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.
Bergeler J, Liske-Schmitz A, Schmitz T, de Camp NV.The First Night Effect is a phenomenon whereby sleep duration and quality are compromised in unfamiliar environments or situations. Horses are often transported to new locations, such as sporting events. We wanted to know if the First Night Effect is also detectable in horses in two different populations. To investigate this, we compared five horses from a professional sports horse barn that are regularly used in competitions, with six horses from a breeding barn, that are less frequently transferred to unfamiliar places. Despite the significant differences observed in electroencephalography (...
Bombardi C, Salamanca G, Tagliavia C, Grandis A, Zamith Cunha R, Gramenzi A, De Silva M, Zannoni A, Chiocchetti R.The amygdala is composed of several nuclei, including the lateral nucleus which is the main receiving area for the input from cortical and subcortical brain regions. It mediates fear, anxiety, stress, and pain across species. Evidence suggests that the endocannabinoid system may be a promising target for modulating these processes. Cannabinoid and cannabinoid-related receptors have been identified in the amygdala of rodents, carnivores, and humans, but not in horses. This study aimed to investigate the gene expression of cannabinoid receptors 1 (CB1R) and 2 (CB2R), transient receptor potential...
Heun F, Delarocque J, Feige K, Hellige M.Nerve atrophy results in trigeminal nerve (TN) asymmetry detectable by magnetic resonance imaging (MRI) in humans, but similar studies have not been performed in horses with idiopathic trigeminal-mediated headshaking (ITMHS). Objective: Horses with ITMHS show greater MRI-detected trigeminal-nerve asymmetry than controls. Methods: A total of 20 adult horses with ITMHS and six unaffected control horses. Methods: Retrospective case-control study of the TN cross-sectional area (TNCSA) based on 3-Tesla MRI scans of the equine brain. TNCSA and its side-to-side differences at four defined measurement...
Fletcher KA, Benedetti B, Limon G, Grist A, Padalino B, Hernández-Gil M, Gibson TJ.There has been limited research into the effectiveness of penetrating captive bolt (PCB) for stunning horses () at slaughter. This study observed 100 horses at a commercial abattoir in Mexico, stunned using pneumatic PCB. Animals were assessed at the time of stunning and immediately after for signs of effective/ineffective stunning and shot positioning, with macroscopic gross brain pathology conducted to determine brain trauma. Twenty-five percent (25/100) received more than one shot and 28% (28/100) displayed behavioural signs of ineffective stunning. Of these 28 animals, all had deviations o...
Pattaro A, Ghibaudi M, Corrente C, Telitsyn N, Graic JM, Aresu L, Sherwood CC, Bonfanti L.Recent research in brain structural plasticity has identified "immature" or "dormant" neurons in layer II of the cerebral cortex (cortical immature neurons; cINs), cells that remain in a prolonged state of arrested development but retain the ability to resume maturation and integrate functionally into mature cortical circuits. These immature cells are far more abundant in large-brained mammals, being restricted to paleocortex (piriform cortex) in small-brained rodents and extending in the widely expanded neocortical mantle of species with large gyrencephalic brains. In a previous systematic an...
Gazzano V, Curadi MC, Capsoni S, Baragli P, Kêdzierski W, Cecchi F, Gazzano A.In humans, aging is often accompanied by cognitive decline, as seen in Alzheimer's disease. In contrast, the aging process in horses remains poorly characterized. This study aims to explore the presence of blood-based biomarkers associated with cognitive degeneration in this species. Twenty-three Arabian horses were enrolled, and 5 mL of blood was collected from each to measure serum levels of β-amyloid peptides (Aβ40 and Aβ42) and phosphorylated tau protein (pTau181), both considered reliable indicators of cognitive impairment in other species. Aβ42 was undetectable in all samples, while ...
Wienhold S, Bär L, Ringleb Z, Zirpel V, Gomolla A, Denk BF, Volkmer N, Gaertner RJ, Klink ESC, Pruessner JC.In any therapeutic setting, the outcome depends in part on the therapeutic alliance, characterized by mutual understanding, empathy and trust among the participants. This also manifests through physiological synchronization (PS) processes involving breathing, heart and brain. This study examined the dynamics of heart rate variability (HRV) synchronization patterns during horse-assisted therapy. We explored the correlations between the therapist's horse preference, levels of early life adversity (ELA), and PS relationships within and across dyads of participants, therapists, and therapy horses....
Kong FKW, Wong ASY, Wan TSM, Ho ENM.Hydrocortisone acetate, a synthetic acetate ester of hydrocortisone, was detected in horse blood samples collected from Thoroughbreds. Hydrocortisone acetate is generally considered an indicator for exogenous administration in horses. As hydrocortisone acetate has been previously reported to be endogenous in selected mammals, a proof-of-concept study was performed to evaluate the possible endogenous nature of hydrocortisone acetate in horses by in vitro incubation experiments using homogenized horse brain tissue.
Mota-Rojas D, Whittaker AL, Bienboire-Frosini C, Buenhombre J, Mora-Medina P, Domínguez-Oliva A, Martínez-Burnes J, Hernández-Avalos I....Recognizing that nonhuman animals are sentient beings has increased interest in studying their emotional state. Similar to humans, research has shown that some nonhuman mammals can modify facial expressions by contraction/relaxation of facial muscles according to their affective state. From a neurophysiological perspective, emotions are processed in several brain structures, mainly from the limbic system, such as the hypothalamus, hypophysis, hippocampus, prefrontal cortex, and amygdala. The converged pathways between the amygdala, the motor cortex, and its projections to the facial nerve cont...
Mota-Rojas D, Whittaker AL, Coria-Avila GA, Martínez-Burnes J, Mora-Medina P, Domínguez-Oliva A, Hernández-Avalos I, Olmos-Hernández A....The growing interest in managing and recognizing pain in animals has led to the search for more sensitive methods to evaluate it, especially because some species conceal any visible changes associated with pain or are not easily assessed. Research has shown that an animal's facial expression changes when exposed to painful stimuli. Thus, developing several pain scales (grimace scales) in species such as horses, cattle, pigs, sheep, donkeys, rabbits, rats, mice, and cats has helped to improve the study of pain in veterinary medicine. The possibility of using facial expression as an indicator of...
Bercovitz GR, Sullivan SN, Reed RA, Ryan CA, Diehl KA.To evaluate the effect of intravenous mannitol and hypertonic saline (HS) on intraocular pressure (IOP) and biometry parameters of horses with elevated intracranial pressure (ICP). Methods: Seven horses with normal ophthalmic exams were anesthetized and placed in lateral recumbency. A subarachnoid transducer was placed, and the head was lowered until ICP measured 40 mmHg +/- 2 mmHg. Five intravenous boluses of mannitol 20% (0.4 g/kg) or HS 7.2% (1 mL/kg) were administered, each 15 min apart. A 2-day washout period ensued, and the procedure was repeated with the other hyperosmotic age...
Haussler KK, le Jeune SS, MacKechnie-Guire R, Latif SN, Clayton HM.The defining characteristic of laterality is the dominance of one side of the brain controlling specific functions of paired organs or on one side of the body. Structural and functional asymmetries are ubiquitous in horses and range from anatomical features (e.g., the length of long bones) to the gathering of sensory information (e.g., which eye is used to observe unfamiliar scenes) and motor functions (e.g., left-right differences in locomotion). There is a common tendency to assign observed structural or functional asymmetries to lateralization, which often involves more than a simple left-r...
Fletcher KA, Padalino B, Felici M, Bigi D, Limon-Vega G, Grist A, Gibson TJ.There is limited research into horse slaughter, particularly ante mortem welfare, and the effectiveness of captive-bolt gun (CBG) stunning, despite this being a widely used method worldwide. To address this evidence gap and explore associations between ante and post mortem factors, the welfare of 62 horses was assessed at a commercial Italian abattoir. Animal-based measures were used to identify stress-related behaviours and stunning effectiveness. A sub-sample (44%; 27/62) of heads were assessed for gross brain pathology. All animals in the study showed stress-related behaviours at all stage...
Itoh K, Kikumura N, Maeda T, Hirata S, Ringhofer M.Despite the long history of the horse-human bond, our understanding of the brain and mind of horses remains limited due to the lack of methods to investigate their brain functions. This study introduces a novel methodology for completely non-invasive, multi-channel recording of electroencephalography (EEG) and evoked potentials in awake horses to examine equine auditory cortical processing. The new approach utilizes specially designed brush-shaped active electrodes that facilitate stable signal acquisition through the hair coat by penetrating electrode pins and integrated pre-amplifiers. A 12-...
Novotna T, Samonilova E, Klan J, Frgelecova L, Mala A, Svobodova Z, Drabkova Z.This case report describes the poisoning of two mares from the same paddock with Robinia pseudoacacia (Black locust) bark. The poisoning manifested itself by the sudden onset of weakness and fever with transient improvement after the administration of non-steroidal anti-inflammatory drugs and fluids. After the initial stabilisation, the mares were left unattended overnight. One of them was found dead in the morning. The surviving mare developed colic and severe encephalopathy and had to be referred to the clinic. Blood tests revealed severe hyperammonaemia. After four days of symptomatic treat...
de Oliveira UV, Varjão JL, de Jesus Deiró AG, Maciel BM, Silva FL, Pinheiro AM, Gondim LFP, Munhoz AD.The aim of this study was to isolate from equids destined for slaughter in a Brazilian slaughterhouse. A total of 354 equids were analyzed, with blood samples collected from all the animals and samples of masseter muscle and brain tissue collected from 319 animals. A serological test was conducted to detect equids with specific antibodies for . Molecular detection of by nested PCR was performed on the tissue samples collected. Tissue samples were tested by murine bioassay in an attempt to isolate either the parasite or the parasite DNA. Real-time PCR was performed on the brain samples from 1...
Martínez-Aranzales JR, Córdoba-Agudelo M, Pérez-Jaramillo JE.Crib-biting is a stereotyped oral behavior with poorly understood etiology and pathophysiology. The relationship between the gut microbiome and brain function has been described in behavioral disorders such as schizophrenia, depression and anxiety in humans. In horses, studies of behavioral problems and the microbiome are very limited. This study aimed to characterize the fecal microbiome and the predicted functional profile of horses with and without aerophagia. Fecal samples were collected from 12 Colombian Creole Horses of both sexes, divided into two groups: group 1, composed of six horses...
Zimmermann B, Castro ANC, Lendez PA, Carrica Illia M, Carrica Illia MP, Teyseyre AR, Toloza JM, Ghezzi MD, Mota-Rojas D.An emotion is defined as the affective response to a stimulus that leads to specific bodily changes, enabling individuals to react to positive or negative environmental conditions. In the absence of speech, emotions in animals are primarily studied by observing expressive components, such as facial expressions. This review aims to analyze the available literature on the influence of environmental stimuli on measurable behaviors in horses, describing the anatomical components involved in perception at the central nervous system level and the efferent pathways that trigger facial muscle contract...
Franzen V, Gruber NA, Klußmann S, Schoster A, May A.Trigeminal-mediated headshaking is a neuropathic facial pain condition in horses. No treatment has been entirely successful. Repetitive transcranial magnetic stimulation (rTMS) is used in human medicine as a treatment for various neuropathic pain conditions, and good results have been achieved in cases of trigeminal neuralgia. Objective: Apply rTMS to horses with trigeminal-mediated headshaking (TMHS) and to evaluate tolerability, application of the setting, and success rate. Methods: Seventeen horses with nonseasonal signs of TMHS. Methods: Other underlying causes of headshaking were ruled ou...
Crawford AE, Picken LK, Gabriel FD, Quade J, Gould S.Equestrian sports continue to gain popularity in the United States and are associated with a high injury rate, especially involving the central nervous system and thorax. Due to this high rate of injury and the potential for long-term consequences associated with participation, an understanding of the unique risks of this sport is needed. Unassigned: To describe severe injury in equestrian sports and review the role that protective gear plays in injury mitigation. Unassigned: The PubMed Database was searched using the search terms "equestrian" and "horse" combined with "spinal cord injury," "h...
Tomberg C, Petagna M, de Selliers de Moranville LA.Spontaneous eye blinks are brief closures of both eyelids. The spontaneous eye blink rate (SEBR) exceeds physiological corneal needs and is modulated by emotions and cognitive states, including vigilance and attention, in humans. In several animal species, the SEBR is modulated by stress and antipredator vigilance, which may limit the loss of visual information due to spontaneous eye closing. Here, we investigated whether the SEBR is modulated by attention in the domestic horse (Equus caballus). Our data supported previous studies indicating a tonic SEBR specific to each individual. We also fo...
Tan Yi Shean L, Milne EM, Shaw DJ, Maxwell S, Del-Pozo J.Lipofuscin is a complex mixture of highly oxidized, cross-linked macromolecules that accumulates in neurons with age and some neurodegenerative diseases. Equine dysautonomia (ED) is a polyneuropathy that mainly affects autonomic and enteric nervous systems, resulting in alimentary tract dysfunction. Our main aim was to determine whether neuronal lipofuscin increased with increasing duration of ED. We investigated the prevalence of lipofuscin in cranial cervical ganglia of horses with acute (AED), subacute (SED), and chronic ED (CED), young controls (of similar age to ED cases), and aged contro...
Kuhlmann C, Scheidemann W, Bachmann M, Schusser GF.The brainstem auditory evoked response (BAER) is a diagnostic approach to examine the hearing system of horses objectively. The aim of this BAER examination was the diagnosis of conductive or sensorineural hearing loss or deafness in horses with external otitis, head trauma, headshaking, tinnitus or skittish horses with eye disease. Brainstem dysfunction is induced by intracranial hypotension. BAER was used in horses with colic surgery which had a low arterial blood pressure during general anesthesia. The endoscopic finding of the guttural pouch was the ipsilateral mild to severe hypertrophy o...
Behroozi M, Graïc JM, Gerussi T.Diffusion-weighted Imaging (DWI) is an effective and state-of-the-art neuroimaging method that non-invasively reveals the microstructure and connectivity of tissues. Recently, novel applications of the DWI technique in studying large brains through imaging enabled researchers to gain insights into the complex neural architecture in different species such as those of (e.g., horses and rhinos), (e.g., bovids, swines, and cetaceans), and (e.g., felids, canids, and pinnipeds). Classical tract-tracing methods are usually considered unsuitable for ethical and practical reasons, in large animals...
Moscovice LR, Sobczak B, Niittynen T, Koski SE, Gimsa U.Although best known for its established role in mediating parturition and lactation, the highly-conserved neuropeptide hormone oxytocin also mediates a range of social and stress-buffering processes across mammalian species. Measurements of peripheral oxytocin in plasma have long been considered the gold standard, but there is increasing interest in developing methods to detect oxytocin non-invasively in saliva. Here we present an analytical and biological validation of a novel method to measure salivary oxytocin (sOXT) in an under-studied research group: farm animals. Given their similarities...
Bruschetta G, Zanghì G, Giunta RP, Ferlazzo AM, Satué K, D'Ascola A, Fazio E.Horse transport is considered a cause of stress in animals and is known to affect the 5-HT concentrations in both the brain and other tissues. The aim of this research was to investigate the effect of horse transportation and slaughter stress on plasma serotonin's concentration and the expression levels of the related 5-HT1B and 5-HT2A receptors in PBMCs. Furthermore, the IL-12 levels and a variety of blood parameters, including triglycerides, total cholesterol, glucose, aspartate aminotransferase, creatine phosphokinase, lactate dehydrogenase, were also considered. This research was carried o...
de Preux M, Precht C, Guevar J, Graubner C, Thenhaus-Schnabel S, Buser L, Lukes A, Koch C.A 16-year-old warmblood mare was referred with a progressive history of behavioral changes and left-sided blindness. Following neuroanatomical localization to the forebrain, magnetic resonance imaging of the head revealed a well-delineated, 4.5 cm in diameter, round pituitary mass causing marked compression of the midbrain and optic chiasm. Euthanasia was recommended but declined by the owners. Veterinary specialists and a human neurosurgeon collaboratively prepared for surgical case management. A novel navigated transmandibular lateral transsphenoidal approach was developed to access the re...
Olofsson KM, van de Velde N, Peletto S, Iulini B, Pratley L, Modabberzadeh B, Małek E, Grandi G.Halicephalobus gingivalis is a nematode with zoonotic potential which can cause fatal opportunistic infections in various mammals. The parasite has never been diagnosed in Sweden, in any species, prior to the presented case. Methods: An imported 21-year-old Icelandic mare developed severe neurological signs. The horse was eventually euthanized and submitted for post-mortem examination where severe lesions in the kidneys were noted. Histopathology revealed the presence of H. gingivalis in both kidneys and the brain. Phylogenetic analysis of the parasite determined it to belong to Lineage 1. Con...
Aleman M, Vedavally U, Pusterla N, Wensley F, Berryhill E, Madigan JE.Comprehensive descriptions of equids with granulocytic anaplasmosis (EGA) with neurologic or muscle disease and other atypical presentations are scarce in the literature. Objective: Describe the clinical signs, laboratory findings, treatment, and outcome of equids with EGA with emphasis on neurologic and muscle disease. Methods: Thirty-eight horses, 1 donkey. Methods: Retrospective study. Equids with EGA were included. The electronic data base was searched from January 2000 to December 2022 using the words anaplasmosis, ehrlichiosis, granulocytic, and rickettsia. Signalment and clinical data w...
Goma AA, Uddin J, Kieson E.Lateralised behavioural responses to environmental stressors have become more frequently used as indicators of social welfare in animals. These lateralised behavioural responses are under the control of asymmetrical brain functions as part of the primary functions of most vertebrates and assist in primary social and survival functions. Lateralised behavioural responses originating from the left hemisphere are responsible for processing familiar conditions, while the right hemisphere is responsible for responding to novel stimuli in the environment. The forced lateralisation and side preference...
Kellerman TS, Marasas WF, Thiel PG, Gelderblom WC, Cawood M, Coetzer JA.Leukoencephalomalacia (LEM) was induced by the oral administration of fumonisin B1 (FB1) to 2 horses: a filly received 59.5 mg/kg of a 50% preparation of FB1, administered in 21 doses of 1.25-4 mg/kg over 33 days; a colt, 44.3 mg/kg of 95% pure FB1 in 20 doses of 1-4 mg/kg in 29 days. Both animals developed nervous signs such as apathy, changes in temperament, inco-ordination, walking into objects, and one showed paralysis of the lips and tongue. Characteristic lesions of LEM were present in the brains. These trials proved conclusively that FB1 can induce LEM in horses.
Morales MA, Barrandeguy M, Fabbri C, Garcia JB, Vissani A, Trono K, Gutierrez G, Pigretti S, Menchaca H, Garrido N, Taylor N, Fernandez F, Levis S....West Nile virus (WNV) was isolated from the brains of 3 horses that died from encephalitis in February 2006. The horses were from different farms in central Argentina and had not traveled outside the country. This is the first isolation of WNV in South America.
Gosztonyi G, Ludwig H.Natural BD is a nonpurulent acute/subacute encephalitis of horses and sheep with a propensity to involve the olfactory and limbic systems, and the brain stem. The inflammation is concentrated primarily in the gray matter, but subcortical white matter may also be affected. Experimental BD can be produced in a series of animals from birds to primates. The neuropathology after experimental infection is similar to that in natural disease but the inflammatory changes are more diffuse. In the rat and mouse, a persistent/tolerant infection can also be induced, in which inflammatory changes are conspi...
Suen WW, Prow NA, Hall RA, Bielefeldt-Ohmann H.West Nile virus (WNV) is an important emerging neurotropic virus, responsible for increasingly severe encephalitis outbreaks in humans and horses worldwide. However, the mechanism by which the virus gains entry to the brain (neuroinvasion) remains poorly understood. Hypotheses of hematogenous and transneural entry have been proposed for WNV neuroinvasion, which revolve mainly around the concepts of blood-brain barrier (BBB) disruption and retrograde axonal transport, respectively. However, an over‑representation of in vitro studies without adequate in vivo validation continues to obscure our...
De Boyer Des Roches A, Richard-Yris MA, Henry S, Ezzaouïa M, Hausberger M.Lateralization of emotions has received great attention in the last decades, both in humans and animals, but little interest has been given to side bias in perceptual processing. Here, we investigated the influence of the emotional valence of stimuli on visual and olfactory explorations by horses, a large mammalian species with two large monocular visual fields and almost complete decussation of optic fibres. We confronted 38 Arab mares to three objects with either a positive, negative or neutral emotional valence (novel object). The results revealed a gradient of exploration of the 3 objects ...
Shirato K, Kimura T, Mizutani T, Kariwa H, Takashima I.West Nile (WN) virus is a mosquito-borne flavivirus that can cause lethal encephalitis in humans and horses. The WN virus endemic in New York City (NY) in 1999 caused large-scale mortality of wild birds that was not evident in endemic areas in other parts of the world, and the pathogenesis of the WN virus strain isolated in NY (NY strain) appears to differ from that of previously isolated strains. However, the pathogenesis of NY strain infection remains unclear. This study examined CC (RANTES/CCL5, MIP-1 alpha/CCL3, MIP-1 beta/CCL4) and CXC (IP-10/CXCL10, B lymphocyte chemoattractant (BLC/CXCL...
Marasas WF, Kellerman TS, Pienaar JG, Naudé TW.When 2 horses were dosed with cultures of a Fusarium moniliforme isolate that had previously caused only hepatosis, 1 developed brain oedema and hepatosis, and the other only leukoencephalomalacia. A 3rd horse developed both leukoencephalomalacia and hepatosis after being dosed with another isolate obtained from maize which was associated with a natural outbreak of the nervous form of the disease. Since leukoencephalomalacia and hepatosis could be induced by the same culture material, it was concluded that both syndromes were manifestations of the same toxicosis. There was also some evidence t...
Fornstedt B, Rosengren E, Carlsson A.The 5-S-cysteinyl derivatives of dopamine, dopa (3,4-dihydroxyphenylalanine) and dopac (3,4-dihydroxyphenylacetic acid) were synthesized and used as reference compounds in high performance liquid chromatography analyses of extracts from various brain regions of eight mammalian species. All three metabolites were detected in the brains of all the species studied. The regional distribution of the metabolites was similar to that of dopamine; the metabolite concentrations ranged from less than 0.1 percent to more than 1 percent of the dopamine level, the highest ratios generally being found in sub...
Gibson SJ, Polak JM, Allen JM, Adrian TE, Kelly JS, Bloom SR.The distribution of neuropeptide Y [NPY]-immunoreactive material was examined in the spinal cord and dorsal root ganglia of rat, guinea-pig, cat, marmoset, and horse. Considerable concentrations of NPY and similar distribution patterns of immunoreactive nerve fibres were found in the spinal cord of all species investigated. The dorsal root ganglia of the cat and the horse contained numerous immunoreactive nerve fibres, but in these species, as in the other three studied [rat, guinea-pig, marmoset], no positively stained cell bodies were found. Neuropeptide Y-immunoreactive nerves were observed...
Decourt C, Tillet Y, Caraty A, Franceschini I, Briant C.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...
Bilzer T, Planz O, Lipkin WI, Stitz L.Tissues from 9 horses and 1 donkey suffering from natural Borna disease were investigated immunomorphologically. Lymphocytic inflammatory reactions and increased expressions of MHC class I and class II antigen were found in the brain as well as in the trigeminal and olfactory system. Perivascular inflammatory infiltrates were dominated by CD4+ T cells, whereas the majority of CD8+ T cells were disseminated intraparenchymally. No evidence of inflammation was found in the retina. Borna disease virus proteins and nucleic acids were present in the hippocampus, thalamus and medulla oblongata in all...
Ludwig H, Furuya K, Bode L, Klein N, Dürrwald R, Lee DS.Borna disease viruses (BDV) isolated from more than 20 naturally infected horses, 2 sheep and a possible feline isolate were included in these studies. Most of these wild-type viruses were grown in rabbit cells. Specifically rabbit-adapted viruses establish persistent infection in immortalized cell lines of various animal species. Brain-, tissue culture-, and cell-free released viruses could all be neutralized with antibodies from naturally and experimentally infected animals (horse; hamster, rat, rabbit, mouse, and chicken), with highest titres in birds. Splenectomized rabbits, which were sub...
Brain lateralization is a phenomenon widely reported in the animal kingdom and sensory laterality has been shown to be an indicator of the appraisal of the stimulus valence by an individual. This can prove a useful tool to investigate how animals perceive intra- or hetero-specific signals. The human-animal relationship provides an interesting framework for testing the impact of the valence of interactions on emotional memories. In the present study, we tested whether horses could associate individual human voices with past positive or negative experiences. Both behavioural and electroencephalo...
Venezuelan equine encephalitis (VEE) virus causes an acute central nervous system infection in human and animals. Melatonin (MLT), minocycline (MIN) and ascorbic acid (AA) have been shown to have antiviral activities in experimental infections; however, the mechanisms involved are poorly studied. Therefore, the aim of this study was to determine the effects of those compounds on the viral titers, NO production and lipid peroxidation in the brain of mice and neuroblastoma cultures infected by VEE virus. Infected mouse (10 LD50) were treated with MLT (500 μg/kg bw), MIN (50mg/kg bw) or AA (50mg...
Siniscalchi M, Padalino B, Lusito R, Quaranta A.Evidence for behavioural and brain lateralisation is now widespread among the animal kingdom; lateralisation of limb use (pawedness) occurs in several mammals including both feral and domestic horses. We investigated limb preferences in 14 Quarter Horse during different motor tasks (walking, stepping on and off a step, truck loading and unloading). Population lateralisation was observed in two tasks: horses preferentially used their left forelimb during truck loading and stepping off a step. The results also revealed that horses showed higher scores for anxious behaviours during truck loading ...
Dubey JP, Davis SW, Speer CA, Bowman DD, de Lahunta A, Granstrom DE, Topper MJ, Hamir AN, Cummings JF, Suter MM.Sarcocystis neuronan n. sp. is proposed for the apicomplexan taxon associated with myeloencephalitis in horses. Only asexual stages of this parasite presently are known, and they are found within neuronal cells and leukocytes of the brain and spinal cord. The parasite is located in the host cell cytoplasm, does not have a parasitophorous vacuole, and divides by endopolygeny. Schizonts are 5-35 microns x 5-20 microns and contain 4-40 merozoites arranged in a rosette around a prominent residual body. Merozoites are approximately 4 x 1 micron, have a central nucleus, and lack rhoptries. Schizonts...
Gonzalez-Salazar D, Estrada-Franco JG, Carrara AS, Aronson JF, Weaver SC.To assess the role of horses as amplification hosts during the 1993 and 1996 Mexican Venezuelan equine encephalitis (VEE) epizootics, we subcutaneously infected 10 horses by using four different equine isolates. Most horses showed little or no disease and low or nonexistent viremia. Neurologic disease developed in only 1 horse, and brain histopathologic examination showed meningeal lymphocytic infiltration, perivascular cuffing, and focal encephalitis. Three animals showed mild meningoencephalitis without clinical disease. Viral RNA was detected in the brain of several animals 12-14 days after...
Morrow KL, Park RD, Spurgeon TL, Stashak TS, Arceneaux B.The head from three horses euthanized due to diseases unrelated to the head and neck was imaged using computed tomography (CT). Gross cross-sectional slices of equine head #1 and skeleton of equine head #2 were compared with the CT images of the three equine heads to identify normal structures of the cranium, brain, paranasal sinuses, nasal cavity, and teeth. Labeled transverse CT images of the equine head are presented sequentially as a reference for normal anatomy.
Ludwig H, Thein P.From 18 horses with clinical symptoms of an affection of the central nervous system and with histopathologic alterations in the brain, four were demonstrated to have Bornavirus-specific antibodies. The antibodies are monospecific, recognizing identical antigens from infected brains of different animal species as well as from persistently infected tissue culture cells. Discrete immunoglobulin species (oligoclonal IgG) can be demonstrated in concentrated horse cerebrospinal fluid; they carry Bornavirus antibody specificity. Their presence, together with the higher antibody titers in the cerebros...
Ojo KK, Dangoudoubiyam S, Verma SK, Scheele S, DeRocher AE, Yeargan M, Choi R, Smith TR, Rivas KL, Hulverson MA, Barrett LK, Fan E, Maly DJ....Sarcocystis neurona is the most frequent cause of equine protozoal myeloencephalitis, a debilitating neurological disease of horses that can be difficult to treat. We identified SnCDPK1, the S. neurona homologue of calcium-dependent protein kinase 1 (CDPK1), a validated drug target in Toxoplasma gondii. SnCDPK1 shares the glycine "gatekeeper" residue of the well-characterized T. gondii enzyme, which allows the latter to be targeted by bumped kinase inhibitors. This study presents detailed molecular and phenotypic evidence that SnCDPK1 can be targeted for rational drug development. Recombinant ...
Hasebe R, Sasaki M, Sawa H, Wada R, Umemura T, Kimura T.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...
Schindler AR, Vögtlin A, Hilbe M, Puorger M, Zlinszky K, Ackermann M, Ehrensperger F.Borna disease is a severe, immunopathological disorder of the central nervous system caused by the infection with the Borna disease virus (BDV). The detection of BDV in diseased animals, mainly sheep and horses, is achieved by histological, immunohistochemical and serological approaches and/or PCR-based technologies. In the present study, reverse transcription, real-time PCR assays were established for the detection of BDV in the brain tissue from sheep and horses, using loci for the p40 (nucleoprotein) and the p24 (phosphoprotein) genes. The PCRs were equally specific and sensitive, detecting...
Sasaki M, Hasebe R, Makino Y, Suzuki T, Fukushi H, Okamoto M, Matsuda K, Taniyama H, Sawa H, Kimura T.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...
Cozzi B, Povinelli M, Ballarin C, Granato A.The horse is a common domestic animal whose anatomy has been studied since the XVI century. However, a modern neuroanatomy of this species does not exist and most of the data utilized in textbooks and reviews derive from single specimens or relatively old literature. Here, we report information on the brain of Equus caballus obtained by sampling 131 horses, including brain weight (as a whole and subdivided into its constituents), encephalization quotient (EQ), and cerebellar quotient (CQ), and comparisons with what is known about other relevant species. The mean weight of the fresh brains in o...
Gosztonyi G, Ludwig H.The brains of eight horses that had suffered from natural Borna disease were examined with virologic, immunohistological, and electron-microscopic methods. All brains harbored infectious virus as shown by inoculation of experimental animals. Regional assessment of the infectivity exhibited the highest titers in the hippocampus and piriform cortex and the lowest in the cerebellum. Conventional histology yielded pathologic alterations very similar to those of the classical description of the disease. Immunohistology demonstrated the highest amounts of Borna disease virus-specific antigen in the ...
Rozovsky I, Hoving S, Anderson CP, O'Callaghan J, Finch CE.Premarin, which contains several equine estrogens, as well as estradiol (E2) as a minor component, is widely used for replacement therapy of estrogen deficits, but little is known of its direct actions on brain cells. In mixed glial cultures, apolipoprotein E (apoE) and glial fibrillary acidic protein (GFAP) are induced by estrogens. GFAP induction showed an inverted-U shape E2 dose response, with a maximum induction at 1 pM, whereas apoE mRNA induction was greatest at 100 pM. GFAP and ApoE mRNAs were induced by equine estrogens in the following order: E2=equilin>estrone>17 alpha-dihydro...
Olivares R, Michalland S, Aboitiz F.A cross-species morphometric study of the corpus callosum was performed in the rat, rabbit, cat, dog, horse, cow and human. Across species, the results indicate a strong, although less than linear, dependency of callosal size on brain weight. This relation tends to lose significance within species. This is consistent with other morphometric studies indicating a tendency to decrease the correlations between morphometric variables in within-species analyses as compared to between-species analyses. There are species differences in the relative size of some callosal segments particularly in the po...
Ballarin C, Povinelli M, Granato A, Panin M, Corain L, Peruffo A, Cozzi B.The domestic bovine Bos taurus is raised worldwide for meat and milk production, or even for field work. However the functional anatomy of its central nervous system has received limited attention and most of the reported data in textbooks and reviews are derived from single specimens or relatively old literature. Here we report information on the brain of Bos taurus obtained by sampling 158 individuals, 150 of which at local abattoirs and 8 in the dissecting room, these latter subsequently formalin-fixed. Using body weight and fresh brain weight we calculated the Encephalization Quotient (EQ)...
Dallaire A, Rucklebusch Y.For several weeks, three ponies kept in an environment with controlled light and temperature, were studied for behaviour (time spent in recumbency and time required to consume hay or oats) and for electrical activity of the brain (cortical and sub-cortical) during the night phase of the circadian rhythm. Recumbency was adopted by all the ponies for six or seven periods during the night. With a regimen of hay ad libitum, about four hours were cumulated in sternal recumbency and only one hour in complete lateral recumbency. Various degree of sleep, as identified by cortical and hippocampal elect...
Zhu X, Suarez-Jimenez B, Zilcha-Mano S, Lazarov A, Arnon S, Lowell AL, Bergman M, Ryba M, Hamilton AJ, Hamilton JF, Turner JB, Markowitz JC....While effective treatments for posttraumatic stress disorder (PTSD) exist, many individuals, including military personnel and veterans fail to respond to them. Equine-assisted therapy (EAT), a novel PTSD treatment, may complement existing PTSD interventions. This study employs longitudinal neuro-imaging, including structural magnetic resonance imaging (sMRI), resting state-fMRI (rs-fMRI), and diffusion tensor imaging (DTI), to determine mechanisms and predictors of EAT outcomes for PTSD. Nineteen veterans with PTSD completed eight weekly group sessions of EAT undergoing multimodal MRI assessme...
