Conditioned Reflexes

I. P. Pavlov, G. V. Anrep

• Publisher: Dover Publications
• Year: 2012
• Print ISBN: 9780486430935
• eBook ISBN: 9780486161211
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

The Nobel Prize-winning scientist offers a precise, full, and accessible exposition of his landmark work in experimental psychology. Pavlov details the technical means by which he established experiments and controls, the experiments, observations on formation of conditioned reflexes, external and internal reflex inhibitions, the function of cerebral hemispheres and cortex, and more. 18 figures.

LECTURE XXI

Pathological disturbances of the cortex, resutt of surgical interference (continued): attempt to correlate the general post-operative behaviour of the animals with the disturbances in the activity of individual analysers.

IT may be considered as firmly established that removal of the entire cerebral cortex converts the dog into a comparatively simple reflex machine. The animal retains the relatively limited number of unconditioned reflexes, but is completely deprived of the more complex and delicate co-ordination of its activities with the external world, since these adjustments are solely based upon innumerable conditioned reflexes established through the intermediation of the cerebral cortex. We possess also some knowledge as to the significance of different areas of the cortex—the cortical analysers, the united function of which determines the complete adjustment of the organism with its surroundings, or, in other words, determines the behaviour of the animal. A great deal can be learned of the physiological activity of the cortex as a whole by careful observation of the general state of the animal after extirpation of definite cortical areas, whether such extirpations are free from post-operative complications or are complicated by a further disintegration of the cortex through the growth of scar tissue or by other secondary effects of the operation. The present lecture will be devoted to the description of changes in the general behaviour of the animal, and an attempt will be made to correlate these changes with the different structural lesions of the cortex. We shall start our description with simpler, going on to more complicated, cases.

In one dog the upper part of the hemispheres was extirpated above the level of the gyrus sylviaticus [experiments by Dr. Orbeli]. The extirpation was made by means of a single incision on each side, the operation being performed in two stages with a long interval of time between. A fortnight after the operation upon the second hemisphere the general state of the animal became definitely constant, remaining unchanged to the end of the experiments (4 months). As before, the animal was extremely lively, and when called reacted quickly, whipping round in the direction of the call. At a first glance its condition could not be distinguished from that of a normal dog. On closer observation, however, it was possible to observe a certain ataxy of the extremities, which on running were thrown up higher and brought down more vigorously than usual. Walking upon a smooth or wet floor the animal would very often slip; moreover, on starting off it always performed some peculiar movements with its head. When walking in a definite direction the animal seldom ran into any obstacle, but as soon as it did encounter an obstacle a surprising abnormality in its behaviour appeared. It became entirely helpless if it ran even against the narrow leg of a table; for a long time it would go on pressing forward, until slipping accidentally it would get by; and this was the only way in which the animal could continue its progression. When placed with the front part of its body on a chair and then called, the dog started disorderly scrambling movements and fell off the chair sideways, or sometimes, moving forwards, it contrived to get its whole body on to the chair, where it remained, helplessly kicking its hind legs in the air. The foregoing is a brief sketch of the general abnormality of the dog.

Coming now to the study of its conditioned reflexes, it was found that all those which were present before the second operation became, with the exception of tactile and thermal reflexes, quickly restored, while new conditioned reflexes to olfactory and visual stimuli were easily established. Unconditioned reflexes to various tactile and thermal cutaneous stimuli were present—various “shaking,” flexion and extension reflexes, responses by whining, howling and turning the head towards the point of application of the stimulus. I shall endeavour to correlate these deviations of the animal from normal with the disturbances of the functions of the different analysers. The activity of the olfactory and acoustic analysers was entirely unimpaired, and the activity of the visual analyser was only slightly disturbed. Remembering the peculiar movements of the head in locomotion, and taking into account that the a...

Table of contents

• Title Page
• Copyright Page
• Dedication
• EDITOR’S PREFACE
• AUTHOR’S PREFACE
• PREFACE TO - THE RUSSIAN EDITION
• Table of Contents
• LECTURE I
• LECTURE II
• LECTURE III
• LECTURE IV
• LECTURE V
• LECTURE VI
• LECTURE VII
• LECTURE VIII
• LECTURE IX
• LECTURE X
• LECTURE XI
• LECTURE XII
• LECTURE XIII
• LECTURE XIV
• LECTURE XV
• LECTURE XVI
• LECTURE XVII
• LECTURE XVIII
• LECTURE XIX
• LECTURE XX
• LECTURE XXI
• LECTURE XXII
• LECTURE XXIII
• BIBLIOGRAPHY
• INDEX