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J R Mérida-velasco - One of the best experts on this subject based on the ideXlab platform.
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Blackwell Publishing Ltd BRIEF COMMUNICATION Origin of the Styloglossus muscle in the human fetus
2013Co-Authors: C. De La Cuadra Blanco, I. Sanchez-montesinos, Jose Francisco Rodríguez-vázquez, J R Mérida-velascoAbstract:The origin of the Styloglossus muscle was histologically studied bilaterally in nine human fetuses (18 sides). In all cases, the muscle originated in Reichert’s cartilage, which gives rise to the temporal styloid process. We identified three types of variation: type A, an accessory muscle fascicle originating from the mandibular angle, found in 7 cases (12 sides); type B, where the Styloglossus muscle was attached to the mandibular angle by fibrous tracts, found in three cases (4 sides); and type C, where an accessory muscle fascicle arose from the fibrous tract connecting Reichert’s cartilage to the mandibular angle; found in one case. In all cases (2 sides), the Styloglossus muscle was innervated by the hypoglossal nerve. Relationships between the Styloglossus muscle and vasculonervous elements of the prestyloid and retrostyloid spaces were analysed. Key words fetus; human; Styloglossus muscle; tongue
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Origin of the Styloglossus muscle in the human fetus.
Journal of Anatomy, 2006Co-Authors: C. De La Cuadra Blanco, I. Sanchez-montesinos, Jose Francisco Rodríguez-vázquez, J R Mérida-velascoAbstract:The origin of the Styloglossus muscle was histologically studied bilaterally in nine human fetuses (18 sides). In all cases, the muscle originated in Reichert's cartilage, which gives rise to the temporal styloid process. We identified three types of variation: type A, an accessory muscle fascicle originating from the mandibular angle, found in 7 cases (12 sides); type B, where the Styloglossus muscle was attached to the mandibular angle by fibrous tracts, found in three cases (4 sides); and type C, where an accessory muscle fascicle arose from the fibrous tract connecting Reichert's cartilage to the mandibular angle; found in one case. In all cases (2 sides), the Styloglossus muscle was innervated by the hypoglossal nerve. Relationships between the Styloglossus muscle and vasculonervous elements of the prestyloid and retrostyloid spaces were analysed.
Michelle R Ciucci - One of the best experts on this subject based on the ideXlab platform.
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functional characterization of extrinsic tongue muscles in the pink1 rat model of parkinson disease
PLOS ONE, 2020Co-Authors: Tiffany J. Glass, Nadine P. Connor, Cynthia A Kelmnelson, John C Szot, Jacob M Lake, Michelle R CiucciAbstract:Parkinson disease (PD) is associated with speech and swallowing difficulties likely due to pathology in widespread brain and nervous system regions. In post-mortem studies of PD, pathology has been reported in pharyngeal and laryngeal nerves and muscles. However, it is unknown whether PD is associated with neuromuscular changes in the tongue. Prior work in a rat model of PD (Pink1-/-) showed oromotor and swallowing deficits in the premanifest stage which suggested sensorimotor impairments of these functions. The present study tested the hypothesis that Pink1-/- rats show altered tongue function coinciding with neuromuscular differences within tongue muscles compared to wildtype (WT). Male Pink1-/- and WT rats underwent behavioral tongue function assays at 4 and 6 months of age (n = 7–8 rats per group), which are time points early in the disease. At 6 months, genioglossus (GG) and Styloglossus (SG) muscles were analyzed for myosin heavy chain isoforms (MyHC), α-synuclein levels, myofiber size, centrally nucleated myofibers, and neuromuscular junction (NMJ) innervation. Pink1-/- showed greater tongue press force variability, and greater tongue press forces and rates as compared to WT. Additionally, Pink1-/- showed relative increases of MyHC 2a in SG, but typical MyHC profiles in GG. Western blots revealed Pink1-/- had more α-synuclein protein than WT in GG, but not in SG. There were no differences between Pink1-/- and WT in myofiber size, centrally-nucleated myofibers, or NMJ innervation. α-synuclein protein was observed in nerves, NMJ, and vessels in both genotypes. Findings at these early disease stages suggest small changes or no changes in several peripheral biological measures, and intact motor innervation of tongue muscles. Future work should evaluate these measures at later disease stages to determine when robust pathological peripheral change contributes to functional change, and what CNS deficits cause behavioral changes. Understanding how PD affects central and peripheral mechanisms will help determine therapy targets for speech and swallowing disorders.
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Functional characterization of extrinsic tongue muscles in the Pink1-/- rat model of Parkinson disease.
'Public Library of Science (PLoS)', 2020Co-Authors: Tiffany J. Glass, Nadine P. Connor, John C Szot, Jacob M Lake, Cynthia A Kelm-nelson, Michelle R CiucciAbstract:Parkinson disease (PD) is associated with speech and swallowing difficulties likely due to pathology in widespread brain and nervous system regions. In post-mortem studies of PD, pathology has been reported in pharyngeal and laryngeal nerves and muscles. However, it is unknown whether PD is associated with neuromuscular changes in the tongue. Prior work in a rat model of PD (Pink1-/-) showed oromotor and swallowing deficits in the premanifest stage which suggested sensorimotor impairments of these functions. The present study tested the hypothesis that Pink1-/- rats show altered tongue function coinciding with neuromuscular differences within tongue muscles compared to wildtype (WT). Male Pink1-/- and WT rats underwent behavioral tongue function assays at 4 and 6 months of age (n = 7-8 rats per group), which are time points early in the disease. At 6 months, genioglossus (GG) and Styloglossus (SG) muscles were analyzed for myosin heavy chain isoforms (MyHC), α-synuclein levels, myofiber size, centrally nucleated myofibers, and neuromuscular junction (NMJ) innervation. Pink1-/- showed greater tongue press force variability, and greater tongue press forces and rates as compared to WT. Additionally, Pink1-/- showed relative increases of MyHC 2a in SG, but typical MyHC profiles in GG. Western blots revealed Pink1-/- had more α-synuclein protein than WT in GG, but not in SG. There were no differences between Pink1-/- and WT in myofiber size, centrally-nucleated myofibers, or NMJ innervation. α-synuclein protein was observed in nerves, NMJ, and vessels in both genotypes. Findings at these early disease stages suggest small changes or no changes in several peripheral biological measures, and intact motor innervation of tongue muscles. Future work should evaluate these measures at later disease stages to determine when robust pathological peripheral change contributes to functional change, and what CNS deficits cause behavioral changes. Understanding how PD affects central and peripheral mechanisms will help determine therapy targets for speech and swallowing disorders
Tiffany J. Glass - One of the best experts on this subject based on the ideXlab platform.
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Progressive Protrusive Tongue Exercise Does Not Alter Aging Effects in Retrusive Tongue Muscles
'Frontiers Media SA', 2021Co-Authors: Tiffany J. Glass, Nadine P. Connor, Joanie E. Figueroa, John A. Russell, Brittany N. KrekelerAbstract:Purpose: Exercise-based treatment approaches for dysphagia may improve swallow function in part by inducing adaptive changes to muscles involved in swallowing and deglutition. We have previously shown that both aging and progressive resistance tongue exercise, in a rat model, can induce biological changes in the genioglossus (GG); a muscle that elevates and protrudes the tongue. However, the impacts of progressive resistance tongue exercise on the retrusive muscles (Styloglossus, SG; hyoglossus, HG) of the tongue are unknown. The purpose of this study was to examine the impact of a progressive resistance tongue exercise regimen on the retrusive tongue musculature in the context of aging. Given that aging alters retrusive tongue muscles to more slowly contracting fiber types, we hypothesized that these biological changes may be mitigated by tongue exercise.Methods: Hyoglossus (HG) and Styloglossus (SG) muscles of male Fischer 344/Brown Norway rats were assayed in age groups of young (9 months old, n = 24), middle-aged (24 months old, n = 23), and old (32 months old, n = 26), after receiving an 8-week period of either progressive resistance protrusive tongue exercise, or sham exercise conditions. Following exercise, HG and SG tongue muscle contractile properties were assessed in vivo. HG and SG muscles were then isolated and assayed to determine myosin heavy chain isoform (MyHC) composition.Results: Both retrusive tongue muscle contractile properties and MyHC profiles of the HG and SG muscles were significantly impacted by age, but were not significantly impacted by tongue exercise. Old rats had significantly longer retrusive tongue contraction times and longer decay times than young rats. Additionally, HG and SG muscles showed significant MyHC profile changes with age, in that old groups had slower MyHC profiles as compared to young groups. However, the exercise condition did not induce significant effects in any of the biological outcome measures.Conclusion: In a rat model of protrusive tongue exercise, aging induced significant changes in retrusive tongue muscles, and these age-induced changes were unaffected by the tongue exercise regimen. Collectively, results are compatible with the interpretation that protrusive tongue exercise does not induce changes to retrusive tongue muscle function
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functional characterization of extrinsic tongue muscles in the pink1 rat model of parkinson disease
PLOS ONE, 2020Co-Authors: Tiffany J. Glass, Nadine P. Connor, Cynthia A Kelmnelson, John C Szot, Jacob M Lake, Michelle R CiucciAbstract:Parkinson disease (PD) is associated with speech and swallowing difficulties likely due to pathology in widespread brain and nervous system regions. In post-mortem studies of PD, pathology has been reported in pharyngeal and laryngeal nerves and muscles. However, it is unknown whether PD is associated with neuromuscular changes in the tongue. Prior work in a rat model of PD (Pink1-/-) showed oromotor and swallowing deficits in the premanifest stage which suggested sensorimotor impairments of these functions. The present study tested the hypothesis that Pink1-/- rats show altered tongue function coinciding with neuromuscular differences within tongue muscles compared to wildtype (WT). Male Pink1-/- and WT rats underwent behavioral tongue function assays at 4 and 6 months of age (n = 7–8 rats per group), which are time points early in the disease. At 6 months, genioglossus (GG) and Styloglossus (SG) muscles were analyzed for myosin heavy chain isoforms (MyHC), α-synuclein levels, myofiber size, centrally nucleated myofibers, and neuromuscular junction (NMJ) innervation. Pink1-/- showed greater tongue press force variability, and greater tongue press forces and rates as compared to WT. Additionally, Pink1-/- showed relative increases of MyHC 2a in SG, but typical MyHC profiles in GG. Western blots revealed Pink1-/- had more α-synuclein protein than WT in GG, but not in SG. There were no differences between Pink1-/- and WT in myofiber size, centrally-nucleated myofibers, or NMJ innervation. α-synuclein protein was observed in nerves, NMJ, and vessels in both genotypes. Findings at these early disease stages suggest small changes or no changes in several peripheral biological measures, and intact motor innervation of tongue muscles. Future work should evaluate these measures at later disease stages to determine when robust pathological peripheral change contributes to functional change, and what CNS deficits cause behavioral changes. Understanding how PD affects central and peripheral mechanisms will help determine therapy targets for speech and swallowing disorders.
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Functional characterization of extrinsic tongue muscles in the Pink1-/- rat model of Parkinson disease.
'Public Library of Science (PLoS)', 2020Co-Authors: Tiffany J. Glass, Nadine P. Connor, John C Szot, Jacob M Lake, Cynthia A Kelm-nelson, Michelle R CiucciAbstract:Parkinson disease (PD) is associated with speech and swallowing difficulties likely due to pathology in widespread brain and nervous system regions. In post-mortem studies of PD, pathology has been reported in pharyngeal and laryngeal nerves and muscles. However, it is unknown whether PD is associated with neuromuscular changes in the tongue. Prior work in a rat model of PD (Pink1-/-) showed oromotor and swallowing deficits in the premanifest stage which suggested sensorimotor impairments of these functions. The present study tested the hypothesis that Pink1-/- rats show altered tongue function coinciding with neuromuscular differences within tongue muscles compared to wildtype (WT). Male Pink1-/- and WT rats underwent behavioral tongue function assays at 4 and 6 months of age (n = 7-8 rats per group), which are time points early in the disease. At 6 months, genioglossus (GG) and Styloglossus (SG) muscles were analyzed for myosin heavy chain isoforms (MyHC), α-synuclein levels, myofiber size, centrally nucleated myofibers, and neuromuscular junction (NMJ) innervation. Pink1-/- showed greater tongue press force variability, and greater tongue press forces and rates as compared to WT. Additionally, Pink1-/- showed relative increases of MyHC 2a in SG, but typical MyHC profiles in GG. Western blots revealed Pink1-/- had more α-synuclein protein than WT in GG, but not in SG. There were no differences between Pink1-/- and WT in myofiber size, centrally-nucleated myofibers, or NMJ innervation. α-synuclein protein was observed in nerves, NMJ, and vessels in both genotypes. Findings at these early disease stages suggest small changes or no changes in several peripheral biological measures, and intact motor innervation of tongue muscles. Future work should evaluate these measures at later disease stages to determine when robust pathological peripheral change contributes to functional change, and what CNS deficits cause behavioral changes. Understanding how PD affects central and peripheral mechanisms will help determine therapy targets for speech and swallowing disorders
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Muscles Selected for Analysis of Young Mice.
2016Co-Authors: Tiffany J. Glass, Nadine P. ConnorAbstract:A) Genioglossus (GG), Styloglossus (SG), Anterior belly of the digastric (ADG), and Posterior belly of the digastric (PDG) were selected from young mice for analysis of MyHC isoform composition. B) Representative SDS-PAGE gel excerpts. 2a/2x = position of myosin heavy chains 2a and 2x. 2b = myosin heavy chain 2b. I = myosin heavy chain I. C) Relative levels of the MyHC 2b isoform protein in each muscle, compared by genotype. Mean and SEM. (* indicates p ≤ .05).
Ralph F Fregosi - One of the best experts on this subject based on the ideXlab platform.
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effect of co activation of tongue protrudor and retractor muscles on tongue movements and pharyngeal airflow mechanics in the rat
The Journal of Physiology, 1999Co-Authors: David D Fuller, J S Williams, P L Janssen, Ralph F FregosiAbstract:Electromyographic recordings in animal models indicate that tongue protrudor (genioglossus, GG) and retractor muscles (Styloglossus, SG; hyoglossus, HG) are co-activated during inspiration (Yasui et al. 1993, Fregosi & Fuller, 1997). Moreover, recent experiments indicate that respiratory-related co-activation of protrudor and retractor muscles results in retraction of the tongue (Fregosi & Fuller, 1997; Fuller et al. 1998). The observation that tongue muscle co-activation causes retraction of the tongue implies that respiratory-related tongue-motor activity narrows, rather than dilates, the oropharynx. However, two groups of investigators have shown that co-activation of the protrudor and retractor muscles evoked by XIIth nerve stimulation results in increased inspiratory flow rates in obstructive sleep apnoea (OSA) patients, in spite of clear tongue retraction (Eisele et al. 1997; De Backer et al. 1998). Protrusion of the tongue, evoked by either medial XIIth nerve branch stimulation (Eisele et al. 1997) or direct GG muscle stimulation (Schwartz et al. 1996) is also associated with increased inspiratory flow rates in human subjects. These observations suggest that either co-activation of tongue protrudor and retractor muscles, or independent protrudor muscle activation will improve pharyngeal flow mechanics. This is in spite of the fact that the tongue retracts during co-activation, and protrudes during unopposed GG contraction. To examine the mechanisms by which both co-activation and independent activation of the protrudor and retractor tongue muscles influence upper airway flow mechanics, we have developed a modification of the experimental model of Schwartz and colleagues (Schwartz et al. 1993). Our preparation allows quantification of both axial tongue movements and pharyngeal flow mechanics while muscle nerves to tongue protrudor and retractor muscles are stimulated simultaneously or selectively. In contrast to previous investigations (Schwartz et al. 1993; Eisele et al. 1995), we elected to leave the mouth of the animal open, enabling quantification of axial tongue movements as well as permitting flow to be oral, nasal, or oronasal. Our hypothesis was that co-activation of protrudor and retractor muscles will decrease the collapsibility of the pharyngeal airway, resulting in higher flow rates at any given transmural pressure. Implicit in this hypothesis is the concept that tongue protrusion (and dilation of the pharyngeal airway) is not required to improve pharyngeal flow mechanics. The hypothesis was retained, and the implications of our results for maintenance of pharyngeal airway patency in the intact animal are discussed.
Nadine P. Connor - One of the best experts on this subject based on the ideXlab platform.
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Progressive Protrusive Tongue Exercise Does Not Alter Aging Effects in Retrusive Tongue Muscles
'Frontiers Media SA', 2021Co-Authors: Tiffany J. Glass, Nadine P. Connor, Joanie E. Figueroa, John A. Russell, Brittany N. KrekelerAbstract:Purpose: Exercise-based treatment approaches for dysphagia may improve swallow function in part by inducing adaptive changes to muscles involved in swallowing and deglutition. We have previously shown that both aging and progressive resistance tongue exercise, in a rat model, can induce biological changes in the genioglossus (GG); a muscle that elevates and protrudes the tongue. However, the impacts of progressive resistance tongue exercise on the retrusive muscles (Styloglossus, SG; hyoglossus, HG) of the tongue are unknown. The purpose of this study was to examine the impact of a progressive resistance tongue exercise regimen on the retrusive tongue musculature in the context of aging. Given that aging alters retrusive tongue muscles to more slowly contracting fiber types, we hypothesized that these biological changes may be mitigated by tongue exercise.Methods: Hyoglossus (HG) and Styloglossus (SG) muscles of male Fischer 344/Brown Norway rats were assayed in age groups of young (9 months old, n = 24), middle-aged (24 months old, n = 23), and old (32 months old, n = 26), after receiving an 8-week period of either progressive resistance protrusive tongue exercise, or sham exercise conditions. Following exercise, HG and SG tongue muscle contractile properties were assessed in vivo. HG and SG muscles were then isolated and assayed to determine myosin heavy chain isoform (MyHC) composition.Results: Both retrusive tongue muscle contractile properties and MyHC profiles of the HG and SG muscles were significantly impacted by age, but were not significantly impacted by tongue exercise. Old rats had significantly longer retrusive tongue contraction times and longer decay times than young rats. Additionally, HG and SG muscles showed significant MyHC profile changes with age, in that old groups had slower MyHC profiles as compared to young groups. However, the exercise condition did not induce significant effects in any of the biological outcome measures.Conclusion: In a rat model of protrusive tongue exercise, aging induced significant changes in retrusive tongue muscles, and these age-induced changes were unaffected by the tongue exercise regimen. Collectively, results are compatible with the interpretation that protrusive tongue exercise does not induce changes to retrusive tongue muscle function
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functional characterization of extrinsic tongue muscles in the pink1 rat model of parkinson disease
PLOS ONE, 2020Co-Authors: Tiffany J. Glass, Nadine P. Connor, Cynthia A Kelmnelson, John C Szot, Jacob M Lake, Michelle R CiucciAbstract:Parkinson disease (PD) is associated with speech and swallowing difficulties likely due to pathology in widespread brain and nervous system regions. In post-mortem studies of PD, pathology has been reported in pharyngeal and laryngeal nerves and muscles. However, it is unknown whether PD is associated with neuromuscular changes in the tongue. Prior work in a rat model of PD (Pink1-/-) showed oromotor and swallowing deficits in the premanifest stage which suggested sensorimotor impairments of these functions. The present study tested the hypothesis that Pink1-/- rats show altered tongue function coinciding with neuromuscular differences within tongue muscles compared to wildtype (WT). Male Pink1-/- and WT rats underwent behavioral tongue function assays at 4 and 6 months of age (n = 7–8 rats per group), which are time points early in the disease. At 6 months, genioglossus (GG) and Styloglossus (SG) muscles were analyzed for myosin heavy chain isoforms (MyHC), α-synuclein levels, myofiber size, centrally nucleated myofibers, and neuromuscular junction (NMJ) innervation. Pink1-/- showed greater tongue press force variability, and greater tongue press forces and rates as compared to WT. Additionally, Pink1-/- showed relative increases of MyHC 2a in SG, but typical MyHC profiles in GG. Western blots revealed Pink1-/- had more α-synuclein protein than WT in GG, but not in SG. There were no differences between Pink1-/- and WT in myofiber size, centrally-nucleated myofibers, or NMJ innervation. α-synuclein protein was observed in nerves, NMJ, and vessels in both genotypes. Findings at these early disease stages suggest small changes or no changes in several peripheral biological measures, and intact motor innervation of tongue muscles. Future work should evaluate these measures at later disease stages to determine when robust pathological peripheral change contributes to functional change, and what CNS deficits cause behavioral changes. Understanding how PD affects central and peripheral mechanisms will help determine therapy targets for speech and swallowing disorders.
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Functional characterization of extrinsic tongue muscles in the Pink1-/- rat model of Parkinson disease.
'Public Library of Science (PLoS)', 2020Co-Authors: Tiffany J. Glass, Nadine P. Connor, John C Szot, Jacob M Lake, Cynthia A Kelm-nelson, Michelle R CiucciAbstract:Parkinson disease (PD) is associated with speech and swallowing difficulties likely due to pathology in widespread brain and nervous system regions. In post-mortem studies of PD, pathology has been reported in pharyngeal and laryngeal nerves and muscles. However, it is unknown whether PD is associated with neuromuscular changes in the tongue. Prior work in a rat model of PD (Pink1-/-) showed oromotor and swallowing deficits in the premanifest stage which suggested sensorimotor impairments of these functions. The present study tested the hypothesis that Pink1-/- rats show altered tongue function coinciding with neuromuscular differences within tongue muscles compared to wildtype (WT). Male Pink1-/- and WT rats underwent behavioral tongue function assays at 4 and 6 months of age (n = 7-8 rats per group), which are time points early in the disease. At 6 months, genioglossus (GG) and Styloglossus (SG) muscles were analyzed for myosin heavy chain isoforms (MyHC), α-synuclein levels, myofiber size, centrally nucleated myofibers, and neuromuscular junction (NMJ) innervation. Pink1-/- showed greater tongue press force variability, and greater tongue press forces and rates as compared to WT. Additionally, Pink1-/- showed relative increases of MyHC 2a in SG, but typical MyHC profiles in GG. Western blots revealed Pink1-/- had more α-synuclein protein than WT in GG, but not in SG. There were no differences between Pink1-/- and WT in myofiber size, centrally-nucleated myofibers, or NMJ innervation. α-synuclein protein was observed in nerves, NMJ, and vessels in both genotypes. Findings at these early disease stages suggest small changes or no changes in several peripheral biological measures, and intact motor innervation of tongue muscles. Future work should evaluate these measures at later disease stages to determine when robust pathological peripheral change contributes to functional change, and what CNS deficits cause behavioral changes. Understanding how PD affects central and peripheral mechanisms will help determine therapy targets for speech and swallowing disorders
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Muscles Selected for Analysis of Young Mice.
2016Co-Authors: Tiffany J. Glass, Nadine P. ConnorAbstract:A) Genioglossus (GG), Styloglossus (SG), Anterior belly of the digastric (ADG), and Posterior belly of the digastric (PDG) were selected from young mice for analysis of MyHC isoform composition. B) Representative SDS-PAGE gel excerpts. 2a/2x = position of myosin heavy chains 2a and 2x. 2b = myosin heavy chain 2b. I = myosin heavy chain I. C) Relative levels of the MyHC 2b isoform protein in each muscle, compared by genotype. Mean and SEM. (* indicates p ≤ .05).
