Showing papers by "A.D. (Bud) Craig published in 2006"
TL;DR: Findings support the concept that VMpo is a primate lamina I spinothalamocortical relay nucleus important for pain, temperature, itch, muscle ache, sensual touch, and other interoceptive feelings from the body, and provide strong evidence for the general hypothesis that the STT consists of several functionally and anatomically differentiable components.
Abstract: The distribution of retrogradely labeled spinothalamic tract (STT) neurons was analyzed in macaque monkeys following variously sized, physiologically guided pressure or iontophoretic injections of cholera toxin subunit B (CTb) in order to determine whether different STT termination sites receive input selectively from different sets of STT cells. This report focuses on posterolateral thalamus, where prior anterograde tracing observations identified the posterior part of the ventromedial nucleus (VMpo) as the major projection target of lamina I STT neurons. Large injections in posterolateral thalamus labeled predominantly STT cells in lamina I throughout the spinal cord. In cases with medium-sized or small injections centered in VMpo, almost all labeled STT cells (∼90%) were lamina I neurons. Small injections revealed a posteroanterior (foot to hand) somatotopographic organization consistent with that observed in prior anterograde tracing work; injections in posterior VMpo labeled primarily lumbosacral lamina I cells, whereas injections placed more anteriorly in VMpo labeled primarily cervical lamina I cells. These findings support the concept that VMpo is a primate lamina I spinothalamocortical relay nucleus important for pain, temperature, itch, muscle ache, sensual touch, and other interoceptive feelings from the body, and they provide strong evidence for the general hypothesis that the STT consists of several functionally and anatomically differentiable components. J. Comp. Neurol. 499:953–964, 2006. © 2006 Wiley-Liss, Inc.
65 citations
TL;DR: The results provide evidence that the main generator of pain-related activity in operculoinsular cortex may participate in both the somatic localization and the intensity discrimination of pain sensations, and they indicate that it may be distinct from the traditional somatosensory cortices.
Abstract: The operculoinsular cortical region has a major role in the representation of noxious stimuli, based on functional imaging observations, clinical lesion studies, and EEG recordings of specifically pain-related laser-evoked potentials (LEPs) in humans. The source of LEPs has not been identified, and several somatic representations and cytoarchitectonic areas may be present in this complex region. To overcome the limitations of human studies, a primate model is needed in which the main LEP generator in this region can be localized and characterized using invasive methods. We obtained EEG recordings of evoked responses to noxious laser stimulation at different intensities and performed dipole source analyses in three anesthetized macaque monkeys. We show that LEPs can be recorded that 1) grade with stimulus intensity, 2) display two distinct responses corresponding to the “late” (Aδ-fiber) and the “ultralate” (C-fiber) LEPs recorded in humans, and 3) originate deep within the operculoinsular region, thus est...
60 citations
TL;DR: Observations indicate that VPL receives STT input almost entirely from lamina V neurons, whereas VPI receivesSTT input from both laminae I and V cells, with two different topographic organizations.
Abstract: The distribution of retrogradely labeled spinothalamic tract (STT) neurons was analyzed in monkeys following variously sized injections of cholera toxin subunit B (CTb) in order to determine whether different STT termination sites receive input from different sets of STT cells. This report focuses on STT input to the ventral posterior lateral nucleus (VPL) and the subjacent ventral posterior inferior nucleus (VPI), where prior anterograde tracing studies identified scattered STT terminal bursts and a dense terminal field, respectively. In cases with small or medium-sized injections in VPL, labeled STT cells were located almost entirely in lamina V (in spinal segments consistent with the mediolateral VPL topography); few cells were labeled in lamina I (<8%) and essentially none in lamina VII. Large and very large injections in VPL produced marked increases in labeling in lamina I, associated first with spread into VPI and next into the posterior part of the ventral medial nucleus (VMpo), and abundant labeling in lamina VII, associated with spread into the ventral lateral (VL) nucleus. Small injections restricted to VPI labeled many STT cells in laminae I and V with an anteroposterior topography. These observations indicate that VPL receives STT input almost entirely from lamina V neurons, whereas VPI receives STT input from both laminae I and V cells, with two different topographic organizations. Together with the preceding observation that STT input to VMpo originates almost entirely from lamina I, these findings provide strong evidence that the primate STT consists of anatomically and functionally differentiable components.
57 citations
01 Jan 2006
TL;DR: Las vias ascendentes que envian la actividad relacionada con el dolor al cerebro en los humanos incluyen el tracto espinotalamico lateral y las proyecciones espinobulbares indirectas mediante sitios homeostaticos del tronco cerebral.
Abstract: Las vias ascendentes que envian la actividad relacionada con el dolor al cerebro en los humanos incluyen el tracto espinotalamico lateral y las proyecciones espinobulbares indirectas mediante sitios homeostaticos del tronco cerebral. Varias areas en el talamo envian actividades relacionadas con el dolor a la corteza, incluyendo la parte posterior del nucleo medianoventral o centromediano (VMpo) y la parte ventral caudal del nucleo mediodorsal (MDvc), asi como el nucleo ventral posterior (VP) y otros sitios adicionales. Se describen estas vias y otras que contribuyen a la constelacion de actividad del cerebro anterior y que se involucran en la sensacion dolorosa del ser humano.