Medicine and Health Sciences Commons^™

Variation In Brain Morphology Of Intertidal Gobies: A Comparison Of Methodologies Used To Quantitatively Assess Brain Volumes In Fish, Gemma E. White, Culum Brown

Veterinary Science and Medicine Collection

When correlating brain size and structure with behavioural and environmental characteristics, a range of techniques can be utilised. This study used gobiid fishes to quantitatively compare brain volumes obtained via three different methods; these included the commonly used techniques of histology and approximating brain volume to an idealised ellipsoid, and the recently established technique of X-ray micro-computed tomography (micro-CT). It was found that all three methods differed significantly from one another in their volume estimates for most brain lobes. The ellipsoid method was prone to over- or under-estimation of lobe size, histology caused shrinkage in the telencephalon, and although micro-CT …

Diffusion Tensor Imaging Of Dolphin Brains Reveals Direct Auditory Pathway To Temporal Lobe, Gregory S. Berns, Peter F. Cook, Sean Foxley, Saad Jbabdi, Karla L. Miller, Lori Marino

Veterinary Science and Medicine Collection

The brains of odontocetes (toothed whales) look grossly different from their terrestrial relatives. Because of their adaptation to the aquatic environment and their reliance on echolocation, the odontocetes’ auditory system is both unique and crucial to their survival. Yet, scant data exist about the functional organization of the cetacean auditory system. A predominant hypothesis is that the primary auditory cortex lies in the suprasylvian gyrus along the vertex of the hemispheres, with this position induced by expansion of ‘associative0 regions in lateral and caudal directions. However, the precise location of the auditory cortex and its connections are still unknown. Here, …

Microhabitat Use Affects Brain Size And Structure In Intertidal Gobies, Gemma E. White, Culum Brown

Veterinary Science and Medicine Collection

The ecological cognition hypothesis poses that the brains and behaviours of individuals are largely shaped by the environments in which they live and the associated challenges they must overcome during their lives. Here we examine the effect of environmental complexity on relative brain size in 4 species of intertidal gobies from differing habitats. Two species were rock pool specialists that lived on spatially complex rocky shores, while the remainder lived on dynamic, but structurally simple, sandy shores. We found that rock pool-dwelling species had relatively larger brains and telencephalons in particular, while sand-dwelling species had a larger optic tectum and …

The Evolutionary History Of Cetacean Brain And Body Size, Stephen H. Montgomery, Jonathan H. Geisler, Michael R. Mcgowen, Charlotte Fox, Lori Marino, John Gatesy

Veterinary Science and Medicine Collection

Cetaceans rival primates in brain size relative to body size and include species with the largest brains and biggest bodies to have ever evolved. Cetaceans are remarkably diverse, varying in both phenotypes by several orders of magnitude, with notable differences between the two extant suborders, Mysticeti and Odontoceti.We analyzed the evolutionary history of brain and body mass, and relative brain size measured by the encephalization quotient (EQ), using a data set of extinct and extant taxa to capture temporal variation in the mode and direction of evolution. Our results suggest that cetacean brain and body mass evolved under strong directional …

Clinical Anesthesia And Analgesia In Fish, Lynne U. Sneddon

Veterinary Science and Medicine Collection

Fish have become a popular experimental model and companion animal, and are also farmed and caught for food. Thus, surgical and invasive procedures in this animal group are common, and this review will focus on the anesthesia and analgesia of fish. A variety of anesthetic agents are commonly applied to fish via immersion. Correct dosing can result in effective anesthesia for acute procedures as well as loss of consciousness for surgical interventions. Dose and anesthetic agent vary between species of fish and are further confounded by a variety of physiological parameters (e.g., body weight, physiological stress) as well as environmental …

Characterisation Of Chemosensory Trigeminal Receptors In The Rainbow Trout, Oncorhynchus Mykiss: Responses To Chemical Irritants And Carbon Dioxide, Jessica J. Mettam, Catherine R. Mccrohan, Lynne U. Sneddon

Veterinary Science and Medicine Collection

Trigeminally innervated, mechanically sensitive chemoreceptors (M) were previously identified in rainbow trout, Oncorhynchus mykiss, but it is not known whether these receptors are responsive only to noxious, chemical irritants or have a general chemosensory function. This study aimed to characterise the stimulus–response properties of these receptors in comparison with polymodal nociceptors (P). Both P and M gave similar response profiles to acetic acid concentrations. The electrophysiological properties were similar between the two different afferent types. To determine whether the receptors have a nociceptive function, a range of chemical stimulants was applied to these receptors, including non-noxious stimuli such as ammonium …

The Efficacy Of Three Types Of Analgesic Drugs In Reducing Pain In The Rainbow Trout, Oncorhynchus Mykiss, Jessica J. Mettam, Lois J. Oulton, Catherine R. Mccrohan, Lynne U. Sneddon

Veterinary Science and Medicine Collection

Recent research has shown the possibility of pain perception in fish; therefore, the use of analgesia or “painkillers” should be considered for invasive procedures. However, there is relatively little information on the effectiveness of analgesic drugs nor on the appropriate dose for fish. This study assessed the efficacy of three types of drug: an opioid, buprenorphine, a non-steroidal anti-inflammatory drug (NSAID), carprofen and a local anaesthetic, lidocaine. Each drug was tested at three doses on rainbow trout that were noxiously stimulated and the most effective dose was also given to fish experiencing no pain to investigate side-effects. Ventilation rate and …

Three Rs Approaches In The Production And Quality Control Of Fish Vaccines, Paul J. Midtlyng, Coenraad F.M. Hendriksen, Elisabeth Balks, Lukas Bruckner, Lawrence Elsken, Øystein Evensen, Kjetil Fyrand, Allison Guy, Marlies Halder, Penny Hawkins, Gunn Kisen, Anne Berit Romstad, Kira Salonius, Patrick Smith, Lynne U. Sneddon

Veterinary Science and Medicine Collection

The workshop on Three Rs Approaches in the Production and Quality Control of Fish Vaccines aimed a) to identify animal tests currently stipulated for the production and quality control of fish vaccines and to highlight animal welfare concerns associated with these tests; b) to identify viable options to replace, reduce, and refine animal use for fish vaccine testing; and c) to discuss the way forward and set out how the Three Rs may be implemented without jeopardizing the quality of the vaccines. The workshop participants -- experts from academia, regulatory authorities, a scientific animal welfare organization, and the fish vaccine …

Neuroanatomy Of The Subadult And Fetal Brain Of The Atlantic White-Sided Dolphin (Lagenorhynchus Acutus) From In Situ Magnetic Resonance Images, Eric W. Montie, Gerald E. Schneider, Darlene R. Ketten, Lori Marino, Katie E. Touhey, Mark E. Hahn

Veterinary Science and Medicine Collection

This article provides the first anatomically labeled, magnetic resonance imaging (MRI) -based atlas of the subadult and fetal Atlantic white-sided dolphin (Lagenorhynchus acutus) brain. It differs from previous MRI-based atlases of cetaceans in that it was created from images of fresh, postmortem brains in situ rather than extracted, formalin-fixed brains. The in situ images displayed the classic hallmarks of odontocete brains: fore-shortened orbital lobes and pronounced temporal width. Olfactory structures were absent and auditory regions (e.g., temporal lobes and inferior colliculi) were enlarged. In the subadult and fetal postmortem MRI scans, the hippocampus was identifiable, despite the relatively small size …

Nociception In Fish: Stimulus–Response Properties Of Receptors On The Head Of Trout Oncorhynchus Mykiss, Paul J. Ashley, Lynne U. Sneddon, Catherine R. Mccrohan

Veterinary Science and Medicine Collection

This study examined stimulus–response properties of somatosensory receptors on the head of rainbow trout, Oncorhynchus mykiss, using extracellular recording from single cells in the trigeminal ganglion. Of 121 receptors recorded from 39 fish, 17 were polymodal nociceptors, 22 were mechanothermal nociceptors, 18 were mechanochemical receptors, 33 were fast adapting mechanical receptors and 31 were slowly adapting mechanical receptors. Mechanical thresholds were higher in polymodal nociceptors than in either slowly adapting or fast adapting mechanical receptors, whereas thermal thresholds of mechanothermal nociceptors were higher than those of polymodal nociceptors. Polymodal nociceptors and mechanochemical receptors gave similar responses to topical applications of …

Ethical Issues In Geriatric Feline Medicine, Bernard E. Rollin

Veterinary Science and Medicine Collection

Most veterinarians hold a ‘pediatric’ rather than ‘garage mechanic’ view of their function. In recent years, sophisticated medical modalities have allowed veterinarians to keep animals alive, and increased value of companion animals in society has increased demand for such treatment. But whereas humans can choose to trade current suffering for extended life, animals seem to lack the cognitive apparatus required to do so. Thus, veterinarians must guard against keeping a suffering animal alive for too long. Clients may be emotionally tied to the animal and blind to its suffering. Part of the veterinarian’s role, therefore, is to lead the client …

Does Diving Limit Brain Size In Cetaceans?, Lori Marino, Daniel Sol, Kristen Toren, Louis Lefebvre

Veterinary Science and Medicine Collection

We test the longstanding hypothesis, known as the dive constraint hypothesis, that the oxygenation demands of diving pose a constraint on aquatic mammal brain size.Using a sample of 23 cetacean species we examine the relationship among six different measures of relative brain size, body size, and maximum diving duration. Unlike previous tests we include body size as a covariate and perform independent contrast analyses to control for phylogeny. We show that diving does not limit brain size in cetaceans and therefore provide no support for the dive constraint hypothesis. Instead, body size is the main predictor of maximum diving duration …

Neuroanatomy Of The Killer Whale (Orcinus Orca) From Magnetic Resonance Images, Lori Marino, Chet C. Sherwood, Bradley N. Delman, Cheuk Y. Tang, Thomas P. Naidisch, Patrick R. Hof

Veterinary Science and Medicine Collection

This article presents the first series of MRI-based anatomically labeled sectioned images of the brain of the killer whale (Orcinus orca). Magnetic resonance images of the brain of an adult killer whale were acquired in the coronal and axial planes. The gross morphology of the killer whale brain is comparable in some respects to that of other odontocete brains, including the unusual spatial arrangement of midbrain structures. There are also intriguing differences. Cerebral hemispheres appear extremely convoluted and, in contrast to smaller cetacean species, the killer whale brain possesses an exceptional degree of cortical elaboration in the insular cortex, temporal …

Neuroanatomical Structure Of The Spinner Dolphin (Stenella Longirostris Orientalis) Brain From Magnetic Resonance Images, Lori Marino, Keith Sudheimer, William A. Mclellan, John I. Johnson

Veterinary Science and Medicine Collection

High-resolution magnetic resonance (MR) images of the brain of an adult spinner dolphin (Stenella longirostris orientalis) were acquired in the coronal plane at 55 antero-posterior levels. From these scans a computergenerated set of resectioned virtual images in the two remaining orthogonal planes was constructed with the use of the VoxelView and VoxelMath (Vital Images, Inc.) programs. Neuroanatomical structures were labeled in all three planes, providing the first labeled anatomical description of the spinner dolphin brain.

The Evidence For Pain In Fish: The Use Of Morphine As An Analgesic, Lynne U. Sneddon

Veterinary Science and Medicine Collection

This paper discusses the evidence for pain perception in fish and presents new data on morphine analgesia in fish. Recent anatomical and electrophysiological studies have demonstrated that fish are capable of nociception, the simple detection of a noxious, potentially painful stimulus and the reflex response to this. To prove pain perception, it must be demonstrated that an animal’s behaviour is adversely affected by a potentially painful event and this must not be a reflex response. The present study examined the acute effects of administering a noxious chemical to the lips of rainbow trout (Oncorhynchus mykiss) to assess what changes occurred …

Magnetic Resonance Images Of The Brain Of A Dwarf Sperm Whale (Kogia Simus), L. Marino, K. Sudheimer, D. A. Pabst, J. I. Johnson

Veterinary Science and Medicine Collection

Cetacean (dolphin, whale and porpoise) brains are among the least studied mammalian brains because of the difficulty of collecting and histologically preparing such relatively rare and large specimens. Among cetaceans, there exist relatively few studies of the brain of the dwarf sperm whale (Kogia simus). Magnetic resonance imaging (MRI) offers a means of observing the internal structure of the brain when traditional histological procedures are not practical. Therefore, MRI has become a critical tool in the study of the brain of cetaceans and other large species. This paper represents the first MRI-based anatomically labelled three-dimensional description of the dwarf sperm …

Do Fishes Have Nociceptors? Evidence For The Evolution Of A Vertebrate Sensory System, Lynne U. Sneddon, Victoria A. Braithwaite, Michael J. Gentle

Veterinary Science and Medicine Collection

Nociception is the detection of a noxious tissue-damaging stimulus and is sometimes accompanied by a reflex response such as withdrawal. Pain perception, as distinct from nociception, has been demonstrated in birds and mammals but has not been systematically studied in lower vertebrates. We assessed whether a fish possessed cutaneous nociceptors capable of detecting noxious stimuli and whether its behavior was sufficiently adversely affected by the administration of a noxious stimulus. Electrophysiological recordings from trigeminal nerves identified polymodal nociceptors on the head of the trout with physiological properties similar to those described in higher vertebrates. These receptors responded to mechanical pressure, …

Trigeminal Somatosensory Innervation Of The Head Of A Teleost Fish With Particular Reference To Nociception, Lynne U. Sneddon

Veterinary Science and Medicine Collection

Trigeminal somatosensory receptors have not been characterised in teleost fish and studies in elasmobranchs have failed to identify nociceptors. The present study examined the trigeminal nerve of a teleost fish, the rainbow trout (Oncorhynchus mykiss) to determine what types of somatosensory receptors were present on the head of the trout specifically searching for nociceptors. Single unit recordings were made from receptive fields on the head of the fish innervated by the trigeminal nerve. Each receptive field was tested for sensitivity to mechanical, thermal and chemical stimulation. Five different receptor types were found: fast adapting receptors responding to mechanical stimulation; slowly …

Neuroanatomy Of The Common Dolphin (Delphinus Delphis) As Revealed By Magnetic Resonance Imaging (Mri), L. Marino, Keith Sudheimer, D. Ann Pabst, William A. Mclellan, David Filsoof, John I. Johnson

Veterinary Science and Medicine Collection

In this study, magnetic resonance (MR) images of the brain of an adult common dolphin (Delphinus delphis) were acquired in the coronal plane at 66 antero-posterior levels. From these scans a computer-generated set of resectioned virtual images in orthogonal planes was constructed using the programs VoxelView and VoxelMath (Vital Images, Inc., Michigan State Univ.). Sections in all three planes reveal major neuroanatomical structures. These structures in the adult common dolphin brain are compared with those from a fetal common dolphin brain from a previously published study as well as with MR images of adult brains of other odontocetes. …

Description Of A Poorly Differentiated Carcinoma Within The Brainstem Of A White Whale (Delphinapterus Leucas) From Magnetic Resonance Images And Histological Analysis, Sam H. Ridgway, Lori Marino, T. P. Lipscomb

Veterinary Science and Medicine Collection

In this study we used magnetic resonance imaging (MRI) to investigate neuroanatomical structure in the brain of a white whale (Delphinapterus leucas) that died from a large tumor within the brainstem. This specimen was also compared with a normal white whale brain using MRI. MRI scans of the white whale specimen show how the tumor deformed surrounding brain structure. Histopathological analysis indicated a poorly differentiated carcinoma of uncertain origin. These analyses demonstrate the usefulness of supplementing histological analyses of pathology with studies of gross morphology facilitated by MRI.

Anatomical And Electrophysiological Analysis Of The Trigeminal Nerve In A Teleost Fish, Oncorhynchus Mykiss, Lynne U. Sneddon

Veterinary Science and Medicine Collection

The trigeminal nerve in the rainbow trout, Oncorhynchus mykiss, was examined for the presence of A-delta and C fibres. Sections of the three branches of the trigeminal nerve were found to comprise a range of fibre types including Adelta and C fibres. The size range of the cell bodies of the trigeminal ganglion reflected the fibre range since they correlated with the size range of axons in the nerve branches. Electrophysiological recordings of evoked activity from the ganglion confirmed the presence of these fibre types and the proportion of these mirrored the proportion of fibre types in the anatomical analyses. …

Anatomy And Three-Dimensional Reconstructions Of The Brain Of The White Whale (Delphinapterus Leucas) From Magnetic Resonance Images, Lori Marino, Timothy L. Murphy, Amy L. Deweerd, John A. Morris, Archibald J. Fobbs, Nathalie Humbolt, Sam H. Ridgway, John I. Johnson

Veterinary Science and Medicine Collection

Magnetic resonance imaging offers a means of observing the internal structure of the brain where traditional procedures of embedding, sectioning, staining, mounting, and microscopic examination of thousands of sections are not practical. Furthermore, internal structures can be analyzed in their precise quantitative spatial interrelationships, which is difficult to accomplish after the spatial distortions often accompanying histological processing. For these reasons, magnetic resonance imaging makes specimens that were traditionally difficult to analyze, more accessible. In the present study, images of the brain of a white whale (Beluga) Delphinapterus leucas were scanned in the coronal plane at 119 antero-posterior levels. Fromthese scans, …

Relative Volume Of The Cerebellum In Dolphins And Comparison With Anthropoid Primates, L. Marino, James K. Rilling, Shinko K. Lin, Sam H. Ridgway

Veterinary Science and Medicine Collection

According to the ‘developmental constraint hypothesis’ of comparative mammalian neuroanatomy, brain growth follows predictable allometric trends. Therefore, brain structures should scale to the entire brain in the same way across mammals. Evidence for a departure from this pattern for cerebellum volume has recently been reported among the anthropoid primates. One of the mammalian groups that has been neglected in tests of the ‘developmental constraint hypothesis’ is the cetaceans (dolphins, whales, and porpoises). Because many cetaceans possess relative brain sizes in the range of primates comparative tests of the ‘developmental constraint hypothesis’ across these two groups could help to delineate the …

Social Deprivation Of Infant Rhesus Monkeys Alters The Chemoarchitecture Of The Brain: I. Subcortical Regions, Lee J. Martin, Dawn M. Spicer, Mark H. Lewis, John P. Gluck, Linda C. Cork

Veterinary Science and Medicine Collection

Rhesus monkeys (Macaca mulatta) reared during the first year of life without social contact develop persistent stereotyped movements, self-directed behaviors, and psychosocial abnormalities, but neurobiological mechanisms underlying the behaviors of socially deprived (SD) monkeys are unknown. Monkeys were reared in total social deprivation for the first 9 months of life; control monkeys were reared socially (SR) with mothers and peers. Subjects were killed at 19-24 yr of age. Because the behaviors of SD monkeys are reminiscent of changes in striatal or amygdalar function, we used immunocytochemistry for substance P (SP), leutine-enkephalin (LENK), somatostatin, calbindin, and tyrosine hydroxylase (TH) to evaluate …

Acceptance Of Simulated Oral Rabies Vaccine Baits By Urban Raccoons, John Hadidian, Suzanne R. Jenkins, David H. Johnston, Peter J. Savarie, Victor F. Nettles, David M. Manski, George M. Baer

Veterinary Science and Medicine Collection

In summer 1986, a study was conducted to evaluate raccoon (Procyon lotor) acceptance of oral baits that could be used for rabies vaccination, One thousand wax-coated sponge bait cubes were filled with 5 mg of a seromarker (iophenoxic acid), placed in polyethylene bags, and hand-distributed in an 80 ha area within an urban National Park in Washington, D.C. (USA), After 3 wk, target and nontarget animals were trapped and blood samples collected to evaluate bait uptake. Thirty-three of 52 (63%) raccoons had elevated blood iodine levels indicating they had eaten at least one bait, 13 (25%) were negative, and six …

To Write A Theriatric Oath, Gretchen Lockwood

Veterinary Science and Medicine Collection

The Veterinarian's Oath was a disappointment to me. When I first read it as a freshman, I suppose I was expecting something along the lines of the Hippocratic Oath; instead I was struck by the contrast to it-by the lack of eloquence, of poetry, of ancient power. As impressionable as I was then, a whole year and a half ago, it left me unmoved. Now, having had my eyes opened to its more troubling ethical difficulties, I feel the desire to create something better, something that is at least more meaningful to me. As an individual, particularly without extensive dialogue …

Veterinary Conduct And Animal Welfare, H. Rozemond

Veterinary Science and Medicine Collection

This paper is a lecture presented to the same Association but fifteen years later: the 131st Annual Congress in 1984. This second presentation contemplates two points: First, it tries to indicate how this criticism has gradually emerged and a historical outline is put forth of the development of veterinary medicine, a differentiation being made between a mythical, a technical, and a critical approach. Second, a discussion of how veterinarians have to associate themselves with this criticism in their professional conduct is presented. This discussion is necessary for two reasons. Veterinarians have increasingly become aware that they bear a professional responsibility …

Applications Of Laboratory Technology In The Evaluation Of The Risk Of Rabies Transmissions By Biting Dogs And Cats, Donald C. Blenden, Manuel J. Torres-Anjel, F. T. Satalowich

Veterinary Science and Medicine Collection

While rabies is not a common disease in domestic animal species of the United States, potential exposures to rabies in the form of bites are very common and increasing. A nationwide study conducted among general hospitals shows that 1 percent of emergency room visits are for animal bites, of which 80-90 percent are inflicted by the dog (Callaham 1980). This figure is conservative, as the study did not include pediatric hospitals, the bite of victims that progress only to a physician's office, or those that receive no medical care at all. In Missouri alone, this study would infer about 1500 …

T-61 Use In The Euthanasia Of Domestic Animals: A Survey, Andrew N. Rowan

Veterinary Science and Medicine Collection

A variety of techniques have been proposed and employed for the killing of domestic animals but relatively few have survived as suitable agents for euthanasia-namely, the induction of painless, suffering-free death. Some agents, such as strychnine, curariform agents, or potassium salts cause suffering while others have other disadvantages. 'lbday, dogs and cats are commonly euthanatized with sodium pentobarbital or with T-61 which is a mixture of a central nervous system narcotic, a paralytic agent, and a local anesthetic. The use of T-61 was first reported in the United States in 1963 (Quin 1963). The substance gradually became more popular because …

Review Of Literature On Use Of T-61 As An Euthanasic Agent, Laura Dalia Barocio

Veterinary Science and Medicine Collection

The tools of evaluating the degree of distress in animals being killed include electroencephalography (EEG), electrocardiography (ECG), and measurement of blood pressure and respiration. Sound clinical and behavioral observations should also not be abandoned in the evaIuation process.

There are many methods which may be employed to reach the same end results, but the ideal method should satisfy several criteria: 1. It should be painless; 2. It should cause unconsciousness instantaneously and death within minutes; 3. It should not cause undue anxiety, alarm, fear, panic, behavior, struggling, vocalization, muscle spasms or clinical signs of automatic activation (e.g., convulsions) before unconsciousness; …