Experimental Neurology By Prof Paul Glees Pp xii + 532 (Oxford: Clarendon Press; London: Oxford University Press, 1961) 75s net

The Nervous System

It is clear that the above can lead to confusion when scientists of different countries are trying to communicate with each other. Another example is the burrowing rodent called a gopher found throughout the western United States. In the southeastern United States the term gopher refers to a burrowing turtle very similar to the desert tortoise found in the American southwest. One final example; two North American mammals known as the elk and the caribou are known in Europe as the reindeer and the elk. We never sing “Rudolph the Red-nosed elk”! Confused? This was the reason for creating an internationally recognized system of naming organisms. To avoid confusion, living organisms are assigned a scientific name based on Latin or Latinized words. The English sparrow is Passer domesticus or Passer domesticus (italics or underlining these two names is the official written representation of a scientific name). Using a uniform naming system allows scientists from all over the world to recognize exactly which life form a scientist is referring to. The naming process is called the binomial system of nomenclature. Passer is comparable to a surname and is called the genus, while domesticus is the specific or species name (like your given name) of the English sparrow. Now scientists can give all sparrow-like birds the genus Passer but the species name will vary. All similar genera (plural for genus) can be grouped into another, “higher” category (see below). Study the following for a more through understanding of taxonomy. Taxonomy Analogy Kingdom: Animalia Country

Diversity of life

The new Conductivity Bridge derives its bridge source. voltage from a self-contained vacuum tube oscilltor adjusted to approximately 1,000 cycles. Voltage for the amplifier and null indicator tubes is provided by a.builtin D.C. power supply which operates directly from the A.C. power source. 9-324 Conductivity Bridge, without Conductivity Cell, for use with 110 volts 5060 cycle A.C. 9-351.Cosi~uCvity Cell, for use with Conductivity Bridge, constant 0.8, $20.00

The Vertebrate Eye and Its Adaptive Radiation.

A novel method, µ-MAR, able to both coarse and fine register 3D point sets.The method overcomes noisy data problem using model based planes registration.µ-MAR iteratively registers a 3D markers around the object to be reconstructed.It uses a variant of the multi-view registration with subsets of data.Transformations to register the markers allow to reconstruct the object accurately. Many applications including object reconstruction, robot guidance, and. scene mapping require the registration of multiple views from a scene to generate a complete geometric and appearance model of it. In real situations, transformations between views are unknown and it is necessary to apply expert inference to estimate them. In the last few years, the emergence of low-cost depth-sensing cameras has strengthened the research on this topic, motivating a plethora of new applications. Although they have enough resolution and accuracy for many applications, some situations may not be solved with general state-of-the-art registration methods due to the signal-to-noise ratio (SNR) and the resolution of the data provided. The problem of working with low SNR data, in general terms, may appear in any 3D system, then it is necessary to propose novel solutions in this aspect. In this paper, we propose a method, µ-MAR, able to both coarse and fine register sets of 3D points provided by low-cost depth-sensing cameras, despite it is not restricted to these sensors, into a common coordinate system. The method is able to overcome the noisy data problem by means of using a model-based solution of multiplane registration. Specifically, it iteratively registers 3D markers composed by multiple planes extracted from points of multiple views of the scene. As the markers and the object of interest are static in the scenario, the transformations obtained for the markers are applied to the object in order to reconstruct it. Experiments have been performed using synthetic and real data. The synthetic data allows a qualitative and quantitative evaluation by means of visual inspection and Hausdorff distance respectively. The real data experiments show the performance of the proposal using data acquired by a Primesense Carmine RGB-D sensor. The method has been compared to several state-of-the-art methods. The results show the good performance of the µ-MAR to register objects with high accuracy in presence of noisy data outperforming the existing methods.

µ-MAR

As the number of fish reproduction studies has proliferated, so has the number of gonadal classification schemes and terms. This has made it difficult for both scientists and resource managers to communicate and for comparisons to be made among studies. We propose the adoption of a simple, universal terminology for the phases in the reproductive cycle, which can be applied to all male and female elasmobranch and teleost fishes. These phases were chosen because they define key milestones in the reproductive cycle; the phases include immature, developing, spawning capable, regressing, and regenerating. Although the temporal sequence of events during gamete development in each phase may vary among species, each phase has specific histological and physiological markers and is conceptually universal. The immature phase can occur only once. The developing phase signals entry into the gonadotropin-dependent stage of oogenesis and spermatogenesis and ultimately results in gonadal growth. The spawning cap...

https://afspubs.onlinelibrary.wiley.com/doi/pdf/10.1080/19425120.2011.555724

A Standardized Terminology for Describing Reproductive Development in Fishes

The innervation of the clasper has been studied in the round stingray, Urolophus halleri. Several large myelinated nerves (diameters approx. 0.7 mm; #60–64 counting from the vagus) innervate the clasper muscles and skin. Low level electrical stimulation (<100 µA) of the nerves evokes clasper movements including: elevation, medial and lateral extension, rotation and opening. Stimulation of the spinal cord in the area of the roots of the clasper nerves also evoked the movements (<100 µA). Retrograde labeling of the clasper nerves using either cobalt-lysine or horseradish peroxidase (HRP) confirmed that motor neurons and sensory components of the nerves are at the levels indicated by stimulation. The motor neurons have large multipolar cell bodies (50–70µm) and occupy a discrete segment of the spinal cord.

Clasper control in the round stingray, Urolophus halleri: lower sensorimotor pathways

The inferior lobes of the shark hypothalamus were examined with light, transmission and scanning electron microscopy. The cells bordering the floor of the lateral recess appear to be typical liquor-contacting neurons. With scanning electron microscopy (SEM) the apical ends of these cells are seen to bulge into the ventricular lumen. In contrast, the roof is lined by a more typical ependymal cell characterized by numerous cilia and microvilli. In addition, SEM reveals several kinds of supraependymal cells with processes that appear to penetrate the ventricular lining. A periventricular nucleus underlies the ependymal cells. Neurons of the periventricular nucleus contain numerous lipofuchsin granules. The rest of the inferior lobe consists of many neuronal fibers. The morphology of the hypothalamic inferior lobe is discussed in relation to its possible role in feeding and aggressive behavior in both elasmobranchs and teleosts.

The structure of the hypothalamic inferior lobes of the blacktip reef shark: Scanning and transmission electron microscopic observations

Until recently relatively little was known concerning the neural mechanisms controlling sound production in fishes. This is not surprising considering that prior to World War II there were few experimental studies on even peripheral sonic mechanisms (see papers in Tavolga 1977). Tavolga (1964, 1971) has reviewed the early work of peripheral innervation patterns in the sonic mechanisms of a variety of teleosts and therefore this will not be covered in detail in this review. Some of the information discussed in an earlier review on central mechanisms of sound production in teleosts (Demski, Gerald, and Popper 1973) has been incorporated into this chapter and updated with the results of recent studies including some experiments on electrically evoked croaking in Micropogon undulatus (Demski, Williams, and Dulka unpublished observations). Neural mechanisms of sound production are considered under the following functional categories: neuromuscular systems, central motor mechanisms, and higher integrative or control systems. Information in all of these categories is then combined into a model that summarizes many of the most significant results. Although there are a great variety of sonic mechanisms in teleosts, only those systems that use skeletal muscles to vibrate the swimbladder have been considered in this chapter.

Neural Control of Teleost Sound Production

The ultrastructure of ependymal cells of the median eminence in young Pacific blacktip reef sharks is described. Three major cell types have been observed. The first type is an irregularly-shaped, electron dense cell with many long microvilli and occasional cilia projecting into the ventricle. A second type contains dense cytoplasmic granules in sizes ranging from 1000–2000 A, and may be morphologically equivalent to “liquor-contacting neurons” observed in ependymal linings elsewhere. The third type appears very similar to crown cells of saccus vasculosus of this and other species. Cells of the third type possess large, lipid-like inclusions, bulbous projections originating from basal bodies, and prominent smooth endoplasmic reticulum. The crown-like cells are compared to cells of saccus vasculosus of young and adult sharks, and their possible significance is discussed.

Ultrastructure of ependymal cells of the shark median eminence.

Brain regions where photic stimuli and reproductive systems may interact in controlling both sexual development and reproductive behavior are considered in detail. Retinal input to the preoptic area and photic stimulation of pineal neural and endocrine systems appear to be major pathways for synchronization of reproductive development with environmental conditions. Both systems most likely influence gonadotropin-releasing hormone (GnRH) production and release and the feedback control of these processes via steroid-concentrating cells. In adult elasmo-branchs, perceptions of visual stimuli are potentially important in certain aspects of mating, e.g., mate recognition and analysis of courtship displays, and the neural substrates for the perceptions are most likely conditioned by the hormonal status of the animal. Breeding fish may thus have visual mechanisms affected by synaptic input from GnRH and steroid-concentrating neurons. The central nucleus of the telencephalon (CN) provides high-level visual integration in elasmobranchs. Preoptic, terminal nerve, and perhaps midbrain reticular areas are suggested origins for hormone-related CN afferents. The optic tectum contains GnRH-immunoreactive fibers in a variety of species. Thus, GnRH modulation of visual function probably occurs at this level. Visual centers of the midbrain tegmentum are near both GnRH-immunoreactive and sex-steroid-concentrating neurons. Sensory-hormonal integrative activity within the tegmental units could provide outputs for modulation of activity in both higher visual (e.g., the CN) and lower sex-related sensorimotor systems (e.g., spinal clasper control pathways) through ascending and descending pathways, respectively.

Leo S. Demski

Papers

Clasper control in the round stingray, Urolophus halleri: lower sensorimotor pathways

The structure of the hypothalamic inferior lobes of the blacktip reef shark: Scanning and transmission electron microscopic observations

Neural Control of Teleost Sound Production

Ultrastructure of ependymal cells of the shark median eminence.

Neural substrates for photic control of elasmobranch sexual development and behavior