Fig 9.

Graphic representation of the distribution of γ-efferents among the spindles supplied by the distal nerve branch in a cat tenuissimus muscle, together with a tracing and a schematic diagram of the arrangement of the spindles and their nerve supply in the whole muscle. At the left, the spindles and nerve supply are shown as tracings of the silver-impregnated, teased preparations made following the physiological experiment. Spindle sensory regions were located in the intact muscle and marked with epimysial stitches. Next right is a schematic diagram of the nerve supply, with spindles represented by short vertical lines. Recorded afferents were all from primary endings; they are identified alphabetically according to the order in which they were isolated in dorsal-root filaments, and are positioned opposite their corresponding spindle. Efferents are identified according to their order of isolation in ventral-root filaments, and are positioned according to their conduction velocities. Afferent E was initially isolated but was lost before any motor actions could be tested. Otherwise all combinations were tested, and the probable intrafusal distribution of the motor axons, based on the afferent responses, are given. P, primary ending; S, secondary ending; b₂(c) signifies that the axon supplied either bag₂ alone or bag₂ and chain fibres together. Modified from Banks (1991).