Brain and Behavior
developingintelligence | May 12, 2008Time pervades our understanding of the world - we use it to coordinate our movements, to perceive motion, to plan our behaviors, and perhaps even to understand causality.
But it is an under-appreciated factor in cognition. Even in the domain of the well-understood visual system, few realize that neurons in visual cortex are tuned not only for sensitivity to visual input of particular orientations, but also tuned also to time - in terms of temporal contrast.
Johnston, Arnold and Nishida were able to manipulate this temporal tuning with a relatively simple method. The authors presented a…
oracknows | May 12, 2008"Detoxification."
Whenever I hear that term, I'm at least 90% certain that I'm dealing with seriously unscientific woo. The reason should be obvious to longtime readers of this blog or to anyone who has followed "alternative medicine" for a while, because "detoxification" is a mainstay of "alternative" treatments and quackery for such a wide variety of diseases and conditions. Of course, toxins are indeed a bad thing, and we close-minded reductionist "allopathic" physicians do indeed use detoxification when appropriate. What differentiates us from "alternative" medicine practitioners is that…
ejohnson | May 9, 2008It's that time of the week again! Here are the large versions of this week's channel photos.
(Have a photo you'd like to send in? Email it to photos@scienceblogs.com, or assign the tag "sbhomepage" to one of your photos on Flickr. Note: be sure to assign your photo an "attribution only" or "share and share alike" Creative Commons license so that we can use it.)
First photo here, the rest below the fold.
Life Science. From Flickr, by dro!d
Physical Science. From Flickr, by jurvetson
Environment. The glacial waters of Patagonia. From Flickr, by angela7dreams
Humanities & Social…
developingintelligence | May 7, 2008Complex cognition can be predicted by remarkably simple tasks. For example, the speed with which you choose one of two possible responses can reliably predict IQ. Some theories propose that this relationship is due to differences in something called "processing speed," but more recent work has shown the effect is really due to the slowness of your slowest reaction times on such simple tasks. Known as the "worst performance rule," this can be revealed through various RT distribution decomposition techniques (e.g., "binning" of reaction times or ex-gaussian analysis).
A particular class of…
clock | May 5, 2008Roaring Bats: New Scientific Results Show Bats Emitting More Decibels Than A Rock Concert:
Researchers studying the echolocation behavior in bats have discovered that the diminutive flying mammals emit exceptionally loud sounds -- louder than any known animal in air.
Young Songbirds Babble Before They Learn To Sing:
Young songbirds babble before they can mimic an adult's song, much like their human counterparts. Now, in work that offers insights into how birds--and perhaps people--learn new behaviors, MIT scientists have found that immature and adult birdsongs are driven by two separate brain…
cortex | May 5, 2008The Times recently had an article on the booming business of brain fitness:
Decaying brains, or the fear thereof, have inspired a mini-industry of brain health products -- not just supplements like coenzyme Q10, ginseng and bacopa, but computer-based fitter-brain products as well.
Nintendo's $19.99 Brain Age 2, a popular video game of simple math and memory exercises, is one. Posit Science's $395 computer-based "cognitive behavioral training" exercises are another. MindFit, a $149 software-based program, combines cognitive assessment of more than a dozen different skills with a personalized…
clock | May 3, 2008Believe me, I love the word "circadian". It is a really cool word, invented by Franz Halberg in the late 1950s, out of 'circa' (Latin - "about") and diem ("a day"), to denote daily rhythms in biochemistry, physiology and behavior generated by the internal, endogenous biological clocks within living organisms.
It's been a while since the last time I found someone mistaking the word for 'cicada' which is a really cool insect. 'Circadian' has become quite common term in the media and, these days increasingly, in popular culture. Names of some bands contain the word. A few blogs' names…
clock | May 2, 2008You and I, as well as all of our mammalian brethren, have just a few photopigments, i.e., colored molecules that change shape when exposed to light and subsequently trigger cascades of biochemical reactions leading to changes in electrical properties of sensory neurons, which lead to modulation of neurotransmitter release, which propagates the information from one neuron to the next until it is integrated and interpreted somewhere in the brain - we see the light!
More under the fold....
Mammals have rhodopsin (in rod-shaped photoreceptor cells in the retina of the eye), three or four color-…
ejohnson | May 2, 2008To make your Friday that much better, here are the large versions of this week's channel photos.
(Have a photo you'd like to send in? Email it to photos@scienceblogs.com, or assign the tag "sbhomepage" to one of your photos on Flickr. Note: be sure to assign your photo an "attribution only" or "share and share alike" Creative Commons license so that we can use it.)
First photo here, the rest below the fold.
Life Science. A whale surfaces off the Brazilian coastline. From Flickr, by Amnemona
Physical Science. Upper Antelope Canyon in Navajo Tribal Park, Arizona. From Flickr, by Farol's…
clock | May 1, 2008
If you really read this blog 'for the articles', you know some of my recurrent themes, e.g., that almost every biological function exhibits cycles and that almost every cell in every organism contains a more-or-less functioning clock. Here is a new paper that combines both of those themes very nicely, but I'll start with a little bit of background first.
Daily Rhythms in Sensory Sensitivity
If almost every biochemical, physiological and behavioral function exhibits daily cycles, it is no surprise that such rhythms have been discovered in sensory sensitivity of many sensory modalities -…
cortex | May 1, 2008Now that the boomers are entering their sixties, the problem of age-related cognitive decline is going to become a serious mental health issue. The aged brain often suffers from a bevy of symptoms, from memory loss to problems with concentration. The question, of course, is what causes these symptoms?
Over at Mind Matters, we recently featured an interesting post on some recent research that tried to answer these pertinent questions. The short answer is that, over time, the different parts of the brain becomes less interconnected.
Jessica Andrews-Hanna and her colleagues at Harvard…
clock | April 30, 2008There are 49 new articles in PLoS ONE this week. Here are some titles I found interesting:
Echolocating Bats Cry Out Loud to Detect Their Prey:
Echolocating bats have successfully exploited a broad range of habitats and prey. Much research has demonstrated how time-frequency structure of echolocation calls of different species is adapted to acoustic constraints of habitats and foraging behaviors. However, the intensity of bat calls has been largely neglected although intensity is a key factor determining echolocation range and interactions with other bats and prey. Differences in detection…
oracknows | April 29, 2008One of the most contentious and difficult aspects of trying to improve medical care in this country is enforcing a minimal "standard of care." Optimally, this standard of care should be based on science- and evidence-based medicine and act swiftly when a practitioner practices medicine that doesn't meet even a minimal requirement for scientific studies and clinical trials to support it. At the same time, going too far in the other direction risks stifling innovation and the ability to individualize treatments to a patient's unique situation--or even to use treatments that have only scientific…
dmunger | April 28, 2008Thank you for "choosing" to read Encephalon #44 here at Cognitive Daily. Every two weeks, Encephalon "selects" the best psychology and neuroscience blog posts from around the blogosphere, giving readers the chance to "decide" which ones they'd like to investigate further.
Unfortunately for all those involved, those "decisions" very likely weren't carried out through the "deciders'" own volition, but instead were precipitated through the confluence of genetic inheritance and circumstance.
Consider this post from Neuroanthropology, for example, which dissects a forthcoming publication in Nature…
evolvingthoughts | April 27, 2008
In the thread on the recent debate between Winston and Dennett, I said that I thought the greatest threat to scientific progress and rationality was antimodernism, which was not always religious. Here, I'm going to elaborate on that cryptic comment.
First of all, some of my commenters think that this doesn't rule out religion being the threat. It may still be the major source of illiberalism, and I cannot deny that, but I think the problem lies not in the instantiation of the antimodernism, but in the psychology that underlies it. For religious ideas would have no issue if they did not…
clock | April 27, 2008Considering I've been writing textbook-like tutorials on chronobiology for quite a while now, trying always to write as simply and clearly as possible, and even wrote a Basic Concepts And Terms post, I am surprised that I never actually defined the term "biological clock" itself before, despite using it all the time.
Since the science bloggers started writing the 'basic concepts and terms' posts recently, I've been thinking about the best way to define 'biological clock' and it is not easy! Let me try, under the fold:
A biological clock is a structure that times regular re-occurence of…
clock | April 26, 2008This is an appropriate time of year for this post (February 05, 2006)...
-----------------------------------------------------
So, why do I say that it is not surprising the exposure to bright light alleviates both seasonal depression and other kinds of depression, and that different mechanisms may be involved?
In mammals, apart from visual photoreception (that is, image formation), there is also non-visual photoreception. The receptors of the former are the rods and cones that you all learned about in middle school. The receptors for the latter are a couple of thousand Retinal Ganglion…
ejohnson | April 25, 2008For your viewing pleasure, here are the large versions of this week's channel photos.
(Have a photo you'd like to send in? Email it to photos@scienceblogs.com, or assign the tag "sbhomepage" to one of your photos on Flickr. Note: be sure to assign your photo an "attribution only" or "share and share alike" Creative Commons license so that we can use it.)
First photo here, the rest below the fold.
Life Science. From Flickr, by mrhappy
Physical Science. A rusted logging chain. From Flickr, by johndan
Environment. Fragments of smooth sea glass. From Flickr, by Akuppa
Humanities &…
gregladen | April 25, 2008Life is complex. The way a living system works can be described in a series of increasingly refined models, each fleshing out details of the previous model. Typically, description at one level raises questions about what is happening at the finer level. These questions induce hypotheses which drive experimental work which produces ever more detailed knowledge.
A paper about memory, just published, is an example of one incremental step in this process. In short, this research works out some of the fine detail at the molecular level for the process of forming visual memories.
In mammals…
cortex | April 25, 2008Razib calls my attention to this new Nature study on the genetic variation underlying the stress response. The researchers focused on neuropeptide Y, an endogenous anxiolytic (it's like an anti-anxiety drug naturally produced by the brain) which is released in response to stress. They focused on a single nucleotide polymorphism (aka SNP) which "alters NPY expression in vitro and seems to account for more than half of the variation in expression in vivo."
The pertinent question, of course, is how they measured variation in vivo. The researchers used a few different, and quite interesting,…