Fluoxetine increases aggressive behavior, affects brain development among adolescent hamsters

Fluoxetine was the first drug approved by the FDA for major depressive disorder (MDD) in children and adolescents, and to this date, it remains one of only two selective serotonin reuptake inhibitors (SSRIs) registered for treatment of MDD in children and adolescents, despite reports that indicate this class of drugs is associated with side effects, such as agitation, hostility and aggression.

SSRIs have been amongst the most widely prescribed medications in psychiatry for over a decade. While there is a wealth of information regarding their effectiveness and safety in adults, considerably less data exists regarding whether they are safe for children. 

 A study published in Behavioral Neuroscience by Prof. Richard Melloni of Northeastern University shows that repeated administration of a low dose of fluoxetine to adolescent hamsters dramatically increased offensive aggression and altered the development of brain areas directly associated with controlling the aggressive response. “These data show clearly that repeated exposure to fluoxetine during adolescence directly stimulates aggressive responding and alters the normal development of two important brain systems, i.e., the serotonin and vasopressin neural systems, in a fashion consistent with the expression of the highly aggressive behavioral characteristics.”

For over a decade, Prof. Melloni and his team have researched the neural and behavioral consequences of illicit drugs and prescribed medications on the adolescent brain. Importantly, the data collected during the study indicates that clinically relevant doses of fluoxetine, when administered during adolescent development, can dramatically alter the wiring of brain circuits implicated in aggression control. “These data support the notion that interactions between adolescent fluoxetine and the developing vasopressin neural system might underlie fluoxetine-induced aggressive behavior and hint that serotonin, perhaps by acting on vasopressin neurons, may play a more permissive role in this response.”

(Image credit: Benjah-bmm27)

(Source: northeastern.edu)

Omega-3 Supplements May Slow A Biological Effect of Aging

Taking enough omega-3 fatty acid supplements to change the balance of oils in the diet could slow a key biological process linked to aging, new research suggests.

The study showed that most overweight but healthy middle-aged and older adults who took omega-3 supplements for four months altered a ratio of their fatty acid consumption in a way that helped preserve tiny segments of DNA in their white blood cells.

These segments, called telomeres, are known to shorten over time in many types of cells as a consequence of aging. In the study, lengthening of telomeres in immune system cells was more prevalent in people who substantially improved the ratio of omega-3s to other fatty acids in their diet.

Omega-3 supplementation also reduced oxidative stress, caused by excessive free radicals in the blood, by about 15 percent compared to effects seen in the placebo group.

“The telomere finding is provocative in that it suggests the possibility that a nutritional supplement might actually make a difference in aging,” said Jan Kiecolt-Glaser, professor of psychiatry and psychology at Ohio State and lead author of the study.

Homolog of mammalian neocortex found in bird brain

A seemingly unique part of the human and mammalian brain is the neocortex, a layered structure on the outer surface of the organ where most higher-order processing is thought to occur. But new research at the University of Chicago has found the cells similar to those of the mammalian neocortex in the brains of birds, sitting in a vastly different anatomical structure.

The work, published in Proceedings of the National Academy of Sciences, confirms a 50-year-old hypothesis about the identity of a mysterious structure in the bird brain that has provoked decades of scientific debate. The research also sheds new light on the evolution of the brain and opens up new animal models for studying the neocortex.

"If you want to study motor neurons or dopamine cells, which are biomedically important, you can study them in mammals, in chick embryos, in zebrafish. But for these neurons of the cerebral cortex, we could only do that in mammals before," said Clifton Ragsdale, PhD, associate professor of neurobiology at University of Chicago Biological Sciences and senior author of the study. "Now, we can take advantage of these other experimental systems to ask how they are specified, can they regenerate, and other questions."

Both the mammalian neocortex and a structure in the bird brain called the dorsal ventricular ridge (DVR) originate from an embryonic region called the telencephalon. But the two regions mature into very different shapes, with the neocortex made up of six distinct cortical layers while the DVR contains large clusters of neurons called nuclei.

Japanese Study Shows Cute Pics Of Puppies May Improve Concentration

New research in The FASEB Journal suggests that serum from animals such as camels, llamas, and alpacas could enhance brain imaging and help drugs pass through the blood-brain barrier

President Obama’s national plan to fight Alzheimer’s disease just got a lift thanks to a team of international researchers whose recent discovery may lead to enhanced imaging of and improved drug delivery to the brain. A research report appearing in The FASEB Journal, describes an entirely new class of antibody discovered in camelids (camels, dromedaries, llamas, and alpacas) that is able to cross the blood-brain barrier, diffuse into brain tissue, and reach specific targets. Having such antibodies, which are naturally available, may be part of a “game changer” in the outcomes for people with brain diseases that are poorly diagnosed and treated, at best, using today’s tools.

"This basic biological investigation opens new pathways toward innovative therapeutic solutions for intractable diseases such as Alzheimer’s disease or brain tumors," said Pierre Lafaye, Ph.D., a researcher involved in the work from the Institut Pasteur, PF: Production de Protéines Recombinantes et d’Anticorps –Proteopole in Paris, France. "The importance of this study is the hope that this novel approach may be a useful tool in crossing the blood brain barrier for diagnostic and therapeutic purposes," added Babbette Weksler, MD, Professor of Medicine, Weill Cornell Medical College, New York, NY, another author of the study and editorial board member of The FASEB Journal.

Penn Researchers Connect Baboon Personalities to Social Success and Health Benefits

Whether human or baboon, it helps to have friends. For both species, studies have shown that robust social networks lead to better health and longer lives. Now, a team of University of Pennsylvania researchers has helped show that baboon personality plays a role in these outcomes, and, like people, some baboons’ personalities are better suited to making and keeping friends than others.

The research was conducted by psychology professor Robert Seyfarth and biology professor Dorothy Cheney, both of Penn’s School of Arts and Sciences. They collaborated with the Arizona State University’s Joan Silk.  

Their work was published in the Proceedings of the National Academy of Sciences

Researchers Halt Autoimmune Disease Myasthenia Gravis in Mice

Working with mice, Johns Hopkins researchers say they have developed a gene-based therapy to stop the rodent equivalent of the autoimmune disease myasthenia gravis by specifically targeting the destructive immune response the disorder triggers in the body.

The technique, the result of more than 10 years of work, holds promise for a highly specific therapy for the progressively debilitating muscle-weakening human disorder, one that avoids the need for long-term, systemic immunosuppressant drugs that control the disease but may create unwanted side effects.

The research, if replicated in humans, could be a big leap in treating not only myasthenia gravis, but also other autoimmune disorders, the researchers say.

“To treat autoimmune diseases, we normally give drugs that suppress not only the specific antibodies and cells we want to inhibit, but that also broadly interfere with other functions of the immune system,” says Daniel B. Drachman, M.D., a professor of neurology and neuroscience at the Johns Hopkins University School of Medicine and leader of the study published this month in the Journal of Neuroimmunology. “Our goal was to suppress only the abnormal response, without damaging the remainder of the immune system, and that’s what we did in these mice.”

New study suggests memory impairment tied to object perception

A new study from Georgia Tech and the University of Toronto suggests that memory impairments for people diagnosed with early stage Alzheimer’s disease may be due, in part, to problems in determining the differences between similar objects. The findings also support growing research indicating that a part of the brain once believed to support memory exclusively – the medial temporal lobe - also plays a role in object perception. The results are published in the October edition of Hippocampus.

Mild cognitive impairment (MCI) is a disorder commonly thought to be a precursor to Alzheimer’s disease. The study’s investigators, partnering with the Emory Alzheimer’s Disease Research Center, tested MCI patients on their ability to determine whether two rotated, side-by-side pictures were different or identical.

Memory load leaves us ‘blind’ to new information

Trying to keep an image we’ve just seen in memory can leave us blind to things we are ‘looking’ at, according to the results of a study by researchers at the Institute of Cognitive Neuroscience.

It’s been known for some time that when our brains are focused on a task, we can fail to see other things that are in plain sight. This phenomenon, known as ‘inattentional blindness’, is exemplified by the famous ‘invisible gorilla’ experiment where people concentrate on a video of players throwing around a basketball and try to count the number of times the ball is thrown, but fail to observe a man in a gorilla suit walk across the centre of the screen.

The new results reveal that our visual field does not need to be cluttered with other objects to cause this ‘blindness’ and that focusing on remembering something we have just seen is enough to make us unaware of things that happen around us.

“An example of where this is relevant in the real world is when people are following directions on a Sat Nav whilst driving,” explains Professor Nilli Lavie from UCL Institute of Cognitive Neuroscience, who led the study. “Our research would suggest that focusing on remembering the directions we’ve just seen on the screen means that we’re more likely to fail to observe other hazards around us on the road, for example an approaching motorbike or a pedestrian on a crossing, even though we may be ‘looking’ at where we’re going.”