To examine neural aspects of motor control in the glenohumeral joint, this study evaluates utilization of an innate spinal segmental pathway, the spinal stretch reflex, as an investigational tool that reflects neural circuitry. The purpose of this study was to determine if this reflex could be evoked from the infraspinatus muscle, if the testing apparatus and protocol for elicitation were relia...

The effect of whole body vibration (WBV) on reflex responses is controversially discussed in the literature. In this study, three different modalities of reflex activation with increased motor complexity have been selected to clarify the effects of acute WBV on reflex activation: (1) the electrically evoked H-reflex, (2) the mechanically elicited stretch reflex, and (3) the short-latency respon...

The interpretation of changes in the soleus H reflex is problematic in the face of reflex gain changes, a nonlinear input/output relationship for the motoneuron pool, and a nonhomogeneous response of different motoneurons to afferent inputs. By altering the stimulus intensity to maintain a constant reflex output, threshold tracking allows a relatively constant population of alpha-motoneurons to...

The masseteric jaw closure reflex was utilized as a model system with which to gauge the functional activity of central noradrenergic neurons. This system was chosen because it is a simple monosynaptic reflex the neuronal substrate of which receives a dense noradrenergic input. The modulatory effects of norepinephrine (NE) on this response in the intact, chloral hydrate-anesthetized rat were st...

The blink reflex and its equivalent glabella tap reflex are behavioural motor responses normally found in neonates and in the physiological startle reflex. Historically, it was described by Overend in 1896 and soon afterwards by McCarthy and by Bekhterev who disputed its origins. Kugelberg in 1952 recorded the early-latency R1 and the late-latency R2 electromyographic responses from orbicularis...