Nervous systems and the study of behaviour

People in antiquity seem to have had no idea that the brain was in any way connected with behaviour. Even that great practical biologist Aristotle was mistaken in his ideas. He observed the rich vascular supply of the brain and concluded that it was an organ for cooling the blood. The ancient Egyptians were positively cavalier in their attitude: when the body of a monarch was being prepared for mummification, the brain was extracted with a spoon and thrown away. The brain was considered unnecessary for the future life, but the entrails were carefully preserved in a jar and kept beside the mummified body.

Modern opinion emphasises the paramount importance of the brain as the source of an individual's behaviour and personality. This trend has gone so far that many a successful work of science fiction has been based on the idea that the brain might be kept alive or transplanted, and that by this means the essential personality of the original individual might be preserved after the rest of the body has been disposed of. This vast change in prevailing opinion about the brain is, of course, due to the anatomical and physiological research of the last 200 years, which has revealed the nature and importance of the central nervous system.

Our present understanding of the way in which nervous systems control animal behaviour owes much to a group of biologists working in the middle of the twentieth century, who pioneered an experimental approach to analysing behaviour. The approach they adopted came to be known as ethology, and one of early ethology's most thoughtful exponents was Niko Tinbergen. In an important paper, 'On aims and methods of ethology' (Tinbergen, 1963), he defined ethology simply as 'the biological study of behaviour'.

Tinbergen himself made an impact on ethology by concentrating on field observations or on elegantly simple experiments carried out on intact animals. But he expected that the results of this work would be integrated with a neural analysis as this became available. This is seen clearly in his book synthesising ethology, entitled The Study of Instinct (1951), in which he referred to contemporary research in neurophysiology and formulated his concepts in terms of the nervous system as far as possible. He expected that the biological methods of ethology would yield 'concrete problems that can be tackled both by the ethologist and the physiologist', and he wrote of 'the fundamental identity of the neurophysiological and the ethological approach'.

The long-term goal of such an approach is to analyse patterns of behaviour in terms of the activity of the underlying neural components. Hence, this field of research is sometimes given the title of neuroethology, a term that first came into use in the 1960s. Neuroethology tries to combine the approaches of both ethology and neurobiology so as to understand the neural basis of behaviour. Often, this involves examining groups of receptors or networks of nerve cells in order to elucidate the interactions relevant to behaviour. In some cases it is possible to bring both neurobiological and ethological analysis to bear on a single phenomenon, as Tinbergen expected.

In the chapters that follow, selected examples are considered in which neural analysis has been carried out in a way that is helpful to an understanding of animals' natural behaviour. As far as possible, attention is concentrated on specific case histories in which a connection has been established between a particular group of nerve cells (also termed neurons) and a particular pattern of behaviour. This field of study is developing rapidly and enough has been accomplished to enable initial conclusions to be drawn about the operation of many basic areas. These studies and conclusions form an essential and fascinating part of ethology, the biological study of behaviour.

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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