From conception to resurrection the science and art of the human body

Joint Meeting with British Assn., Western Branch

Colin Blakemore, FRS, Professor of Physiology & Director of the Centre for Cognitive Neuroscience, University of Oxford & Joint Editor: `Oxford Companion to the Body' (OUP 2001), on 28 November 2001.

Professor Blakemore commenced his fascinating talk by dipping at random into the newly published Oxford Companion to the Body and commenting on the immense variety of topics covered, both scientific and non-scientific. The latter ranged from advertisements for Charles Atlas's body-building courses to pubic wigs, and from the foot of a giant statue of the Buddha to Picasso's treatment of the body.

Pictures are constructed by the brain from the sense data received. A photograph of neolithic footprints which was published upside down appeared to show a foot in relief, but when viewed the right way up was clearly of a footprint.

The direction of the light had been assumed by the brain, thus giving a different interpretation. The speaker went on to discuss other examples of the complex, indirect and subjective nature of human visual perception. What we see is a construct of the brain in the body. For example, a silhouette can look like either two faces or a vase (see picture). An MRI scan of two areas of the brain shows how it switches every few seconds between the two interpretations using different parts of the brain for each. This tells us where things happen in the brain but little about how the brain works.

Though the human genome had changed little in the past 100,000 years, the range and complexity of the environments in which humans could survive had greatly increased. Genetic evolution had virtually stopped, replaced by cultural evolution made possible by the genetically programmed flexibility and adaptability of the human brain.

This flexibility had enabled humans to create a huge variety of tools and technologies, and develop extensions to the body. These encompassed extensions to the senses, including microscopes and telescopes, extensions to the muscular system, such as power tools, and extensions to the locomotion system, such as boats, cars and aeroplanes. This flexibility had also enabled humans to survive in hostile environments, such as Antarctica, ocean and space, and to develop a variety of body part repairs, including spectacles, hearing aids, artificial limbs and bypass surgery. Contemporary scientists had invented a variety of types of brain scanners, which produce images in which different parts of the brain `light up' to reveal their involvement in specific functions like perceiving or remembering. But these scientists shared the same gene pool with the earliest Homo sapiens.

Communication and cooperation were fundamental to the development of these technologies, and were made possible by the creation of sophisticated languages, and the genetic anomalies could interfere with some of the underlying processes involved in writing and reading, literacy had resulted from cultural not genetic evolution.

Professor Blakemore emphasised that as the brain is part of the body, its processes have very much in common with it. `Use it or lose it', for example, applies to both, and this adaptability continues for much longer in the healthy elderly than had been previously recognised. He went on to discuss some of the research recently carried out by himself and his colleagues into how the brain adapts to the way it is used in particular environments. Some of this employed new technologies created to provide functional brain scans, including fMRI (functional Magnetic Resonance Imaging) and MEG (Magneto-encephalography). For example, scans were recorded before and after London taxi drivers spent up to 2 years learning the `knowledge' of the roads of London. Compared with the scans of controls, these scans had shown that part of the right posterior hippocampus, known to be involved in spatial memory, had grown larger with use. Each second of our lives the brain can make about a million new connections and this enables us to go on learning and adapting.

Such studies provided more direct evidence than had previously been available of the way human brains both create and physically adapt to culture. Genes in part provide the predisposition for the human brain to adapt to the environment, and for evolution to continue at a cultural level. The human genome is necessary but not sufficient.

John Barrett