Facilitation During the H-Reflex Recovery Cycle

Masland, William S.

doi:10.1001/archneur.1972.00490100043003

Cited by 33 publications

(13 citation statements)

References 8 publications

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“…Based on findings with the recovery of monosynaptic reflex amplitudes after subliminal conditioning stimuli in normal and spinal man, it may be concluded provisionally that long latency (150-250 ms) facilitatory effects may occur in normal subjects (Tabotikova and Sax, 1969;Gassel, 1970a;Delwaide, 1971;Robinson et al, 1979) and in patients with complete spinal transection (Masland, 1972), while type Ia nerve fibres are not involved in these effects (Katz et al, 1977). This supports Gassel's (1970b) (Gillies et al, 1969;Delwaide, 1971;Dindar and Verrier, 1975) and, in the case of the tendon reflex, of a less effective response of the primary endings to the tendon tap during vibration (Burke et al, 1976).…”

mentioning

confidence: 99%

Selective effects of vibration on monosynaptic and late EMG responses in human soleus muscle after stimulation of the posterior tibial nerve or a tendon tap.

Boxtel¹

1979

Journal of Neurology, Neurosurgery & Psychiatry

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S U M M A RY In normal subjects it was possible to evoke tendon and Hoffman reflexes which were followed by late EMG responses with a latency of In normal subjects, electrical stimulation of the posterior tibial nerve or a tap to the Achilles tendon is, under isometric conditions, in the relaxed soleus muscle usually only followed by a monosynaptic EMG response. During a weak isometric voluntary contraction of the calf muscles, the monosynaptic reflex may be followed by one or more late EMG responses at regular intervals of 150-250 ms (Agarwal and Gottlieb, 1972;Stein and Bawa, 1976;Hayes and Clarke, 1978). The late responses niay be viewed as weakly damped oscillations in the monosynaptic stretch reflex arc.It has been found that primary muscle spindle endings discharge during the relaxation phase of an electrically induced twitch, both during a weak isometric contraction (Hagbarth and Vallbo, 1968) and in relaxed muscles (Wallin et al., 1973;Szumski et al., 1974). The response of the primary spindle endings may elicit a succeeding EMG discharge. In agreement with this view, the latency of the late response was found to be related to the duration of the preceding contraction and the results of linear systems analysis were consistent with the presumed role of primary endings .

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mentioning

confidence: 99%

Selective effects of vibration on monosynaptic and late EMG responses in human soleus muscle after stimulation of the posterior tibial nerve or a tendon tap.

Boxtel¹

1979

Journal of Neurology, Neurosurgery & Psychiatry

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“…Furthermore, Masland also observed pronounced H‐reflex facilitation at short ISIs in cSCI. However, the small sample size and the heterogeneity of SCI were important limitations in this study …”

Section: Discussionmentioning

confidence: 79%

Influence of spinal cord lesion level and severity on H‐reflex excitability and recovery curve

et al. 2015

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“…The finding that ACh is tonically released in retinal cultures shows a remarkable similarity to results obtained in the intact mammalian retina. Masland andcolleagues (1984, 1987) have demonstrated, in addition to light-evoked release, a nonquantal leak of ACh from the intact rabbit retina. In order to determine if the endogenous level of ACh in the retinal cultures was secondary to a nonquantal leakage, experiments using (1) extracellular cobalt (3mM), (2) high extracellular magnesium (nom-inally 20 mM) and low calcium (0.2 mM) (Lipton, 1986) or (3) high extracellular calcium (15 mM; Vyskocil et al, 1983) were attempted.…”

Section: Discussionmentioning

confidence: 99%

Spontaneous release of acetylcholine affects the physiological nicotinic responses of rat retinal ganglion cells in culture

Lipton

1988

J. Neurosci.

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Nictonic cholinergic responses have been previously documented in mammalian retinal ganglion cells. In the present study, dissociated retinal cells were densely plated and grown in a specific batch of rat serum. When held at negative potentials during whole-cell recording with a patch electrode, the retinal ganglion cells located close to presumptive cholinergic amacrine cells in these cultures were found to respond to acetylcholine (ACh; 20–200 microM) with an apparent outward current in the presence of physiological salines on both sides of the membrane. Other nicotinic agonists (nicotine, carbachol) produced the same effect. Conductance measurements revealed that this apparent outward current was actually a decrease in a tonic inward current. Nicotinic antagonists such as d-turbocurarine (10 microM) and dihydro- beta-erythroidine (20 microM), when applied in dishes that had never been exposed to exogenous ACh, produced a similar decrease in a tonic inward current. The reversal potential of the tonic current suppressed by ACh was similar to the nicotinic current previously studied in these central neurons. Furthermore, purified acetylcholinesterase was capable of modulating the tonic inward current of the retinal ganglion cells. Lowering an excised patch of muscle into dense areas of the retinal cultures activated nicotinic channels in the muscle membrane, indicating the presence of endogenous ACh in the culture fluid. Divalent cations such as Co2+ blocked the tonic inward current of retinal ganglion cells in these cultures. Finally, direct biochemical measurements indicated that low levels of endogenous ACh (on the order of 0.5 microM near putative cholinergic amacrine cells) were present in the retinal cultures. Taken together, these results show that ACh was being spontaneously released into these cultures, resembling at least to some degree the tonic leakage of ACh found in the intact retina. This concentration of ACh was capable of tonically depolarizing the membrane potential of retinal ganglion cells exposed to this dosage. This culture system allows the study of trophic effects of ACh on a central mammalian neuron in a precisely controlled extracellular environment.

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Facilitation During the H-Reflex Recovery Cycle

Abstract: A period of facilitation at 200 msec has been studied in the H-reflex recovery cycle, or period during which a second (test) reflex is influenced by a first (conditioning). Three

Cited by 33 publications

References 8 publications

Selective effects of vibration on monosynaptic and late EMG responses in human soleus muscle after stimulation of the posterior tibial nerve or a tendon tap.

Selective effects of vibration on monosynaptic and late EMG responses in human soleus muscle after stimulation of the posterior tibial nerve or a tendon tap.

Influence of spinal cord lesion level and severity on H‐reflex excitability and recovery curve

Spontaneous release of acetylcholine affects the physiological nicotinic responses of rat retinal ganglion cells in culture

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