Electromyographic indices of neuromuscular reflexes

Abstract

Herein, we describe the use of two neuromuscular reflexes, the acoustic startle eye blink reflex and the Hoffmann (H‐) reflex, in the context of exercise neuroscience. The reflex probe paradigm has advantages for use in the field of exercise neuroscience and can be obtained without distraction during the performance of an experimental task. The startle eye blink reflex, measured from the orbicularis oculi muscles, is modulated by the affective foreground context and reflects the relative activation of the appetitive and defensive motivational systems of the brain. The H‐reflex, measured most often from the soleus muscle, reflects the efficacy of synaptic transmission between the la afferent fiber and alpha motoneuron. Changes in the amplitude of the startle eye blink reflex and H‐reflex after exercise have been observed; however, the meaning of the changes is not clear. Further research using these indices among those diagnosed with an affective disorder, or among individuals with multiple sclerosis or spinal cord injuries, will greatly enhance our understanding of the effects of physical activity on the central nervous system