. Design for a brain. Brain -- Physiology; Central nervous system -- Mathematical models; Neurophysiology. 5/14 DESIGN FOR A BRAIN Any inco-ordination would be shown by a divergence from the intended line. A second example is given by the record of Figure 5/13/2. The subject, a patient with a tumour in the left cerebellum, was asked to follow the dotted lines with a pen. The left- and right-hand curves were drawn with the respective hands. The tracing shows clearly that the co-ordination is poorer in the left hand. What criterion reveals the fact? The essential distinction is that the deviatio
. Design for a brain. Brain -- Physiology; Central nervous system -- Mathematical models; Neurophysiology. 5/14 DESIGN FOR A BRAIN Any inco-ordination would be shown by a divergence from the intended line. A second example is given by the record of Figure 5/13/2. The subject, a patient with a tumour in the left cerebellum, was asked to follow the dotted lines with a pen. The left- and right-hand curves were drawn with the respective hands. The tracing shows clearly that the co-ordination is poorer in the left hand. What criterion reveals the fact? The essential distinction is that the deviations of the lines from the dots are larger on the left than on the right. The degree of motor co-ordination achieved may therefore be measured by the smallness of the deviations from some standard line. Later it will be sug- gested that there are mechanisms which act to maintain variables within narrow limits. If the identification of this section is accepted, such mechanisms could be regarded as appropriate for the co-ordination of motor Figure 5/13/2 : Record of the attempts of a patient to follow the dotted lines with the left and right hands. (By the courtesy of Dr. W. T. Grant of Los Angeles.) 5/14. So far we have noticed in stable systems only their pro- perty of keeping variables within limits. But such systems have other properties of which we shall notice two. They are also shown by animals, and are then sometimes considered to provide evidence that the organism has some power of ' intelligence' not shared by non-living systems. In these two instances the assump- tion is unnecessary. The first property is shown by a stable system when the lines of behaviour do not return directly, by a straight line, to the resting state ( Figure 4/5/3). When this occurs, variables may be observed to move away from their values in the resting state, only to return to them later. Thus, suppose in Figure 5/14/1 that the field is stable and that at the resting state R x and y
Size: 1346px × 1857px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookpublishernewyorkwiley, booksubjectneurophys
