in one of 13 cases, a patient showed all the same brain activity patterns that a normal person would. what should be done in this case?
treatment
try to distinguish the good from the bad. we have a track record of mistakes (the inventor of the frontal lobotomy received a nobel prize long before the technique was discredited.
a cocaine effects-blocker. should it be mandatory?
enhancement
making people “better than healthy”. improved memories.
brain-computer interfaces (as for quadriplegics, or the cochlear implant, which has been around for 25 years. see michael chorost)
beta blockers to prevent deep emotions following traumatic stress. it’s already being used in the military and for rape victims.
this neuroethics week is essential to educate the public not on the answers, or even the questions (which depend on the technology development), but on the class of questions we do and will face.
(and an important point during the discussion)
how good must a test be to use it (false positives and and negatives)? should this be administered by FDA?
the salk just announced a january symposium called biological complexity: genes, circuits, and behavior. it includes such nobel laureates as richard axel, eric kandel, and susumu tonegawa, along with other heavy hitters like karl deisseroth, rusty gage, tom jessel, edvard moser, and ranulfo romo. place your bets!
see here for details. and thanks to baseball fan and neural star ba for the tip.
welcome to the twenty-eighth edition of encephalon, a circus of recent highlights from the neuroscience blogentsia. this time around, we had many reviews of some interesting original research, along with posts on everything from aesthetics to eulogies. enjoy!
neo-neuro fields
one of the beauties of neuroscience is its universality: at some level, everything involves the brain. too often, though, people affix “neuro-” to the front of their favorite subject, then claim victory over a paradigm-shifting new discipline. two blogs dealt with this issue recently: neuroaesthetics led to some deep insights, whereas “neuro-leadership” just fell flat. both posts were entertaining and insightful.
over at the third culture, jon follows up his two part series on neuroaesthetics with a post on art, context, and the brain. he asks with subtlety, “if we are to believe that there is some way to understand reactions to art by understanding the brain (or to understand the brain by understanding art), how are we to incorporate context-specific reactions?” jon takes on the question with a review of some neuroeconomics and an apropos reference to ucsd neuro-rocker ramachandran.
meanwhile, the trusted advisor asks “is neuroleadership more than reinventing wheels?” he decides that neuroscience hasn’t contributed novel insights to business management, despite the claims of people like the prolific jeffrey schwartz. i couldn’t agree more: projects such as “neuroleadership theory” only detract from more legitimate descriptive science aimed at understanding the brain more than making a buck.
and now for some reviews… biology and neuroscience
yeastbeast of ouroborosreviews a recent science article reinvestigating the role of a receptor gene previously shown important to insulin signaling. among the findings was that mutant mice lacking the gene had much smaller brains, leading to some sweet speculations.
at neurophilosophy, mo writes of two recent studies that challenge some long-held dogmas in neuroscience. first, and perhaps more important, researchers in roger traub’s lab discovered gap junctions in hippocampal cells, with obvious implications for epilepsy. second, he writes about a two-neuron digestive system circuit that transmits signals in two modes, the faster one using action potentials and the slower (on order of minutes) using a ceramide-activated second messenger system. as always, he provides great historical context.
medopedia briefly reviews two papers, one on brains and one on hearts. the first connects glutamate receptor mGluR1 in its role in memory and addiction, as described by johns hopkins researcher david linden, who stopped by recently to talk about two photon imaging of cerebellum. the second looks at regenerating cardiac cells. medopedia speculates on melding the two studies to rewire brains, an idea that already has a lot of steam in neurodevelopmental labs, such as anirvan ghosh’s here at ucsd.
brain in a vatreviews a paper on integrator neurons. the duke researchers report neuronal subpopulations in lateral intraparietal area (a part of the parietal lobe) that use spike rate to encode the number of dots in the monkey’s visual field. nice!
psychology and neuroscience
cognitive daily reviews a new paper on multitasking and stress. in the study, average performance of human subjects on two different tasks was not different between high- and low-stress situations. however, the researchers pursue a subtler point, arguing from reaction times that the high-stress group uses the same strategy for both tasks, whereas the low-stress group uses different strategies. in my opinion, making conclusions from reaction times is always a tricky business, but historically it has provided some useful insights into brain processing.
jeremy, of psyblog fame, discusses a study showing that couples tend to look more similar as they grow older. the researchers speculate that, because married folks empathize with one another, they mutually mimic facial expressions, leading to similar-looking faces. however, happiness–and thus, perhaps, the degree to which couples empathize with one another–didn’t correlate significantly with apparent similarity. good find!
brain in a vat reports that a new anti-smoking pill may treat alcohol dependence. rats trained to self-administer ethanol reduced their consumption when treated with the active ingredient in a popular smoke-stick-stopping drug. the ingredient, varenicline, works as a competitive antagonist on nicotinic acetylcholine receptors. it may point to a shared mechanism mediating addiction of both flavors.
in a related post at mindhacks, contributor vaughan bell discusses addiction as more than a mere “brain disease”. he puts the neuroscience of addiction into the larger context of psychology and sociology. he also quotes the delightful theodore dalrymple, who warns against the excesses of medicalization in substance abuse. importantly, vaughan points out that diagnosing a “brain disease” can reduce the stigma that comes with being different.
sudip at brain blogger writes a meditation for troubled minds, a review of a metastudy on meditation. apparently, mindfulness meditation has a checkered record in ameliorating stress.
the neurocriticreviews an fmri study suggesting that ten year olds better able to resist peer pressure also have better executive control in prefrontal cortex and a higher correlation between prefrontal and posterior brain activity during certain activities.
reviews of books and lives
providentia gives us worm running, a reflection on the life of the late iconoclastic researcher and joker james mcconnell. you may remember him from a famous research project called memory transfer through cannibalism in planaria, in which worms learned a task faster after eating compatriots who had already learned the task. the underlying theory of memory rna never caught on, much to the chagrin of the food industry (how much would you pay for nobel laureate soup?).
alvaro at sharpbrains records an interview with yaakov stern, a columbia doc who studies alzheimer’s. he has tried to tackle a central paradox in the disease: pathology without presentation. it’s like DC, only weirder.
thinking meat’s mary gives a nice review of two new books on neuroplasticity, one on personal accounts of the phenomenon (norman doidge) and one on the plasticity research in animal models, including young and adult humans (sharon bergley).
and in other news…
at sharpbrains, andreas describes how dancing is mental exercise. he created a video on the neural substrates of dance, and goes on to cite a study in the new england journal of medicine showing that dancing, more than any other physical activity studied, is correlated with less presentation of dementia later in life. sudip at brain blogger provided a brief discussion of a recent science article on the role of nmda receptors in dentate cells of the hippocampus. the exciting work was done in the lab of susumu tonegawa, a ucsd grad and nobel laureate. brain in a vat gave a shout-out to america’s nerdiest videos, a.k.a. the journal of visualized experiments. to be sure, it looks less like a journal and more like a youtube with citations. but it seems like a useful, if small, repository for teaching biological methods.
phew! that’s all folks. the next stop is at memoirs of a postgrad in mid-august. as always, submit here. happy posting!
alas, my month-long blogging break turned into an all-out two-and-a-half month sabbatical. but instead of reflecting on all of the advances in systems neuroscience and the interactions among science, faith, and culture since the ides of may, i’ll point to a nice post from the free geek. back in june, he sent me his do-it-yourself guide to becoming a cyborg (maybe i should take a hint?). it’s an entertaining write-up on some of the human-machine interface options, broadly conceived, that recently have come to market or are in the line-up. watch out especially for RFID implants to gain nightclub admission and nerve implants that record and input sensory signals (that’s right, you can now experience someone else’s peripheral sensations!).
be sure to stop back here tomorrow, when the twenty-eighth encephalon blog carnival will perform at the bohemian scientist’s shop. for the last encephalon edition, just so you know what neurific excellence to expect, see here.
{picture credits: free geek (1) and sloan-swartz (2)}
gerstner’s group in lausanne, switzerland has announced a competition to predict the electrical behavior of individual neurons in two respects:
1) predict the timing of every spike that a neuron emits with a precision of 2ms.
2) predict the subthreshold membrane potential with a precision of 2mV for arbitrary input.
details on the competition, including the dataset (released 16 March 2007), are here.
note that the first prize receives:
- 4 nights of hotel in Lausanne at the Lake Geneva, June 23-27.
- Free participation in the Quantitative Neuron Modeling workshop June 25/26
- 35-minute-slot for talk as an Invited Speaker in the workshop.
on friday, sebastian seung stopped by ucsd and the salk. he gave two talks, one on machine learning and a second on connectomics (see this review). this post won’t be critical. these are notes from his second talk. facts that should be noted before starting are that 1) the experimental work was done by winfried denk and kevin briggman, a ucsd comp neuro grad, and 2) the theoretical work was done by machine learning theorists long ago. also, this is just in-seminar note-taking; there’s been no attempt to make it appreciable to people unfamiliar with the topic (i’ll give you a post soon). enjoy!
the tools of neuroanatomy are the microscope, the stain, and the knife.
two problems of connectomics (the complete connection matrix of all cells) are
determining what constitute synapses
determining to which cells each axon is synapsed.
techniques: use diamond knife, image slice with TEM, or (denk) image block with SEM (serial block face-sem… “the denktome”) (denk and horstmann, PLoS Biology, 2004; denk and briggman, Current Opinion in Neurobiology, 2006)
limitations: staining a block is hard, electrons going too deep in the block (if too high energy) which will blur the z-resolution. so the x-y resolution is less, ~25-30 nm) (consider)
nematode is example of successful reconstruction, but done by hand.
near future: teravoxel datasets. 1 cubic mm, entire brains of small animals, small brain areas of large animals (the lore: c. elegans shows no individual diversity.)
computational challenges of an automated reconstruction
accuracy- (following neurites: image segmentation (contour completion is easier for humans than for algorithms. which is a bad omen for 3d images, since even humans stink at 3d contour completion); recognizing synapses (object recognition).
note that medical imagers have somewhat solved this. but the problems they solve are easier. note: 6 sigma imaging (reference to engineering: wikipedia article)
speed: teravoxel datasets
technical details
NICE: briggman came up with a stain that only stains the membrane = contours (HRP), making comp sci problem easier. machine learning approach: train neural network on sample data (contour completion done by hand by undergrads) and generalize to whole set. in computer vision, david marr thought everything could be bottom-up. that failed. high-level knowledge is required. same for speech processing. harvey brings up the importance of light microscopy.
the neural network details: convolutional network (related to a late 80s concept, the neocognitron, designed by kunihiko fukushima, a bell labs guy).
network of convolution operations in 3D. progressively different convolutions (filters in feature maps). linear filter, folllowed by sigmoidal “squashing function”. to arrive at the filters, all parameters are adjustable by training (30,000 parameters, using backprop “gradient learning”, as from rumelhart and hinton. (n.b. from dm: see also werbos).
each layer (from fukushima): reduced the resolution in each layer (like areas of cortex). this yields spatially invariant representations. here, their algorithm has a biological analog in multiple time steps in V1. “unfolding in time”.
there are unsupervised approaches that one could do. they did this because it was guaranteed to work.
shows a fly-through of reconstructed neurons to the bladerunner soundtrack. “though we can’t do science yet, we can do movies”. only 20 um
three potential payoffs
structure-function relationships in neural networks
neural development - how the brain wires and rewires itself
example. avian brain area HVC (test synaptic chain theory of motor sequences)
as compared with lichtman’s projectome.
moore’s law for neuroanatomy? two years is the doubling time for number of transistors. given featuers of human brain.
30 um slices of raw images. 50,000 petavoxels (1mil for 1 petabytes); connectome is 5 petabytes, which would fit in google’s storage (around 15 petabytes); 10^11 neurons, 37 bit address (5 bytes), 10^4 connetions/ neuron. in a few decades of moore’s law this’ll work. but this will require nanelectronics.
terry’s less optimistic that even in decades they’ll be able to do this. only harvey karten can do 3d intuition… the rest of us are not evolved for it.
References.
K. Fukushima. Neocognitron: A self-organizing neural network model for a mechanism of pattern recognition unaffected by shift in position. Biological Cybernetics, 36(4): 93-202, 1980.
Denk W, Horstmann H. Serial block-face scanning electron microscopy to reconstruct three-dimensional tissue nanostructure. PLoS Biol. 2004 Nov; 2(11): e329.
Briggman KL, Denk W. Towards neural circuit reconstruction with volume electron microscopy techniques. 2006 Oct; 16(5): 562-70.
to counterbalance last week’s historical narrative on a single reference, i’ll give a citation-rich but summary-scant review of noteworthy papers in systems neuroscience, broadly conceived, this past week. but first, enjoy a moment of zen with some cover art from pnas.
what was that? a network structure visualization of an algorithm involving tempered preferential attachment. for more, see the article on optimization. back to neuroscience (don’t forget, though, how important optimization is).
not much in nature for systems neuro this time around, but there was a cool paper from chris dawes (a ucsd poli.sci. phd student) et al. exploring egalitarian motives in humans. nice, chris.
because of the mammoth importance of one of this week’s papers (and some time crunches on my end), this week’s paper picks are but one. but you won’t be disappointed.
if you’re not involved in the neuro imaging community (or you’ve had your head in the sand for the last few months), things have been on the upswing. in this week’s nature, karl diesseroth and crew have described their implementation of optical control over cell activities: “NpHR and ChR2 form a complete system for multimodal, high-speed, genetically targeted, all-optical interrogation of living neural circuits.” (full text, medline). what does that mean? well, ChR2 is a light-activated protein from algae that allows for precise depolarization of cells containing the protein. karl and his then-postdoc, ed boyden, reported its use in nature neuroscience two years back. now, NpHR is the hyperpolarizing equivalent of ChR2; in other words, it can silence specific cells’ activities with millisecond precision. because each protein is activated by a different range of wavelengths (they have “well separated action spectra”), they can be incorporated into the same cells. with targeted introduction of the proteins, we can now activate and deactivate sub-populations of cells with millisecond precision, and record the effects on other cells within relevant neural circuits with techniques like calcium imaging. demolition man certainly could have used these to great effect in changing human behavior in the future, but we might be able to do this in mice even now…
for more science, see here, but for the juicy sociology and intellectual property disputes gearing up, check thisnature article.
as my advisor’s quoted saying in the article: “We are really psyched up about it.”
here are your weekly paper-picks, courtesy of your local science newsie. they’re a bit late… but i’ll bet you can’t stay angry for too long with this shoeless, down-and-out bohemian.
first up, science reports that the addition of a single human photopigment gene in mice allows them to discriminate colors their dichromatic brothers can’t. to appreciate this finding, remember that primates have three types of cones, each type sensitive to a particular range of the visible light spectrum. many lower mammals only have two, and their vision is generally poorer. in terms of evolution, a single gene mutation conferring photosensitivity to a previously indiscriminable range of wavelengths would seem advantageous. but, it could be tricky for an individual containing the mutation to exploit it, if the rest of the brain wasn’t wired in such a way to use the novel information. the insight we gain from the work of jacobs et alii is that such a genetic abberation could be immediately useful. the original lit is here, a layman’s explanation by the editors at science is here, a wikipedia article on color vision is here (i also ganked the absorbance vs wavelength plot from there).
pnas served up a really wide-ranging article, called functional, fractal nonlinear response with application to rate processes with memory, allometry, and population genetics. for brief background, you can think of this work in terms of scaling laws: fundamental relationships between variables in a system. for example, there’s a scaling law relating the lifespan of mammals and their heart rates: as the average heart rate of a particular species increases, their life span decreases. depending on how the data look, you might be able to describe this kind of simple relationship with a single value representing the slope of the line on a graph of the logs of beats per minute vs life span (you may remember from high school math that the slope of the log of a variable is related to the exponent or power of the variable… so these are sometimes called power laws). then you’d have a simple description relating a so-called “excitation” variable to a “response” variable. while a lot of people don’t like scaling laws for various reasons, i think that they can provide some intuition into more general principles of complex systems. in fact, recent research on scaling principles in neural systems attracted me to my undergrad advisor a few years back. back to the story, sometimes the relationships get a bit more complicated than a simple power law. vlad et al.’s research is significant because it demonstrates a more general framework for thinking about scaling (fractal response) laws. it’s especially exciting since so many fields (from neuroscience to the rest of biology, physics, and chemistry) are replete with such relationships.
back to systems neuroscience proper, massimo and court, two researchers here at ucsd, review two new papers discussing the timing of excitation and inhibition in thalamocortical microcircuits… an action-packed review of the subfield. also in nature neuroscience, john lisman reviews gyogry buzsaki’s rhythms of the brain. since i’m in the middle of that book myself, i’ll reserve my comments for a future post. finally, journal of neuroscience publishes a report exploring photic integration for establishing or disturbing circadian rhythms. for background, the suprachiasmatic nucleus in the brain responds to the energy content–roughly, the number of photons–in visual stimuli to help establish the 24-hour cycle seen in animal behavior. the result of this study was therefore pretty surprising: vidal and morin report that the hamster visual system responds to very brief flashes of light by offsetting the phase of the circadian rhythm, and suggest that this phase-advance may result from a secondary pathway than the one responsible for longer and dimmer photic stimuli. maybe i could exploit this to actually wake up before noon…
alright, that’s all for this week… if you’d like to see more (or less) background or detail in these weekly reviews, please let me know what you’re thinking!
and finally, neuro folks know that the past week of brain science was really dominated by the cold spring harbor labs meeting on Imaging Neurons and Neural Activity. to make up for the lack of synopses this week, i’ll refer readers to my good friend andrew’s daily reviews of the conference over at brain windows.
some more science articles of note from this past week. for part one, in which the bohemian rants against the brits, see below
up the road at the neurosciences institute, bruno van swinderen tells science that flies have selective attention. flies exposed to novel visual stimuli had repeatable local field potential properties, which were changed by affecting short-term memory formation genes. so think twice before you swat that next drosophila.
nature spent a lot of time celebrating carl linnaeus, the naturalist now dubbed the father of taxonomy. they address some important issues, like the relationship of taxonomy proper to the rest of biology (html) and of taxonomy to genome research (html)… and some others, like whether “pro” taxonomists can make room for the amateur naturalist (html).
also in nature, gyorgy buzsaki writes a quick but interesting essay on consciousness and brain wiring. he specifically proposes, as he does in the last chapter, er, “cycle” of his book rhythms of the brain, that the subjective record of experience may come from long range connections between neurons. the cerebellum has one simple and repeated circuit responsible for things like motor movements, but it apparently doesn’t generate spontaneous activity and doesn’t have long-range connections. meanwhile, the neocortex boasts both spontaneous activity and long-range connections, which may work to record conscious percepts. it’s all speculative, of course, and, like most theories of consciousness, hard to test.
neuron had some nice papers, as always, but not much systems work. one that caught my eye, though, was from riken (medline|html). it used non-stationary fluctuation analysis, a technique that separates out single-channel currents from recordings of full EPSCs, to quantify the number of GABA-A receptors on the soma and proximal dendrite. the group went on to show that the right proportion of these receptors seems to enable plasticity… too many or too few, and the poor mouse won’t develop a satisfactory visual cortex. as borat would say, “very nice!”
pnas had more neuro than usual. one paper demonstrated that gene expression used for assembling synapses was independent of network activity… kind of surprising, since activity is typically hypothesized to control expression. in other news, saxe et al found that ablating neurogenesis in the dentate gyrus actually improved working memory dependent on the hippocampus. very strange, since dentate neurogenesis is thought to help with memory. plus, it’s one of only two places in the adult brain that consistently gets new cells…so if they’re not helping memory, what are they doing? in fact, the authors call it a paradox. for reference, see this recent post.
alright… if you made it this far, i’ll send you a kudos bar. see you next week.
since several blogs o’ neuro deal with general and popular issues in the field, BoSci might contribute a bit with posts specific to systems neuroscience. in that spirit, here’s a roundup of some papers that caught my eye over the last week… this might become a weekly review.
first off, something unrelated to neuroscience, though. a somewhat quizzical editorial in nature suggests that “brain drain” ain’t so bad. the argument, put forward by economist michael clemens at an aaas meeting a few weeks back, points out the benefits of shipping out home-trained professionals: greater knowledge of global trends, more money earned and sent home, and the return of nearly half of further-trained emigres later in their careers. the trick, as the article points out, is figuring out the balance of proximally deleterious versus long-term beneficial effects. but then the editorial goes whack… on what i think is a point of pride for the brits. here are the last three paragraphs in full:
Similar observations could be made regarding emigration flows between wealthy nations. According to the World Bank, Britain has more professional émigrés than any nation on Earth. But it doesn’t seem to be hurting. California’s research labs may be crawling with Brits, yet UK science has gone from strength to strength. According to surveys of citations against expenditure, Britain has one of the most productive research systems in the world. How can this be?
Well, say the revisionists, science departments at British universities may actually benefit from the ambition to depart, and, to a lesser degree, from their connections with those who have done so. Perish the thought, but some of these mobile researchers may even do the best work of their lives at Salford, say, only to take their foot ever-so-slightly off the gas when they ‘arrive’ at Stanford.
Woody Allen once observed that the sole cultural advantage of California (over his native New York, presumably) was its law permitting you to turn right at a red light. To be fair, science and industry in the Golden State have clearly benefited to a massive degree from immigrant talent gleaned from every corner of the planet. But the notion that other places have necessarily suffered a corresponding loss — or that emigration is a zero-sum game — is misplaced.
huh? what starts as a legitimate point on the concerns of developing countries becomes a juvenile, postcolonial hissyfit about how britian’s still damn good. fair enough, san diego has about as much culture as my left birkenstock, but what do woody allen and culture have to do with the best science in the world? brits take note: the best researcher might be the one in the lab, not the theater.
hmmm, since that editorial got me a bit riled, i’ll take a break and return with some actual science in part II
scientific american runs a blog on new and interesting science stories… they just asked my good friend brad aimone to review a new study from nature neuroscience. the research focuses on the role of new neurons in the dentate gyrus (a part of the hippocampus) for memory formation. his comment is here. for a good introduction to a similar subject, see brad’s review of adult neurogenesis at scholarpedia, from whence the gif is taken.
as most BoSci readers know, practicing scientists don’t sit back and dispassionately evaluate evidence. they skip sleep, sweat blood, lose friends, end marriages. they toil and swear, dream and dread, triumph and fail. they–we–definitely don’t do it without passion, and, well, it didn’t take postmodernism to point out that this can cloud our vision.
neuroscience sees a lot of impassioned debates, thanks to our fledgling understanding of the brain, our competition for funding, and our general distrust of other people’s ideas and experiments. every field’s pioneers are immortalized (or ridiculed) for their fistfights in the parking lots outside of conferences. for example, 1906 nobel laureate camillo golgi used his award ceremony lecture as a soapbox for demonstrating why his co-winner, ramon y cajal, was a “stupidhead”. alright, that’s a blatant lie, but he did have harsh words for any proponent (including cajal) of “the neuron doctrine”, that is, the idea that neurons are the basic unit of signal transmission in the brain… and yes, that’s what virtually all neuroscientists believe today. the pdf of his lecture is here.
another example, of equal hilarity, if slightly less import, has taken place over the last few weeks. about six months ago, nature published a report from some german theorists claiming that the hodgkin-huxley model of membrane potential (an essential model in quantitative neuroscience) was wrong! their argument had to do with some features of experimental recordings that didn’t square with model predictions. one of the two main differences they saw was a “kink” in the beginning of the action potential deflection. see the difference at the arrowheads? at any rate, it generated quite a buzz (here’s a generous neurodudes post on it, which i appreciate, despite what i’ll say below).
a few weeks ago, a retort, again in nature, came out of an experimental lab demonstrating that the germans were, well, off. but they didn’t just publish a retort. oh no. they advertised it on their lab website. they designed “a new seminar”, complete with comically large font. they even made a movie, the best 10 seconds of which are below:
it’s not my goal here to evaluate the science (though, in the interest of full disclosure, i think the germans need to consider that neurons aren’t single compartments). instead, i’d like to mention a few facts, both as potential object lessons for the neuroscience community, and as amusement for the interested non-neuroscientist who has admirably and surprisingly read this far… if only in hopes of seeing another movie with a scientist saying the word “kinky”.
the observation of the ‘kink’ was known to electrophysiologists for 30 years, but was understood to be a result of the spatial extent of action potential generation… it was apparently obvious enough to avoid publishing.
this paper was rejected from the journal science (oops, is that common knowledge) before it ended up on the pages of nature.
because it showed up in nature, passers-by without the incentive to check the evidence will think it’s a real challenge to hodgkin-huxley… even when electrophysiologists think it’s the result of a sloppy oversight.
science can’t prove anything, it just generates, evaluates, and synthesizes evidence. but that doesn’t mean one theory can’t be better than another… and this seems like a case of overselling, under-researching, and the human need to save face.
last night, i heard a strange patter on the roof of the home i was visiting. i vaguely remembered the soft sound from my days on the east coast, but couldn’t put my finger on its source until after dinner, when we all looked outside and beheld one of the most terrifying sights, to the best of my knowledge, in the history of southern california. prepare yourself. water… was falling from… the sky! i know… i too was dumbstruck. i’ll give you a moment.
i checked the weather for today, and was bummed to see a prediction of clouds and near-freezing temperatures:
but then i was emailed the below (incomplete!) list of talks in the next week and a half, and was reminded of one of the few universal laws i believe: even when you can’t trust the weather in san diego, you can trust the neuroscience:
1/30: Samuel Wang on synaptic learning rules
2/1: John Reynolds on spatial attention in visual cortex
2/2: Fred Dyer on navigation in insects
2/2: Vilayanur Ramachandran on synesthesia
2/6: Emergence of Language Structures Workshop
2/7: Linda Buck on smell
2/7: Laura Schreibman on autism
2/8: Dmitry Chklovskii on cortical column wiring principles
2/8: Robert Malinow on receptor trafficking
2/8: David Rubinow on affective dysregulation and reproductive neuroscience 2/9: Takeo Watanabe on inhibitory control and learning
2/10: William Bechtel on the meaning of biological mechanisms
a few highlights: sam was my old advisor from princeton; john is a salk physiologist-convert from economics, ramachandran got some previous air time here at BoSci; buck is a nobel laureate; chklovskii is a theoretical physicist-turned-neuroscientist; malinow’s helped craft the last 15 years of in vitro physiology; and watanabe may or may not be the brother of katsumoto from the last samurai.
alas, my month-long blogging break turned into an all-out two-and-a-half month sabbatical. but instead of reflecting on all of the advances in systems neuroscience and the interactions among science, faith, and culture since the ides of may, i’ll point to a nice post from the free geek. back in june, he sent me his 
be sure to stop back here tomorrow, when the twenty-eighth 
as most BoSci readers know, practicing scientists don’t sit back and dispassionately evaluate evidence. they skip sleep, sweat blood, lose friends, end marriages. they toil and swear, dream and dread, triumph and fail. they–we–definitely don’t do it without passion, and, well, it didn’t take postmodernism to point out that this can cloud our vision.
the pdf of his lecture is 
2/9: Takeo Watanabe on inhibitory control and learning