Exercise and its effect on NEUROGENESIS

Exercise increases key chemicals in the brain that promote neurogenesis, the growth of new brain cells. It has been said that one of the key ways to protect an aging mind from wear and tear is to EXERCISE. Exercising isn’t just good for the body, it’s good for the brain, which is part of the body, and thus the mind itself.

A New York Times article entitled “Lobes of Steel” recently came out and while it didn’t give me any direct numbers, it did give me something to compare to… an idea of just how *much* of a difference exercise makes, at least in mice:

All of the mice showed this vivid proof of what’s known as “neurogenesis,” or the creation of new neurons. But the brains of the athletic mice in particular showed many more. These mice, the ones that scampered on running wheels, were producing two to three times as many new neurons as the mice that didn’t exercise.

Clearly the tremendous benefits of exercise on neurogenesis weren’t limited to only mice, either:

At the University of Illinois at Urbana- Champaign, a group of elderly sedentary people were assigned to either an aerobic exercise program or a regimen of stretching. (The aerobic group walked for at least one hour three times a week.) After six months, their brains were scanned using an M.R.I. Those who had been doing aerobic exercise showed significant growth in several areas of the brain. These results raise the hope that the human brain has the capacity not only to produce new cells but also to add new blood vessels and strengthen neural connections, allowing young neurons to integrate themselves into the wider neural network. “The current findings are the first, to our knowledge, to confirm the benefits of exercise training on brain volume in aging humans,” the authors concluded.

Oh, and I was aware that exercise helped depression, but this one was new to me!:

Exercise speeds the brain’s production of serotonin, which could, in turn, prompt new neurons to grow.

NYTimes articles really are comprehensive, and anytime they release something on neuroscience I enjoy prowling it. I’m sure to learn something new.

ADHD and OCD: Implication of the TONSILS

So I recently posted a link to an article that happened to mention streptococcal infection — which is known to attack the tonsils — being linked to OCD. No sooner could I blink than another article surfaces discussing a new treatment for ADHD: the removal of the tonsils.

Parkinson, the psychiatrist interviewed for this particular story of a three year old who had his “ADHD cured,” mentions that there is a strong correlation to sleep disorders and daytime hyperactivity. Essentially, the enlarged tonsils caused by multiple infections obstruct breathing during sleep causing sleep apnea.

So… When are we going to hear about some studies of removing tonsils to treat OCD? And is the correlation with streptococcal infection in OCD, seemingly like the ADHD implication, stemming from physically obstructing breathing during sleep? (Evidence seems to point in that direction.)

It may also be of note that both OCD and ADHD “disorders” are tied to unusual development of the prefrontal cortex.

A Simulation of the Universe vs A Brain Cell

One image is a simulation of how the universe grew and evolved. The other is a real an image of how three brain cells connect.

Brain Cell and Universe

Within us resides a seemingly infinite universe. Outside of us resides a seemingly infinite universe. We’re mere observers between infinity stretching in two directions: internally and externally.

Image originally comes from: http://www.nytimes.com/imagepages/2006/08/14/science/20060815_SCILL_GRAPHIC.html

Adults Haver Richer *Contextual* Memories

From Eurekalert:

In the August 5 advance online edition of Nature Neuroscience, the MIT team reports that children rival adults in forming basic memories, but adults do better at remembering the rich, contextual details of that information. The MIT study provides new insights into how children learn that are not only theoretically important, but could also inform practical learning in everyday settings.

The ability to remember factual information – who, what, where, when – emerges gradually during childhood, and plays a critical role in education. The brain systems underlying it have been extensively studied in adults, but until now little was known about how they mature during child development.

The MIT study indicates that a more developed prefrontal cortex (PFC) – an area of the brain long associated with higher-order thinking, planning, and reasoning — may be responsible for creating richer memories in adults.

“Activation in the PFC follows an upward slope with age in contextual memories. The older the subjects, the more powerful the activation in that area,” explains senior author John Gabrieli of MIT’s McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, and Harvard-MIT Division of Health Sciences and Technology.

“That makes sense, because there’s been a convergence of evidence that the PFC develops later than other brain regions, both functionally and structurally…. But this is the first study that asks how this area matures and contributes to learning.”

For the study, Noa Ofen, a postdoctoral associate in Gabrieli’s lab, forewarned 49 healthy volunteers ranging in age from eight to 24 that they would be tested on their recognition of 250 common scenes, such as a kitchen, shown to them as they lay in a functional magnetic resonance imaging scanner. She recorded their brain responses as the volunteers tried to commit each picture to memory. Shortly after the volunteers left the scanner, she showed them twice as many scenes. Had they seen each one before, and if so, how vividly did they recall the scene”

Ofen then went back to the brain activation patterns. In both children and adults, several areas in the PFC and the medial temporal lobe (MTL) showed higher activation at the time when subjects studied a scene they would later remember. No age-related differences showed up in the activation patterns of the MTL regions in children and adults, but differences did appear in the PFC when looking at pictures that were later correctly recognized.

Those age-related differences related to the quality of the volunteers’ memories. The older the volunteers, the more frequently their correct answers were enriched with contextual detail. Going back to the brain scans, Ofen found that the enriched memories also correlated with more intense activation in a specific region of the PFC.

“We found no change with age for memories without context,” Ofen explains. “All the maturation is in memories with context. Our findings suggest that as we mature, we are able to create more contextually rich memories, and that ability evolves with a more mature PFC.”

I love my prefrontal cortex

A Strange Correlate of OCD

TIME just put out a large article on OCD which brought up something rather interesting that I’d never heard of:

Other compelling, if controversial, research has long pursued an entirely different cause of OCD: streptococcal infection. As long ago as the 17th century, British physician Thomas Sydenham first noticed a link between childhood strep and the later onset of a tic condition that became known as Sydenham’s chorea. Modern researchers who saw a link between tics and OCD began wondering if, in some cases, strep might be involved with both.Last year investigators from the University of Chicago and the University of Washington studied a group of 144 children– 71% of whom were boys–who had tics or OCD. All the kids, it turned out, were more than twice as likely as others to have had a strep infection in the previous three months. For those with Tourette’s symptoms, the strep incidence was a whopping 13 times as great.

The tics and OCD are probably the result of an autoimmune response, in which the body begins attacking its own healthy tissue. Blood tests of kids with strep-related tics and OCD have turned up antibodies hostile to neural tissue, particularly in the brain’s caudate nucleus and putamen, regions associated with reinforcement learning. “There certainly seems to be an epidemiological relationship there,” says Dr. Cathy Budman, associate professor of psychiatry and neurology at New York University, “but what it means needs to be further investigated.”