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RTD info logoMagazine on European Research Special Issue - April 2005   
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The limits of computing power
computer chip © CERN
© CERN
We know the law formulated by Gordon Moore in 1964, namely that the number of transistors that can be placed on a silicon chip doubles every 18 months. Computational power, that is the number of operations a computer can perform per second, also doubles every 18 months. So much so, that we have reached the point where the capacity of a simple greetings card that plays ‘Happy Birthday’ when you open it up is more than the total computational power on Earth in the 1950s. But this progress only has significance, if microprocessors can access ever-larger volumes of data more rapidly. Hence, the importance of memory capacity. This, however, does not increase exponentially but rather experiences periods of linear growth punctuated by technological leaps, such as the switch from magnetic recording (on diskette) to optical recording (on CR-ROM). There is no theoretical limit to growth in memory capacity. By contrast, the increase in computational power is set to reach a threshold by around 2020, after which physically reducing transistor size will no longer be possible. But perhaps new revolutions, such as the quantum computer, will have appeared on the scene by then. 

Animal memories
In 1991, two Californian biologists (Colleen Kastak and Ronald Schusterman) taught Rio – a young (female!) sea lion – to recognise cards bearing certain symbols in the form of letters or numbers.
An elephant never forgets – not a female elephant, anyway. Karen McComb, a British researcher working in Kenya’s Ambesoli National Park, has tested the auditory memory of pachyderms. When the females who inhabit the reserve hear trumpeting (pre-recorded for the occasion) of familiar herds they do not react. But when they hear the trumpeting of unfamiliar herds they move closer to baby elephants to protect them. Many other species also have a memory capacity. In 1991, two Californian biologists (Colleen Kastak and Ronald Schusterman) taught Rio – a young (female!) sea lion – to recognise cards bearing certain symbols in the form of letters or numbers. They, then, moved onto something else. Ten years later, they tried the exercise again and found that Rio remembered. As to the drosophila, French researchers (Thomas Préat and Alberto Pascual) have identified the location of their memory as being in the peduncular lobes, the site of 5 000 of their 200 000 neurons. Drosophila do not store information for short-term retrieval in the same place in which they retain longer-term memories. 

The virtues of the ginko biloba
The virtues of the ginko biloba © MNHN
© MNHN
The ginko looks like a mythical tree. Its leaf fossils date back 270 million years and it has survived, in Asia, every imaginable ecological disaster, including the Hiroshima bomb. One of the surviving specimens can be seen today, incorporated into the temple built at the site to symbolise peace. Asians have used its seeds and fruits for thousands of years, and Western medicine has been studying it since the 1950s. In 1990, Elias J Corey was awarded the Nobel Prize for chemistry for his work that included the complete synthesising of Ginkgolide B. Although its effects are a subject of controversy among members of the medical profession, it seems to be a valuable ‘vitamin’ for memory, one tested and used in Alzheimer-type diseases.

Mozart and the musical ear
Mozart and the musical ear
At the age of 14, Mozart, accompanied by his father, attended a performance of Allegri’s Miserere  a work which, by order of Pope Urban VIII, could not be performed outside the walls of the Vatican. That evening the young Mozart recalled from memory the complete 15-minute-long score that consists of nine voices for two choirs and is particularly complex. The next morning he reread it and made a few changes. In his Le cerveau de Mozart (Mozart’s brain), published by Odile Jacob, the neurologist and neuropsychologist Bernard Lechevalier studies the specific nature of musical genius in the organisation of the brain. He believes there is a very particular musical memory. Functional magnetic resonance imagery has made it possible to detect the brain structures involved in perceiving tonality. These structures were found to be different in people who possess a perfect ear – the ability to identify a musical note without any further reference. Those who possess this ability do not use the same neuronal circuits as other musicians. Melody, timbre and rhythm are processed separately in distinct areas located in the two hemispheres.

Gamm and integrated arithmetic
Who is Rüdiger Gamm, you may ask? At the age of 28, this genius of mental arithmetic knows by heart all the squares of double-digit numbers, reeling them off as easily as we can say 3x2 = 6. He can divide two prime numbers by each other, multiply two- or three-digit numbers, raise two-digit numbers to the 15th power, repeat a sequence of 11 numbers (in reverse order if you like!), and give the day of the week for any date in the past or the future. A number of researchers, most notably Mauro Pesenti of the University of Louvain (BE), have examined the functioning of his brain at work. Yet Rüdiger claims he was never particularly brilliant at school and only became interested in maths at the age of 20 when he wanted to be a contestant in a TV quiz show. It is then that he started the intensive memorising of numbers and calculating processes. 

Positron Emission Tomography (PET) studies that compared his mathematical activity with that of ‘normal’ volunteers showed both similarities between their brain activities (involvement of the short-term visuo-spatial memory) as well as differences (use of cognitive strategies that enabled him to exceed the limits of his short-term memory). Brian Butterworth, a professor of cognitive neuropsychology at University College, London (UK), believes that the key to Rüdiger’s prowess lies in his ability to switch quickly from one memory to another, but “the reason he is so exceptional in what he does is that the rest of us do not make the effort to learn.” 

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