Dr P. Kirkwood
My core interest for many years has been the study
of the control of muscles involved in respiratory movements. Because
this motor act persists in experimental animals under anaesthesia,
including under neuromuscular blockade, we can study the behaviour,
connections and morphology of functionally defined neurones. The
neurones of interest are the motoneurones and interneurones of the
thoracic spinal cord and their antecedent neurones in the pathway
conveying the respiratory drive from the medulla, the respiratory
bulbospinal neurones. As for most neurones in motor systems, all of
these neurones are multifunctional, but the stereotyped repetitive
pattern of activity during respiration allows the assignment of
specific roles to individual neurones during that particular motor act.
The measurement of connections between individual neurones by
spike-triggered averaging and cross-correlation are important
experimental techniques for this. The development of these techniques
and their interpretation has been a central theme in the work of the
laboratory. For characterizing the interneurones we have more recently
used morphological methods, including immunocytochemistry in
conjunction with intracellular labelling.
It has always been the intention that such investigations should yield results that are useful in the understanding of clinical conditions, including spinal cord injury (for instance Kirkwood et al. 1984, J.Physiol. 350 : 225-251). In more recent years the direction of research has shifted more firmly in the direction of spinal cord injury and repair. One important reason for this was the results from several laboratories around the world, where success at achieving regeneration of nerve fibres across experimental lesions of the spinal cord has been achieved. In the 1980s this was only a distant prospect. When it became a reality it also became clear that good neurophysiology was a necessary, but largely missing element in the studies performed. Another reason was the realisation that the same factors which made the respiratory system a useful one for motor control studies made it equally valuable as an experimental system for developing techniques for spinal cord repair. In current work we are therefore investigating neural connections in the thoracic spinal cord, their plasticity and, hopefully, their regeneration in the situation of experimental spinal cord injury.
International Spinal Cord Research Trust.
MRC (we are part of the MRC Co-operative Group 'Neural Control of Movement', and have one MRC studentship).
We are also part of the Institute for Movement Neuroscience.