neuroscience
clock | August 26, 2006Bumble Bees Can Estimate Time Intervals:
In a finding that broadens our understanding of time perception in the animal kingdom, researchers have discovered that an insect pollinator, the bumble bee, can estimate the duration of time intervals. Although many insects show daily and annual rhythms of behavior, the more sophisticated ability to estimate the duration of shorter time intervals had previously been known only in humans and other vertebrates.
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Bees and other insects make a variety of decisions that appear to require the ability to estimate elapsed…
j7uy5 | August 25, 2006Years ago, I read a paper in which the authors proposed a model, in
which the immune system was conceptualized as a sensory organ for the
central nervous system. They did not think of it as the
primary purpose of the immune system, but they wanted to highlight the
fact that immune system activity does provide information to the brain,
and that information is, to some extent, perceptible of a conscious
level.
I have to get ready for work, so I am not going to try to find the
reference. At least right now. I might get curious
enough to go looking for it later.
Now, we hear of another…
purepedantry | August 22, 2006Before, I talk about a mouse model that is resistant to depression, I think I had better talk about mouse models of depression so that everyone is on the same page. If you ask a nonscientist whether they think there can be a mouse model of depression, you would probably get a raised eyebrow if the person didn't totally laugh in your face. But mouse models of depression -- ridiculous as they may sound -- are actually important learning tools for understanding the disease...that is as long as you think of them in context.
How would we define a mouse model of depression? Well, since it is…
neurotopia | August 21, 2006Looks like yet another interesting toxin was found, this time in a venomous snail. This discovery comes from the lab of an old player in the field, who apparently discovered the conotoxin that is used in Prialt.
McIntosh says the OmIA toxin will be useful in designing new medicines because it fits like a key into certain lock-like "nicotinic acetylcholine receptors" found on nerve cells in the brain and the rest of the nervous system.
"Those are the same types of receptors you activate if you smoke a cigarette," he says, explaining that nicotine in cigarette smoke "binds" to the receptor to…
purepedantry | August 20, 2006Babies smarter than average high school student:
In a discovery that could shed light on the development of the human brain, University of Oregon researchers determined that infants as young as six months old can recognize simple arithmetic errors.
The researchers used puppets to portray simple addition problems. For example, in order to illustrate the incorrect equation 1 + 1 = 1, researchers showed infants one puppet, then added a second. A board was then raised to block the infant's view of both puppets, and one was removed. When the board was lowered, only a single puppet remained.
To…
clock | August 20, 2006Mapping The Neural Landscape Of Hunger
The compelling urge to satisfy one's hunger enlists structures throughout the brain, as might be expected in a process so necessary for survival. But until now, studies of those structures and of the feeding cycle have been only fragmentary--measuring brain regions only at specific times in the feeding cycle.
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In their paper, Ivan de Araujo and colleagues implanted bundles of infinitesimal recording electrodes in areas of rat brain known to be involved in feeding, motivation, and behavior. Those areas include the…
clock | August 19, 2006Correct me if I am wrong, but I think this is really ground-breaking:
Study Finds Brain Cell Regulator Is Volume Control, Not On/off Switch:
He and his colleagues studied an ion channel that controls neuronal activity called Kv2.1, a type of voltage-gated potassium channel that is found in every neuron of the nervous system.
"Our work showed that this channel can exist in millions of different functional states, giving the cell the ability to dial its activity up or down depending on the what's going on in the external environment," said Trimmer. This regulatory phenomenon is called '…
purepedantry | August 17, 2006LTP activated genes are clustered on chromosomes -- or so says some work by Park et al in JBC.
LTP -- or long-term potentiation -- is a process by which synaptic strength -- the ability of one neuron to talk to the next neuron -- is increased by activity. It involves the combination of several processes with different time courses, but some of the best characterized aspects of LTP are genes who transcription is activated by a protein called CREB. CREB is activated during LTP, and CREB activated genes are go on to consolidate LTP at the activated synapse.
There are temporally distinguished…
purepedantry | August 17, 2006This is rather clever. Houle et al at Case Western show in the Journal of Neuroscience that you can use a bacterial enzyme called chondroitinase to degrade scars in spinal cord lesions and enable regeneration of axons.
Just for background, there is some interesting neurobiology when it comes to spinal cord regeneration. If you sever peripheral nerve axons and then reconnect it, the axons will regrow to find their old targets leading to a functional restoration. However, something different happens in the central nervous system (CNS). Instead of regrowing, the axons just stop.
For many…
clock | August 17, 2006Snuck into the very end of this, otherwise very interesting article on neurobiology of cephalopods and moths, is this little passage:
As for flies, Tublitz outlined a tantalizing question, as yet unanswered, that has continued to take flight out of his lab for the last decade. Scientists for years, he said, have held "one hard rule" about what constitutes a neuron -- that a neuron cell always arises from the ectoderm of a developing embryo. However, a discovery in Drosophila -- fruit flies -- has softened that assumption.
Cells arising from the mesoderm rest in a layer on top of the fruit fly…
clock | August 15, 2006Jenna has been nagged by NAAG recently, to the point of obsession. It is also one of the molecules I included in the Synapse puzzle.
So, if you want to learn a little bit of nitty-gritty detailed neurochemistry of this exciting (as of recently) neuromodulator (and possibly neurotransmitter), you should check her two-part post reviewing what is known about it: Part I and Part II.
cortex | August 15, 2006In response to my last post on Musical Geniuses, I was accused of being a simple minded nurturist, a proponent of environmental determinism. So I thought I would take a moment and elaborate on why people with extraordinary talent - like Mozart, or Michael Jordan, or this Jay Greenberg kid - aren't testaments to genetics. Rather, they are testaments to neural plasticity and the benefits of practice.
For one thing, there's a lot of empirical evidence that suggests I'm right. Virtually every psychological study that investigates expert "performers" - from chess grandmasters to concert pianists…
cortex | August 14, 2006Everytime I walk into a wine store, and see that collage of numerical stickers (This Chianti is a 91! This Pinot Grigio is an 88!), the neuroscientist in me wants to tear them all down an go on a long rant about unconscious biases. The idea that the human olfactory system can reliably decipher the difference between a wine worth 90 points and a wine worth 89 points is patently ridiculous. And yet the trend shows no signs of abating.
"On many levels [rating wines on a numerical scale] is nonsensical," Joshua Greene, the editor and publisher of Wine & Spirits, said. He has been using the…
cortex | August 12, 2006In this otherwise excellent summary of the physiology of testosterone, the NY Times leaves out one crucial element: it's psychological effect. And no, I'm not just talking about the placebo effect. As I mentioned earlier, testosterone is well known for producing a euphoric high. We already know Landis was drowning his stage 16 sorrows in whisky. Why not add a little hormone to the mix as well? As researchers at USC note, "Testosterone overdose resembles opiate intoxication."
Obviously, we might never know if Landis broke the rules and took synthetic hormone. (Athletes have no incentive to be…
purepedantry | August 10, 2006Keeping to my week long theme of gender differences in cognition (here and here), here is an article by Diane Halpern in eSkeptic. It not only summarizes a lot of what is known about gender differences (even though it is reprinted from 1993) but also goes into confounding factors like prenatal hormones, sexual preference and most importantly handedness -- all of which affect verbal and mathematical ability. I found this passage about the confounds of handedness and homosexuality particularly interesting:
The idea that the brain is a sex-typed organ has generated a great deal of interest.…
j7uy5 | August 5, 2006About 15 years ago, I was giving a lecture on psychiatric medication to
a group of MSW
students. One student asked a question that was intended to
be
provocative. She asked, "how can you justify giving
medication to
treat a problem that is obviously psychological in origin, like
posttraumatic stress disorder?"
What she was referring to, was a paradigm that was commonly held at the
time. Specifically, there was this notion that some problems
were
psychological, and others were biological, in origin. It was
thought, by some, that there was a clear distinction between the two
kinds of…
purepedantry | August 3, 2006Neurodegenerative diseases, including Parkinson's, were for many years regarded as exclusively diseases of molecular crud. You would look at brains of patients with Alzheimer's and Parkinson's patients and notice that there were all these aggregates of protein crud forming in specific locations. This led scientists to conclude that the crud must be causing the neurons to do die through a mechanism that was not at the time clear.
The reality we are learning is far more complicated.
There is a form of inherited Parkinson's disease that is caused by loss-of-function mutations in the gene…
j7uy5 | August 2, 2006I just finished reading a news release pertaining to a finding in
psychiatric genetics. I was prepared to be irritated, but was
pleased instead.
href="http://www.med.umich.edu/opm/newspage/2006/ocd.htm">New
genetic findings add to understanding of obsessive-compulsive disorder
Kara Gavin
July 26, 2006
ANN ARBOR, MI – Obsessive-compulsive disorder tends to
run in families, causing members of several generations to experience
severe anxiety and disturbing thoughts that they ease by repeating
certain behaviors. In fact, close relatives of people with
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