Published online by Cambridge University Press: 13 August 2009
The ancient view that the spinal cord is a nerve-like prolongation of the brain received experimental support from Galen, who showed that by cutting the cord transversely, sensation from the body below the level of the cut was lost, as was motor power – effects mimicking those seen when cutting a peripheral nerve (Chapter 2). Even as late as the seventeenth century, Descartes looked on the cord as only a conduit for nerve tubules passing sensation to the brain, where reflexes are controlled (Figure 5.5). But, study of the decapitated animal indicated that reflexes remained present in the spinalized animal, with its purposive-like behavior leading to the hypothesis that some mind-like principle was present in the cord. As the anatomy and physiology of the nervous system became better understood, aided in large part by the discovery of the Bell-Magendie law in the early part of the nineteenth century, the question was then asked whether mind-like behavior could be accounted for by the complex interconnectivity of neurons in the spinal cord. This question was also raised with respect to the instinctive behavior seen in lower forms and the emergence of higher functions in the course of evolution. The development of the brain with centers for higher functions of learning and memory; in man ideation; caused the lower centers of the spinal cord to become more machine-like in its reflex behavior.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.