neurobiology
pharyngula | August 21, 2007It's nice to see these casual references to PZ Myers, as if anyone would have heard of me:
The lab is at 101 Theory Drive, a developer's idea of a scientific street name that Lynch found presumptuous.
It is a mark of the difficulty of life sciences — biology and its many descendants — that to call something a theory is to honor, not slight it. Theory, evolutionary biologist P.Z. Myers has written, is what scientists aspire to. Lynch, for all of his bombast, was respectful of the intellectual protocols of his science.
"I would have called it Hypothesis Drive," he said.
The article is part of…
pharyngula | August 20, 2007If it existed, it might also be profoundly autistic and … diabetic? So science cannot disprove the existence of a soul, but one thing we're learning is how much valued human properties such as love and attachment and awareness of others are a product of our biology — emotions like love are an outcome of chemistry, and can't be separated from our meaty natures.
The latest issue of BioEssays has an excellent review of the role of the hormone oxytocin in regulating behaviors. It highlights how much biochemistry is a determinant of what we regard as virtues.
Anyone with a little familiarity with…
pharyngula | July 28, 2007Shelley has a good post on the biology of ADHD—the lesson, once again, is that the mind is regulated by physical and chemical processes, and we're learning more and more about how seemingly nebulous, fuzzy, higher level functions of thought can be traced back to relatively simple material causes.
The basic story is that norepinephrine is the molecule behind ADHD, and that what the stimulants given to people do is increase the effective concentration of NE. I've never been a victim of ADHD — as a kid, I'd say I was more often characterized as being the extreme opposite of what we see in ADHD…
pharyngula | June 25, 2007Cosma Shalizi has written a two part dialog that is amazingly well in line with my own thoughts on the subject of the heritability of intelligence: g is a statistical artifact, we have brains that evolved for plasticity, not specificity, and that while many behavioral traits have a heritable component, it's not anything like what the naive extremists among the cognitive science crowd think. There are no genes that specify what you will name your dog — in fact, most of the genes associated with the brain have very wide patterns of expression and functions that are not neatly tied to behaviors…
pharyngula | June 15, 2007Egnor's at it again, trying to support his idea of dualism. His latest example is much less insane than his last one, so this won't be as entertaining. There's actually a serious question imbedded in it.
He's using an analogy with a cell phone (personally, I think he'd have made much more sense if he'd just gone straight to his explanatory metaphor for the brain; the comparison of the mind with a cell phone has too many distracting details that don't fit.) What he is proposing is that, rather than being a local generator of the mind, all that elaborate stuff in the circuitry of the brain is…
pharyngula | June 7, 2007No, actually they don't — but they do have some proteins that are essential components of synapses, and it tells us something important about the evolution of the nervous system. A new paper by Sakarya et al. really isn't particularly revolutionary, but it is very interesting, and it does confirm something many of us suspected.
First, in case you don't know what I'm talking about, here's a synapse:
A synapse is a kind of gateway for the transmission of electrical impulses in the nervous system. What's portrayed above is the terminal of a generic neuron; electrical signals travel down from…
pharyngula | June 4, 2007Egnor, the smug creationist neurosurgeon, is babbling again, but this time, it's on a subject that he might be expected to have some credibility: the brain (he has one, and operates on them) and the mind (this might be a problem for him). It's an interesting example of the religious pathology that's going to be afflicting us for probably the next century — you see, creationism is only one symptom. We're seeing an ongoing acceleration in scientific understanding that challenge the traditional truisms of the right wing religious culture warriors, and represent three fronts in our future battles…
pharyngula | March 13, 2007At last, it's time for Encephalon, the carnival of neuroscience. There were a lot of submissions, and I've tried to organize them into four categories: basic and cognitive neuroscience addresses the problem of understanding brains, more medically and psychiatrically inclined work tries to fix brains, a few crazy dreamers think about technological ways to improve brains, and some rare individuals wonder about how brains evolved. I should mention that brains are incredibly complex and all of these efforts are struggling against the immensity of the problems…but it's fun to try and to watch, and…
pharyngula | February 10, 2007Via GrrlScientist, here's a fun little demo of what drugs do to your brain. Drag the stoned mice to the special chair, and you get to peek in at what marijuana and ecstasy and cocaine and etc. do to the synapses.
pharyngula | January 10, 2007
I'm teaching a course in neurobiology this term, and it's strange how it warps my brain; suddenly I find myself reaching more and more for papers on the nervous system in my reading. It's not about just keeping up with the subjects I have to present in lectures (although there is that, too), but also with unconsciously gravitating toward the subject in my casual reading, too.
"Unconsciously"…which brings up the question of exactly what consciousness is. One of the papers I put on the pile on my desk was on exactly that subject: Evolution of the neural basis of consciousness: a bird-mammal…
pharyngula | December 4, 2006
One of my favorite signal transduction pathways (what? You didn't know that true nerds had favorite molecular pathways?) is the one mediated by the receptor Notch. Notch is one of those genes in the metazoan toolkit that keeps popping up in all kinds of different contexts—it's the adjustable wrench of the toolbox, something that handles a general problem very well and therefore gets reused over and over again, and the list of places where it is expressed in Drosophila is impressive.
The general problem that Notch solves is the resolution of a binary decision in cell fate, one where a few…
pharyngula | November 13, 2006
Oh happy day, the Sea Urchin Genome Project has reached fruition with the publication of the full sequence in last week's issue of Science. This news has been all over the web, I know, so I'm late in getting my two cents in, but hey, I had a busy weekend, and and I had to spend a fair amount of time actually reading the papers. They didn't just publish one mega-paper, but they had a whole section on Strongylocentrotus purpuratus, with a genomics mega-paper and articles on ecology and paleogenomics and the immune system and the transcriptome, and even a big poster of highlights of sea urchin…
pharyngula | October 31, 2006This is a gross violation of my expectations: the Halloween edition of The Synapse doesn't even once crack a zombie joke. I was terribly disappointed.
At least it does serve up a nice platter of brains.
pharyngula | October 3, 2006
How we sense the world has, ultimately, a cellular and molecular basis. We have these big brains that do amazingly sophisticated processing to interpret the flood of sensory information pouring in through our eyes, our skin, our ears, our noses…but when it gets right down to it, the proximate cause is the arrival of some chemical or mechanical or energetic stimulus at a cell, which then transforms the impact of the external world into ionic and electrical and chemical changes. This is a process called sensory signaling, or sensory signal transduction.
While we have multiple sensory…
pharyngula | September 14, 2006
We are all familiar with the idea that there are strikingly different kinds of eyes in animals: insects have compound eyes with multiple facets, while we vertebrates have simple lens eyes. It seems like a simple evolutionary distinction, with arthropods exhibiting one pattern and vertebrates another, but the story isn't as clean and simple as all that. Protostomes exhibit a variety of different kinds of eyes, leading to the suggestion that eyes have evolved independently many times; in addition, eyes differ in more than just their apparent organization, and there are some significant…
pharyngula | September 13, 2006
Everyone knows the story of Konrad Lorenz and his goslings, right? It was a demonstration of imprinting: when young animals are exposed to a stimulus at a critical time, they can fix on it; Lorenz studied this phenomenon in geese, which if they saw him shortly after hatching, would treat him like their mother, following him around on his walks. Similarly, many animals seem to experience sexual imprinting, where they acquire the sexual preferences that will be expressed later on.
I just ran across a charming short letter about imprinting in cephalopods, and somehow the story seems so…
pharyngula | September 12, 2006I'm a little surprised at the convergence of interest in this news report of a conserved mechanism of organizing the nervous system—I've gotten a half-dozen requests to explain what it all means. Is there a rising consciousness about evo-devo issues? What's caused the sudden focus on this one paper?
It doesn't really matter, I suppose. It's an interesting observation about how both arthropods and vertebrates seem to partition regions along the dorso-ventral axis of the nervous system using exactly the same set of molecules, a remarkable degree of similarity that supports the idea of a common…
pharyngula | September 7, 2006I was reading a review paper that was frustrating because I wanted to know more—it's on the evolution of complex brains, and briefly summarizes some of the current confusion about what, exactly, is involved in building a brain with complex problem solving ability. It's not as simple as "size matters"—we have to jigger the formulae a fair bit to take into account brain:body size ratios, for instance, to get humans to come out on top, and maybe bulk is an inaccurate proxy for more significant matters, such as the number of synapses and nerve conduction velocities.
There's also a growing amount…
pharyngula | August 20, 2006These things are just sneaking up on me today: the Synapse #5 is out.
Are there any more carnivals lurking out there today?
pharyngula | August 7, 2006Let's start the week with another open thread, and a few carnivals.
The Synapse 1(4)
Carnival of the Godless #46