Neurophysiological Aspects Of Manned Extraterrestrial Space Flight

Abstract

It may well be asked what is the value of studying neuro-physiology in relation to manned space flight, since it has now been amply demonstrated that man is capable of withstanding the environmental stresses of orbital flight and has continued to work and make full use of his mental faculties, whilst in orbit.

Neuro-physiology, however, is one of the disciplines which it has been found necessary to practise, of late, in the solution of some of the problems of flight in the atmosphere and the contributions made in this field by interdisciplinary research, including the study of behaviour by psychophysiological methods, neuro- or biochemistry, as well as neurophysiology, have been marked.

A training in neuro-physiological and behavioural techniques may, in certain instances, be the basic factor in investigations of bizarre reactions in normal man, even though the methodology of research, as compared to work on animals, may be limited to some degree in that it is dependent upon advances in electronics and computational analysis.

The scope of the subject cannot, therefore, deal with neuro-physiology as a whole; inter-and intra-neuronal transmission in relation to electrical sources and links, polarisation and ionic fluxes may give background knowledge, but play little part in the technology, as used, except when, for example, artefacts are being evaluated in any particular experiment.

On the other hand, when dealing with complex control systems it is the acknowledged capabilities and limitations of the human which most directly influence, not only their design but their overall reliability, and hence it is worthwhile examining the characteristics of the human operator in the realm of psychological constructs, such as attention and perception.

Where failures of the human controller occur, as in the onset of unawareness, it is now acknowledged that a full understanding cannot be achieved without fundamental work on the neural correlates, such as the coding of sensory impulses, or the control of transmission in relation to motor responses.

An understanding of illusions may not be possible without consideration of the organised relationship of brain stem and cortical activity. Similarly, it is of importance to have understanding of conditioning processes in order to differentiate between the trained and the untrained man in the stability of selected responses.

Whilst these are but a few of the problems of great magnitude, neurophysiology can make definite contributions in specific areas such as the modification of motor responses by sensory inputs from angular accelerations, the study of environmental variations which affect cortical responses such as accelerations, vibration, radiation.

It may then be considered that it is worthwhile formulating techniques for orbital laboratories in order to investigate further the abnormalities which man may evince in space flight over the next 10 to 20 years.