Unique spinal nerve cell activity discovery

Scientists from the University of Leicester have hit upon unique forms of spinal nerve activity that shape output of nerve cell networks controlling motor behaviours.

The breakthrough in the Department of Biology at the University of Leicester is announced in the journal Current Biology. The three-year study was funded by the Biotechnology and Biological Sciences Research Council (BBSRC).

Although the neural basis of motor control has been studied for over a century, the processes controlling maturation of locomotor behaviours – like walking and swimming - are not fully understood.

The University of Leicester research into nerve cells responsible for motor behaviours was carried out on fish. The team aimed to understand how spinal networks produce rhythmic activity from a very immature stage - and how such activity changes during maturation.

The team used zebrafish, a freshwater fish native to northern India and Bangladesh, because their motor networks are similar to humans.  However, as they are fertilized outside the mother and their embryos are transparent, scientists can readily monitor motor network development from its onset - something that is very difficult to do in mammals.

Researchers Find Why Nicotine in Cigarettes May Relieve Anxiety in Smokers

Preclinical data suggests inactivation of a specific sub-class of nicotinic receptors may be an effective strategy to help smokers quit without feeling anxious, according to Virginia Commonwealth University researchers.

These findings could one day point researchers to the development of novel therapies to help smokers quit without feeling anxious.

Smokers use cigarettes for many reasons, but many report that they smoke to relieve anxiety, despite the health danger of cigarette smoking. Researchers are now working to understand the underlying neurochemical pathways that support smoking behavior.

In a study, published online this week in PLoS ONE, researchers observed that low doses of nicotine and a nicotinic receptor blocker had similar effects to reduce anxiety-like behavior in an animal model. They found that inactivation of beta2 subunit, a specific sub-class of nicotinic receptors that bind nicotine, appears to reduce anxiety. This is different from the mechanism that regulates nicotine reward and likely occurs in a separate brain area.

“This work is unique because it suggests that nicotine may be acting through inactivation, rather than activation, of the high affinity nicotinic receptors,” said Darlene Brunzell, Ph.D., assistant professor in the Department of Pharmacology and Toxicology in the VCU School of Medicine.

“Nicotine acts like a key that unlocks nicotine receptors in the brain. Usually that key opens the receptor, but at other times nicotine is like a key that has gotten broken inside of the lock. Our findings suggest that low-dose nicotine may block a specific subtype of receptor from opening that is important for regulating anxiety behavior,” she said, adding that anxiety is a major reason why people relapse to smoking.

Making Memories: Drexel Researchers Explore the Anatomy of Recollection

What was your high school mascot? Where did you put your keys last night? Who was the first president of the United States?

Groups of neurons in your brain are currently sending electromagnetic rhythms through established pathways in order for you to recall the answers to each of these questions. Researchers in Drexel’s School of Biomedical Engineering, Science and Health Systems are now getting a rare look inside the brain to discover the exact pattern of activity that produces a memory.

Dr. Joshua Jacobs, a professor in Drexel’s School of Biomedical Engineering, Science and Health Systems, is analyzing data accumulated from 60 epilepsy patients who have had electrodes implanted on their brains in order to determine the causes of their epileptic episodes.

"When performing seizure mapping, surgeons implant electrodes in many brain areas, while searching for seizure activity,” Jacobs said. “Thus, there many electrodes end up being in normal brain tissue, and they measure neuronal activity that reflects normal brain function – this is the function that we’re studying to learn about the nature of working memory."

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Hallucinations with Oliver Sacks, November 9, 8 P.M. EST [Live]

The renown neurologist talks about how the brain creates hallucinations — watch this hour-long discussion live and send questions to him via Twitter (using the hashtag #AskOliver to @WorldSciFest).

The conversation, at Cooper Union in New York City, will canvass the rich cultural history and contemporary science of the hallucinatory experience and will also touch on Sacks’ own early psychedelic forays that helped convince him to dedicate his life to neurology and to write about the myriad riddles of the human mind.

Can’t wait? Listen to the Nature podcast interview with Sacks by Kerri Smith, Nature’s podcast editor. Sacks recounts some interesting drug-induced trips, including one in which he has a philosophical discussion with a spider.

(Source: scientificamerican.com)

Birds of a feather don’t share a sick bed

House finches avoid sick members of their own species, say scientists, in a finding that could be useful for tracking the spread of diseases like bird flu that also affects humans.

Laboratory tests showed that the house finch, a particularly social North American species (Carpodacus mexicanus), was able to tell the difference between sick and healthy fellow birds and tended to avoid those that were unwell.

This was the first time that avoidance of sick individuals, already observed in lobsters and bullfrog tadpoles, has been shown in birds, according to a paper published in the journal Biology Letters.

"In addition, we found variation in the immune response of house finches, which means that they vary in their ability to fight off infections," says co-author Maxine Zylberberg of the California Academy of Sciences.

"As it turns out, individuals who have weaker immune responses and therefore are less able to fight off infections, are the ones who most avoid interacting with sick individuals."

This all meant that there were differences between individual birds’ susceptibility to disease, the time it would take them to recuperate and their likeliness to pass on the disease.

"These are key factors that help to determine if and when an infectious disease will spread through a group of birds," says Zylberg - and how quickly.

(Image credit)

The Mysterious Motivational Functions of Mesolimbic Dopamine

Nucleus accumbens dopamine is known to play a role in motivational processes, and dysfunctions of mesolimbic dopamine may contribute to motivational symptoms of depression and other disorders, as well as features of substance abuse. Although it has become traditional to label dopamine neurons as “reward” neurons, this is an overgeneralization, and it is important to distinguish between aspects of motivation that are differentially affected by dopaminergic manipulations. For example, accumbens dopamine does not mediate primary food motivation or appetite, but is involved in appetitive and aversive motivational processes including behavioral activation, exertion of effort, approach behavior, sustained task engagement, Pavlovian processes, and instrumental learning. In this review, we discuss the complex roles of dopamine in behavioral functions related to motivation.