LINK BETWEEN EYE AND BRAIN

Press, Volume XCIX, Issue 29336, 15 October 1960, Page 10

LINK BETWEEN EYE AND BRAIN

Sydney Scientists Probe Secret Australia News and Information Service] SYDNEY, October 9. J?OR 13 years Australian scientists at Sydney University have been endeavouring to break the code system which holds the secrets to some of the human mind’s innermost workings. Led by Professor P. O. Bishop, head of the Physiology Department of the University, the scientists are probipg the coding and transfer systems of the human eye. Key to the research is a machine known as a multi-beam ophthalmoscope which a team of technicians in the Physiology Department took six years to develop.

The experiments are attracting world-wide scientific interest because they may eventually make possible the collation of new infornfation , on how the human nervous system works. Doctors, for example, will probably learn much more intimately the reactions of certain drugs on the human body. Although much is known about them, the inner workings of the eye still remain one of the big mysteries of the human body. Scientists have always been intrigued by the ability of the eye to transmit within a fraction of a second an image it sees to the brain and for the brain to register instantly the exact nature of the object

All this information—the size of the object, its colour, shape, contours and movement—the eye sends to the brain by way of certain nerve centres and in code signals not unlike Morse. When an eye looks at an object the retina records an image of it upside down and back to front similar to the impression on an exposed film in a camera.

The Optic Nerve The light that enters the eye and outlines the features and nature of the object looked at is transformed by the retina into electrical impulses which travel toward the brain through the optic nerve. Scientists estimate the human optic nerve to be made up of at least a million fibres of differing sizes, but so minute are these fibres that even the closest mircroscopic examination of them has so far not revealed their exact number.

The retina partly processes these impulses into a code and the impulses pass along the optic nerve th a collection of nerve cells called lateral geniculate—a processing station, as it were, which does the final and complete job of converting the impulses into an intricate code suitable for transmission to the brain’s visual centres. In this way one of the marvels of the human body lets the brain know in ' perfect detail what the eye sees. For many years scientists have been aware that this processing of information—the actual coding —occurs, but exactly how it is

done is what has had them baffled.

The multi-beam ophthalmoscope with which Professor Bishop and his team hope to discover the answers is an advanced version of a machine built some time ago ago by scientists engaged on similar research at Johns Hopkins University, 1 Baltimore, U.S.A. Neuro-Physiology Australian-born and' educated, 43-year-old - Professor Bishop is widely recognised for his work in the field of neurophysiology. Associated with him in his current work are Professor D. G. Lampard, formerly of the Commonwealth Scientific and Industrial Research Organisation, who was recently appointed to the University of New South Wales as Professor of Electrical Engineering, and Dr. W. R. Levick. With tiie multi-bean ophthalmoscope physiologists are able to stimulate the eye with light beams, which make the eye work naturally, and because the light input is known they are able to analyse the reactions of the eye. Tests have been made on human beings, but the more, detailed research is carried out with cats. In this research Professor Bishop is assisted by his staff and students who include some Asians studying at the University under the Colombo Plan. Tests With Cats’ Eyes The researchers play three beams of light into the cat’s eye. As the- beams strike the retina and then go through the whole process of becoming coded signals to the brain, electrodes pick up the complex messages, of electrical impluses and transmit them into amplifiers. These recorded sounds are fed into an electronic computer which records the code signals in digits printed op sheets of paper, and also attempts to analyse the code. Professor Bishop plans to extend his experiment soon to rabbits and monkeys which also have eye and nerve structures similar to those in humans. In human experiments a student stands in front of the ophthalmoscope and as the light beams are played into his eyes he reports verbally what the

lights are doing.' By comparing these verbal reports . with the machine computations ’ from the workings of the . cats’ eyes, scientists will add to their knowledge. When completed ProfesSor Bishop’s research will be of world value. For example? it will probably shed more information on why the human eye is able to see as a continuous and steadily 'flowing picture of cinema film thrown on to a screen although the film itself is projected in a series of fast-moving but separate frames. As Professor Bishop< says with the traditional caution of a man of science: “We’ve been at work on this project for a long time now, and I’ll probably be an old man before -we’ve satisfactorily sorted out the bewildering variety of code signals our eyes send to our brains.”