the purpose of the this study was to investigate the effect of direct current on montoneuron reflex exitability. thirty six subjects (18 males, 18 females) 19.36 years of age ( x= 24.06, sd= 3.63) participated in this study. the reflex excitability of soleus motoneruons was assessed by measuring the amount of change in the peak to peak ampitude of the h-reflex before and after direct current wa...

the purpose of this study was to investigate the validity of the modified ashworth scale (mas) by using both the conventional (hmax/mmax ratio) and the new indicators (hslp/mslp) of motoneuron excitability. this research was a correlational study on twenty post-stroke patients. main outcome measures were the mas and electrophysiologic assessments. the latter was performed using both conventiona...

The effect of short duration and sustained manual acupuncture on alpha-motoneuron excitability was studied using the Soleus H-reflex. The acupuncture points GB-34 and SP-9 were needled and stimulated manually. Normalised H-reflex and M-wave recruitment curves were constructed and the ratio of the slope of the ascending part of the H-reflex recruitment curve (Hslp) to the slope of the ascending ...

Motoneuron populations possess a range of intrinsic excitability that plays an important role in establishing how motor units are recruited. The fact that this range collapses after axotomy and does not recover completely until after reinnervation occurs suggests that muscle innervation is needed to maintain or regulate adult motoneuron excitability, but the nature and identity of underlying me...

The purpose of this communication is to report on the analysis of the effects of muscle pressure on altering motoneuron excitability. Motoneuron excitability was assessed by measuring changes in the H-reflex in 30 neurologically healthy individuals. The results indicate that muscle pressure is excitatory, but of such low intensity as to be of dubious therapeutic benefit. Methodological limitati...

The influence of motoneuron pool properties on the stability of the stretch reflex at the ankle in subjects with spinal cord injury was tested using a comprehensive model of the reflex pathway. This model included the passive and active components of the triceps surae muscles, muscle spindles, neural transport delays, limb mechanical properties, and a lumped parameter model of the motoneuron po...

Human studies have not assessed corticospinal excitability of an upper-limb prime mover during arm cycling. The purpose of the present study was to determine whether supraspinal and/or spinal motoneuron excitability of the biceps brachii was different between arm cycling and an intensity-matched tonic contraction. We hypothesized that spinal motoneuron excitability would be higher during arm cy...

Clonus is defined as an involuntary rhythmic muscle contraction that generally occurs in people who have sustained lesions involving descending motor pathways in the neuraxis, and is usually accompanied by other signs of reflex hyperexcitability such as spasticity. This paper hypothesizes that clonus arises when two conditions occur simultaneously: 1) the reflex pathway contains long delay time...

The responsiveness of the human central nervous system can change profoundly with exercise, injury, disuse, or disease. Changes occur at both cortical and spinal levels but in most cases excitability of the motoneuron pool must be assessed to localize accurately the site of adaptation. Hence, it is critical to understand, and employ correctly, the methods to test motoneuron excitability in huma...

The movements that define behavior are controlled by motoneuron output, which depends on the excitability of motoneurons and the synaptic inputs they receive. Modulation of motoneuron excitability takes place over many time scales. To determine whether motoneuron excitability is specifically modulated during the active versus the quiescent phase of rhythmic behavior, we compared the input-outpu...