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UNLABELLED Numerous methods have been pursued to evaluate function in central motor pathways during surgery in the anesthetized patient. At this time, no standard has emerged, possibly because each of the methods described to date requires some degree of compromise and/or lacks sensitivity. OBJECT The goal of this study was to develop and evaluate a(More)
We examined Hoffmann (H) and tendon (T) reflexes in 3 populations of adult subjects: acute SCI (< 2 weeks post injury), controls, and chronic SCI (> 1 year post injury). We further investigated the effects of continuous tendon vibration and different stimulus rates on the size of evoked H reflexes in these subject populations. All reflex amplitudes were(More)
OBJECTIVES To examine the basis for delay in the excitatory effects of transcranial magnetic stimulation (TMS) of motor cortex on motoneuron pools of muscles left partially-paralyzed by traumatic spinal cord injury (SCI). METHODS The effect of subthreshold transcranial magnetic stimulation (TMS) on just-suprathreshold H-reflex amplitude was examined in(More)
Noninvasive transcranial magnetic stimulation (TMS) of the motor cortex was used to evoke electromyographic (EMG) responses in persons with spinal cord injury (n = 97) and able-bodied subjects (n = 20, for comparative data). Our goal was to evaluate, for different levels and severity of spinal cord injury, potential differences in the distribution and(More)
1. The extracellular activity of 196 single neurons in subnucleus caudalis (medullary dorsal horn) of the trigeminal (V) spinal tract nucleus was examined in chloralose-anesthesized, paralyzed cats. Electrical, mechanical, and algesic chemical stimuli were applied to the exposed temporomandibular joint (TMJ) in order to activate TMJ afferents. Seventy-eight(More)
Muscle weakness and failure of central motor drive were assessed in triceps brachii muscles of individuals with chronic cervical spinal cord injury (SCI) and able-bodied controls. Electrical stimuli were applied to the radial nerve during rest and during triceps submaximal and maximal voluntary contractions (MVCs). The mean forces and integrated EMGs(More)
OBJECTIVE Previous reports from our laboratory have described short-latency contractions in muscles of the distal upper limb following stimulation of lower limb nerves or skin in persons with injury to the cervical spinal cord. It takes 6 or more months for interlimb reflexes (ILR) to appear following acute spinal cord injury (SCI), suggesting they might be(More)
Force was measured from triceps brachii motor units in individuals with chronic cervical spinal cord injury (SCI) and in able-bodied (A-B) control subjects using spike-triggered averaging (175 and 48 units, respectively). Eleven percent of units from the SCI population generated normal electromyograms (EMGs) but exerted no measurable force, 65% generated(More)
In persons who have sustained severe injuries to the cervical spinal cord, electrical stimulation of mixed peripheral nerves in a lower limb can evoke short-latency, bilateral motor responses in muscles of the distal upper limbs; such motor responses have been termed interlimb reflexes. In the present study, we investigated the role that cutaneous(More)
Morphine sulfate (0.75 micrograms) was microinjected into (rat) rostral and caudal trigeminal areas singly and simultaneously, using cannula-electrode combinations. Also, 0.5 micrograms or 1.0 micrograms of morphine was injected into nucleus reticularis paragigantocellularis (PGC). Both single trigeminal nuclear microinjections significantly elevated the(More)