Demyelination and remyelination in the central nervous system.

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Demyelination and remyelination in the central nervous system. Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). Source: Wellcome Collection.

About this work


Dr W. Ian McDonald presents a fascinating and dramatic account of demyelination, a pathological process which can affect the central nervous system and which is frequently associated with diseases such as multiple sclerosis. Using large scale slide projections of nerve fibres, McDonald runs through the process of demyelination in great detail, explaining each aspect of his talk in clear, concise terms. 5 segments.


London : University of London Audio-Visual Centre, 1974.

Physical description

1 encoded moving image (25.29 min.) : sound, black and white.




Copyright note

University of London

Terms of use

Creative Commons Attribution-Non-Commercial 2.0 UK: England & Wales

Language note

In English

Creator/production credits

Presented by Dr W Ian MacDonald, Professor of Clinical Neurology, Institute of Neurology. Produced by David R Clarke. Made for British Postgraduate Medical Federation. Made by University of London Audio-Visual Centre.


This video is one of around 310 titles, originally broadcast on Channel 7 of the ILEA closed-circuit television network, given to Wellcome Trust from the University of London Audio-Visual Centre shortly after it closed in the late 1980s. Although some of these programmes might now seem rather out-dated, they probably represent the largest and most diversified body of medical video produced in any British university at this time, and give a comprehensive and fascinating view of the state of medical and surgical research and practice in the 1970s and 1980s, thus constituting a contemporary medical-historical archive of great interest. The lectures mostly take place in a small and intimate studio setting and are often face-to-face. The lecturers use a wide variety of resources to illustrate their points, including film clips, slides, graphs, animated diagrams, charts and tables as well as 3-dimensional models and display boards with movable pieces. Some of the lecturers are telegenic while some are clearly less comfortable about being recorded; all are experts in their field and show great enthusiasm to share both the latest research and the historical context of their specialist areas.


Segment 1 McDonald begins by defining how demyelinating processes tend to go through phases of recovery, as with multiple sclerosis; however, after each attack on the nerve fibres, recovery is never back to complete health. McDonald describes how he is going to discuss the damaging effects of demyelination on the nerves and whether or not remyelination plays a role in the recovery period. McDonald shows a large projection of nerve fibres and describes in detail their various parts. McDonald then looks at a further slide comparing demyelination with another nerve fibre abnormality, Wallerian degeneration. He explains the difference between the two processes. A further slide shows demyelination in the fibres of the optic nerve and McDonald describes how this has occurred due to optic neuritis. Time start: 00:00:00:00 Time end: 00:06:25:00 Length: 00:06:25:00
Segment 2 McDonald focuses on a series of animated diagrams detailing changes in electrical conduction due to demyelination. He describes these in detail, outlining how the changes occur. Time start: 00:06:25:00 Time end: 00:09:46:00 Length: 00:03:21:00
Segment 3 McDonald shows an animated diagram which details how nerve fibres transmit long trains of impulses through the nervous system. A further animated diagram is used to highlight how conduction velocity changes in demyelinated parts of single nerve fibres. This shows how demyelinating lesions give rise to nerve conduction block, thus problems of the central nervous system. McDonald then shows an illustration of the optic system, followed by a man having his optic nerve patterns recorded onto an averaging computer which measures them. McDonald describes the process. Time start: 00:09:46:00 Time end: 00:15:08:00 Length: 00:05:22:00
Segment 4 McDonald continues to focus on the optic nerve. He shows diagrams of optic nerve conduction in patients with optic nerve defects; explaining what can be seen in each case. McDonald then moves on to discuss recovery or remyelination, in which patients suffering from diseases such as multiple sclerosis experience periods of remission. he shows a large slide projection which details the remyelination of nerve fibres. Time start: 00:15:08:00 Time end: 00:20:24:00 Length: 00:05:16:00
Segment 5 McDonald queries whether or not restored conduction in periods of remission from central nervous system disease, is due to remyelinated fibres. He admits that, so far, there is no absolute evidence either way. In conclusion to the lecture, he outlines the arguments both for and against considering remyelination as a 'repair' process and feels confident that future research into the central nervous system will solve this problem. Time start: 00:20:24:00 Time end: 00:25:25:02 Length: 00:05:01:02


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