草鱼脑的发育和结构

对刚孵化至全长500毫米草鱼脑的发育过程中的形态变化和脑在颅腔中的位置变动作了详细观察;对发育完善脑的结构进行了研究,并叙述了副脑上腺、脑上脑、脑垂体和血管囊的形态和位置变化.全长7.4毫米端脑前端分化出嗅球,全长53.4毫米嗅球开始与大脑分离,真正的嗅神经位于嗅囊和嗅球之间一些细而短的神经.全长125毫米以后脑的发育已基本趋于完善,形态构造亦基本稳定;全长227毫米以后脑已位于颅腔后部.       

Long-term subarachnoid catheter placement in the middle cranial fossa of the rat

Research using rats sometimes requires long-term placement of catheters in the subarachnoid space, the cavity between the arachnoid mater and the pia mater in the brain. These catheters can be used to experimentally induce subarachnoid bleeding by injecting blood or to locally administer drugs or other substances. To date, published techniques for penetrating the subarachnoid space of small experimental animals require the use of inflexible or relatively inflexible catheters. These catheters typically consist of metal or stiff plastic and are used to access the occipital or frontal cranial cavity or to directly access the cisterna magna via the atlantooccipital membrane. However, inflexible catheters are not ideal for long-term placement in the subarachnoid space. In this paper, the authors describe a reliable procedure for long-term catheterization of the subarachnoid cavity of the rat. For this method, personnel insert the catheter and keep it in place in the rat's middle cranial cavity, in the vicinity of the cerebral arterial circle. This new approach allows personnel to repeatedly use the catheter for a period of at least 2 weeks. The catheter, which is well-tolerated by rats, can be used for administering saline solutions and for injecting blood that has not been treated with heparin into the subarachnoid space.     

Anatomy of the Cranial Endocast of the Bottlenose Dolphin, Tursiops truncatus, Based on HRXCT

Endocranial surfaces, volumes, and interconnectivities of extant and fossil odontocetes potentially offer information on the general architecture of the brain and on the structure of the specialized cetacean circulatory system. Although conventional methods for acquiring such data have generally involved invasive preparation of the specimen, particularly in the case of fossils, new tomographic technologies afford nondestructive access to these internal morphologies. In this study we used high-resolution X-ray computed tomography (HRXCT) to scan a skull of the extant Tursiops truncatus (Cetacea: Odontoceti). We processed the data to reveal the cranial endocast and details of internal skeletal architecture (data at www.digimorph.org). Major features that can be discerned include aspects of the specimen's hypertrophied retia mirabilia, the major canals and openings of the cranial cavity, and the relationship of the brain and endocranial circulatory structures to the surrounding skeleton. CT data also provide information on the shape of the brain that may be lost in conventional anatomical preparations, and readily provide volumetric and linear measurements of the endocast and its individual segments. These results demonstrate the utility of HRXCT for interpreting the internal cranial anatomy of both extant and fossil cetaceans.     

The effect of craniotomy on the intracranial hemodynamics and cerebrospinal fluid dynamics in humans

The goal of the research was to study the effect of the trephination of the human cranial cavity on the intracranial hemodynamics and cerebrospinal fluid (CSF) dynamics. The sample comprised 15 patients of a neurosurgical clinic in whom a trephine opening in the cranial bones was made for medical indications. In these patients, at rest and during an appropriate functional load, we recorded pulse changes in blood circulation (by transcranial Doppler sonography) and in the ratio between the pulse fluctuations in the blood and CSF volumes (by rheoencephalography) before and after surgery. Simultaneous recording of these parameters followed by computer pattern and phase analyses allowed evaluation of the complex biomedical compliance of the cranium during successive phases of the cardiac rhythm: the inflow of arterial blood, the redistribution of blood/CSF volumes, and the outflow of venous blood. Analysis of the results showed a beneficial influence of craniotomy on the intracranial hemodynamics and CSF dynamics. This was reflected in an increase in the cranial compliance, which increased the pulse increment in the volume of the arterial blood in the skull almost twofold. After craniotomy, the cross-flow of CSF between the cranial and spinal cavities decreased significantly, giving way to volumetric compensatory translocations of blood and CSF within the cranial cavity per se during the cardiac cycle, which increased the intracranial utilization of the energy of the cardiac output and contributed to the outflow of venous blood from the cranium. The results suggest a beneficial effect of craniotomy on the physiological mechanisms of the circulatory and metabolic maintenance of the brain activity.     

The rete mirabile cranica in the genus Mobula: A comparative study

Devil rays (Mobulidae) have large brains that rest in a voluminous chondrocranium almost completely filled by a rete mirabile cranica (RMC). The RMC is a massive arterial network grossly divisible into a “caudal RMC” supplying blood to the brain, and an expanded, more complex “precerebral RMC” nested within the large cranial cavity rostral to the telencephalon. Both the caudal and precerebral retia originate from the posterior portion of the profundae cerebri arteries, which lie ventral to the brain and form the sides of a vascular triangle, the base of which is anterior and formed by the joining of the internal carotids; the vertex is posterior and median, corresponding to the anterior extreme of the spinalis impar artery. Vessels of the caudal RMC branch posteriorly from the profundae cerebri and course over and into the brain. Vessels branching more anteriorly course rostrally to form the precerebral RMC, which takes the shape of the cranial cavity and completely envelops the olfactory peduncles. Large retial arteries (1-mm diameter) branch and taper to about 50–150 μm, forming a system of small arteries or arterioles. Many give rise to a mesh of tertiary vessels (precapillary arterioles or capillaries, ca. 20–50 μm in diameter), which, along with arterioles, are embedded in the adventitia of these arteries, with which they communicate by numerous anastomoses. Although the function of the RMC remains enigmatic, its complexity and fine structure are suggestive, and hypotheses of its role are discussed.     

Expression pattern of Siaz gene during the zebrafish embryonic development

Siah is a mammalian homolog of Drosophila seven in absentia (SINA). Here we report the identification of a new member of the SINA/Siah gene family. This new gene, designated Siaz, was found in zebrafish, and its product is predicted to share extensive amino acid sequence homology with Drosophila SINA. Siaz is maternally inherited, with zygotic expression in all blastomeres starting at the mid-blastula transition. After the 20-somite stage, Siaz expression occurs in a stage-specific manner in particular regions, including the brain, eye, cranial cavity, otic vesicle, optic chiasm and gut.     

Review of French literature on Latimeria, notably since 1972

French research on Latimeria published before 1972 is first briefly recalled. After the Anglo-Franco-American Expedition of 1972, the material obtained enabled us to focus attention on the histology of the kidney and ureter and on ultrastructural aspects of the postnatal gland. Ovarian eggs of unusual volume have been collected, measured and weighed. Kinematic analysis of the intracranial articulation was carried out in 1973 on a frozen coelacanth that reached Paris. Studies in 1974 of a 41 cm specimen, the smallest known at that time and estimated to be 3 1/2 years old, showed that the brain still filled the cranial cavity: thus, it is later that allometric growth of the cranial cavity relegates the brain to the posterior part of the skull. In the same specimen, radiographed after injection with colloidal barium oxide, we were able to specify the likely role of the contractile organs fused to the branchial arteries: they may serve to regulate arterial pressure in the head during sudden movements of the jaws, and thus of the anterior cranium, as prey is captured. Lastly, the structural characteristics of the teeth, scale denticles, and spines on the lepidotrichia have been revealed, as also has the lamellar structure of the scales, in which there is a crossed orientation of the fibres in the different layers.     

Penetration of phosphorothioate oligodeoxynucleotides into rainbow trout brain in vivo. A technique for chronic infusion of substances into the brain of free-living adult fish

This paper describes a method for infusing chronically substances into the cranial cavity of free-living rainbow trout Oncorhynchus mykiss for several weeks. The efficacy of the method was established by examining the penetration of radioactively labelled phosphorothioate oligodeoxynucleotides and a blue-coloured dye, xylene cyanole, into brain tissue. No problems with pump patency were encountered, and the contents of the pump diffused consistently throughout the brain ventricular system, including the anterior lateral ventricles of the olfactory lobes, the third ventricle under the optic tecta and into the hypothalamus, including the lateral ventricular recesses. Autoradiographic examination of frozen sections demonstrated variable penetration of labelled probe into brain interstitium to a depth of up to approximately 200 μm. At the end of the experiment, >50% of radioactivity within brain tissue was shown to be of similar size to intact, labelled oligodeoxynucleotides.     

The homologies of the lorisoid internal carotid artery system

The development of the “internal carotid” arterial system of the lesser galago (Galago senegalensis senegalensis)is described. The first artery to be formed is a typical promontory artery which runs through the middle-ear cavity and gives off the stapedial artery. It terminates in the cranial cavity by dividing into the middle cerebral, anterior cerebral, and two ophthalmic arteries. It is accompanied by the internal carotid nerve. A medially directed artery to the external carotid rete arises from the commencement of the promontory artery and joins the caudal end of the rete, whose cranial end lies in the foramen lacerum. As the promontory artery enters the cranial cavity, it communicates with the cranial end of the rete. The promontory artery, between the origin of the artery to the rete and its connection with the rete, becomes narrowed and eventually disappears. Thus the internal carotid artery is formed from the commencement of the promontory artery, the artery to the rete, the external carotid rete, and the terminal intracranial part of the promontory artery. The relationships of the artery to the rete indicate that it is the homologue of the human ascending pharyngeal artery.     

The arterial system of the sperm whale (Physeter macrocephalus)

The angioarchitecture of the sperm whale is basically similar to that of other mammals, but it has specific attributes associated with the aquatic environment of this animal and its tolerance for deep and long diving. Specialized features include an expansive aortic arch, unusually far anterior localization of the arch, symmetrical branching of common carotid and subclavian arteries from the aorta, the absence of direct connection between internal carotid arteries and brain arteries, the absence of a costocervical artery, and the presence of a well-developed occipital artery. The sperm whale has extraordinarily well-developed retia mirabilia, distributed in the cranial cavity, vertebral canal, neck and thoracic cavity, around the optic nerve, and in the walls of the uterus. These retia are more extensively developed in the sperm whale than in any other cetacean previously studied. J. Morphol. 234:37–50, 1997. © 1997 Wiley-Liss, Inc.     

Hydrodynamic modeling of cerebrospinal fluid motion within the spinal cavity

The fluid that resides within cranial and spinal cavities, cerebrospinal fluid (CSF), moves in a pulsatile fashion to and from the cranial cavity. This motion can be measured hy magnetic resonance imaging (MRI) and may he of clinical importance in the diagnosis of several brain and spinal cord disorders such as hydrocephalus, Chiari malformation, and syringomyelia. In the present work, a geometric and hydrodynamic characterization of an anatomically relevant spinal canal model is presented. We found that inertial effects dominate the flow field under normal physiological flow rates. Along the length of the spinal canal, hydraulic diameter was found to vary significantly from 5 to 15 mm. The instantaneous Reynolds number at peak flow rate ranged from 150 to 450, and the Womersle number ranged from 5 to 17. Pulsatile flow calculations are presented for an idealized geometric representation of the spinal cavity. A linearized Navier-Stokes model of the pulsatile CSF flow was constructed based on MRI flow rate measurements taken on a healthy volunteer. The numerical model was employed to investigate effects of cross-sectional geometry and spinal cord motion on unsteady velocity, shear stress, and pressure gradientfields. The velocity field was shown to be blunt, due to the inertial character of the flow, with velocity peaks located near the boundaries of the spinal canal rather than at the midpoint between boundaries. The pressure gradient waveform was found to be almost exclusively dependent on the flow waveform and cross-sectional area. Characterization of the CSF dynamics in normal and diseased states may be important in understanding the pathophysiology of CSF related disorders. Flow models coupled with MRI flow measurements mnay become a noninvasive tool to explain the abnormal dynamics of CSF in related brain disorders as well as to determine concentration and local distribution of drugs delivered into the CSF space.     

Biomechanical properties of the human cranium: aging aspects

Biomechanical properties of the human skull affect its dynamic tensility (pliability, compliance) by changes of intracranial volume and pressure (deltaV/deltaP). The goal of this study is to substantiate a possibility of noninvasive and dynamic evaluation of cranial compliance. The transcranial dopplerogram of middle cerebral artery and hemispheric bioimpedance were synchronously recorded, which represent information about pulsative changes of intracranial pressure and volume, respectively. The parameters were recorded at rest and during adequate hemo- and liquorodynamic tests in different age groups--20-30, 40-50, and 70-85 years. As compared with the young group, a decrease of the cranial compliance in the intermediate age group was revealed due to an observed increase if rigidity of skull bones and ligaments, which indicates a decrease of stability of the intracranial circulatory system. However, in the group of 70-85 years the compliance rose again due to an enlargement of intracranial liquor spaces and facilitation of liquor circulation inside the intracranial cavity; this can be suggested to be a compensatory mechanism for supporting the adequate brain circulatory-metabolic state.     

Use of the free vastus lateralis flap in skull base reconstruction

Free flaps in skull base reconstruction are indicated for providing an effective separation of the intracranial cavity from the oronasal space, for eliminating a dead space, and for the treatment of established wound complications such as dural exposures and cerebrospinal fluid leaks. Seven patients with cranial base defects underwent reconstructions using a free vastus lateralis muscle flap. In two cases, a vastus lateralis flap was raised to incorporate the anterolateral thigh skin as a myocutaneous flap. In four cases, a free flap was indicated for reconstruction following tumor ablation, and in three cases, for the resolution of wound or cerebrospinal fluid leak complications following previous cranial base surgery. All flaps were successful, with no partial failures. In those patients undergoing tumor ablative surgery, the cranial cavity was effectively sealed from the oronasal cavity. Patients with established wound complications following previous cranial base surgery had a complete resolution of their symptoms. This report discusses the suitability of the vastus lateralis flap for skull base reconstruction in terms of the availability of adequate muscle volume to fill dead space, vascularized fascia to augment dural repairs, and the freedom to use skin if required for internal lining or external skin cover. This flap also provides an extremely long pedicle, allows simultaneous flap harvest, and has low donor site morbidity.     

Two Intracranial Ligaments Supporting the Brain of the Brachiopterygian Fish Polypterus senegalus

Two hitherto unknown ligaments that assist in holding the brain in position occur in the brachiopterygian fish Polypterus senegalus. These rounded fibrous cords, placed one behind the other, are called ligamentum intracraniale transversum and ligamentum intracraniale obliquum. The former spans the orbitotemporal division of the cranial cavity and passes through the velum transversum. The latter, which is paired, extends from the roof to the sidewall of the endocranium and runs in the rhombomesencephalic sulcus in company with the trochlear nerve. It is argued that these intracranial ligments, like the spinal denticulate ligaments, are derivatives of a pair of fibrous bands which in early craniate phylogeny extended throughout the length of the neuraxial meninx and enhanced its tensile strength. It is also argued that at least the transverse intracranial ligament was already in existence some 350 million years ago.     

The acquirement of growth ability for third-stage larvae of Strongyloides ratti during the head-passage in the rat

The role of larval passage through the head in the course of the migration of Strongyloides ratti in rats was investigated. Third-stage larvae (L3) recovered from various portions of donor rats were re-injected into the skin, cranial cavity and small intestine of recipient rats to check their ability for further growth. Cultured L3 (L3c) and the L3 recovered from the skin of donor rats (L3s) did not survive in the small intestine after intestinal inoculation. However, intestinal inoculation of L3 recovered from the head of donor rats (L3h) revealed growth to the adult stage. Cultured L3 injected into the cranial cavity of rats also became adult worms in the small intestine. L3 incubated in the cranial cavity for more than 24 h could grow in the small intestine of the recipient rats. These experiments suggest that S. ratti L3 acquire their ability to mature in the small intestine during their migration through the head of rats.     

What did the “Unossified zone” of the non‐mammalian therapsid braincase house?

Most nonmammalian synapsids possess a mid‐dorsal depression in the brain cavity known as the “unossified zone.” It remains obscure which structures this zone contained, and, as candidates, the vermis of the cerebellum, the superior sagittal sinus, a junction of several blood vessels, the pineal gland or other midbrain structures were considered. Neutron tomography of a skull of Diictodon feliceps (Therapsida, Anomodontia) revealed some clear impressions of canals in this region of the brain cavity. Furthermore, the prootic sinus probably ran on the internal surface of the pila antotica and had a similar course in anomodonts as it has been proposed for cynodonts and Mesozoic mammals. Comparisons with the vascular systems of nonmammalian synapsids and mammals suggest that the unossified zone is best interpreted as a terminal chamber of the anterior segment of the medial head vein, which housed the junction of the superior sagittal sinus and the transverse sinuses. Consequently, the system of cranial vessels in Diictodon reveals a partial division of the medial head vein system into an anterior and a posterior segment at an early stage of synapsid evolution, which is consistent with the well‐known common pattern of early ontogenetic development in amniotes. J. Morphol., 2017. © 2017 Wiley Periodicals, Inc.     

Acanthonus armatus, a deep-sea teleost fish with a minute brain and large ears

Acanthonus armatus, a deep-water benthopelagic fish, has, per unit body weight, the smallest brain and largest semicircular canals of any known teleost and possibly any vertebrate. Pertinent areas of the brainstem and the cerebellum are large; this observation suggests that the fish's lateral line and vestibular senses are particularly acute. The huge cranial cavity also contains heavy saccular otoliths, which may indicate that the fish is sensitive to low-frequency sound. Brain size and specialization are consistent with an apparent pattern of low energy requirement, hovering and slow movement over the deep-sea floor, and consumption of small benthic prey in a dark environment.     

Spinal curvature of cultured Japanese mackerel Scomber japonicus associated with a brain myxosporean, Myxobolus acanthogobii

Skeletal deformities were found in the cultured Japanese mackerel Scomber japonicus. External and radiographical observations showed the deformed fish to exhibit a dorso-ventral spinal curvature (kyphosis) without fracture or dislocation of the vertebrae. Numerous myxosporean cysts, ca. 0.3 to 1.0 mm in diameter, formed in the 4th ventricle, the cavity of the optic tectum, the surface of the olfactory lobe and bulb, the optic lobe and the inferior lobe of the brain. Spore morphology and molecular analysis of the small subunit ribosomal RNA gene sequence identified the myxosporean parasite as Myxobolus acanthogobii, a parasite which also causes scoliosis in yellowtail Seriola quinqeradiata. Histopathological observation showed that the myxosporean cysts were encapsulated within the host's collagenous layer although some had disintegrated to disperse mature spores into the cranial cavity. Occasionally, lymphocytic infiltration and local granulomatous inflammation were found to be associated with spore dispersion.     

An electromyographic analysis of the biting mechanism of the lemon shark,Negaprion Brevirostris: Functional and evolutionary implications

The kinetics of the head and function of select jaw muscles were studied during biting behavior in the lemon shark, Negaprion brevirostris. High speed cinematography and electromyography of seven cranial muscles were recorded during bites elicited by a probe to the oral cavity. In weak bites mandible depression was followed by mandible elevation and jaw closure without cranial elevation. In strong bites cranial elevation always preceded lower jaw depression, lower jaw elevation, and cranial depression. The average duration of the strong bites was rapid (176 msec), considering the size of the animal relative to other fishes. Different electromyographic patterns distinguished the two forms of bite, primarily in activity of the epaxial muscles, which effect cranial elevation. A composite reconstruction of the activity of seven cranial muscles during biting revealed that epaxial muscle activity and consequently cranial elevation preceded all other muscle activity. Mandible depression was primarily effected by contraction of the common coracoarcual and coracomandibularis, with assistance by the coracohyoideus. Simultaneous activity of the levator hyomandibulae is believed to increase the width of the orobranchial chamber. The adductor mandibulae dorsal was the primary jaw adductor assisted by the adductor mandibulae ventral. This biomechanically conservative mechanism for jaw opening in aquatic vertebrates is conserved, with the exception of the coracomandibularis, which is homologous to prehyoid muscles of salamanders.