List of contributors. Preface. I. Perspectives. 1. The segmental motor system - advances, issues, and possibilities (D.G. Stuart). II. Mechanisms underlying repetitive firing in motoneurons. 2. Repetitive impulse firing in motoneurons: facts and perspectives (D. Kernell). 3. Plateau potentials and their role in regulating motoneural firing (H. Hultborn). 4. Synaptic integration in bistable motoneurons (C.J. Heckman, R.H. Lee). 5. Adapting motoneurons for motor behavior (R. Delgado-Lezama, J. Hounsgaard). III. Input-output functions of motoneurons. 6. Assessing the strengths of motoneuron inputs: different anatomical and physiological approaches compared (P.A. Kirkwood, T.W. Ford, R. Donga, S.A. Saywell, G. Holstege). 7. Models of spike encoding and their use in the interpretation of motor unit recordings in man (R.K. Powers, M.D. Binder). 8. Non-linear summation of synaptic currents on spinal motoneurons: lessons from simulations of the behaviour of anatomically realistic models (P.K. Rose, S. Cushing). 9. Selectivity of presynaptic inhibition: a mechanism for independent control of information flow through individual collaterals of single muscle spindles (P. Rudomin). IV. Properties and central actions of muscle receptors. 10. Why are there three types of intrafusal muscle fibers? (A. Taylor, P.H. Ellaway, R. Durbaba). 11. Quantifying proprioception (A. Prochazka). 12. Movement detection thresholds at the human elbow joint (U. Proske, A.K. Wise, J.E. Gregory). 13. A positive feedback circuit involving muscle spindle secondaries and gamma motoneurons in the cat (E. Jankowska, M.H. Gladden). 14. Neurotrophin-3 and maintenance of muscle afferent function (J.B. Munson, R.D. Johnson, L.M. Mendell). V. Motor unit properties and recruitment. 15. Revisiting the notion of 'motor unit types' (R.E. Burke). 16. Orderly recruitment tested across muscle boundaries (T.C. Cope, A.J. Sokoloff). 17.