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Seeing What You See

[ 5 ] November 20, 2010

In a study by Tootell et al. (1982), researchers were able to inject metabolic radio-isotope markers into visual cortex area 1 of monkeys when the monkeys saw this pattern:

The marker stains brain cells that are active. When the monkeys were sacrificed and the brain dissected, the researchers saw this, almost haunting, image:

This is a remarkable, beautiful demonstration of how the V1 area of the brain is retinotopically organized. That is, this part of the brain is organized similarly to how the light hits our retinas. Unfortunately, after V1, this information is scrambled and sent to various other parts of the brain for different levels of processing.

Cranially Conjoined Twins May Share Thoughts

[ 4 ] November 8, 2010

Sometimes the truth is stranger than fiction. This incredible story of two young girls conjoined at the head is inspiring, bizarre, and potentially a first in human history: Tatiana and Krista recently turned four, an event that was not expected by a team of doctors in Vancouver who predicted a myriad of fatal health complications that have yet to be realized. T and K are joined at the head and actually share regions of their thalamus.

Because the thalamus plays a vital role in sensory processing and integration – in essence, it is the “gatekeeper” of higher cognitive functioning – some scientists and doctors believe the girls may share sensory experiences and perhaps even thoughts.  If the girls do indeed see what each other sees, this would be a first set of conjoined twins to do so.  Researchers eagerly await the day the girls can report any possible “mind-sharing” experiences.

Read more on this incredible story here

image/http://www2.macleans.ca

Remembering Before We Can Remember

[ 1 ] November 2, 2010

It has long been expected that what a mother eats during pregnancy is directly related to the type of food her child will be attracted to. In a recent study, newborn babies were subjected to two swabs of amniotic fluid (the fluid that protects and provides nutrients for a baby). You can see in the video below, babies actually “inhale” and “exhale” this fluid.

The researchers found that the babies are consistently positively biased towards the amniotic fluid it developed in. It shows that the human fetus is capable of detecting and storing olfactory stimuli, even before their brains are fully developed. This could be because olfaction is an evolutionarily old sense, developing sooner in fetuses than senses that rely heavily on the neocortex.

A side note, during this experiment, the researchers noted that the amniotic fluid of smoking mothers actually smelled like smoke. Rather disturbing, and the idea of fetal olfactory detection and storage could have implications in the study of high levels of nicotine dependance.

More Uses Than You Think

[ 0 ] November 2, 2010

The fusiform gyrus is known to be important in facial recognition. This area of the brain is most associated with prosopagnosia (“face blindness”) in which the ability to recognize faces is damaged. Oliver Sacks and Chuck Close both have this disorder, and apparently there is a large portion of the population that has this disorder but goes undiagnosed.

In a study by Gauthier, Skudlarski, Gor, and Anderson, the fusiform gyrus was found to have larger implications than facial recongition. When car experts and bird experts were shown pictures of cars and birds, respectively, the fusiform gyrus lit up as if seeing pictures of faces.

This indicates that with enough training and experience, this specialized area of the brain can be recruited to recognize and categorize certain objects. Looking at the larger picture, this is more evidence of plasticity and the brain’s ability to adapt “specialized” functions of various cortical areas.

The Brain in Three Dimensions

[ 1 ] October 28, 2010

MRI scans of the brain display colorful splotches in areas where there is a higher-than-usual level of activity, which calls for increases in bloodflow to that region (MRI machines tracks the magnetism of iron in our blood as it moves through the brain). These images are classically two-dimensional. As valuable as MRI imaging has been, showing a flat perspective of a structure than can only be understood in three dimensions is eventually quite limited in its medical applications.

Now, researchers at Eindhoven University of Technology have developed a software tool that doctors can use to convert MRI scans into three-dimensional images, such as the image seen below.

Imaging tools like this one should increase the accuracy of diagnosing brain disfunction and allow doctors to pinpoint regions for surgery with greater precision. Read more in the official press release here. (Special thanks to TBB reader Maarten Boos for the tip).

Losing an Overlooked Gift

[ 9 ] October 24, 2010

A virus destroyed Ian Waterman’s kinesthetic and other mechano-cutaneous nerves when he was 19 years old. Lacking proprioception, the sense of knowing the relative position of various part of the body, Ian was bound to a wheelchair for a long time. Now, he relies on vision to know where his limbs are. If there is no light, he cannot tie his shoes, walk up or down stairs, or clap his hands. At one point in his life, he was stuck in an elevator, with the lights off. He was unable to remain standing and could only stand when the lights turned back on. Proprioception is one of many senses we take for granted, being able to know where your limbs are, even while closing your eyes. Here’s a less than scientific, but informative, video about Ian Waterman.

You can read more in Jonathon Cole’s book, Pride and a Daily Marathon.