The Brain's Silent Majority

Glial cells make up almost 90% of the brain, yet these cells have been a mystery to scientist for many years. Once thought of as just "nerve cement" there is now evidence that glial cells do much more. The new evidence in astrocytes, a certain type of glial cell, is shedding new light on how neurons actually work and how neurodegenerative diseases happen.

This article is very interesting as it concentrates on the 90% of the brain that most people don't know about. As you go up the evoltionary complexity ladder, the more complex the organism, the more glial cells they have. If the scientific community can figure out exactly the role glial cells play in the brain, there may be substantial breakthroughs in treating diseases such as Alzheimers, ALS, glaucoma, MS, and many others.

Link
http://www.stumbleupon.com/su/3ZeMYw/stanmed.stanford.edu/2009fall/article6.html

http://stanmed.stanford.edu/2009fall/article6.html

Synthetic Brains

Researchers at the University of Southern California are building neurons from carbon nanotubes that could emulate human brain function.

Unlike computer software that simulates brain function, the challenges of creating a synthetic brain will include hardware that emulates brain cells, the brains amazing complexity and plasticity. Not forgetting the scale factor. If the team is able to construct the synthetic brain it would take 100 billion artificial neurons and a very large brain. Power is another consideration, mainly because our brains never turn off (unless we are dead.)Do this numbers sound familiar? Remember the first digital computer, ENIAC, way back in 1946 that weighed 50 tons and occupied almost 1,800 square feet and consumed almost 150kW of power?

Right now, the researchers are building mathematical models that can accurately reflect the byzantine connections of all neurons and their ability to communicate with each other. Each neuron in the cortex will represent a part of the brain that significantly contributes to conscious thought and intelligence.

Portions of the neuron can already be modeled electronically using carbon nanotube circuit models. The researchers also believe that carbon nanotubes would be the ideal material for the synthetic brain.

But beyond all the math, material and scaling required, the question of incorporating emotions to the synthetic brain will be paramount for effective learning and function.

If this is not a waste of the National Science Foundation’s money (and I dare not imply that it is) then I can only imagine the immense applications in could revolutionize neural prosthetics and bionics.

Source: http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=112947&org=NSF

Christine Otieno

VTTP 434-501

Brain Plasticity Boosts Sense of Sight in Deaf

Dr. Stephen G. Lomber of the Centre for Brain and Mind at the University of Ontario in Canada lead a team of researchers that found that the brain reorganizes parts of itself normally used for hearing in order to boost sight in deaf people. The research was published online in the journal Nature Neuroscience.

The specific study involved studying the brains of cats that were born deaf. It has been known that deaf and blind people often report an enhanced ability in other senses but it was not known how this process came about neurologically. The research team found that the brain has a certain “plasticity” to reassign areas normally dedicated to one sense in order to boost the performance of a remaining sense. More specifically, the team found that the brains of the deaf utilize the redundant auditory brain areas to improve visual performance in two ways: enhancing peripheral vision and detecting how fast things around them are moving. Lomber said, “The brain is very efficient, and doesn’t let unused space go to waste,” further hypothesizing that, “cross-modal reorganization of deaf auditory cortex may provide the neural substrate mediating compensatory visual function.” After putting congenitally deaf cats and hearing cats through a series of tests, it was found that the deaf cats had superior localization in the peripheral field and lower visual movement detection thresholds. When the posterior auditory complex (part of the brain that detects peripheral sound) was deactivated through surgery, it was found that the cats lost their enhanced peripheral visualizing skills. This lead the team to suggest that the function of the brain area to detect peripheral signals stayed the same but it switched from auditory to visual in nature. Lomber concluded that, “Our results indicate that enhanced visual performance in the deaf is caused by cross-modal reorganization of deaf auditory cortex and it is possible to localize individual visual functions in discrete portions of reorganizaed auditory cortex.”

I found this article to be interesting because of the analysis of the brain’s characteristic quality of “plasticity” that allows it to modify itself to suite new situations. This quality of the brain encompasses much of the focus of our course on human physiology which is the body’s response to different stimulate in an attempt to maintain a homeostasis. In this example, the body has lost one of its senses and therefore the information from the physical world associated with that sense. In response, the body boosts another intact sense to allow another avenue for more information to be processed. This fascinating plasticity of the brain was also explored in one of our SNBAL assignments. Brain plasticity has a promising future for teaching us more about the brain and its manipulation in order to prevent and treat different diseases that affect the brain.

Article Source: http://www.medicalnewstoday.com/articles/204333.php
Alexander J. Quante '13 -- VTPP 434

Introspective ability linked to prefrontal cortex

A higher level of introspective ability, or the examination of one's own mental processes, has been linked with the volume of gray matter in the prefrontal cortex along with the density of the connections.

A recent study tested subjects' perception of geometric images along with their level of confidence in their answer. The subjects were shown the image, asked to identify it, and then assessed the accuracy of their answers. People with greater introspection have the tendency to know whether they have answered correctly or incorrectly, and with the usage of Magnetic Resonance Imaging (MRI), researchers found a significant correlation between gray-matter volume in the prefrontal cortex and increased introspection. Additionally, people with greater introspective ability generally had denser connections between the gray matter and the connected, myelinated white matter. It is currently unknown whether the correlation between the gray matter of the prefrontal cortex and introspective ability is innate or cultivated.

The relationship is interesting because it indicates that the validity of a person's testimony (or some other assertion) could be gauged with the examination of the prefrontal cortex. Generally, we tend to believe confident statements; however, a person with poor metacognition may be confident in their answers without intuitively knowing that they are incorrect.

I decided to blog on this article because of our recent discussion of teenagers and the development of the prefrontal cortex as the "decision-making center". I am particularly curious about the contrast or lack thereof between teenagers with exceptional metacognition and adults with poor metacognition. What would a comparision of their prefrontal cortices show?

Source: Scientific American online, accessed 14 Oct. 2010. http://www.scientificamerican.com/article.cfm?id=introspection-accuracy