Interaction between voluntary contraction and tonic stretch reflex transmission in normal and spastic patients
AUTOR(ES)
Neilson, Peter D.
RESUMO
Transmission characteristics of tonic stretch reflex (TSR) pathways in both normal and spastic patients have been measured during different levels of sustained voluntary contraction of the biceps brachii muscle. A cross-correlation technique of analysis was used to separate reflex responses from the total electromyographic activity. TSR transmission in normal subjects was observed to change with the level of voluntary contraction; sensitivity to stretch increased approximately three-fold as the subject stiffened the arm by simultaneously contracting flexor and extensor muscles. In contrast, TSR transmission did not alter during voluntary contraction in spastic patients. It is proposed that in spastic patients supraspinal modulation of reflex transmission is impaired because hypersensitive spinal reflexes short-circuit long loop pathways.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=494192Documentos Relacionados
- Effect of contraction level and magnitude of stretch on tonic stretch reflex transmission characteristics.
- Comparison of the tonic stretch reflex in athetotic patients during rest and voluntary activity
- Measurements of excitatory postsynaptic potentials in the stretch reflex of normal subjects and spastic patients.
- Voluntary and reflex control of the biceps brachii muscle in spastic-athetotic patients
- Interaction between the vestibulo-collic reflex and the cervico-collic stretch reflex in the decerebrate cat.