Tuesday, 13 October 2009

Start of week 2.

Week two began once again with Structure and Measurement of the Brain, delivered by Marty Sereno, who I hadn’t quite appreciated until now is one of the world leading researchers in his field. Anyone interested can see him at work below.

The topic this week focused on the development of the brain in the womb, with a detailed explanation of how a small cluster of cells begin to slowly divide and form the beginnings of the spine, the eyes and gradually folds over on itself to take shape as the infant brain. This was fascinating, and I was really impressed by Marty’s knowledge, with frequent deviations to discuss the brains of other mammals and assorted creatures of all different sizes.

He then went on to discuss the visual system, and how surprisingly complex it is. We have no idea quite how much our brain needs to do in order to make sense of the world around us. For example, what we perceive as a single field of vision is actually processed in several different parts of the brain, such as an area for the periphery, an area for our immediate focus etc. These different maps are then seamlessly patched together in order that they be perceived as one single image. This on top of flipping the image (due to the convex shape of the retina), and creating a 3D image of the world via depth perception, all happening simultaneously without us knowing it. He also discussed the limitations of our knowledge of just how this is done, with particular reference to objects moving across our field of vision.

We had an extended lecture with Marty, 3 hours rather than the usual 2. He actually managed to maintain my full and undivided attention for almost the full 3 hours, until that is he started talking about areas of the visual cortex known as (I kid you not) ‘blobs’. This was about the point when both my interest and understanding trailed off, the final straw being the point that the areas between the ‘blobs’ are known as ‘interblobs’. Frankly if scientists can’t be bothered to name these things properly, I can’t be bothered to understand.

The reading Marty set us this week is much more accessible too. One bit I found particularly interesting is how the brain of a tennis player will come to perceive his or her racquet as an extension of their arm, increasing it’s mental map of their immediate surroundings to compensate for this increased ‘body shape’.

This follows research by Iriki et al (1996) on monkey using sticks as primitive tools, and the science is explained thusly:

“The visual receptive fields expand when the monkey uses the rake as an extension of its hand, while the somatosensory receptive fields are unchanged. This is interpreted as a change in the body image: The enlargement of the visual receptive field reflects the neural correlate of a hand representation that now incorporates the tool. The visual receptive fields return to their original size within a few minutes after tool use is discontinued. They do not expand at all if the monkey simply holds the rake without intending to use it. These rapid changes in visual receptive field size indicate that the neural connections that allow for the expansion must be in place all along.”

(Colby, C.L. and M.E. Goldberg (1999) Space and attention in parietal cortex. Annual Review of Neurosciences 22:319-349).

Anyway, as challenging as this module is I feel it may end up being a very rewarding one, and perhaps even a personal favourite, as long as I can keep up with the reading material, and maintain the pretence of understanding it.

The afternoon talk was delivered by a guest lecturer who gave a talk on Autism and Williams syndrome, both examples of what can happen when certain parts of the brain don’t function as they should. Frustratingly, all she did was read out her lecture slides without any elaboration, meaning she may as well have just emailed us all and we could have read the bloody things in 20 minutes. It didn’t help that she pitched the thing at GCSE to A-level standard, not far above the quality of science you would expect on ‘loose women’. And yes, I am fully aware that last week I was complaining about things being too hard, only to complain this week that it is too easy.

But then I’m a fussy little so-and-so.

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