Derek Denny-Brown (1901–1981)

Although it had been known since Charcot made his landmark discoveries that demyelination occurs within MS lesions, the effects of this loss were not established until 1944 (15).

Derek Denny-Brown, a professor of Neurology working at Harvard, USA, provided the key to this uncertainty from experiments on damaged peripheral neurons.

The slide shows the neural tissue used in these studies. The arrow marks an area of demyelination.

Denny-Brown observed that when a damaged nerve was stimulated, it failed to pass the impulse to the connected muscle. He concluded that it was the demyelination associated with lesions on the nerve that was responsible for the block in conduction (15).

Demyclination was therefore shown to prevent or slow the conduction of impulses through a nerve (15).

Extrapolating from these observations made in peripheral nerves, it was recognised that the demyelination seen in MS lesions caused the impaired central nerve conduction within the brain and spinal cord, which in turn led to neurological symptoms.

Reproduced with permission from Arch Neurol Psych, July 1944, v. 52, p 1-19.  Copyright American Medical Association

==> John W Prineas (1937-present)

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