Prof. I.M.L. Donaldson
Abstract:
Exploration of the world is the principal means by which organisms
acquire information about it. Information collection which sometimes,
but by no means always, leads to sensation is largely an active process.
The movements required for exploration necessarily lead to the
stimulation of proprioceptors (for example in muscles and joints) and
sometimes of exteroceptors also (for example during eye-movements). Thus
the organism must distinguish between afferent input from the effects of
its own movements and that which arises from changes in the external
world. How this is done has been controversial for more than a century
and is still imperfectly understood. Note that the information content,
in the technical sense, of the signals in the two cases may be
indistinguishable but the significance of the information differs
greatly. Evidence that organisms must, and do, use information both from
proprioceptors and from the motor commands which control movement in both
motor control and the generation of sensation and percepts will be
presented and some of the implications of this will be discussed.
I.M.L. Donaldson,
Professor of Neurophysiology,
University of Edinburgh