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Presidential Address. Proceedings of the Royal Society of Medicine, 1951, 44, 38–42.
The author attempts to define what is happening in the nervous system when a conscious state is experienced.
Discussing local sign in sensation he points out that one becomes conscious of the position of a point on the body which has been stimulated because the afferent impulses are perceived in relation to a representation of the body as a whole (unconscious schema or conscious body image), and not in isolation. So the 'big toe area' in the post-central convolution is simply a nodal point at which afferent impulses from that region are brought into relation with the body image as a whole by means of widely ramifying pathways through the posterior halves of both cerebral hemispheres and through the corpus callosum.
An example of disorder of the body image is a lesion in the right parieto-occipital region causing failure to attend to the limbs on the left side, and in extreme cases also failure even to recognize them as part of the body, showing that the same neurones are activated in remembering the body image as in current awareness of it. Again stimulation of various different parts of the cortex can produce visual pictures of remembered scenes, so that the anatomical basis of memory is now looked upon as a widespread neural network which can be set vibrating in an almost infinite variety of patterns in space and time.
The author traces evolution from the most primitive nervous systems which have mainly reflex actions to the higher types which have formed distance-receptors, for reacting to objects at a distance by means of a course of action which takes time. This is made possible by two new types of nervous function—feeling or motive power, and representation of the external world. The organism must possess an enduring representation of the object towards which feeling is being directed for an indefinite time.
Perceptions of objects at a distance occur when the nervous impulses