Joel G. Pickar

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  • Joel G. Pickar
  • The spine journal : official journal of the North…
  • 2002
BACKGROUND CONTEXT Despite clinical evidence for the benefits of spinal manipulation and the apparent wide usage of it, the biological mechanisms underlying the effects of spinal manipulation are not known. Although this does not negate the clinical effects of spinal manipulation, it hinders acceptance by the wider scientific and health-care communities and(More)
1. In barbiturate-anesthetized cats we examined the interaction of lactic acid and static contraction on the discharge of group III muscle afferents. Only afferents whose receptive fields were located in the triceps surae muscles were studied. 2. Twelve of 20 afferents were stimulated by a 60-s static contraction. The majority of firing occurred within the(More)
This paper describes a method for applying controlled loads to a lumbar vertebra while recording in vivo from primary afferents innervating the lumbar paraspinal tissues. Unlike the appendicular skeleton, the vertebral column poses a unique challenge for neurophysiological investigations. Distances between paraspinal tissues and the spinal cord are short.(More)
OBJECTIVE To examine the effect of spinal manipulation on electromyographic (EMG) activity in areas of localized tight muscle bundles of the low back. METHODS Surface EMG activity was collected from 16 participants in 2 chiropractic offices during the 5 to 10 minutes of the treatment protocol. Electrodes were placed over the 2 sites of greatest paraspinal(More)
STUDY DESIGN The response of mechanosensitive afferent nerve endings in the lumbar spine to manipulation of a lumbar facet isolated using a unique surgical approach was studied in anesthetized adult cats. OBJECTIVES To characterize sensory nerve endings in the lumbar spine with respect to their receptive field and conduction velocity and to assess their(More)
OBJECTIVE The mechanisms underlying the benefits of spinal manipulation are not well understood. Neurophysiological mechanisms likely mediate its effects, at least in part, yet we know little about how the nervous system is affected by spinal manipulation. The purpose of the present study was to determine whether muscle spindles and Golgi tendon organs in(More)
OBJECTIVE More than 90% of chiropractic patients receive high-velocity, low-amplitude spinal manipulation (HVLA-SM) as part of their chiropractic care. The purpose of the current study was determine how the duration of a lumbar HVLA-SM given under force control affects the discharge of paraspinal muscle spindle afferents. METHODS Experiments were(More)
Eleven horses (3 mares, 7 stallions, 1 gelding) with clinical and biochemical evidence of hyperkalemic periodic paralysis were studied. Each horse had history of episodic weakness, muscular tremors, or collapse, which lasted for periods of a few minutes to hours. Diagnosis was based on hyperkalemia in association with a spontaneous episode of paralysis or(More)
Proprioceptive information from paraspinal tissues including muscle contributes to neuromuscular control of the vertebral column. We investigated whether the history of a vertebra's position can affect signalling from paraspinal muscle spindles. Single unit recordings were obtained from muscle spindle afferents in the L6 dorsal roots of 30(More)
STUDY DESIGN Histologic analysis of normal human facet capsules to determine the density and distribution of encapsulated nerve endings in the thoracic and lumbar spine. OBJECTIVES To quantify the extent of mechanoreceptor innervation in normal facet tissues and determine the relative distribution of three specific receptor types with respect to thoracic(More)