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The
spinoreticular tract
Another prominent
pathway involved in nociceptive processing is the spinoreticular
tract (Blair
et al., 1984 a & b).
This pathway is similar to the spinothalamic tract in that it
is excited by similar sensory fibers and its axons course in the
anterolateral region of the spinal white matter.
Although most
spinoreticular neurons ascend on the contralateral side, there
is an ipsilateral component. Rather than ascend to the thalamus,
spinoreticular neurons terminate at all levels of the brain stem
reticular formation. Furthermore, axon collaterals of spinothalamic
tract neurons terminate in similar regions of the reticular formation.
Polysynaptic reticulothalamic projections terminate in the intralaminar
thalamic nuclei, particularly the centromedian and parafascicular
nuclei. Thalamocortical axons from the intralaminar nuclei project
to multiple regions of cerebral cortex (Figure
1).
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