neurophilosophy | August 5, 2007From Nature:
Catherine Dulac and her colleagues at Harvard University genetically engineered female mice to lack a gene called TRPC2. This gene is essential for the functioning of a pheromone-sensing organ in the nose called the vomeronasal organ.
Without the gene, female mice acted exactly like males - even towards male mice - complete with mounting, pelvic thrusts and the ultrasound calls that males use to attract a mate.
Watch the film clip below.
Related:
Alpha male pheromone stimulates neurogenesis in the female brain
neurophilosophy | August 5, 2007
According to a new paper in the British Medical Journal, there is an association between duration of deployment and incidence of alcohol problems and post-traumatic stress disorder in British troops:
Personnel who were deployed for 13 months or more in the past three years were more likely to fulfil the criteria for post-traumatic stress disorder...and have multiple physical symptoms...A significant association was found between duration of deployment and severe alcohol problems. Exposure to combat partly accounted for these associations. The associations between number of deployments in…
neurophilosophy | August 4, 2007
IN The Matrix (Andy and Larry Wachowski, 1999) Keanu Reeves plays a computer programmer who leads a double life as a hacker called "Neo". After receiving cryptic messages on his computer monitor, Neo begins to search for the elusive Morpheus (Laurence Fishburn), the leader of a clandestine resistance group, who he believes is responsible for the messages. Eventually, Neo finds Morpheus, and is then told that reality is actually very different from what he, and most other people, perceives it to be.
Morpheus tells Neo that human existence is merely a facade. In reality, humans are being '…
neurophilosophy | August 4, 2007
Resident ScienceBlogs psychiatrist Joseph has found some interesting papers about various types of cognition-induced epilepsy, including this one from the Hong Kong Medical Journal:
Mah-jong induced seizures: case reports and review of twenty-three patients.Chang, R. S. K., et al.
'Mah-jong epilepsy' is a rare reflex epilepsy syndrome, manifesting as recurrent epileptic seizures triggered by either playing or just watching mah-jong. We present three patients with this condition and review all the reported cases. Mah-jong-induced seizures can be considered a subtype of cognition-…
neurophilosophy | August 4, 2007
Skeleton, brain, nerves, from John Banister's Anatomical Tables, c. 1580.
From the Anatomy Acts Exhibition website (via Morbid Anatomy).
neurophilosophy | August 3, 2007In the English language, the term "bird brain" is often used in reference to intellectually challenged individuals. This is, of course, based on the notion that birds are dim-witted creatures whose behaviour is largely based on instinct.
The main assumption is that a six-layered neocortex, like that of humans, is a prerequisite for anything that might be classed as intelligent, and even ornithologists have generally believed that, because they have a "smooth" brain, birds aren't too clever.
However, it has in recent years become clear that we have grossly underestimated the cognitive…
neurophilosophy | August 2, 2007
Researchers report in today's issue of Nature that they have improved brain function in a minimally conscious patient by implanting electrodes into his brain.
Schiff et al used deep brain stimulation (DBS), an experimental surgical technique that has previously been used to treat Parkinson's Disease and depression, to increase the level of arousal and motor control in the patient, who had been in a minimally conscious state for more than 6 years.
Neurologists define disorders of consciousness according to specific criteria based on behavioural responses. According to these criteria,…
neurophilosophy | August 1, 2007 This essay I wrote was shortlisted in the Association of British Science Writers competition in 2002. It was the first thing I posted on the old blog.
It was written as an introduction to what were generally believed to be the fundamentals of brain function, starting from the molecular level and working all the way up.
But our understanding of the brain has advanced dramatically since then, and there is now evidence to suggest that some of these assumptions are now wrong.
For example, it was, I think, taken for granted that all neurons fire action potentials, but it now appears that…
neurophilosophy | July 31, 2007
This one only has two, but Wolfgang Jacob and Bernd Schierwater, of Yale University and Hanover University of Veterinary Medicine, respectively, have created jellyfish with up to 12 heads.
The multiple-headed hydromedusa (Eleutheria dichotoma) specimens were created by using RNA inhibition or antisense oligonucleotides to silence various homeobox genes (Cnox-2 and Cnox-3) that are involved in head formation.
neurophilosophy | July 31, 2007 Females have a natural preference for mating with dominant males, because this confers a genetic advantage upon the offspring produced. When selecting a mate, animals rely on chemical cues called pheromones, which relay information about the social status and genetic health of a potential mate.
Reproductive success therefore depends upon the encoding and recall of olfactory memories; the neural circuitry in which these memories are formed consists of the olfactory bulb and the dentate gyrus of the hippocampus. But although both these sites are principle regions for neurogenesis (formation…
neurophilosophy | July 31, 2007 Encephalon #28 is now online at the Bohemian Scientist's blog.
The next edition will be hosted at Memoirs of a Postgrad on August 13th. If you'd like to contribute, send permalinks to your neuroscience or psychology blog posts to encephalonb.hoat{at}gmail{dot{com}, or use this submission form.
neurophilosophy | July 29, 2007Black peoples' brains are, of course, no more or less peculiar than those of any other people. The human brain is an extraordinarily complex organ, and there are just as many differences between the brains of people from the same ethnic group as there between the brains of people from different groups.
Some racial peculiarities of the Negro brain is the title of a long and technical paper by the anthropologist Robert Bennett Bean, published in the American Journal of Anatomy in 1906. It is one of a series of scientific papers written by Bean in the early 20th Century, in which he tried to…
neurophilosophy | July 29, 2007
We had the pleasure of entertaining the delightful Jessica Palmer at our place last night. And earlier today, Jessica and I ate pizza on the King's Road before visiting the Chelsea Physic Garden.
Jessica writes the fantastic Bioephemera blog (where you can read more about her visit to London), and created four of my beautiful custom header images.
neurophilosophy | July 29, 2007 This week's New Yorker contains an article by Oliver Sacks about a condition called musicophilia, in which one feels sudden urges to listen to, or play, music follwing brain injury:
In 1994, when Tony Cicoria was forty-two, and a well-regarded orthopedic surgeon, he was struck by lightning. He had an out-of-body experience. "I saw my own body on the ground. I said to myself, 'Oh shit, I'm dead.' ...Then--slam! I was back." Soon after, he consulted a neurologist--he was feeling sluggish and having some difficulties with his memory. He had a thorough neurological exam, and nothing seemed…
neurophilosophy | July 29, 2007
This artificial big toe, which was found on the foot of an ancient Egyptian mummy, has been dated to 1069- 664 BCE, and is on display at the Cairo Museum in Egypt.
Researchers from Manchester University's KNH Centre for Biomedical Egyptology have made a replica of the prosthesis to determine whether or not it was of any practical use.
They are seeking volunteers who have had their right toe amputated, in order to test their replica.
"If we can prove it was functional then we will have pushed back prosthetic medicine by as much as 700 years," said lead researcher Jacky Finch.
Related:…
neurophilosophy | July 28, 2007The single most famous case study in the history of neuropsychology is that of an anonymous memory-impaired man usually referred to only by the initials H.M. This patient has one of the most severe cases of amnesia ever observed; he has been followed for over 40 years by more than 100 researchers, and is the subject of dozens of research papers and book chapters. The early studies of H.M. provide a basis for modern neuropsychology, and the findings of those who have studied him are today a cornerstone in memory research.
H.M. (sometimes referred to as Henry M.) was born in Hartford,…
neurophilosophy | July 28, 2007Earlier this week, I posted an email I received about a nutritional supplement called EM Power Plus. The makers of this product, a Canadian company called TrueHope, claim that it can alleviate the symptoms of bipolar disorder.
In the comments to that post, PalMD, author of the WhiteCoatUnderground blog, is having what appears to be an on-going debate with Peter Helgason, the quack who emailed me.
Update: PalMD has written about the miracle cure.
neurophilosophy | July 28, 2007
My recent post on prefrontal lobotomy has been the most popular thing on this blog so far, and the comments on it are worth reading.
While searching for more information about lobotomies and the neuroleptic drugs that replaced them, I came across this fantastic webpage at NobelPrize.org, which contains more information about Egas Moniz, the Portugese surgeon who first performed the procedure.
That's where I found this diagram of the instrument designed by Moniz for the prefrontal leucotomies he performed with his colleague. From the diagram, one can see how the instrument (called a…
neurophilosophy | July 27, 2007
This week's issue of The Lancet contains the most comprehensive meta-analysis to date of the link between cannabis and psychosis:
The evidence is consistent with the view that cannabis increases risk of psychotic outcomes independently of confounding and transient intoxication effects, although evidence for affective outcomes is less strong. The uncertainty about whether cannabis causes psychosis is unlikely to be resolved by further longitudinal studies such as those reviewed here. However, we conclude that there is now sufficient evidence to warn young people that using…