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Background

The honeybee has to detect, process and learn numerous complex odours from her natural environment on a daily basis. Most of these odours are floral scents, which are mixtures of dozens of different odorants. To date, it is still unclear how the bee brain unravels the complex information contained in scent mixtures.

Methodology/Principal Findings

This study investigates learning of complex odour mixtures in honeybees using a simple olfactory conditioning procedure, the Proboscis-Extension-Reflex (PER) paradigm. Restrained honeybees were trained to three scent mixtures composed of 14 floral odorants each, and then tested with the individual odorants of each mixture. Bees did not respond to all odorants of a mixture equally: They responded well to a selection of key odorants, which were unique for each of the three scent mixtures. Bees showed less or very little response to the other odorants of the mixtures. The bees' response to mixtures composed of only the key odorants was as good as to the original mixtures of 14 odorants. A mixture composed of the other, non-key-odorants elicited a significantly lower response. Neither an odorant's volatility or molecular structure, nor learning efficiencies for individual odorants affected whether an odorant became a key odorant for a particular mixture. Odorant concentration had a positive effect, with odorants at high concentration likely to become key odorants.

Conclusions/Significance

Our study suggests that the brain processes complex scent mixtures by predominantly learning information from selected key odorants. Our observations on key odorant learning lend significant support to previous work on olfactory learning and mixture processing in honeybees.

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The cellular form of the prion protein, PrP^C, undergoes extensive proteolysis at the ? site (109K?H110). Expression of non-cleavable PrP^C mutants in transgenic mice correlates with neurotoxicity, suggesting that ?-cleavage is important for PrP^C physiology. To gain insights into the mechanisms of ?-cleavage, we generated a library of PrP^C mutants with mutations in the region neighbouring the ?-cleavage site. The prevalence of C1, the carboxy adduct of ?-cleavage, was determined for each mutant. In cell lines of disparate origin, C1 prevalence was unaffected by variations in charge and hydrophobicity of the region neighbouring the ?-cleavage site, and by substitutions of the residues in the palindrome that flanks this site. Instead, ?-cleavage was size-dependently impaired by deletions within the domain 106–119. Almost no cleavage was observed upon full deletion of this domain. These results suggest that ?-cleavage is executed by an ?-PrPase whose activity, despite surprisingly limited sequence specificity, is dependent on the size of the central region of PrP^C.

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Background

Of all organs and tissues in adult mammals, the brain shows the most limited regeneration and recovery after injury. This is one reason why treating neurological damage such as ischemic injury after stroke presents such a challenge. Here we report a novel mode of regeneration which the slug's cognitive center, the procerebrum, shows after surgical lesioning in the adult. It is well known that the land slug Limax possesses the capacity to demonstrate conditioned food aversion. This learning ability critically depends on the procerebrum, which is the higher olfactory center in the brain of the terrestrial mollusk.

Principal Findings

In the present study, after a 1-month recovery period post-surgical lesioning of the procerebrum we investigated whether the brain of the slug shows recovery from damage. We found that learning ability, local field potential oscillation, and the number of cells in the procerebrum (PC) all recovered spontaneously within 1 month of bilateral lesioning of the PC. Moreover, neurogenesis was enhanced in the lesioned PC. However, memory acquired before the surgery could not be retrieved 1 month after surgery although the procerebrum had recovered from injury by this time, consistent with the notion that the procerebrum is the storage site of odor-aversion memory, or deeply involved in the memory recall process.

Significance

Our findings are the first to demonstrate that a brain region responsible for the associative memory of an adult organism can spontaneously reconstitute itself, and can recover its function following injury.

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Last week, the New York Times printed an editorial entitled A Welcome Retraction.  The article lauds the Lancet for retracting the 1998 study by Dr. Andrew Wakefield which sparked public anxiety that the MMR vaccine might have a causal link to autism.

The editorial goes on to share this quaint hope:

What is indisputable is that vaccines protect children from dangerous diseases. We hope that The Lancet's belated retraction will finally lay this damaging myth about autism and vaccines to rest.

In fact, of course, far from laying anything to rest, the retraction served as a galvanizing call to action.  Parents and other supporters of Dr. Wakefield have been active in defending the man and his work through press releases, blogs, media statements and more.

Most significantly, the potent team of Jenny McCarthy and Jim Carrey produced and delivered an impassioned statement which included this accusation:

Dr. Andrew Wakefield is being discredited to prevent an historic study from being published that for the first time looks at vaccinated versus unvaccinated primates and compares health outcomes, with potentially devastating consequences for vaccine makers and public health officials.

It is our most sincere belief that Dr. Wakefield and parents of children with autism around the world are being subjected to a remarkable media campaign engineered by vaccine manufacturers reporting on the retraction of a paper published in The Lancet in 1998 by Dr. Wakefield and his colleagues.

McCarthy and Carrey make it clear that they will be actively promoting their perspective in the weeks and months to come.  In fact, the biomedically-oriented Autism One conference planned for May, where Jenny and Jim will be keynote speakers, will also feature Dr. Andrew Wakefield.

Look for much more information to come about this conference and its outcomes.  Already, its promotional material is headlined "The World Changes in May."  Promises are made of surprise announcements.  And this rather ominous statement is included on the conference website's front page:

Together we will redefine autism as a biomedical condition that can be treated and prevented. The past has been unkind to autism. The future is ours. We'll see you in Chicago.

Lancet's Retraction of Wakefield Paper Like Gasoline on a Fire originally appeared on About.com Autism on Sunday, February 7th, 2010 at 09:57:09.

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I am unutterably frustrated to say that we don't get HBO.  As a result, though I've read and heard plenty about last night's HBO presentation of the biopic "Temple Grandin," starring Claire Danes, I was NOT able to see it.

I can tell you that, according to several interviews, Temple Grandin thought it was terrific.  From the Star-Ledger, for example:

"I just couldn't believe how she played me," Grandin says. "It was like going back in a weird time machine.

Melissa Silverstein of Huffington Post raves:

Claire Danes is revelatory as Temple Grandin animal behaviorist, best-selling author, autistic and expert in autism. This is a fascinating movie and I learned so much about this woman and about autism. Temple did not speak until she was four and if not for her mother would have probably ended up spending her life in an institution. What a loss that would have been.

Because I wasn't able to watch Temple Grandin last night, I did finally manage to rent and view Adam, the Sundance-winning film about a young man with Asperger syndrome and his romantic involvement with a gorgeous, wealthy neighbor...  I had heard great things about it, and while I did find the acting to be compelling, the story itself was a bit weak.

So how was the Temple Grandin film?  Are these reviewers really correct?  Is the movie as good as they say?  And - what do you think about the media response to Temple Grandin as a sort of emissary from the world of autism?

Share your thoughts!

Join the Autism at About.com community on Facebook!

Did You See Claire Danes as Temple Grandin? Share Your Review! originally appeared on About.com Autism on Sunday, February 7th, 2010 at 07:03:38.

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Dong Wu, Qi-Dai Chen, Jia Yao, Yong-Chao Guan, Jian-Nan Wang et al. The study of anisotropic wetting has become one of the most important research areas in biomimicry. However, realization of controlled anisotropic surfaces remains challenging. Here we investigated anisotropic wetting on grooves with different linewidth, period, and height fabricated by laser interf ... [Appl. Phys. Lett. 96, 053704 (2010)] published Fri Feb 5, 2010. (Source: Applied Physics Letters)

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California Stem Cell, Inc. (CSC) and ALS Therapy Development Institute (ALS TDI) are pleased to announce an extension and expansion of their collaboration aimed at advancing a potential stem cell therapy for ALS (amyotrophic lateral sclerosis)... (Source: Muscular Dystrophy News From Medical News Today)

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California Stem Cell, Inc. (CSC) and ALS Therapy Development Institute (ALS TDI) are pleased to announce an extension and expansion of their collaboration aimed at advancing a potential stem cell therapy for ALS (amyotrophic lateral sclerosis). This effort will build on work that has already been completed as part of this on-going partnership to understand how stem cells, and their derivatives, may be applied to treatment of this fatal neurodegenerative disease... (Source: Health News from Medical News Today)

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USING a taser on someone with epilepsy could cause them to suffer a seizure, campaigners have warned. (Source: Scotsman.com News - Health)

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A LITTLE girl who suffered from 20 epileptic fits a day, was stuck in a wheelchair, and has never been able to communicate, should now be able walk and talk, according to doct (Source: Scotsman.com News - Health)

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