Rhythmic Activity Patterns of Motoneurones and Interneurones in the Embryonic Chick Spinal Cord
We have studied the organization of patterned motor activity in the developing spinal cord of the chick embryo using optical and electrophysiological methods. Optical imaging of motoneurones filled with calcium dyes revealed the presence of fluorescence transients that were synchronized with the electrical activity recorded from hindlimb muscle nerves. Optical imaging was also used to demonstrate the rhythmic activity of a population of interneurones that is believed to provide some of the excitatory drive to motoneurones. Calcium transients were synchronized between motoneurones and these interneurones. Whole cell recordings from interneurones around the lateral motor column confirmed the optical findings and showed that many interneurones receive rhythmic synaptic drive in phase with that of motoneurones. Dye injections into individual interneurones failed to demonstrate the existence of widespread dye-coupling implying that synaptic mechanisms are responsible for the widespread synchrony in the activity of embryonic spinal neurones.
KeywordsSucrose NMDA Stein Dextran Biocytin
Unable to display preview. Download preview PDF.
- Garner, L.K., Mendelson, B.M., Albers, K.M., Kindy, M. and B. M. Davis (1992) Effect of activity on Enkephalin and Substance P mRNA in the developing chick spinal cord. Society for Neuroscience Abstracts. 18: 420Google Scholar
- Ho, S. and O’Donovan, M. J. (1991) Properties of propriospinal neurones involved in the rhythmic excitation of motor pools in the isolated embryonic chick spinal cord. Society for Neuroscience Abstracts. 17: 120Google Scholar
- Ho, S., and O’Donovan, M.J. (1992) Optical and pharmacological studies of propriospinal neurones involved in rhythmic motor activity in the embryonic chick spinal cord. Society for Neuroscience Abtstracts. 18: 1057Google Scholar
- Mendelson, B. (1992) Activity dependent alterations in substance P and CGRP immunoreactivity in neurones and fibers in the embryonic chick spinal cord. Society for Neuroscience Abstracts. 18: 420Google Scholar
- O’Donovan, M.J. and Ho, S. (1992) The role of extracellular calcium and calcium channels in activity dependent intracellular calcium changes in embryonic chick motoneurones. Society for Neuroscience Abstracts. 18: 1303Google Scholar
- O’Donovan, M.J., Ho., S and Yee, W. (1994) Calcium imaging of rhythmic network activity in the developing spinal cord of the chick embryo. In Press. J.NeuroscienceGoogle Scholar
- Ritter, A. and O’Donovan, M.J. (1993) Firing patterns and membrane properties of rhythmically active interneurones in the embryonic chick spinal cord. Society for Neuroscience Abstracts. 19: 557.Google Scholar
- Roberts, A., Soffe, S.R. and Dale, N. (1986) Spinal interneurones and swimming in frog embryos. In “Neurobiology of Vertebrate Locomotion” Ed. S. Grillner, P.S.G. Stein, D.G. Stuart, H. Forssberg and R.M. Herman pp. 279-306, Macmillan.Google Scholar