Enhancements in the strength of corticospinal projections to muscles are induced in conscious humans by paired associative stimulation (PAS) to the motor cortex. Although most of the previous studies support the hypothesis that the increase of the amplitude of motor evoked potentials (MEPs) by PAS involves long-term potentiation (LTP)-like mechanism in cortical synapses, changes in spinal excit...

bstract—Depression is characterized by alterations in the ircadian secretion of hormones, sleep and motor activity, all f which are regulated by suprachiasmatic nuclei (SCN). The estibular system in the inner ear registers the amount of otor activity. To test the integrity of this motion sensitive ystem in depression, we studied the vestibulo-ocular reflex VOR) in depressive patients who were n...

Depression of the ankle reflex is the most common neurological change in patients with impairment of conduction of the 51 nerve root. Unilateral absence of the ankle jerk is easily recognised, but it may be difficult to detect a slight reduction of response. This may be important, not only for diagnosis, but also for prognostic and therapeutic purposes, since the decrease in the reflex is very ...

Hyperreflexia and spasticity are chronic complications in spinal cord injury (SCI), with limited options for safe and effective treatment. A central mechanism in spasticity is hyperexcitability of the spinal stretch reflex, which presents symptomatically as a velocity-dependent increase in tonic stretch reflexes and exaggerated tendon jerks. In this study we tested the hypothesis that dendritic...

Motor cortical modulation of cutaneous reflex responses in the hindlimb of the intact cat. Summary We have used the technique of spatial facilitation to examine the interactions between the signals conveyed by the corticospinal tract and those of cutaneous afferents in the hindlimb of the intact, walking cat. Microstimulation was applied to 20 cortical sites in the hindlimb representation of th...

H-reflexes are progressively depressed, relative to the first response, at stimulation frequencies above 0.1 Hz (postactivation depression; PAD). Presently, we investigated whether H-reflexes "recover" from this depression throughout 10-s trains of stimulation delivered at physiologically relevant frequencies (5-20 Hz) during functionally relevant tasks (sitting and standing) and contraction am...

We have studied the effect of acute hypertensive episodes on the renal sympathetic baroreceptor reflex in conscious rabbits and the role played by cardiac afferents and endogenous opiate mechanisms. Renal sympathetic nerve activity was recorded during brief perivascular balloon-induced ramp changes in mean arterial pressure before and during 40-minute elevations in resting pressure. Methoxamine...

Functional neuroplasticity in response to stimulation and motor training is a well-established phenomenon. Transcutaneous stimulation of the spine is used mostly to alleviate pain, but it may also induce functional neuroplasticity, because the spinal cord serves as an integration center for descending and ascending neuronal signals. In this work, we examined whether long-lasting noninvasive cat...

The reflex bradycardia produced by a transient phenylephrine-induced rise of arterial pressure was investigated in man during rest and supine exercise, before and after autonomic blockade of the heart. Reflex bradycardia diminished proportionally to the tachycardia of exercise. Propranolol slowed the heart at rest and during exercise, but increased the reflex response only at rest, having no ef...