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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.

Smelling Attraction

[ 5 ] October 10, 2010

Pheromones have almost gained a mythological status in popular culture, thanks to the goat extract at the gas station or perfumes that supposedly uses pheromones to make you irresistible. (Side note: perfumes often use glandular excretions from other animals as one of their main ingredients.) But there is some credence to the layers of fantasy. Several tests have been conducted that provide good evidence that humans can indeed sense pheromones from other humans. But there is still the mystery of what the sensory organ is for pheromones. One theory is that cranial nerve zero is at least in part responsible for our responses to pheromones. This nerve is barely noticeable and often destroyed during dissection, which is why it is not included in many textbooks yet.
Scientists have even found this nerve in whales, an animal that, through evolution, has long lost its olfactory cranial nerves. This supports the idea that cranial nerve zero is separate from the olfactory system. But more importantly, it underlines an evolutionary importance of cranial nerve zero, withstanding millennia of evolution.

Scientists’ Double Lives

[ 0 ] October 4, 2010

NOVA has a great new online series called “The Secret Life of Scientists.” The videos take a look at some leading scientists’ alternative, non-science lives – much like neuroscientist and Beautiful Brain contributor Joe Ledoux’s musical project, the Amygdaloids.

Here’s one of my favorite videos, featuring Joe DeGeorge, who is a physics student and lead singer/songwriter of the great Harry-Potter themed indie rock band Harry and The Potters.

Can We Measure Consciousness?

[ 4 ] October 1, 2010

Carl Zimmer has a nice piece in the New York Times on Neuroscientist Giulio Tononi’s quest to “quantify” consciousness. Zimmer writes,

Consciousness, Dr. Tononi says, is nothing more than integrated information. Information theorists measure the amount of information in a computer file or a cellphone call in bits, and Dr. Tononi argues that we could, in theory, measure consciousness in bits as well. When we are wide awake, our consciousness contains more bits than when we are asleep.

Interesting.

[I look forward to buying a “Consciometer” in 2050 – Imagine…when you’re sharp you measure 9.5 consciousness-units. When you space out and grab a hot pan on the stove you’re floating around 4.8 units.  Sleep is zero, and daydreaming is 3].

image/wired.com

The Mystery of Qualia

[ 0 ] September 30, 2010

One of the largest philosophical mystery of the science of sensation and perception begins with the idea of “qualia.” Qualia is defined as the qualities of a conscious experience. When you see a striking painting, you may notice its vibrant colors, its beautiful brush strokes, or even the smell of aging canvas. These are all qualia. In the following video, Dr. V.S. Ramachandra delves into the idea of qualia and how it relates to consciousness.

The mystery arises when you consider the mechanism of sensation and perception. Do we need an ineffable, subjective experience to sense and to perceive a film, a song, or a painting? If not, why do we have qualia? And even more puzzling, where does it come from? As your grade school teacher might have once said, “there are no right answers.” But as is the nature of science, perhaps the proper adage is “there are no right answers yet.”