Brain and brain waves in epilepsy

Caption: 3D magnetic resonance imaging (MRI) scan of a brain (seen from the front), overlaid with an electroencephalogram (EEG) of a 17-year-old’s brain during an epileptic episode (chaotic brain activity). This EEG shows generalized epilepsy, where the whole brain cortex is affected: all the EEG traces show chaotic brain waves. Epilepsy can have many causes, but when the cause is unknown, as here, it is called essential epilepsy. An EEG measures the electrical activity of the brain using electrodes attached to the scalp. The electrode locations are labelled at far left, on diagrams of the head seen from above, with the front of the head at left.

Credit: SOVEREIGN, ISM/SCIENCE PHOTO LIBRARY

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)

Musical Training as a Framework for Brain Plasticity: Behavior, Function, and Structure

Musical training has emerged as a useful framework for the investigation of training-related plasticity in the human brain. Learning to play an instrument is a highly complex task that involves the interaction of several modalities and higher-order cognitive functions and that results in behavioral, structural, and functional changes on time scales ranging from days to years. While early work focused on comparison of musical experts and novices, more recently an increasing number of controlled training studies provide clear experimental evidence for training effects. Here, we review research investigating brain plasticity induced by musical training, highlight common patterns and possible underlying mechanisms of such plasticity, and integrate these studies with findings and models for mechanisms of plasticity in other domains.

Caffeine Improves Left Hemisphere Processing of Positive Words

A positivity advantage is known in emotional word recognition in that positive words are consistently processed faster and with fewer errors compared to emotionally neutral words. A similar advantage is not evident for negative words. Results of divided visual field studies, where stimuli are presented in either the left or right visual field and are initially processed by the contra-lateral brain hemisphere, point to a specificity of the language-dominant left hemisphere. The present study examined this effect by showing that the intake of caffeine further enhanced the recognition performance of positive, but not negative or neutral stimuli compared to a placebo control group. Because this effect was only present in the right visual field/left hemisphere condition, and based on the close link between caffeine intake and dopaminergic transmission, this result points to a dopaminergic explanation of the positivity advantage in emotional word recognition.

Young brain develops activity peaks while it is still growing

After a short period of growth, cultured networks of neurons regularly exhibit major activity in the absence of external stimulation. These “bursts” are entirely related to growth. At this stage, they have little to do with learning behaviour, as the network is still too young to sustain a process of memory formation. This has now for the first time been simulated for networks ranging in size from 10,000 to 50,000 neurons. The simulations provide insight into the role of the growth process in initial activity. Researchers at the University of Twente’s MIRA Institute recently published details of this work in PLOS ONE.

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Brain study provides new insight into why haste makes waste

Why do our brains make more mistakes when we act quickly?

A new study demonstrates how the brain follows Ben Franklin’s famous dictum, “Take time for all things: great haste makes great waste.”

The research – conducted by Research Assistant Professor Richard Heitz and Jeffrey Schall, Ingram Professor of Neuroscience, at Vanderbilt University – has found that the brain actually switches into a special mode when pushed to make rapid decisions.

The study was published Nov. 7 in the journal Neuron.