This Anatomical Society symposium, held at University College,
Cork in September 1995 was the first of its kind. The objective was to
stimulate and facilitate constructive interaction between experts on
topics relating to the various types of glial barrier which form
partitions within the nervous system. Some of these barriers are
transient and are found only during development, for example, those
which define the limits of developing nuclei or fibre bundles. Others
are permanent, such as those at the transitional zones which separate
the CNS and PNS milieux at nerve root attachments to the neuraxis.
Still others, such as glial scars, are seen only following injury when
they tend to inhibit neurite regeneration. In experimental
circumstances, for example following irradiation or chemical damage,
glial barriers may be broken down and even relocated. This may be
associated with Schwann cell invasion of the CNS and, experimentally,
with Schwann cell and glial cell transplantation into demyelinated
areas. Such transplantation studies are in turn related to
remyelination and CNS axon regeneration and the factors which
facilitate these. Twelve review lectures were given on these topics.
Five articles based on these communications are reproduced here. The
underlying theme was the relationship between advances in the
understanding of fundamental nervous tissue biology, especially as
related to glial cells, and potential developments aimed at treating
CNS demyelinating diseases and achieving CNS regeneration.