scholarly journals Adipose fin development and its relation to the evolutionary origins of median fins

2018 ◽  
Author(s):  
Thomas A. Stewart ◽  
Robert K. Ho ◽  
Melina E. Hale
Keyword(s):  
Spinal Cord ◽  
Facial Nerve ◽  
Sensory Innervation ◽  
Evolutionary Origins ◽  
Evolution And Development ◽  
Dorsal Rami ◽  
Adipose Fin ◽  
Median Fins ◽  
Fin Development

AbstractThe dorsal, anal and caudal fins of vertebrates are proposed to have originated by the partitioning and transformation of the continuous median fin fold that is plesiomorphic to chordates. Evaluating this hypothesis has been challenging, because it is unclear how the median fin fold relates to the adult median fins of vertebrates. To understand how new median fins originate, here we study the development and diversity of adipose fins. Phylogenetic mapping shows that in all lineages except Characoidei (Characiformes) adipose fins develop from a domain of the larval median fin fold. To inform how the larva’s median fin fold contributes to the adipose fin, we study Corydoras aeneus (Siluriformes). As the fin fold reduces around the prospective site of the adipose fin, a fin spine develops in the fold, growing both proximally and distally, and sensory innervation, which appears to originate from the recurrent ramus of the facial nerve and from dorsal rami of the spinal cord, develops in the adipose fin membrane. Collectively, these data show how a plesiomorphic median fin fold can serve as scaffolding for the evolution and development of novel, individuated median fins, consistent with the median fin fold hypothesis.

scholarly journals Adipose fin development and its relation to the evolutionary origins of median fins

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Thomas A. Stewart ◽  
Melvin M. Bonilla ◽  
Robert K. Ho ◽  
Melina E. Hale
Keyword(s):  
Evolutionary Origins ◽  
Adipose Fin ◽  
Median Fins ◽  
Fin Development

scholarly journals The evolutionary origins and diversity of the neuromuscular system of paired appendages in batoids

2019 ◽  
Vol 286 (1914) ◽  
pp. 20191571 ◽  
Author(s):  
Natalie Turner ◽  
Deimante Mikalauskaite ◽  
Krista Barone ◽  
Kathleen Flaherty ◽  
Gayani Senevirathne ◽  
...  
Keyword(s):  
Body Wall ◽  
Spinal Nerves ◽  
Evolutionary Origins ◽  
Neuromuscular Systems ◽  
Terrestrial Habitats ◽  
Fundamental Pattern ◽  
Genetic Programme ◽  
Migratory Muscle Precursors ◽  
Fin Development ◽  
Appendage Patterning

Appendage patterning and evolution have been active areas of inquiry for the past two centuries. While most work has centred on the skeleton, particularly that of amniotes, the evolutionary origins and molecular underpinnings of the neuromuscular diversity of fish appendages have remained enigmatic. The fundamental pattern of segmentation in amniotes, for example, is that all muscle precursors and spinal nerves enter either the paired appendages or body wall at the same spinal level. The condition in finned vertebrates is not understood. To address this gap in knowledge, we investigated the development of muscles and nerves in unpaired and paired fins of skates and compared them to those of chain catsharks. During skate and shark embryogenesis, cell populations of muscle precursors and associated spinal nerves at the same axial level contribute to both appendages and body wall, perhaps representing an ancestral condition of gnathostome appendicular neuromuscular systems. Remarkably in skates, this neuromuscular bifurcation as well as colinear Hox expression extend posteriorly to pattern a broad paired fin domain. In addition, we identified migratory muscle precursors (MMPs), which are known to develop into paired appendage muscles with Pax3 and Lbx1 gene expression, in the dorsal fins of skates. Our results suggest that muscles of paired fins have evolved via redeployment of the genetic programme of MMPs that were already involved in dorsal fin development. Appendicular neuromuscular systems most likely have emerged as side branches of body wall neuromusculature and have been modified to adapt to distinct aquatic and terrestrial habitats.

Active tactile exploration influences the functional maturation of the somatosensory system

1996 ◽  
Vol 75 (5) ◽  
pp. 2192-2196 ◽  
Author(s):  
M. A. Nicolelis ◽  
L. M. De Oliveira ◽  
R. C. Lin ◽  
J. K. Chapin
Keyword(s):  
Facial Nerve ◽  
Somatosensory System ◽  
Tactile Perception ◽  
Sensory Innervation ◽  
Medial Nucleus ◽  
Functional Maturation ◽  
Body Regions ◽  
The Face ◽  
Posterior Medial Nucleus ◽  
Active Exploration

1. The hypothesis that active exploration of objects is required for the functional maturation of neuronal circuits subserving tactile perception was tested by subjecting 8- to 11-day old rats to a complete unilateral section of the facial nerve. This procedure selectively abolished whisker protraction movements without affecting the sensory innervation of the facial vibrissae, the tactile organs used by rats to discriminate object texture and shape. 2. Six to 14 mo after the facial nerve section, simultaneous recordings of neuronal ensembles located in the ventral posterior medial nucleus (VPM) of the thalamus revealed a marked reduction in receptive field (RF) size (in terms of number of whiskers), and the formation of abnormal RF surrounds, spanning the face and contiguous body regions. In addition, the directional organization of VPM RFs, represented by caudal to rostral shifts in RF centers over 30 ms following whisker stimulation, was greatly reduced in these animals. 3. These results suggest that neonatal active tactile exploration is required to establish normal spatiotemporal patterning of neuronal RFs within the somatosensory system, and consequently, to develop normal tactile perception.

scholarly journals Hindbrain and Spinal Cord Contributions to the Cutaneous Sensory Innervation of the Larval Zebrafish Pectoral Fin

2020 ◽  
Vol 14 ◽  
Author(s):  
Katharine W. Henderson ◽  
Alexander Roche ◽  
Evdokia Menelaou ◽  
Melina E. Hale
Keyword(s):  
Spinal Cord ◽  
Sensory Innervation ◽  
Pectoral Fin ◽  
Larval Zebrafish

Myelinated fibers of spinal cord blood vessels—sensory innervation?

2000 ◽  
Vol 4 (5) ◽  
pp. 353-355 ◽  
Author(s):  
James E. Heavner ◽  
Penelope W. Coates ◽  
Gabor Racz
Keyword(s):  
Spinal Cord ◽  
Cord Blood ◽  
Blood Vessels ◽  
Sensory Innervation ◽  
Myelinated Fibers

scholarly journals Neuroanatomical Characteristics of Deep and Superficial Needling Using Li11 as An Example

2015 ◽  
Vol 33 (6) ◽  
pp. 472-477 ◽  
Author(s):  
Meiling Wu ◽  
Jingjing Cui ◽  
Dongsheng Xu ◽  
Kun Zhang ◽  
Xianghong Jing ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Sensory Neurons ◽  
Subcutaneous Injection ◽  
Intramuscular Injection ◽  
Subcutaneous Tissue ◽  
Acupuncture Point ◽  
Sensory Innervation ◽  
Neural Basis ◽  
Neural Tracing ◽  
Superficial Needling

Objectives To compare the neuroanatomical characteristics of the deep and superficial tissues at acupuncture point LI11 using a neural tracing technique, in order to examine the neural basis of potential differences between deep and superficial needling techniques. Methods In order to mimic the situations of the deep and superficial needling, the retrograde neural tracer Alexa Fluor 488 conjugate of cholera toxin subunit B (AF488-CTB) was injected into the muscle or subcutaneous tissue, respectively, at acupuncture point LI11 in eight rats (n=4 each). Three days following injection, the distribution of motor and sensory neurons labelled with AF488-CTB was examined in the spinal cord and dorsal root ganglia (DRG) under a fluorescent microscope. Results For both types of injection, labelled motor and sensory neurons were distributed on the side ipsilateral to the injection in the spinal cord and DRG between spinal levels C5 and T1. The number of labelled motor neurons following intramuscular injection was significantly higher than subcutaneous injection. By contrast, the number of labelled sensory neurons following subcutaneous injection was significantly higher in number and extended over a greater number of spinal segments compared to intramuscular injection. Conclusions These data indicate that the motor and sensory innervation of muscle and subcutaneous tissue beneath LI11 differ, and suggest that acupuncture signals induced by deep and superficial needling stimulation may be transmitted through different neural pathways.

scholarly journals The evolutionary origins and diversity of the neuromuscular system of paired appendages in batoids

2019 ◽  
Author(s):  
Natalie Turner ◽  
Deimante Mikalauskaite ◽  
Krista Barone ◽  
Kathleen Flaherty ◽  
Gayani Senevirathne ◽  
...  
Keyword(s):  
Body Wall ◽  
Spinal Nerves ◽  
The Past ◽  
Evolutionary Origins ◽  
Neuromuscular Systems ◽  
Terrestrial Habitats ◽  
Fundamental Pattern ◽  
Migratory Muscle Precursors ◽  
Fin Development ◽  
Appendage Patterning

AbstractAppendage patterning and evolution have been active areas of inquiry for the past two centuries. While most work has centered on the skeleton, particularly that of amniotes, the evolutionary origins and molecular underpinnings of the neuromuscular diversity of fish appendages have remained enigmatic. The fundamental pattern of segmentation in amniotes, for example, is that all muscle precursors and spinal nerves enter either the paired appendages or body wall at the same spinal level. The condition in finned vertebrates is not understood. To address this gap in knowledge, we investigated the development of muscles and nerves in unpaired and paired fins of skates and compared them to those of chain catsharks. During skate and shark embryogenesis, cell populations of muscle precursors and associated spinal nerves at the same axial level contribute to both appendages and body wall, perhaps representing an ancestral condition of gnathostome appendicular neuromuscular systems. Remarkably in skates, this neuromuscular bifurcation as well as colinear Hox expression extend posteriorly to pattern a broad paired fin domain. In addition, we identified migratory muscle precursors (MMPs), which are known to develop into paired appendage muscles with Pax3 and Lbx1 gene expression, in the dorsal fins of skates. Our results suggest that muscles of paired fins have evolved via redeployment of the genetic program of MMPs that were already involved in dorsal fin development. Appendicular neuromuscular systems most likely have emerged as side branches of body wall neuromusculature and have been modified to adapt to distinct aquatic and terrestrial habitats.

Brain and Spinal Cord Tumors of Children

1966 ◽  
Vol 52 (4) ◽  
pp. 303-311 ◽  
Author(s):  
Irena Światkowska
Keyword(s):  
Spinal Cord ◽  
Facial Nerve ◽  
Fourth Ventricle ◽  
Spinal Tumors ◽  
Spinal Cord Tumors ◽  
Early Symptoms ◽  
Cerebral Tumors ◽  
Brain And Spinal Cord ◽  
Visual Disturbances

Two hundred and twenty cases of cerebral tumors and 8 cases of spinal cord tumors in infancy are reported. The incidence of cerebral tumors reaches its peaks at 3–4 and 6–10 years of age; as regards sex, there were 125 females and 103 males. Medulloblastomas, ependymomas and craniopharyngiomas were more frequent in boys, meningiomas and neurinomas in girls. Histologically the more frequent types were gliomas (179 cases) especially astrocytomas (83 cases); malignant medulloblastomas (50 cases) and ependymomas (26 cases) followed in order of frequency; craniopharyngiomas were observed in 15 cases and meningiomas in 9 cases. There were 74 supratentorial and 146 subtentorial localizations; the fourth ventricle was site of tumors in 46 cases. The most frequent of early symptoms was headache; sudden and projectile vomiting was also frequent, while ataxia and visual disturbances were more rare; when illness was fully developed the more frequent symptoms were reeling, papilledema, paresis of extremities and of facial nerve, nystagmus and hydrocephalus. Among the 8 cases of spinal tumors, there were 2 neurinomas, 2 dermoids, 1 ependymoma, 1 meningioma, 1 chordoma and 1 sarcoma.

Nociceptive cutaneous stimuli evoke localized contractions in a skeletal muscle

1988 ◽  
Vol 60 (2) ◽  
pp. 446-462 ◽  
Author(s):  
E. Theriault ◽  
J. Diamond
Keyword(s):  
Skeletal Muscle ◽  
Spinal Cord ◽  
Cervical Spinal Cord ◽  
Muscle Fibers ◽  
Sensory Stimulation ◽  
Sensory Innervation ◽  
Reflex Response ◽  
Emg Activity ◽  
Adult Rats ◽  
Sensory Stimuli

1. The cutaneus trunci muscle (CTM) is a thin broad sheet of skeletal muscle that originates bilaterally on the humerus and inserts beneath the dermis of back and flank skin. A nociceptive stimulus applied to the skin elicits a localized reflex contraction in that region of the CTM underlying the site of sensory stimulation. While this "local sign" character of the CTM reflex corresponds to the segmental distribution of the afferent nerves (the dorsal cutaneous nerves, or DCNs) that enter the spinal cord in the lower thoracic and the lumbar levels, the motor output originates entirely from a circumscribed region of the cervical spinal cord. 2. Electrophysiological analysis of EMG activity in the muscle reflexly evoked by direct electrical stimulation of individual DCNs revealed a distinct topographic relationship, in that the shortest latency response of EMG activity in the muscle was consistently located approximately 1.0 cm rostral to the dermatome of the stimulated DCN. 3. Histochemical studies of the CTM show that individual muscle fibers run rostrocaudally, are focally innervated, and in adult rats, are approximately 3.0 cm in length. The major motor nerves exit from the brachial plexus, and functionally they divide the muscle into longitudinal (rostrocaudal) territories, which thus lie orthogonal to the dermatomal pattern of sensory innervation. The localized reflex responses to focal sensory stimuli indicate that the major longitudinal muscle fields contain many "reflex compartments." 4. The compartmentalized nature of the reflex response in the CTM suggests that nociceptive input from any one sensory dermatome has a preferred access to that fraction of the motoneuron pool that supplies the area of muscle underlying that specific region of skin, i.e., there is a sort of "matching" between groups of primary sensory neurons, interneurons, and motoneurons, which relates to the peripheral location of the stimulated nerve endings and of the muscle fibers that are reflexly activated. Although the partitioning of sensory input to motor nuclei has been shown most clearly for monosynaptic Ia connections, the CTM reflex suggests that sensory partitioning may also be demonstrated in a polysynaptic circuit.

Prenatal development of somatosensory primary afferent connections in the sheep

1995 ◽  
Vol 7 (3) ◽  
pp. 427 ◽  
Author(s):  
S Rees ◽  
I Nitsos ◽  
J Rawson
Keyword(s):  
Spinal Cord ◽  
Dorsal Root Ganglion ◽  
Dorsal Horn ◽  
Dorsal Root ◽  
Muscle Spindles ◽  
Sensory Innervation ◽  
Muscle Fibres ◽  
Fetal Sheep ◽  
Primary Afferent ◽  
Dorsal Horn Neurons

A summary is presented of recently published studies on the structural and functional development of cutaneous and muscle receptors and the connections of their afferent fibres in fetal sheep (n = 26) aged between 67 and 143 days gestation (term, 146 days). In these studies it was shown that primary afferent fibres projected to, and made synaptic connections with, dorsal horn neurons in lumbosacral spinal cord by 56-61 days gestation. Sensory innervation of the skin occurred later by about 75 days gestation and, at this age, stimulation of the skin first activated cutaneous afferent fibres and evoked a discharge in dorsal root ganglion and dorsal horn neurons. Muscle stretch first activated muscle spindles and evoked a discharge in dorsal root ganglion cells by about 75 days. Prior to this (by about 67 days) primary afferent fibres had begun to innervate motoneuron pools in the spinal cord, and motor nerves had begun to innervate muscle fibres. Both muscle spindle and cutaneous innervation were relatively simple at mid gestation indicating that the structure of sensory receptors need not be complex in order to generate a response. Neural pathways necessary for reflex activity involving muscle spindles are therefore present and functional by mid gestation as are cutaneous pathways projecting from the skin to the spinal cord.

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