Distributions of spinothalamic, spinohypothalamic, and spinotelencephalic fibers revealed by anterograde transport of PHA-L in rats

Abstract

Fibers projecting from several levels of the spinal cord to the diencephalon and telencephalon were labeled anterogradely with Phaseolus vulgaris leucoagglutinin injected iontophoretically. Labeled fibers in the thalamus confirmed projections previously observed. In addition, many labeled fibers were seen in the hypothalamus and in telencephalic areas not generally recognized previously as receiving such projections. In the hypothalamus, these areas included the lateral hypothalamus (including the medial forebrain bundle), the posterior hypothalamic area, the dorsal hypothalamic area, the dorsomedial nucleus, the paraventricular nucleus, the periventricular area, the suprachiasmatic nucleus, and the lateral and medial preoptic areas. In the telencephalon, areas with labeled fibers included the ventral pallidum, the globus pallidus, the substantia innominata, the basal nucleus of Meynert, the amygdala (central nucleus), the horizontal and vertical limbs of the diagonal band of Broca, the medial and lateral septal nuclei, the bed nucleus of the stria terminalis, the nucleus accumbens, infralimbic cortex, and medial orbital cortex. These results suggest that somatosensory, possibly including visceral sensory, information is carried directly from the spinal cord to areas in the brain involved in autonomic regulation, motivation, emotion, attention, arousal, learning, memory, and sensory-motor integration. Many of these areas are associated with the limbic system.

Nuclei-and condition-specific responses to pain in the bed nucleus of the stria terminalis

“…We hypothesized that noxious stimulation would trigger neuronal activity and hence c-Fos expression in the BST since it receives direct (and potentially indirect) afferents from the dorsal horn of the spinal cord (Braz et al, 2005;Burstein and Giesler, 1989;Cliffer et al, 1991). Our observations confirm that these afferents carry noxious (but not innocuous) information from the periphery to the BST.…”

Long-term changes in behavior and regional cerebral blood flow associated with painful peripheral mononeuropathy in the rat

“…The involvement of limbic areas in pain could reflect the evidence of alternative pathways for nociception as provided by anatomical and physiological studies showing direct spinal projections to various limbic areas (Burnstein et al, 1987;Geisler et al, 1994). Such projections can transmit nociceptive information to the limbic areas, either directly (Burnstein et al, 1987;Cliffer et al, 1991), or after a relay in the brainstem (Bernard and Besson, 1990). The areas within the limbic system are thought to play a role in motivational or emotional aspects of behavior, including learning and memory (Melzack and Casey, 1968;Gabriel et al, 1980aGabriel et al, ,b,1983Bouckoms, 1994).…”

CREB activity in the nucleus accumbens shell controls gating of behavioral responses to emotional stimuli

“…We show here that CREB activity in the nucleus accumbens shell participates in setting the nociceptive threshold. The neuroanatomical basis for this influence is not yet fully understood, but the nucleus accumbens does receive direct afferents from spinal cord neurons (44). It also receives inputs from or sends projections to several structures (45) that are involved in nociceptive responses, including periaqueductal gray, VTA, habenula, lateral hypothalamus, and amygdala.…”