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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.

Tooling Around

[ 0 ] October 21, 2010

Tool use is extremely important to humans.  Much research has suggested a complex neural underpinning of tool-using behavior: it involves real-time 3D mapping of objects, extreme tactile sensitivity, planning ahead, and, well, patience.

Like language, humans have a special knack for tool-making.  And, also like language, this knack is represented in specialized neural circuits.  “Tool circuits” would presumably be designed for manipulating objects in meaningful, complicated, and even artful ways.  Research published earlier this year in Psychological Science revealed that individuals who are born blind may have the neural architecture in place for tool manipulation, even though they have never seen a tool.  When a sighted individual thinks about a tool, say a hammer, circuits in the left parietal cortex light up, and these same circuits fail to light up when the imagined object is not tool-like (i.e. a bed, a dog, etc).  Interestingly, individuals who have never actually seen tools show this same pattern of activation.

This research suggests that our neural representations are not shaped only by experience.  Tools have been vital for our species for so long –  evolution has likely built into our brains the necessary architecture to treat tools with special attention, whether we can actually use them or not.

Now, Where Was I?

[ 0 ] October 17, 2010

In an experiment by Foster and Wilson (2006), researchers placed a rat into a long narrow corridor and taught it to walk down to each end, where it would find a treat. The rat repeated this, and it enjoyed the treat. It was being fed, after all. But researchers noticed something unusual. The rat would get to one end, eat its treat, then just stop and sit there for a moment. When the researchers plotted the activity of “place cells” (which, in theory fire according to where the rat is in a particular environment) in the rat’s hippocampus, they exhibited bursts of activity when the rat was stationary. The researches expanded a split second’s worth of this strange firing:

You can see that there is successive activation from place cell #19-#1. What they found was that the rat’s brain was actually firing the place cells in such a way that it was repeating the course it had just run, and repeating it backwards. It was as if the mouse was thinking “ok, I just got this treat by walking down this hallway…how did I get here? Where was I?” Perhaps even more interesting is that when the rat was asleep, it continued to do this, except much much faster, theoretically because it was redoing what it had learned but without physical limitations; it could walk down that corridor as fast as its neurons allowed it.