Remembering the rings of Saturn


Friday night and my next World Science Festival was a discussion on memory.

As the lights went down, the screen flickered into life with an old clip from the film Gigi (1958). As Maurice Chevalier tries to impress his love with memories of their affair, we see how recollections fade and skew as we get older. He is corrected on nearly every account and the audience can only laughsas they seem to relate all to well.

Presented by ABC co-anchor Dan Harris (The Anchorman! hehe), 4 neurologists, psychologists and memory heavyweights have been rounded up from the various and numerous East Coast scientific institutions to teach us laypeople about the complexities of memory acquisition and storage. Daniel L. Schacter from Harvard University explained how memory is not simply storing an event or detail in neurons and synapses. So far it is understood that there are 4 distinct types of memory: Episodic- referring to the personal events and details we experience, Priming- a method of recalling specific numbers or images that we have seen previously in some other setting, Semantic- our ability to store and recollect general knowledge-type intelligence like dates and figures and finally Conditioning memory- a necessary process of storing emotional experiences for our survival instincts and to prepare us perhaps for traumatic events we may yet encounter.

Professor Schacter has written a book on the “sins” of memory and described to us one example of how a colleague in the field was one day arrested when policemen arrived at his door with a woman who claimed he had brutally raped her. She was certain beyond a shadow of a doubt that he was the perpetrator and it was only after his airtight alibi proved her wrong that the truth came out. He had in fact been giving a live talk on Australian TV about his research on memory (ironically) and the victim had been watching it when she was attacked. Through her traumatic experience she had stored the vivid image of this man’s face and completely been misled by her own mind, dangerously mixing the facts of the event. Had the discussion been recorded this truth may have never come to light.

Professor Nadel then went on to teach us about the hippocampus and explained how sufferers of amnesia and other neurological diseases or defects had been instrumental in uncovering the important role this portion of the brain plays in storing memory alongside spacial information. One man, named HM in the literature, had been treated in the 1950s for his increasingly severe epilepsy. At the time little was known about the importance of the hippocampus  and so to prevent his dangerous seizures, nearly 2/3 of this area was removed as part of the surgical procedure. They found that HM now suffered acute memory loss for newly experienced events. Anything post-1953 now evaded him.

Next Professor Sacktor from Columbia University tells us about his cleverly designed experiments that have led to the better understanding of how memories are laid down in the brain. He was able to show that through inhibiting a particular enzyme known as protein kinase C (PKC), memories were no longer stored, demonstrating that this protein kinase is the chemical link necessary to actively catalyse the making of memories. Since adding enzyme inhibitors to the brains of humans would be unethical (for fear of innumerable side effects) this research is ongoing, but it was fascinating to watch how animal experiments can prove so ingenious in breaking down the fundamentals in this complicated organ we call the brain.

Which leads very nicely to our final expert. Dr Elizabeth Phelps is interested in the conditioning, and specifically the fear conditioning, aspect of memory acquisition. She described a wonderful experiment where rats were trained or conditioned to fear a beep accompanied by a small electrical shock. Having taught the rats to dislike this beep (that was always associated with a little unappreciated shock) Dr Phelps’ team was able to demonstrate that when a memory is made it takes time before effective storage is achieved. They have shown that each time a memory is reviewed this process of laying down and storing the memory must again be executed; a process known as reconsolidation. During this review exercise, the memory can be modified or strengthened depending on whether or not the memory storage is disrupted. In the experiment, the rat in question is injected with a chemical into it’s hippocampus just after the new or previous memory had been initiated. She was able to show us definitively that immediately after a beep sounded the rat would store the memory or, if disrupted by chemical means, would be unable to store the memory effectively and subsequently any further recollection of this memory could be controllably updated by the experimenter. So that if the memory making process is disrupted in any way, a specific memory cannot be effectively stored.

So one and a half hours later and the crowd seemed highly satisfied with the brimming knowledge they had just obtained. There was so much more but I was only able to remember what I described above. Pardon the humour. World Science Festival. Bravo. A well scripted and informative event.

Next up, my partner in crime and I jumped on the subway and journeyed down to Brooklyn Bridge for a final dose of what was had been a science-filled treat. For under the Brooklyn Bridge, on the Brooklyn side, we were afforded both wonderful views of an illuminated Lower Manhattan and the stargazing event of the Festival. People wielding telescopes of all sizes and powers had gathered to point their instruments at the visible Saturn, complete with rings, so that we the public could marvel at the enormity of the universe and the seemingly false clarity of the bands of this distant planet. We were thoroughly impressed by that and then clambered willingly into a NASA borrowed mini inflatable planetarium. We viewed the Northern Hemisphere as it was last night and watched how NASA had landed on Saturn’s largest moon, Titan. We observed the pictures they took as the probe hurtled through Titan’s vicious atmosphere. Squeezing safely out we were delighted by our evening of popular science and again felt tremendously encouraged by our chosen career paths. Roll on Monday morning and another week in the lab!

Saturn and her rings


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