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Topic:Brain
The equine brain is a complex organ responsible for processing sensory information, regulating behavior, and controlling motor functions in horses. It plays a part in cognitive processes such as learning, memory, and decision-making. The equine brain is divided into several regions, each with distinct functions, including the cerebrum, cerebellum, and brainstem. Research in this area often focuses on understanding the neurological pathways and mechanisms that underlie equine behavior and performance. This topic encompasses studies that explore brain anatomy, neurophysiology, and the effects of various factors such as stress, training, and disease on brain function in horses. This page compiles peer-reviewed research studies and scholarly articles that investigate the structure, function, and health of the equine brain.
Toxic equine parkinsonism: an immunohistochemical study of 10 horses with nigropallidal encephalomalacia. Chronic ingestion of yellow star thistle (Centaurea solstitialis) or Russian knapweed (Acroptilon repens) causes nigropallidal encephalomalacia (NPE) in horses with an abrupt onset of neurologic signs characterized by dystonia of lips and tongue, inability to prehend food, depression, and locomotor deficits. The objectives of this study were to reexamine the pathologic alterations of NPE and to conduct an immunohistochemistry study using antibodies to tyrosine hydroxylase and α-synuclein, to determine whether NPE brains show histopathologic features resembling those in human Parkinson disease...
Molecular epidemiology of the rabies virus in Slovenia 1994-2010. A molecular epidemiology study was performed on a selection of 30 rabies-positive brain samples collected between 1994 and 2010 in Slovenia and originating from the red fox (n=19), badger (n=3), cattle (n=3), dog (n=2), cat (n=1), marten (n=1) and horse (n=1). Based on the comparison of 1092 and 672 nucleotide sequences of nucleoprotein (N) and partial glycoprotein (G) gene regions, a low genetic diversity of the circulating strains was detected, but both phylogenetic trees were consistent with the topology where partial nucleoprotein or glycoprotein genes were used. A high sequence identity i...
Magnesium disorders in horses. Magnesium (Mg) is an essential macroelement that is required for cellular energy-dependent reactions involving adenosine triphosphate and for the regulation of calcium channel function. Subclinical hypomagnesemia is common in critically ill humans and animals and increases the severity of the systemic inflammatory response syndrome; worsens the systemic response to endotoxins; and can lead to ileus, cardiac arrhythmias, refractory hypokalemia, and hypocalcemia. This article discusses the clinical signs, consequences, and treatment of hypomagnesemia in horses and describes the association of Mg...
Use of BAER to identify loss of auditory function in older horses. To use the brainstem auditory evoked response (BAER) to test the hypothesis that auditory function could be worse in older horses than in younger horses. Methods: BAER waveforms in response to click stimuli were measured in five younger horses (5-8 years) and four older horses (17-22 years). Results: Compared with the younger horses, the older horses showed significantly (P < 0.02) worse BAER thresholds and significantly (P < 0.02) worse BAER wave V amplitudes to the 90 decibels above normal hearing level stimulus. These results were consistent with partial deafness in the older horse gr...
Equine major histocompatibility complex class I molecules act as entry receptors that bind to equine herpesvirus-1 glycoprotein D. The endotheliotropism of equine herpesvirus-1 (EHV-1) leads to encephalomyelitis secondary to vasculitis and thrombosis in the infected horse central nervous system (CNS). To identify the host factors involved in EHV-1 infection of CNS endothelial cells, we performed functional cloning using an equine brain microvascular endothelial cell cDNA library. Exogenous expression of equine major histocompatibility complex (MHC) class I heavy chain genes conferred susceptibility to EHV-1 infection in mouse NIH3T3 cells, which are not naturally susceptible to EHV-1 infection. Equine MHC class I molecule...
Effects of isoflurane anesthesia on cerebrovascular autoregulation in horses. To test a hypothesis predicting that isoflurane would interfere with cerebrovascular autoregulation in horses and to evaluate whether increased mean arterial blood pressure (MAP) would increase cerebral blood flow and intracranial pressure (ICP) during isoflurane anesthesia. Methods: 6 healthy adult horses. Methods: Horses were anesthetized with isoflurane at a constant end-tidal concentration sufficient to maintain MAP at 60 mm Hg. The facial, carotid, and dorsal metatarsal arteries were catheterized for blood sample collection and pressure measurements. A sub-arachnoid transducer was used to...
Perosomus elumbis, cerebral aplasia, and spina bifida in an aborted thoroughbred foal. Perosomus elumbis represents a rare congenital anomaly characterized by aplasia of the lumbosacral spinal cord and vertebrae. This anomaly is often associated with arthrogryposis and malformations of the urogenital and intestinal tract. This report describes the first case of perosomus elumbis in an aborted Thoroughbred foal associated with cerebral aplasia with meningocele, cranioschisis, spina bifida, a fused urogenital and intestinal tracts lined by a cutaneous mucosa without uterine glands, atresia ani, and arthrogryposis of the hind legs. Immunohistochemistry detected no abnormalities in ...
Biomarkers of brain injury in foals with hypoxic-ischemic encephalopathy. Neonatal hypoxic-ischemic encephalopathy (NHIE) is a disease affecting newborn foals for which there is no antemortem diagnostic test. Objective: Ubiquitin C-terminal hydrolase 1 (UCHL1) and the phosphorylated axonal forms of neurofilament H (pNF-H) are markers of brain injury in foals with NHIE. Methods: Thirty-three foals with a clinical diagnosis consistent with NHIE and 17 healthy foals. Methods: Retrospective study. Concentrations of UCHL1 and pNF-H in plasma were measured by ELISA. The performance of the assays for the diagnosis of NHIE was assessed by receiver operating characteristic c...
Bilateral internal carotid and vertebral artery dissection after a horse-riding injury. Blunt cerebrovascular injuries, defined as blunt injuries to the internal carotid or vertebral arteries, are uncommon and usually occur in victims of high-speed deceleration motor vehicle crashes. A blunt cerebrovascular injury after an equestrian accident is an extremely unusual presentation. In recent years, advances in screening and treatment with pharmacologic anticoagulation before the onset of neurologic symptoms have improved outcomes for these patients. Endovascular stenting and embolization, although unproven, offer a new potential approach for these complex injuries. We present a uni...
A component of Premarin(®) enhances multiple cognitive functions and influences nicotinic receptor expression. In women, ovarian hormone loss at menopause has been related to cognitive decline, and some studies suggest that estrogen-containing hormone therapy (HT) can mitigate these effects. Recently, the Women's Health Initiative study found that conjugated equine estrogens, the most commonly prescribed HT, do not benefit cognition. Isolated components of conjugated equine estrogens (tradename Premarin(®)) have been evaluated in vitro, with delta(8,9)-dehydroestrone (∆(8)E1) and equilin showing the strongest neuroprotective profiles. It has not been evaluated whether ∆(8)E1 or equilin impact cogn...
Finite element modelling of equestrian helmet impacts exposes the need to address rotational kinematics in future helmet designs. Jockey head injuries, especially concussions, are common in horse racing. Current helmets do help to reduce the severity and incidences of head injury, but the high concussion incidence rates suggest that there may be scope to improve the performance of equestrian helmets. Finite element simulations in ABAQUS/Explicit were used to model a realistic helmet model during standard helmeted rigid headform impacts and helmeted head model University College Dublin Brain Trauma Model (UCDBTM) impacts. Current helmet standards for impact determine helmet performance based solely on linear acceleration....
Diagnostic utility of computed tomography imaging in equine intracranial conditions. The use of computer tomography (CT) and contrast-enhanced CT (CCT) to image the head is common. However, the validity of CT as a neurodiagnostic indicator of intracranial diseases in horses is unknown. Objective: To define the validity of CT and CCT in horses with suspected intracranial disorders. Methods: The validity of CT imaging was estimated by comparing clinical, clinicopathological and histopathological findings to CT findings in 15 horses presented for intracranial disorders, for which pre- and post contrast CT images and post mortem examination of the brain and skull were reviewed. Po...
Anatomical studies of maxillary cheek teeth infundibula in clinically normal horses. Although clinical disorders of equine maxillary cheek teeth (CT) infundibula are common, anatomical knowledge of these structures is poor. Objective: Anatomical examinations of sectioned CT infundibula will better define their shapes and sizes and allow identification of infundibular cemental variations and changes. Methods: Cheek teeth were extracted post mortem from 33 horses, aged 3-30 years, without a clinical history of dental disease. The CT were sectioned longitudinally in the bucco-palatal plane through the widest aspects of both infundibula. The infundibular surfaces were then assesse...
Fumonisin B1 neurotoxicity in young carp (Cyprinus carpio L.). For years scientists have suspected that the environment plays a role in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. Mycotoxin fumonisin B1 (FB1) is produced by several Fusarium species, mainly by Fusarium verticilioides, which is one of the most common fungi associated with corn worldwide. Fumonisins are known to cause equine leukoencephalomalacia, a disease associated with the consumption of corn-based feeds contaminated with FB1. Here we have reported chronic experimental toxicosis in one-year-old carp (Cyprinus carpio L.) receiving f...
A grade IV glioblastoma with an oligodendroglial component (GBM-O) in a horse. A 4-year-old Dutch warmblood mare was presented with a 10-month history of ataxia and proprioceptive deficits. Computed tomography defined a large, non-contrast enhancing mass in the left cerebral hemisphere. Necropsy examination revealed a tumour that effaced much of the piriform and temporal lobes. Microscopically the lesion was classified as a grade IV glioblastoma with an oligodendroglial component (GBM-O). The tumour was composed of highly pleomorphic cells organized in different patterns within a fibrillary stroma. There were multiple foci of necrosis. At the periphery of the tumour neop...
Parenchymal and vascular lesions in ageing equine brains: histological and immunohistochemical studies. Many age-related changes are described in the nervous system of different species, but detailed studies of brain lesions in ageing horses are lacking. The aim of the present study was to systematically characterize lesions in the brains of 60 horses aged from 7 to 23 years. No gross changes were present in any brain. Microscopically, spongiform changes, lipofuscin storage, corpora amylacea, gliosis and satellitosis were common, together with axonal and neuronal swellings. The most important findings were the presence of pseudocalcium-calcium (pCa-Ca) deposits and arterial wall degeneration. Sc...
Ivermectin toxicosis in three adult horses. 3 adult Quarter Horses were evaluated for acute, progressive neurologic signs 18 hours after oral administration of 1 dose of 1.87% ivermectin paste. Results: Clinical signs included depression, forelimb and hind limb ataxia, drooping of the superior and inferior lips, and muscle fasciculations. Bilateral mydriasis, decreased pupillary light reflexes, and absent menace reflexes were evident. Clinical signs progressed in severity for 36 hours after administration of the ivermectin. Results: All horses were treated supportively with IV administration of fluids and anti-inflammatory medications. ...
Infectious entry of equine herpesvirus-1 into host cells through different endocytic pathways. We investigated the mechanism by which equine herpesvirus-1 (EHV-1) enters primary cultured equine brain microvascular endothelial cells (EBMECs) and equine dermis (E. Derm) cells. EHV-1 colocalized with caveolin in EBMECs and the infection was greatly reduced by the expression of a dominant negative form of equine caveolin-1 (ecavY14F), suggesting that EHV-1 enters EBMECs via caveolar endocytosis. EHV-1 entry into E. Derm cells was significantly reduced by ATP depletion and treatments with lysosomotropic agents. Enveloped virions were detected from E. Derm cells by infectious virus recovery a...
[Serious accidents caused by horses. Warnings and prevention rules]. Children's equestrian activities in the domestic, play activities, sports and educational areas are relatively frequent, and are not exempt from risks. Nevertheless, there is a lack of data on horse-related injuries, their circumstances and the key points for their prevention. Methods: Retrospective and descriptive study of pediatric equestrian injuries admitted to Hospital between July 1997 and September 2008. Results: A total of 17 patients with ages between 4 and 17 years were analyzed. There were 14 accidental falls, 2 kicks and 1 bite, and 8 patients had lost consciousness after the accid...
Biological and anatomical evidence for kisspeptin regulation of the hypothalamic-pituitary-gonadal axis of estrous horse mares. The purpose of the present study was to evaluate the effects of kisspeptin (KiSS) on LH and FSH secretion in the seasonally estrous mare and to examine the distribution and connectivity of GnRH and KiSS neurons in the equine preoptic area (POA) and hypothalamus. The diestrous mare has a threshold serum gonadotropin response to iv rodent KiSS decapeptide (rKP-10) administration between 1.0 and 500 microg. Administration of 500 microg and 1.0 mg rKP-10 elicited peak, mean, and area under the curve LH and FSH responses indistinguishable to that of 25 microg GnRH iv, although a single iv injection...
Differential place and response learning in horses displaying an oral stereotypy. Significant similarities exist between the neural and behavioural features of environmentally and drug-induced stereotypy. For example, exposure to dopamine agonists, such as amphetamine, induces stereotypy and causes alterations in midbrain neurophysiology similar to those observed following chronic stress. An additional behavioural feature of these neural changes in the drug-induced phenotype is an enhanced rate of switching from response-outcome (R-O) to stimulus-response (S-R) learning. The aim of the current experiment was to examine R-O and S-R learning in horses displaying environmental...
The role of dietary antioxidant insufficiency on the permeability of the blood-brain barrier. Our previous studies implicated vitamin E deficiency as a risk factor for equine motor neuron disease, a possible model of human amyotrophic lateral sclerosis, and showed direct effects of this deficiency on brain vascular endothelium. To gain better understanding of the pathogenesis of equine motor neuron disease, we determined the effects of dietary antioxidant insufficiency and the resultant brain tissue oxidative stress on blood-brain barrier permeability. Rats (n = 40) were maintained on a diet deficient of vitamin E for 36 to 43 weeks; 40 controls were fed a normal diet. Permeability of ...
Computed tomography-guided brain biopsy for in vivo diagnosis of a cholesterinic granuloma in a horse. An 8-year-old warmblood mare was evaluated following an acute onset of neurologic abnormalities. Results: Computed tomography of the head revealed large masses in both lateral ventricles, and a presumptive diagnosis of cholesterinic granuloma was made. Results: Freehand biopsy of the intracranial masses was performed under computed tomographic guidance, and histologic examination of biopsy specimens confirmed the diagnosis. No adverse effects associated with the brain biopsy procedure were encountered. Clinical signs resolved, and long-term follow-up did not reveal any recurrence of neurologic...
The demographics of equestrian-related injuries in the United States: injury patterns, orthopedic specific injuries, and avenues for injury prevention. It was the purpose of this study to review equestrian-related injuries using a large nation wide database and analyze predictors of significant injury. Methods: The National Electronic Surveillance System database was queried for equestrian injuries from 2002 to 2004. The presence of a fracture, dislocation, traumatic brain injury, musculoskeletal injury, orthopedic injury, and spinal injury, as well as injury mechanism, geographical location, and emergency room disposition were noted. Bivariate, cosinor seasonal, and multiple logistic regression analyses were performed. p 18 years, traumatic ...
Kisspeptin immunoreactive neurons in the equine hypothalamus Interactions with GnRH neuronal system. To determine if kisspeptin could be implicated in the control of reproduction in equine species, we studied the distribution of kisspeptin neurons and their anatomical interactions with GnRH neurons in the hypothalamus of pony mares. Brains were collected in three pony mares between 2 and 4h after ovulation. One major population of kisspeptin immunoreactive cell bodies was found in the arcuate nucleus (ARC), where they extended from the middle of the nucleus to the premammillary recess. Kisspeptin immunoreactive varicose fibers extended from the preoptic area to the mammillary nuclei, with imp...
Brainstem auditory-evoked responses in horses with temporohyoid osteoarthropathy. Facial and vestibulocochlear nerve dysfunction occurs commonly in horses with temporohyoid osteoarthropathy (THO); however, auditory dysfunction has not been thoroughly assessed. Objective: To determine if auditory abnormalities occur in horses with THO. Methods: Eleven diseased and 8 control horses. Methods: This is a prospective study in which brainstem auditory-evoked responses (BAER) were recorded in 11 horses diagnosed with THO through neurologic, endoscopic, radiographic, or computed tomographic examinations. BAER findings were compared with those recorded from 8 adult control horses. Re...
Molecular characterization and expression of the equine M(1) and M(2)-pyruvate kinase gene. To elucidate the molecular properties of the equine glycolytic enzymes equine M(1) (eM(1)) and M(2) (eM(2))-pyruvate kinase (PK), mRNAs were isolated from thoroughbred horse skeletal muscle and hair roots, respectively. The full-length eM(1) and eM(2)-PK cDNAs consist of 2,320 and 2,376 bp, respectively, containing a 1596 bp open reading frame. The cDNAs were mapped to equine chromosome 1, and the equine pyruvate kinase M (PKM) gene consists of twelve exons. Exon 9 of eM(1)-PK and exon 10 of eM(2)-PK were further investigated in five equine species. Out of 55 amino acids encoded by exon 9 in e...
Immunohistochemical characterization of mononuclear cells and MHC II expression in the brain of horses with experimental chronic Trypanosoma evansi infection. An histochemical and immunohistochemical study was carried out to evaluate the mechanisms of immune response of horses experimentally infected by Trypanosoma evansi. For this purpose the HE histochemical stain and the avidin biotin peroxidase method were used. To determine the presence and immunoreactivity of immune cells we used anti-major histocompatibility complex II antibodies. Cellular infiltration phenotype was characterized with the aid of anti-CD3 antibody for T lymphocytes and by anti-BLA 36 antibodies for B lymphocytes. Macrophages were marked with an antibody against myeloid/histyoc...
Impaired instrumental choice in crib-biting horses (Equus caballus). Horses displaying an oral stereotypy were tested on an instrumental choice paradigm to examine differences in learning from non-stereotypic counterparts. Stereotypic horses are known to have dysfunction of the dorsomedial striatum, and lesion studies have shown that this region may mediate response-outcome learning. The paradigm was specifically applied in order to examine learning that requires maintenance of response-outcome judgements. The non-stereotypic horses learned, over three sessions, to choose a more immediate reinforcer, whereas the stereotypic horses failed to do so. This suggests...
