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September 10th 2009 05:50
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Researchers have found that nicotine, the addictive component in cigarettes, "tricks" the brain into creating memory associations between environmental cues and smoking behavior. This could help explain why former smokers miss lighting up when they are in a bar or after a meal.
The findings from researchers at Baylor College of Medicine are in the Sept. 10 issue of the journal Neuron.
"Our brains normally make these associations between things that support our existence and environmental cues so that we conduct behaviors leading to successful lives. The brain sends a reward signal when we act in a way that contributes to our well being," study co-author Dr. John A. Dani, professor of neuroscience at BCM said in a college news release. "However, nicotine commandeers this subconscious learning process in the brain so we begin to behave as though smoking is a positive action." AJC
St. Jude Medical Inc. said Wednesday that it has received European approval for a device that treats Parkinson’s disease by delivering electric pulses to the brain.
Little Canada-based St. Jude (NYSE
TJ) claims its Brio neurostimulator, a 1-ounce device slightly larger than the typical man’s watch, is one of the world’s smallest.A 67-year-old man who has suffered from Parkinson’s disease for more than 26 years has become the first person to be implanted with the Brio neurostimulator, St. Jude said. The procedure was performed at a hospital in Cologne, Germany.
The Brio system delivers mild electrical pulses to specific targets in the brain. It’s meant to stimulate the structures that are involved in motor control.
Minneapolis St Paul Business journal
Cocaine alters brain cell shape
Adolescents are highly at risk for abusing drugs. Now, Yale researchers may have a better understanding as to why.
A new study published this week in the journal of the Proceedings of the National Academies of Science builds on previous research which claimed that cocaine changes the shape of brain cells. Postdoctoral fellow Shannon Gourley and her team, however, took this one step further by investigating whether this change in the structure of neurons had any effect on behavior. They discovered that learning ability and sensitivity to cocaine may indeed determined by the shape of brain cells, and this, mental health workers say, could explain why adolescents have such a hard time dealing with drugs.
“One of the things we’ve known is that psycho-stimulants like amphetamine, which is a key component in Ritalin and cocaine, can change shape of brain cells,” Gourley said. “What we’ve done in this study is turned that question on its head.”
The research project came about as a result of Gourley’s and fellow author Anthony Koleske’s common interest in the connectivity of neurons. Koleske’s previous research concerns the stabilization of connections between neurons, and Gourley had insight into how this knowledge might be relevant to issues involving the pre-frontal cortex of the brain, said Koleske, who is an associate professor of molecular biophysics and biochemistry and of neurobiology.
Cell shape is critically important to the ability of neurons to communicate with each other, Gourley said.
“A cell is like a tree,” she said. “If it’s really big and complex, it is very likely to touch other trees in the forest. If it is damaged, or has only a few branches, then there will be fewer points of contact.”
Neurons in the frontal cortex of the brain, which controls higher-order mental functions, do not stabilize until late adolescence in part due to a gene called Arg, which is key to adolescent development. In this study, Koleske created “knock-out” mice in which Arg was disabled. As a result, the mice had unstable neurons even as adults.
At this point, the mice were given either cocaine or salt water. Gourley said mice who had been given cocaine, a stimulant, ran around a lot more. Interestingly, the “knock-out” mice were a lot more active, even when given amounts of cocaine so small that the normal mice were not affected — underscoring that immature brain cells heightens one’s sensitivity to drugs like cocaine.
The second part of the experiment looked at the behavioral flexibility of the mice after exposure to cocaine.
“Behavioral flexibility is the ability to change one’s behavior,” Gourley said. “For instance, if you grew up and lived in one house for 15 years and then moved, you’d need to be able to drive to your new house.”
The researchers found cocaine severely affected the “knock-out” mice’s ability to learn new things, even after the cocaine had left the animals’ systems.
Mary Torregrossa , a postdoctoral fellow at the Connecticut Mental Health Center, said this new study provides the first evidence of a neurobiological mechanism that explains why adolescents might be more sensitive to the effects of drug abuse than adults.
“The research suggests that it is of particular importance to educate adolescents about the dangers of drug use, as they may be especially vulnerable,” she said.
Torregrossa also added that some individuals might have certain genetic predispositions or environmental experiences that affect cortical development. This, she said, leaves the individual susceptible to develop addictions. If these factors were identified, treatments could be developed to specifically target these individuals.
Gourley said that the next step is to find out what part of the changing neuron causes the increased sensitivity to drugs like cocaine.
“What we want to know is, which receptor that we are losing is really important?” Gourley said. “And if we could rescue these receptors, could we reverse the effects?”
The study was funded by the National Institutes of Health and the Connecticut Department of Mental Health and Addiction Services.
Yale Daily News
Alzheimer's chemicals may be natural part of brain function
The chemicals that cause tissue degeneration in Alzheimer's disease may be a natural part of human brain function, recent research suggests.
"You are actively forgetting and remembering all the time," said Dr. Dale Bredesen, founding president and CEO of the Buck Institute for Age Research, during a presentation Tuesday at the University of Utah. "Alzheimer's Disease is just a fundamental imbalance in those signals."
Most researchers look at Alzheimer's as a disease of toxicity, said Bredesen, who works out of Novato, Calif.
"It's like having acid on your brain," he said. "Something's eating it."
But the chemical associated with tissue destruction in Alzheimer's patients is also present in the brains of young, healthy people — a phenomenon none of the more than 500,000 scientific papers published on the topic can explain.
"We argue the amyloid beta peptide does have a normal function," Bredesen said. "We think Alzheimer's is more of a signaling disorder rather than a disease of toxicity."
Bredesen's theory links brain development to brain deterioration.
As a fetus grows, it produces more nerve cells than it will ultimately use. Some of those cells build connections with one another, some die. Both outcomes are determined by naturally occurring chemicals
Deseret News
U.S. soldiers returning from Iraq with post-traumatic stress disorder (PTSD) appear to show growing attention deficits in the year following their return, Boston University researchers report.
In addition, intense combat experiences were associated with faster, survival-linked reaction times. Earlier research has found that as soldiers encounter stressful and life-threatening situations, there are changes in their brains that direct their thinking, learning and memory toward survival, the researchers noted.
"It's important to realize that the problems with attention that we saw were relatively mild," stressed lead researcher Jennifer J. Vasterling, chief of psychology at the VA Boston Healthcare System and a professor of psychiatry at Boston University School of Medicine. "But what they suggest is that we should be thinking about the broader picture of how people function when they return from war."Atlanta Health
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