Occurrence of the H reflex and the F wave in the rat

Consistent repeated M- and H-wave recording in the hind limb of rats

“…Those from stimulation at 1.2 × I Mmax are reported here. In many cases we observed relationships of response amplitude to stimulus intensity generally similar to that illustrated by Meinck,29 in which the H-wave amplitude was maximal at a stimulation intensity below that eliciting the maximal M wave (i.e., I Hmax < I Mmax ), then reduced to a lower plateau with increasing stimulus, but still at a substantial amplitude. However, very often, the H max was obtained with stimuli equally or more intense than that eliciting M max (I Hmax ജ I Mmax ), 60% of the time from tibial stimulation and 39% of the time from sciatic stimulation.…”

“…The size, stability, and rate depression of the later wave are all characteristics of an H wave, in contrast to the much smaller, more inconsistent, but less fatigue-prone F wave. 29,36 The late wave essentially disappeared upon severence of the L4 and/or L5 dorsal roots, while the M wave persisted, as illustrated in Figure 1. When a dorsal root other than L4 or L5 was cut first (e.g., sacral), the late wave remained until L4 and/or L5 was cut.…”

“…2), and that were of similar amplitude to large recordings from inserted electrodes (see Refs. 21,29), with little sensitivity to small differences in electrode position. Table 1 presents means and standard deviations of the parameters, averaged over two recordings of the same set of 10 animals, 5 weeks apart.…”

Restoration of frequency-dependent depression of the H-reflex by passive exercise in spinal rats

“…Exposed tissue was covered with mineral oil to prevent drying. A wire electrode was inserted subcutaneously in the digital interosseous muscles between the fourth and fifth metatarsals for EMG recording as previously demonstrated, 26,27 and referenced to a clip applied to the skin on the digits. A ground electrode was attached to the skin of the tail.…”

Low frequency depression of H-reflexes in humans with acute and chronic spinal-cord injury

“…It is well known that Hand tendon reflexes decrease in amplitude when conditioned with vibration (DeGail et al 1966;Rushworth and Young 1966;Delwaide 1973;Van Boxtel 1986), passive muscle lengthening (Mark et al 1968;Delwaide 1973;Gerilovsky et al 1977;Robinson et al 1982;Burke et al 1983;Davies and Lander 1983;Hultborn et al 1996), and a series of identical reflex stimuli such as paired H-reflexes or tendon taps (Eccles and Rall 1951;Lloyd and Wilson 1957;Meinck 1976;Hoeler et al 1981;Rothwell et al 1986;Van Boxtel 1986;Crone and Nielsen 1989;Kohn et al 1997). However, these depressive effects are reduced or absent in spastic subjects (Calancie et al 1993).…”