Wednesday, September 05, 2012

Recent Research in Brain Science - Stress, Stem Cells, Switchboards, and More

It seems there is a new and important brain science research study published almost every day - and sometimes multiple studies in the same day. I do my best to blog the biggest ones, but sometimes there is not time to get them all up, so then I do a post like this one - a kind of link dump of new and important studies.

First up (in no particular order), a study that provides some clues at to how neurological disorders develop in the brain, by looking at neural circuitry.

Circuits In The Brain Reveal Why Neurological Disorders Occur

The human brain contains billions of neurons that are arranged in complex circuits, which enable people to function with regard to controlling movements, perceiving the world and making decisions. In order to understand how the brain works and what malfunctions occur in neurological disorders it is crucial to decipher these brain circuits.
Read the whole article.

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This piece looks at a study from Scripps Research Institute that may have identified the stem cell population that develops into the brain cells of the cerebral cortex.

Study Of Brain Development Reveals Brain Stem Cells That May Be Responsible For Higher Functions, Bigger Brains

Published in the journal Science, the new research reveals how neurons in the uppermost layers of the cerebral cortex form during embryonic brain development.

"The cerebral cortex is the seat of higher brain function, where information gets integrated and where we form memories and consciousness," said the study's senior author Ulrich Mueller, a professor and director of the Dorris Neuroscience Center at Scripps Research. "If we want to understand who we are, we need to understand this area where everything comes together and forms our impression of the world." 
Read the whole article.

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We have long known that someplace in the brain there are circuits or a module that sorts through all of the incoming stimuli (sound, vision, scent, taste, touch, temperature, and so on) and decides what needs to make it into awareness and what does not. Now we think we have found that "switchboard."

After producing neural connection maps, the researchers used electrodes (blue arrows and green crosshairs) to monitor the direct communication paths (yellow-orange) between the pulvinar and clusters of brain cells, which in this case are in the temporal lobe. (Credit: Courtesy of /AAAS)

Brain's Mysterious Switchboard Operator Revealed

ScienceDaily (Aug. 17, 2012) — A mysterious region deep in the human brain could be where we sort through the onslaught of stimuli from the outside world and focus on the information most important to our behavior and survival, Princeton University researchers have found.

The researchers report in the journal Science that an area of our brain called the pulvinar regulates communication between clusters of brain cells as our brain focuses on the people and objects that need our attention. Like a switchboard operator, the pulvinar makes sure that separate areas of the visual cortex -- which processes visual information -- are communicating about the same external information, explained lead author Yuri Saalmann, an associate research scholar in the Princeton Neuroscience Institute (PNI). Without guidance from the pulvinar, an important observation such as an oncoming bus as one is crossing the street could get lost in a jumble of other stimuli.

Read the whole article.

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Lastly, we have two studies that reveal the impact of stress on cells (including brain cells) and on the brain directly. Let's just say, It ain't good.

Control Of Gene Activity Altered By Acute Stress

Acute stress alters the methylation of the DNA and thus the activity of certain genes. This is reported by researchers at the Ruhr-Universitat Bochum together with colleagues from Basel, Trier and London for the first time in the journal Translational Psychiatry. "The results provide evidence how stress could be related to a higher risk of mental or physical illness", says Prof. Dr. Gunther Meinlschmidt from the Clinic of Psychosomatic Medicine and Psychotherapy at the LWL University Hospital of the RUB. The team looked at gene segments which are relevant to biological stress regulation.

Epigenetics - the "second code" - regulates gene activity

Our genetic material, the DNA, provides the construction manual for the proteins that our bodies need. Which proteins a cell produces depends on the cell type and the environment. So-termed epigenetic information determines which genes are read, acting quasi as a biological switch. An example of such a switch is provided by methyl (CH3) groups that attach to specific sections of the DNA and can remain there for a long time - even when the cell divides. Previous studies have shown that stressful experiences and psychological trauma in early life are associated with long-term altered DNA methylation. Whether the DNA methylation also changes after acute psychosocial stress, was, however, previously unknown.

Read the whole article.

The second article showed that chronic stress, like chronic depression, can shrink the brain - literally.

Stress, Depression Reduce Brain Volume Thanks to Genetic ‘Switch’

By Senior News Editor
Reviewed by John M. Grohol, Psy.D. on August 13, 2012 
Stress, Depression Reduce Brain Volume Thanks to Genetic 'Switch'  

Scientists have known that stress and depression can cause the brain to retract or lose volume, a condition associated with both emotional and cognitive impairment. Now, a new study discovers why this occurs.

Yale scientists have found that the deactivation of a single genetic switch can instigate a cascading loss of brain connections in humans and depression in animal models.

Researchers say the genetic switch, known as a transcription factor, represses the expression of several genes that are necessary for the formation of synaptic connections between brain cells. The loss of connections, in turn, can contribute to loss of brain mass in the prefrontal cortex, say the scientists.
Read the whole article.

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