Corticofugal projections to the motor nuclei of the brainstem and spinal cord in humans

Iwatsubo, Takeshi; Kuzuhara, Shigeki; Kanemitsu, Akira; Shimada, Hiroyuki; Toyokura, Y

doi:10.1212/wnl.40.2.309

Cited by 127 publications

(78 citation statements)

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“…Evidence from anterograde degeneration studies of corticobulbar connections in macaques, chimpanzees, and humans suggests that there are interspecific differences in the projections of layer V pyramidal neurons of primary motor cortex. Compared to macaques, chimpanzees [Kuypers, 1958b] and humans [Kuypers, 1958a;Iwatsubo et al, 1990] were observed to have a greater density of degenerating fibers within the trigeminal motor nucleus and all parts of the facial nucleus following cortical ablation. This increase in direct cortical input to orofacial motor nuclei is attended by a reduction in indirect cortical projections to the reticular formation.…”

Section: Phylogenetic Patterns Of Npnfp-immunoreactive Neuron Distribmentioning

confidence: 91%

“…This increase in direct cortical input to orofacial motor nuclei is attended by a reduction in indirect cortical projections to the reticular formation. It should be noted, however, that older methods for silver impregnation of degenerating axons, such as the Nauta-Gygax method employed by Kuypers [1958a, b] and Iwatsubo et al [1990], are known to produce capricious and inconsistent results [Heimer and Robards, 1981], and therefore should be interpreted with caution. However, ethical considerations prohibit the application of more modern tract-tracing methods to study the distribution of cortical axon terminals in the orofacial motor nuclei of great apes and humans.…”

Section: Phylogenetic Patterns Of Npnfp-immunoreactive Neuron Distribmentioning

confidence: 99%

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Cortical Orofacial Motor Representation in Old World Monkeys, Great Apes, and Humans

et al. 2004

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This study presents a comparative stereologic investigation of neurofilament protein- and calcium-binding protein-immunoreactive neurons within the region of orofacial representation of primary motor cortex (Brodmann’s area 4) in several catarrhine primate species (Macaca fascicularis, Papio anubis, Pongo pygmaeus, Gorilla gorilla, Pan troglodytes, and Homo sapiens). Results showed that the density of interneurons involved in vertical interlaminar processing (i.e., calbindin- and calretinin-immunoreactive neurons) as well pyramidal neurons that supply heavily-myelinated projections (i.e., neurofilament protein-immunoreactive neurons) are correlated with overall neuronal density, whereas interneurons making transcolumnar connections (i.e., parvalbumin-immunoreactive neurons) do not exhibit such a relationship. These results suggest that differential scaling rules apply to different neuronal subtypes depending on their functional role in cortical circuitry. For example, cortical columns across catarrhine species appear to involve a similar conserved network of intracolumnar inhibitory interconnections, as represented by the distribution of calbindin- and calretinin-immunoreactive neurons. The subpopulation of horizontally-oriented wide-arbor interneurons, on the other hand, increases in density relative to other interneuron subpopulations in large brains. Due to these scaling trends, the region of orofacial representation of primary motor cortex in great apes and humans is characterized by a greater proportion of neurons enriched in neurofilament protein and parvalbumin compared to the Old World monkeys examined. These modifications might contribute to the voluntary dexterous control of orofacial muscles in great ape and human communication.

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Section: Phylogenetic Patterns Of Npnfp-immunoreactive Neuron Distribmentioning

confidence: 91%

Section: Phylogenetic Patterns Of Npnfp-immunoreactive Neuron Distribmentioning

confidence: 99%

Cortical Orofacial Motor Representation in Old World Monkeys, Great Apes, and Humans

et al. 2004

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“…In fact, in contrast to the monkey cortical larynx area, electrical stimulation of the human LPA does indeed produce vocalization (Penfield and Boldrey, 1937), and lesions may cause mutism and other speech disorders. Furthermore, the human LPA projects monosynaptically to the laryngeal lower motor neurons in the nucleus ambiguus (Kuypers, 1958;Iwatsubo et al, 1990), while the monkey larynx area projects to the nucleus ambiguus only indirectly via synapses in the reticular formation (Simonyan and Jü rgens, 2003;Jü rgens and Ehrenreich, 2007).…”

Section: Introductionmentioning

confidence: 99%

Pitch underlies activation of the vocal system during affective vocalization

Belyk

Brown

2015

Social Cognitive and Affective Neuroscience

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Affective prosody is that aspect of speech that conveys a speaker's emotional state through modulations in various vocal parameters, most prominently pitch. While a large body of research implicates the cingulate vocalization area in controlling affective vocalizations in monkeys, no systematic test of functional homology for this area has yet been reported in humans. In this study, we used functional magnetic resonance imaging to compare brain activations when subjects produced affective vocalizations in the form of exclamations vs non-affective vocalizations with similar pitch contours. We also examined the perception of affective vocalizations by having participants make judgments about either the emotions being conveyed by recorded affective vocalizations or the pitch contours of the same vocalizations. Production of affective vocalizations and matched pitch contours activated a highly overlapping set of brain areas, including the larynx-phonation area of the primary motor cortex and a region of the anterior cingulate cortex that is consistent with the macro-anatomical position of the cingulate vocalization area. This overlap contradicts the dominant view that these areas form two distinct vocal pathways with dissociable functions. Instead, we propose that these brain areas are nodes in a single vocal network, with an emphasis on pitch modulation as a vehicle for affective expression.

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“…In fact, although external bladder sphincter motoneurons in ON directly innervate the striated sphincter muscles and are under voluntary control of the motor cortex, albeit not directly (Iwatsubo et al, 1990), they also behave as autonomic motoneurons. For example, ON motoneurons are smaller than most other somatic motoneurons.…”

Section: Motoneurons Innervating Bladder and Bladder Sphinctermentioning

confidence: 99%

Micturition and the soul

Holstege

2005

J of Comparative Neurology

125

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There is a close connection between micturition and emotion. Several species use micturition to signal important messages as territorial demarcation and sexual attraction. For this reason, micturition is coordinated not in the spinal cord but in the brainstem, where it is closely connected with the limbic system. In cat, bladder afferents terminate in a cell group in the lateral dorsal horn and lateral part of the intermediate zone. Neurons in this cell group project to supraspinal levels, not to the thalamus but to the central periaqueductal gray (PAG). Neurons in the lateral PAG, not receiving direct sacral cord afferents, project to the pontine micturition center (PMC). The PMC projects directly to the parasympathetic bladder motoneurons and to sacral GABA-ergic and glycinergic premotor interneurons that inhibit motoneurons in Onuf's nucleus innervating the external striated bladder sphincter. Thus, PMC stimulation causes bladder contraction and bladder sphincter relaxation, i.e., complete micturition. Other than the PAG, only the preoptic area and a cell group in the caudal hypothalamus project directly to the PMC. The ventromedial upper medullary tegmentum also sends projections to the PMC, but they are diffuse and also involve structures that adjoin the PMC. Neuroimaging studies in humans suggest that the systems controlling micturition in cat and human are very similar. It seems that the many structures in the brain that are known to influence micturition use the PAG as relay to the PMC. This basic organization has to be kept in mind in the fight against overactive bladder (OAB) and urge-incontinence.

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Corticofugal projections to the motor nuclei of the brainstem and spinal cord in humans

Cited by 127 publications

References 0 publications

Cortical Orofacial Motor Representation in Old World Monkeys, Great Apes, and Humans

Cortical Orofacial Motor Representation in Old World Monkeys, Great Apes, and Humans

Pitch underlies activation of the vocal system during affective vocalization

Micturition and the soul

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