Sunday, June 17, 2012

It's all in your mind

Drinking wine with any level of seriousness raises fundamental issues of perception. Is taste objective or subjective? What's the relationship between the locus of sensation and the mind? And so on. Once the province of philosophy, such questions have over the last century become the object of scientific inquiry. Thanks largely to the insights of James Watson and Francis Crick, who discovered RNA and DNA, researchers have been able to study these questions at the molecular level for the last several decades.

Richard Axel of Columbia University won a Nobel Prize in 2004 for his work on the olfactory system and how the brain interprets smell, but he has not produced an explanation of his work for non-scientists. Eric Kandel, a colleague of Axel at Columbia and a Nobel laureate for his own work on the biology of memory, has. In Search of Memory is a surprisingly comprehensible history of scientific research into memory and the workings of the mind. Kandel makes his research on memory in Aplysia, a species of sea slug, intelligible and even engrossing. (He chose the species because its physiology - long, thick neurons, and relatively few of them - made the research into their workings easier.)

Modern neuroscience investigates how the brain's molecular physiology enables its plasticity, its ability to learn and change, to respond to experience. In the 1930s, the American scientist Wade Marshall showed that the cortex contains "precise maps of the body's sensory receptors," with the hands, the feet, and the face being larger on that figurative map than they are physically. Michael Merzenich of the University of California San Francisco significantly advanced that research in the 1970s and 1980s by showing that repeated use does increase the sensitivity of a given body part - in other words, increases the area of the cortex devoted to that body part.

That would seem to true for taste buds as well. The more wine you taste, the greater your ability to perceive changes in the wine and, perhaps, to describe them, a problem that Kandel would not have faced with sea slugs or Merzenich with monkeys. It's also true that the brain becomes less plastic as it ages. Does this mean that people "know" the smells they were familiar with growing up better than those they encounter as adults? It would seem so, analogizing to the violinists who began playing the instrument before age 13 and have larger images of their left hand in their cortexes than those who began playing the instrument after that age, but Kandel has other issues to explore.

In the process, he raised a number of fascinating issues in this drinker's mind. I often lament when I drink an unfamiliar wine - Austrian rieslings, for example - that I don't understand the smells the wine emits. In Adventures on the Wine Route, Kermit Lynch recommends that budding connoisseurs buy a case of a wine they like and study it as they drink through the twelve bottles. In doing so, the drinker is training his nose and therefore his brain to perceive certain smells and understand how the wine is constructed, just as children learn how narratives are constructed by hearing the same one over and over and over. But this in turn raises the question of how similar learning a language is neurologically to learning how to recognize a smell (quite similar on a molecular level, I think Kandel would say). The questions multiply quickly, even dizzyingly in reading Kandel's book.


No comments:

Post a Comment