scholarly journals Multimodal Imaging and Analysis of the Neuroanatomical Organization of the Primary Olfactory Inputs in the Brownbanded Bamboo Shark, Chiloscyllium punctatum

2020 ◽  
Vol 14 ◽  
Author(s):  
Victoria Camilieri-Asch ◽  
Harrison T. Caddy ◽  
Alysia Hubbard ◽  
Paul Rigby ◽  
Barry Doyle ◽  
...  
Keyword(s):  
Water Flow ◽  
Functional Organization ◽  
Light And Electron Microscopy ◽  
Imaging Study ◽  
Anterior Portion ◽  
Terrestrial Vertebrates ◽  
Somatotopic Organization ◽  
Bamboo Shark ◽  
Enhanced Computed Tomography ◽  
Olfactory Rosette

There is currently a limited understanding of the morphological and functional organization of the olfactory system in cartilaginous fishes, particularly when compared to bony fishes and terrestrial vertebrates. In this fish group, there is a clear paucity of information on the characterization, density, and distribution of olfactory receptor neurons (ORNs) within the sensory olfactory epithelium lining the paired olfactory rosettes, and their functional implications with respect to the hydrodynamics of incurrent water flow into the nares. This imaging study examines the brownbanded bamboo shark Chiloscyllium punctatum (Elasmobranchii) and combines immunohistochemical labeling using antisera raised against five G-protein α-subunits (Gαs/olf, Gαq/11/14, Gαi–1/2/3, Gαi–3, Gαo) with light and electron microscopy, to characterize the morphological ORN types present. Three main ORNs (“long”, “microvillous” and “crypt-like”) are confirmed and up to three additional microvilli-bearing types are also described; “Kappe-like” (potential or homologous “Kappe” as in teleosts), “pear-shaped” and “teardrop-shaped” cells. These morphotypes will need to be confirmed molecularly in the future. Using X-ray diffusible iodine-based contrast-enhanced computed tomography (diceCT), high-resolution scans of the olfactory rosettes, olfactory bulbs (OBs), peduncles, and telencephalon reveal a lateral segregation of primary olfactory inputs within the OBs, with distinct medial and lateral clusters of glomeruli, suggesting a potential somatotopic organization. However, most ORN morphotypes are found to be ubiquitously distributed within the medial and lateral regions of the olfactory rosette, with at least three microvilli-bearing ORNs labeled with anti-Gαo found in significantly higher densities in lateral lamellae [in lateral lamellae] and on the anterior portion of lamellae (facing the olfactory cavity). These microvilli-bearing ORN morphotypes (microvillous, “Kappe-like,” “pear-shaped,” and “teardrop-shaped”) are the most abundant across the olfactory rosette of this species, while ciliated ORNs are less common and crypt cells are rare. Spatial simulations of the fluid dynamics of the incurrent water flow into the nares and within the olfactory cavities indicate that the high densities of microvilli-bearing ORNs located within the lateral region of the rosette are important for sampling incoming odorants during swimming and may determine subsequent tracking behavior.

scholarly journals A case report of thrombosed varicosities of pubic collateral veins: Ideal treatment strategy and contribution of era imaging technologies in diagnosis

2018 ◽  
Vol 6 ◽  
pp. 2050313X1875738
Author(s):  
Daniel Paramythiotis ◽  
Patroklos Goulas ◽  
Petros Bangeas ◽  
Argiris Giannopoulos ◽  
Kostantinos Kapoulas ◽  
...  
Keyword(s):  
Imaging Study ◽  
Iliac Vein ◽  
Low Molecular Weight ◽  
External Iliac Vein ◽  
The Past ◽  
Contrast Enhanced ◽  
Enhanced Computed Tomography ◽  
Deep Vein ◽  
Artery Obstruction ◽  
Contrast Enhanced Computed Tomography

Collateral circulation is an alternative path occurring in case of venous or artery obstruction. This path may usually develop after primary recanalization. In our case, a 62-year-old woman presented to our Emergency Department complaining about a suprapubic swelling with a cyanotic discoloration of the overlying skin for the past 10 days for which she had been previously prescribed antibiotics. Investigation with ultrasound and contrast-enhanced computed tomography was performed. An imaging study revealed thrombosed pubic varicose collateral veins due to deep vein obstruction and occlusion of the left external iliac vein. The patient was treated with low-molecular-weight heparin, and swelling subsided gradually. Collateral veins of the abdominal wall and over the pubic tubercle are highly predictive of deep venous obstructive disease proximal to the groin level. These collaterals should never be removed, and the patient should be subjected to a diligent laboratory and imaging investigation.

Quantitative correlative microscopy reveals the ultrastructural distribution of endogenous endosomal proteins

2021 ◽  
Vol 221 (1) ◽  
Author(s):  
Jan van der Beek ◽  
Cecilia de Heus ◽  
Nalan Liv ◽  
Judith Klumperman
Keyword(s):  
Electron Microscopy ◽  
Fluorescence Microscopy ◽  
Functional Organization ◽  
Light And Electron Microscopy ◽  
Correlative Microscopy ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Endocytic Vesicles ◽  
Endosomal System

The key endosomal regulators Rab5, EEA1, and APPL1 are frequently applied in fluorescence microscopy to mark early endosomes, whereas Rab7 is used as a marker for late endosomes and lysosomes. However, endogenous levels of these proteins localize poorly in immuno-EM, and systematic studies on their native ultrastructural distributions are lacking. To address this gap, we here present a quantitative, on-section correlative light and electron microscopy (CLEM) approach. Using the sensitivity of fluorescence microscopy, we label hundreds of organelles that are subsequently visualized by EM and classified by ultrastructure. We show that Rab5 predominantly marks small, endocytic vesicles and early endosomes. EEA1 colocalizes with Rab5 on early endosomes, but unexpectedly also labels Rab5-negative late endosomes, which are positive for PI(3)P but lack Rab7. APPL1 is restricted to small Rab5-positive, tubulo-vesicular profiles. Rab7 primarily labels late endosomes and lysosomes. These data increase our understanding of the structural–functional organization of the endosomal system and introduce quantitative CLEM as a sensitive alternative for immuno-EM.

Representation of head and face in postcentral gyrus of the macaque

1975 ◽  
Vol 38 (3) ◽  
pp. 714-733 ◽  
Author(s):  
D. A. Dreyer ◽  
P. R. Loe ◽  
C. B. Metz ◽  
B. L. Whitsel
Keyword(s):  
Functional Organization ◽  
Receptive Fields ◽  
Cortical Cell ◽  
Posterior Part ◽  
Extracellular Recording ◽  
Cortical Region ◽  
Anterior Portion ◽  
Body Regions ◽  
Peripheral Innervation ◽  
Postcentral Gyrus

The receptive field and submodality characteristics of individual neurons within the cytoarchitectural and topographic subdivisions of the head and face areas of the postcentral gyrus (SI) were determined with the technique of extracellular recording. Correlation of the single-unit data with the intracortical location of the recording electrode provided a detailed description of the functional organization within each of the several cytoarchitecturally distinct regions contributing to the representation of the head and face in SI. The data indicate that the functional organization of the SI cortex which receives its principal input from trigeminal mechanoreceptors is comparable to the organization within those SI regions which receive their input from the mechanoreceptors of the limbs, trunk, and tail. In each topographic subdivision of the SI cortex 1) a single region in the periphery is represented several times in widely separated locations, each time in a context of different submodalities and peripheral receptive fields; and 2) neurons belonging to the different submodality classes are segregated so that projections from cutaneous afferents terminate mainly in cytoarchitectural area 3 in the adjacent anterior portion of area 1, while projections from the afferents innervating deep tissues terminate mainly in cytoarchitectural area 3a, area 2, and the posterior part of each 1. Although the mechanoreceptor input to SI is segregated according to submodality and the mechanoreceptors from most body regions project to multiple widely separated regions within SI, neurons with receptive fields confined to the ophthalmic division of the trigeminal peripheral innervation field are found within a restricted region of the anterior postcentral gyral crown which is positioned symmetrically about the junction of cytoarchitectural areas 1 and 3. Neurons with receptive fields confined to the maxillary division of the trigeminal innervation field are found within a ring of cortex which a) completely surrounds the representation of the ophthalmic field, and b) includes parts of cytoarchitectural area 2, 1, 3, and 3a. SI neurons with receptive fields restricted to the mandibular division of the trigeminal innervation field occupy the largest portion of the SI face area and form a ring of cortical cell columns which completely surrounds that cortical region which receives its input from the maxillary peripheral innervation field.

A light- and electron-microscope study of the oocyte nucleus during development of the antral follicle in the prepubertal mouse

1975 ◽  
Vol 17 (3) ◽  
pp. 589-615
Author(s):  
L.A. Chouinard
Keyword(s):  
Meiotic Prophase ◽  
Functional Organization ◽  
Current Knowledge ◽  
Light And Electron Microscopy ◽  
Antral Follicle ◽  
Mouse Oocyte ◽  
Oocyte Nucleus ◽  
Follicle Development ◽  
Preovulatory Follicle ◽  
Functional Changes

The ordered changes which occur in the structural organization of the mouse oocyte nucelus during the preparatory, the maturative and the preovulatory stages of antral follicle development, have been studied under both light and electron microscopy. All observations have been made on those antral follicles whose development is initiated on postnatal day 14 and completed by postnatal day 28 in prepubertal animals of the ICR albino mouse strain. The formed entities that can be recognized within the oocyte nucleus during that period are the condensing bivalents, the heterochromatic knobs, the nucleolus and the extranucleolar bodies. At the onset of antral follicle development, the highly unravelled dictyate bivalents are seen to take on a lampbrush-type configuration. Subsequent condensation of these lampbursh bivalents appears to be a very gradual and lengthy process that extends over almost the entire period of antral follicle development. The shortening and thickening of the lampbrush bivalents are best interpreted as resulting from the withdrawal of their lateral loop-like projections into the chromosome axes and from the focal aggregation of these axes into compact chromatin masses. Electron-opaque granules, which appear within the oocyte nucleus during the preparatory and maturative follicle stages, are seen to be intimately associated with these condensing bivalents. A number of Feulgen-positive heterochromatic knobs make their appearance in contact with certain bivalents during the preparatory follicle stage. These knobs are not reincorporated as such into the condensing chromatin masses and undergo disintegration and dissolution during the preovulatory follicle stage. The size, shape and ultrastructural features of the nucleolus remain unchanged thoughout the period of antral follicle development. Breakdown and dissolution of the nucleolar mass is a swift process that takes place only in the fully mature preovulatory follicle and more or less concomitantly with the dismantling of the nuclear envelope. The extranucleolar bodies increase noticeably in size during the preparatory and the maturative follicle stages; they shrink in size and undergo dissolution during the preovulatory stage of antral follicle development. An attempt is made to interpret these morphological changes in the light of current knowledge concerning the architectural and functional organization of the oocyte nucleus in general during meiotic prophase. The relevant observational evidence would be consistent with the view that, during antral follicle deveopment, the mouse oocyte nucleus is not, as too often assumed, in a period of arrested evolution; its formed components undergo structural, maturational and functional changes which are of significance not only for the resumption of the first meiotic prophase but also for the early development of the embryo.

Microstimulation of primate motor thalamus: somatotopic organization and differential distribution of evoked motor responses among subnuclei

1996 ◽  
Vol 75 (6) ◽  
pp. 2486-2495 ◽  
Author(s):  
J. L. Vitek ◽  
J. Ashe ◽  
M. R. DeLong ◽  
Y. Kaneoke
Keyword(s):  
Functional Organization ◽  
Reticular Nucleus ◽  
Modular Organization ◽  
Active Movement ◽  
Single Muscle ◽  
Differential Distribution ◽  
Motor Responses ◽  
Somatotopic Organization ◽  
Motor Thalamus ◽  
Area X

1. The functional organization of motor responses to microstimulation throughout the primate “motor” thalamus including nucleus ventralis lateralis, pars oralis (VLo); nucleus ventralis posterior lateralis, pars oralis (VPLo); nucleus ventralis lateralis, pars caudalis (VLc); and portions of ventralis anterior (VA) and area X, was systematically studied in awake monkeys. A total of 2,021 sites were examined for their response to microstimulation. Of these, 1,123 were histologically verified as to their location within the motor thalamus. At or near each site, isolated neurons were examined for their responses to somatosensory examination and active movement (n = 1,272). This study was carried out as part of a larger study examining the responses of neurons in the motor thalamus to somatosensory examination, torque-induced limb perturbations, and active movement in a visuomotor step-tracking task. 2. Microstimulation at < or = 40 microA evoked movements in the contralateral limbs, trunk, or face. Evoked movements of the limb were generally maximal about a single joint. 3. There was a differential response to microstimulation between subnuclei of the motor thalamus. In order of decreasing frequency, the percentages of sites within each subnucleus from which movements were evoked were as follows: VPLo, 93% (449 of 483); VLo, 21% (57 of 272); VLc, 11% (15 of 140); VA, 1% (1 of 85); and reticular nucleus, 0% (0 of 65). In VPLc, 44% (34 of 78) of sites examined were microexcitable. However, these were almost all within 500 microns of the border of VPLo, suggesting they may have occurred as a result of current spread to adjacent VPLo. Although area X was not sampled in its entirety, it did not appear to be microexcitable. 4. Microexcitable responses had a somatotopic organization, similar to that for neuronal responses to sensorimotor examination, with leg responses found most laterally and arm and face responses found progressively more medially. 5. Zones in VPLo generally ranging from 500 to 1,500 microns were found in which microstimulation resulted in the same motor response. These microexcitable zones resemble those described for the striatum and were termed thalamic microexcitable zones (TMZ). TMZs also resemble cortical efferent zones in that both are somatotopically organized, may affect a single muscle or group of muscles, have low thresholds for microstimulation with sharp boundaries that lie adjacent to other microexcitable zones with the opposite effects, and are of approximately the same dimension. 6. This study suggest that a fundamental unit of motor organization, i.e., single muscle or joint, is preserved at the thalamic level in the form of TMZs, and that these fundamental units of organization may contribute to the modular organization of the cortex.

Extreme intraneural ganglion cysts

2011 ◽  
Vol 114 (1) ◽  
pp. 217-224 ◽  
Author(s):  
Robert J. Spinner ◽  
Marie-Noëlle Hébert-Blouin ◽  
Michael G. Rock ◽  
Kimberly K. Amrami
Keyword(s):  
Sciatic Nerve ◽  
Mr Imaging ◽  
Mr Arthrography ◽  
Imaging Study ◽  
Intraneural Ganglion ◽  
Anterior Portion ◽  
Posterior Portion ◽  
Articular Branch ◽  
Joint Connection ◽  
Recurrent Cyst

Object The mechanism responsible for exceptional examples of intraneural ganglia with extensive longitudinal involvement has not been understood. Such cases of intraneural cysts, seemingly remote from a joint, have been thought not to have articular connections. Decompression and attempted resection of the cyst has led to intraneural recurrence and poor neurological recovery. The purpose of this report is not only to clarify the pathogenesis of these cysts, but also to discuss their treatment based on modern concepts of intraneural ganglia. Methods Two examples of extreme longitudinal propagation of intraneural ganglia are presented. Results A patient with a moderate tibial neuropathy was found to have a tibial intraneural ganglion. Prospective interpretation of the MR imaging study demonstrated the cyst's origin from the posterior portion of the superior tibiofibular joint (STFJ), with proximal extension within the sciatic nerve to the lower buttock region. Communication between the STFJ and the cyst was confirmed with direct knee MR arthrography. The tibial intraneural cyst was treated successfully by a relatively limited exposure in the distal popliteal fossa: the cyst was decompressed, the articular branch disconnected, and the STFJ resected. Postoperatively, the patient improved neurologically and there was no evidence of recurrent cyst on postoperative MR imaging. A second patient, previously reported by another group, was reexamined 22 years after surgery. This patient had an extensive peroneal intraneural ganglion that extended into the sciatic nerve from the knee to the buttock; no joint connection or recurrent cyst had initially been described. In this patient, the authors hypothesized and established with MR imaging the presence of both: a joint connection to the anterior portion of the STFJ from the peroneal articular branch as well as recurrent cyst within the peroneal and tibial nerves. Conclusions This paper demonstrates that extreme intraneural cysts are not clinical outliers but represent extreme examples of other more typical intraneural cysts. They logically obey the same principles, previously described in the unified articular (synovial) theory. The degree of longitudinal extension is probably due to high intraarticular pressures within the degenerative joint of origin. The generalizability of the mechanistic principles is highlighted by the fact that these 2 cases, involving the tibial and the peroneal nerve respectively, both extended well distant (that is, to the buttock) from the STFJ via their respective articular branch of origin. These extensive intraneural cysts can be treated successfully by disconnecting the affected articular branch and by resection of the joint of origin, rather than by a more aggressive operation resecting the cyst and cyst wall.

scholarly journals Formation of Nuclear Splicing Factor Compartments Is Independent of Lamins A/C

2004 ◽  
Vol 15 (11) ◽  
pp. 4904-4910 ◽  
Author(s):  
Jaromíra Večeřová ◽  
Karel Koberna ◽  
Jan Malínský ◽  
Evi Soutoglou ◽  
Teresa Sullivan ◽  
...  
Keyword(s):  
Functional Organization ◽  
Light And Electron Microscopy ◽  
Mrna Splicing ◽  
Splicing Factor ◽  
Splicing Factors ◽  
Knock Out ◽  
Structural Role ◽  
Structural Support ◽  
Nuclear Lamins ◽  
Matrix Fraction

Nuclear lamins are major architectural elements of the mammalian cell nucleus, and they have been implicated in the functional organization of the nuclear interior, possibly by providing structural support for nuclear compartments. Colocalization studies have suggested a structural role for lamins in the formation and maintenance of pre-mRNA splicing factor compartments. Here, we have directly tested this hypothesis by analysis of embryonic fibroblasts from knock-out mice lacking A- and C-type lamins. We show that the morphology and cellular properties of splicing factor compartments are independent of A- and C-type lamins. Genetic loss of lamins A/C has no effect on the cellular distribution of several pre-mRNA splicing factors and does not affect the compartment morphology as examined by light and electron microscopy. The association of splicing factors with the nuclear matrix fraction persists in the absence of lamins A/C. Live cell microscopy demonstrates that the intranuclear positional stability of splicing factor compartments is maintained and that the exchange dynamics of SF2/ASF between the compartments and the nucleoplasm is not affected by loss of lamin A/C. Our results demonstrate that formation and maintenance of intranuclear splicing factor compartments is independent of lamins A/C, and they argue against an essential structural role of lamins A/C in splicing factor compartment morphology.

Functional parasagittal compartments in the rat cerebellar cortex: an in vivo optical imaging study using neutral red

1996 ◽  
Vol 76 (6) ◽  
pp. 4169-4174 ◽  
Author(s):  
G. Chen ◽  
C. L. Hanson ◽  
T. J. Ebner
Keyword(s):  
Optical Imaging ◽  
Cerebellar Cortex ◽  
Functional Organization ◽  
Imaging Techniques ◽  
Imaging Study ◽  
Neutral Red ◽  
Zebrin Ii ◽  
Optical Responses ◽  
Crus I

1. The spatial patterns of activation in the rat cerebellar cortex evoked by peripheral stimulation were studied in vivo using optical imaging techniques. 2. Crus I and Crus II were stained with the pH sensitive dye, neutral red. Electrical stimulation of the vibrissae area of the ipsilateral face evoked optical responses consisting of parasagittal bands. The bands were 100–300 microns in width, elongated in the anterior-posterior direction, commonly extended across at least two folia, and varied in number from 1 to 7. 3. The optical responses were dependent on activation of postsynaptic elements since they were decreased substantially by the non-N-methyl-D-aspartate antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione. The optical bands were shown to correspond anatomically with the parasagittal compartments revealed by immunostaining with anti-zebrin II. 4. The present study demonstrates that functional parasagittal compartments exist in the rat cerebellar cortex and suggests that zebrin-positive Purkinje cell subgroups are anatomically related to this functional organization.

A Light- And Electron-Microscope Study of the Nucleolus During Growth of the Oocyte in the Prepubertal Mouse

1971 ◽  
Vol 9 (3) ◽  
pp. 637-663
Author(s):  
L. A. CHOUINARD
Keyword(s):  
Structural Organization ◽  
Functional Organization ◽  
Current Knowledge ◽  
Light And Electron Microscopy ◽  
Fold Increase ◽  
Dense Fibrillar Component ◽  
Parallel Increase ◽  
Nucleolar Material ◽  
Nucleolar Volume ◽  
Fibrillar Component

The ordered changes which occur in the structural organization of the nucleolus during growth of the mouse oocyte have been studied by both light and electron microscopy. All observations have been made on those oocytes whose growth is initiated on the day of birth and completed by postnatal day 14 in prepubertal animals of the ICR albino mouse strain. During that period the oocyte nucleolus undergoes an approximate 90-fold increase in volume. During the unilaminar follicle stage (from birth to postnatal day 4), the growing nucleolus exhibits an overall reticulated-type of structure consisting of: (1) a moderately electron-dense fibrillogranular component occupying most parts of the nucleolar framework; (2) an electron-transparent nucleoplasm-like component filling the numerous interstices of the nucleolar framework; (3) an electron-dense fibrillar component located in the peripheral portion of a number of small islands widely and uniformly scattered within the nucleolar framework, and (4) a slightly less-dense fibrillar component situated in the central portion of these same islands and referred to as fibrillar centres. Increase in nucleolar volume during that stage is brought about mainly through an increase in the overall dimensions of the fibrillogranular framework, accompanied by a parallel increase in the number and, to a certain extent, the size of its electron-transparent interstices. During the bilaminar follicle stage (postnatal day 5 through 8), the following structural and organizational changes take place more or less concomitantly within the still enlarging nucleolar mass: (1) the fibrillogranular framework becomes predominantly fibrillar in texture as a result of what appears to be an unravelling or unfolding of its constituent granules of ribosomal dimensions; (2) the nucleolar interstices decrease rapidly both in number and size because of the accumulation within their interior of a material the texture and density of which match that present in the nucleolar framework itself; and (3) a number of rounded electron-transparent spaces, the nucleolar vacuoles, make their appearance in the regions formerly occupied by some of the fibrillar islands and adjacent interstices. Increase in nucleolar volume during that stage is largely due to the appearance and subsequent enlargement of the nucleolar vacuoles in question. During the plurilaminar follicle stage (postnatal day 9 through 14), the following sequential events take place within the nucleolar mass: (1) a moderately electron-dense fibrillogranular material accumulates within the nucleolar vacuoles; (2) this fibrillogranular material, which eventually fills all vacuolar spaces, undergoes degranulation and a concomitant increase in density, eventually matching that of the rest of the nucleolar mass; (3) all remnants of the lightly stained nucleolar interstices disappear from view; and (4) the fully grown rounded nucleolus finally appears as a dense, compact mass, exclusively fibrillar in texture, and exhibiting no internal structural organization. An attempt is made to interpret these changes in the light of current knowledge concerning thearchitectural and functional organization of the mammalian nucleolus in general. The observations are consistent with the view that the nucleolus, during growth of the primary oocyte, is the site of massive synthesis and storage of nucleolar material.

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