The reason for detecting more frequent SP1 latency abnormalities is that the SP1 response is mediated to the ipsilateral trigeminal nucleus through a mono- or oligosynaptic circuit and is therefore quantitatively more sensitive, while the SP2 response is elicited by a more complex circuit with a more caudally located polysynaptic
chain of interneurons.
(2,12) It is generally believed to be a polysynaptic
reflex generated in the deep layers of the skin by activation of sweat glands via sudomotor sympathetic efferent fibers.
Monosynaptic and polysynaptic
pathways have been shown to mediate TVR (Desmedt and Godeaux, 1980; Luo et al., 2005).
Nevertheless, WBV has been shown to activate the tonic vibration reflex, a polysynaptic
reflex resulting in many small reflex contractions of the targeted musculature [16,17,19-22].
Teskey and colleagues showed that epidural currents at a frequency of 50 Hz or higher are associated with long-term improvements in skilled movement and potentiation of the polysynaptic
component of cortical evoked potentials in vitro and in vivo [44,83,84].
R2 is transmitted to the spinal tractus in the dorsolateral region of the pons and medulla oblongata before the fibers of the reflex pathway reach the caudal end of spinal trigeminal nuclei, and it is then transmitted to facial nucleus in reticular formation through polysynaptic
These observations suggest that extensor spasms are mediated by polysynaptic
pathways involving activation of organized interneuronal circuits located within the isolated spinal cord that are modulated similarly by both hip and knee proprioceptive inputs.
"Muscle relaxant" medications may inhibit polysynaptic
myogenic reflexes in animal models, but their analgesic properties for muscle pain are unrelated to relief of muscle spasm.
In fact, Morrison is one of the very few exponents of mainstream comics today who actually challenges the medium in its own terms, taking established tropes like word and thought balloons and exposing them to polysynaptic
The remainder of the response is mediated by peripheral motor neurons (Perlman, 1979), which also receive monosynaptic input from the LE neurons (Bailey et al., 1979), other unidentified sensory neurons (Frost et al., 1997), and polysynaptic
inputs onto the LFS neurons from excitatory and inhibitory interneurons (Frost and Kandel, 1995).
(l, 10) Field-potential recordings demonstrate that the H1 antagonist diphenhydramine decreases firing of polysynaptic
pathways in the lateral vestibular nucleus.