Effect of exogenous sperm capacitation inducers on stallion sperm.

Although under appropriate laboratory conditions, sperm from different mammalian species can be capacitated in vitro, the optimal conditions for sperm capacitation in the stallion have been elusive. This study evaluated the effect of different capacitating inducers in Whitten and Tyrode media and assessed their impact on capacitation-related factors. Stallion sperm were incubated with different combinations of capacitating inducers at 38.5 °C in an air atmosphere. Sperm quality variables such as motility, mitochondrial membrane potential, and lipid peroxidation were assessed. Membrane fluidity and intracellular calcium levels were evaluated as early markers of capacitation, while tyrosine phosphorylation events and the sperm's ability to perform acrosomal exocytosis were used as late capacitation markers. Finally, these sperm were evaluated using a heterologous zona pellucida binding assay. The findings confirm that capacitating conditions evaluated increase intracellular calcium levels and membrane fluidity in both media. Similarly, including 2 or 3 inducers in both media increased tyrosine phosphorylation levels and acrosomal exocytosis after exposure to progesterone, confirming that stallion sperm incubated in these conditions shows cellular and molecular changes consistent with sperm capacitation. Furthermore, the zona pellucida binding assay confirmed the binding capacity of sperm incubated in capacitation conditions, a key step for stallion in vitro fertilization success. Further studies are needed to evaluate the effect of these conditions on in vitro fertilization in the horse.

Effects of Reactive Oxygen and Nitrogen Species on Male Fertility.

Significance: In recent decades, male fertility has been severely reduced worldwide. The causes underlying this decline are multifactorial, and include, among others, genetic alterations, changes in the microbiome, and the impact of environmental pollutants. Such factors can dysregulate the physiological levels of reactive species of oxygen (ROS) and nitrogen (RNS) in the patient, generating oxidative and nitrosative stress that impairs fertility. Recent Advances: Recent studies have delved into other factors involved in the dysregulation of ROS and RNS levels, such as diet, obesity, persistent infections, environmental pollutants, and gut microbiota, thus leading to new strategies to solve male fertility problems, such as consuming prebiotics to regulate gut flora or treating psychological conditions. Critical Issues: The pathways where ROS or RNS may be involved as modulators are still under investigation. Moreover, the extent to which treatments can rescue male infertility as well as whether they may have side effects remains, in most cases, to be elucidated. For example, it is known that prescription of antioxidants to treat nitrosative stress can alter sperm chromatin condensation, which makes DNA more exposed to ROS and RNS, and may thus affect fertilization and early embryo development. Future Directions: The involvement of extracellular vesicles, which might play a crucial role in cell communication during spermatogenesis and epididymal maturation, and the relevance of other factors such as sperm epigenetic signatures should be envisaged in the future.

Standardization of a Sex-Sorting Protocol for Stallion Spermatozoa by Means of Absolute RT-qPCR.

Sperm sexing is a technology that can generate great economic benefits in the animal production sector. Techniques such as sex-sorting promise over 90% accuracy in sperm sexing. However, for the correct standardization of the technique, some laboratory methodologies are required. The present manuscript describes in detail a standardized equine sperm sex-sorting protocol using an absolute qPCR-based methodology. Furthermore, the results of absolute qPCR were implemented and validated by generating equine/bovine heterologous embryos by intracytoplasmic sperm injection (ICSI) of presumably sexed equine spermatozoa into bovine oocytes using a piezoelectric system (Piezo-ICSI). Our results indicated that equine sex-sorting spermatozoa had a 97% and 94% certainty for X and Y sperm, respectively, while presumptive female and male equine/bovine hybrid embryos, generated by Piezo-ICSI, had an accuracy of 92% with respect to the desired sex. Therefore, it is concluded that the presented methodology is a reliable, cost-effective, and relatively simple option for standardizing sex-sorting of equine spermatozoa. This is supported by the results of the correct sexing of Piezo-ICSI heterologous embryos generated with the sexed spermatozoa, validating the correct sexing and viability of these gametes.

Cellular and Molecular Consequences of Stallion Sperm Cryopreservation: Recent Approaches to Improve Sperm Survival.

Cryopreservation of stallion semen does not achieve the post-thaw quality or fertility results observed in other species like cattle. There are many reasons for this, but the membrane composition and intracellular changes in stallion sperm predispose them to low resistance to the cooling, freezing, and subsequent thawing process. Damage to the sperm results from different processes activated during cryopreservation, including oxidative stress, apoptosis, and structural modifications in the sperm membrane that increase the deleterious effect on sperm. In addition, significant individual variability is observed among stallions in the ability of sperm to survive the freeze-thaw process. Recent advances in genomics, transcriptomics, proteomics, metabolomics, and epigenetics are making it possible to advance our understanding of the cellular and molecular processes involved in the cryopreservation process, opening new possibilities for improvement. This review addresses the ongoing research on stallion semen cryopreservation, focusing on the cellular and molecular consequences of this procedure in stallions and discusses the new tools currently available to increase the tolerance of equine spermatozoa to freeze-thaw.

Bovine ICSI: limiting factors, strategies to improve its efficiency and alternative approaches.

Intracytoplasmic sperm injection (ICSI) is an assisted reproductive technique mainly used to overcome severe infertility problems associated with the male factor, but in cattle its efficiency is far from optimal. Artificial activation treatments combining ionomycin (Io) with 6-dimethylaminopurine after piezo-ICSI or anisomycin after conventional ICSI have recently increased the blastocyst rate obtained. Compounds to capacitate bovine spermatozoa, such as heparin and methyl-ß-cyclodextrin and compounds to destabilize sperm membranes such as NaOH, lysolecithin and Triton X-100, have been assessed, although they have failed to substantially improve post-ICSI embryonic development. Disulfide bond reducing agents, such as dithiothreitol (DTT), dithiobutylamine and reduced glutathione, have been assessed to decondense the hypercondensed head of bovine spermatozoa, the two latter being more efficient than DTT and less harmful. Although piezo-directed ICSI without external activation has generated high fertilization rates and modest rates of early embryo development, other studies have required exogenous activation to improve the results. This manuscript thoroughly reviews the different strategies used in bovine ICSI to improve its efficiency and proposes some alternative approaches, such as the use of extracellular vesicles (EVs) as 'biological methods of oocyte activation' or the incorporation of EVs in the in vitro maturation and/or culture medium as antioxidant defence agents to improve the competence of the ooplasm, as well as a preincubation of the spermatozoa in estrous oviductal fluid to induce physiological capacitation and acrosome reaction before ICSI, and the use of hyaluronate in the sperm immobilization medium.

Extracellular vesicles in mammalian reproduction: a review.

Over the last decades, extracellular vesicles (EVs) have been found to be implicated in a complex universal mechanism of communication between different cell types. EVs are nanostructures of lipid nature that have an exosomal or ectosomal biogenesis, responsible for the intercellular transport of proteins, lipids, carbohydrates, nucleic acids, ions, among other molecules. The content of EVs can vary due to various factors such as hormonal stimuli, non-physiological conditions, metabolic state, etc. Once EVs reach their target cell, they can modulate processes such as gene expression, metabolism, response to external factors, and can even be associated with the delivery of molecules involved in epigenetic inheritance processes in germ cells. In mammalian reproduction, EVs have been shown to play an important role, either in vivo or in vitro, modulating a variety of processes in sperm, oocytes and embryos, and in their respective environments. Moreover, EVs represent a biodegradable, harmless and specific vehicle, which makes them attractive allies to consider when improving assisted reproductive technologies (ARTs). Therefore, the present review aims to describe the content of the main EVs involved in mammalian reproduction and how they can vary due to different factors, as well as to detail how EVs modulate, directly or indirectly, different molecular processes in gametes and embryos. In addition, we will highlight the mechanisms that remain to be elucidated. We will also propose new perspectives according to the characteristics of each particular EV to improve the different ARTs.

Bioaccessibility of Anthocyanins on in vitro Digestion Models: Factors Implicated and Role in Functional Foods Development.

BACKGROUND: Worldwide, the prevalence of obesity and related non-communicable chronic diseases is high and continues to grow. In that sense, anthocyanins (ANC) have shown beneficial health effects in preventing obesity and metabolic risk factors. Moreover, the demand for functional foods incorporating these compounds has risen significantly in the past years. Thus, there is a need for validations of the functional properties of these formulations; nevertheless, in vivo assays are complex and require a lot of resources. One approach for estimating bioactive compounds' functionality and health benefits is to evaluate their bioaccessibility on a specific food matrix, determined by various factors. This article aims to review different factors influencing the bioaccessibility of ANC evaluated on in vitro digestion models as a functionality parameter, elucidating the effect of chemical composition, raw materials, food matrices, and vehicles for the delivery of ANC. METHODS: Study searches were performed using PubMed, Web of Science, Scopus, and Science Direct databases. RESULTS: Different factors influenced bioaccessibility and stability of ANC studied by in vitro digestion: i) the raw material used for ANC obtention; ii) food processing; iii) other food components; iv) the extraction method and solvents used; v) the structure of ANC; vi) delivery system (e.g., microencapsulation); vii) pH of the medium; viii) the digestion stage. CONCLUSION: Simulated digestion systems allow to determine free or encapsulated ANC bioaccessibility in different food matrices, which offers advantages in determining the potential functionality of a food product.

Cryopreservation of stallion semen: Effect of adding antioxidants to the freezing medium on sperm physiology.

Cryopreservation of stallion semen has not reached the level of efficiency and positive results described in other species. This is mainly due to the greater sensitivity of stallion sperm to the freezing process, showing higher rates of oxidative stress and plasma membrane damage, which trigger the activation of several cell damage pathways that ultimately culminate in DNA fragmentation and cell death. Therefore, finding molecules that improve the efficiency of this technique in stallion by preventing oxidative stress and cell damage is required. Thus, the aim of the present study was to evaluate the effect of adding three antioxidants (MnTBAP, NAC and FeTPPS) to the freezing medium on the quality and functional parameters of stallion sperm. Semen samples from three stallions frozen with the antioxidants were evaluated in two conditions: (a) adding the antioxidants before freezing, and (b) before and after freezing. Plasma membrane integrity, mitochondrial membrane potential, lipid peroxidation, intracellular ROS levels, membrane lipid disorder, DNA damage, sperm motility and binding to the zona pellucida were assessed. The results showed that MnTBAP was the antioxidant treatment that best controlled the oxidative stress process and post-thaw cell damage, showing higher plasma membrane integrity, mitochondrial membrane potential, sperm motility, number of spermatozoa bound to the zona pellucida of bovine oocytes and lower lipid disorder. Additionally, it was determined that a second post-thaw application of antioxidants is detrimental since induced higher cell damage and lower sperm motility, without showing any beneficial effect on the spermatozoa.

Effect of human tubal fluid medium and hyperactivation inducers on stallion sperm capacitation and hyperactivation.

Conventional in vitro fertilization has not yet been implemented in the equine species. One of the main reasons has been the inability to develop a culture medium and incubation conditions supporting high levels of stallion sperm capacitation and hyperactivation in vitro. Although different culture media have been used for this purpose, human tubal fluid (HTF) medium, widely used in the manipulation of human and mice gametes, has not been reported so far in stallion sperm culture. The first part of this study aimed to compare HTF and Whitten's media on different stallion sperm quality and capacitation variables. Additionally, the effect of procaine, aminopyridine and caffeine in both media was evaluated on sperm motility parameters at different incubation times. Integrity and destabilization of the plasma membrane were evaluated by merocyanine 540/SYTOX Green (MC540), mitochondrial membrane potential (∆Ψm) using tetramethylrhodamine methyl ester perchlorate (TMRM), acrosome membrane integrity by PNA/FITC and tyrosine phosphorylation by P-tyrosine mouse mAb conjugated to Alexa Fluor® by flow cytometry. Motility parameters were evaluated using the integrated semen analysis system (ISAS®). We found no differences between Whitten's and HTF media and incubation time in terms of sperm viability, uninduced acrosome membrane damage or mitochondrial membrane potential at 30- and 120-min incubation. Membrane fluidity (MC540) increased in both media at 30- and 120-min incubation compared to noncapacitating conditions. Similarly, tyrosine phosphorylation increased in both media in capacitating conditions at 2- and 4-hr incubation compared to noncapacitating conditions. Although procaine showed the best result in terms of sperm hyperactivated motility in both media, aminopyridine also showed parameters consistent with the hyperactivation including an increase in curvilinear velocity and decrease in straightness. In conclusion, HTF medium and aminopyridine equally support capacitation-related parameters in stallion sperm.

Experiencia de diagnóstico comunitario bajo el modelo de enfermería de Elizabeth Anderson / Community diagnosis experience on the model of nursing

RESUMEN Introducción: Trabajar con y para la comunidad permite integrar la perspectiva de las personas respecto a su estado de salud, los beneficios que otorga su entorno, el gobierno y los sistemas de salud, identificar problemas que afectan el bienestar integral de las personas que la forman. Objetivo: Describir la experiencia de aplicar un diagnóstico comunitario bajo el modelo de enfermería de Elizabeth Anderson. Métodos: Estudio descriptivo de corte transversal, con una muestra de 285 personas de 63 familias en la comunidad "Los Microbuseros" de Peñalolén, Santiago de Chile. Para obtener la información se aplicó una encuesta que se procesó en el programa SPSS. Las variables estudiadas fueron los 8 subsistemas del modelo Elizabeth Anderson. Resultados: De la muestra, padecían diabetes mellitus II el 34,92 por ciento, hipertensión arterial el 42,85 por ciento, sedentarismo el 67,36 por ciento y tabaquismo el 31,22 por ciento; el 55,55 por ciento no participaba en organizaciones comunitarias; el 96,82 por ciento no usaba programas municipales, el 80,95 por ciento de las familias no recibía información sobre programas gubernamentales de salud, el 95,23 por ciento aumentó el consumo de alcohol y drogas en la vía pública en el último año, el 74,60 por ciento desconocía el número de seguridad policial del sector. El 80,85 por ciento no conocía el programa de salud cardiovascular, el 96,82 por ciento no acudía al Centro de salud. Conclusión: El modelo de Anderson permite valorar la comunidad de manera holística, evidenciar que la salud puede ser influenciada por otros sistemas como la economía, la seguridad, la educación, entre otros. Por ello surge la necesidad de fortalecer los factores protectores e intervenir sobre los riesgos para mejorar la calidad de vida de la comunidad(AU)

ABSTRACT Introduction: Working with and for the community allows integrating the perspective of people regarding their health status, the benefits of their environment, government and health systems, identify problems that affect the well-being of the people who form it . Objective: To describe the experience of applying a community diagnosis under the nursing model of Elizabeth Anderson in community "Los Microbuseros" of Peñalolén, Santiago de Chile. Methods: Descriptive cross-sectional study with a sample of 285 people from 63 families. To obtain the information a survey was applied and processed in the SPSS program. The variables studied were the 8 subsystems of the Elizabeth Anderson model. Results: Diabetes Mellitus II presents 34.92 percent, arterial hypertension 42.85 percent, sedentarism 67.36 percent, smoking 31.22 percent, does not participate in community organizations 55.55 percent, does not use municipal programs 96.82 percent Does not receive information on government health programs, 80,95 percent of families increased alcohol and drug consumption on public roads in the last year 95.23 percent, did not know the number of police security in the sector 74,60 percent. 80.85 percent did not know the cardiovascular health program, 96.82 percent did not go to the Health Center. Conclusion: The Anderson model allows valuing the community in a holistic way, showing that health can be influenced by other systems such as economy, safety, education, among others. Therefore, the need to strengthen the protective factors and intervene on the risks to improve the quality of life of the community arises(AU)

Improved expression of green fluorescent protein in cattle embryos produced by ICSI-mediated gene transfer with spermatozoa treated with streptolysin-O.

The ICSI-sperm mediated gene transfer (ICSI-SMGT) has been used to produce transgenic mice with high efficiency; however, the efficiency of this technique in farm animals is still less than desirable. Pretreatment of sperm with membrane destabilizing agents can improve the efficiency of ICSI in cattle. The objective of the present study was to evaluate streptolysin-O (SLO) as a novel treatment to permeabilize the bovine sperm membrane and assess its effect on efficiency of generating transgenic embryos by ICSI-SMGT. First, there was evaluation of the plasma membrane integrity (SYBR/PI), acrosome membrane integrity (PNA/FITC), DNA damage (TUNEL) and binding capacity of exogenous DNA (Nick Translation) in bull sperm treated with SLO. Subsequently, there was assessment of embryonic development and the efficiency in generating transgenic embryos with enhanced expression of the gene for green fluorescent protein (EGFP). Results indicate that SLO efficiently permeabilizes the plasma and acrosome membranes of bull spermatozoa and increases binding of exogenous DNA mostly to the post-acrosomal region and tail without greatly affecting the integrity of the DNA. Furthermore, treatment of bull spermatozoa with SLO prior to the injection of oocytes by ICSI-SMGT significantly increased the rate of embryo expression of the EGFP gene. Future experiments are still needed to determine the effect of this treatment on the development and transgene expression in fetuses and animals produced by ICSI-SMGT.

Recovery of glomerular morphology in the olfactory bulb of young mice after disruption caused by continuous odorant exposure.

Olfactory glomeruli are the first synaptic site of the olfactory system and are formed by the convergence of axons of the same type of sensory neurons onto the olfactory bulbs of the brain. Although the anatomical organization of glomeruli is conserved across species, their particular role in olfactory processing remains uncertain. We studied the composition and maintenance of glomeruli by means of a genetic model, mI7-IRES-tauGFP knock-in young mice, where the cytoskeleton of sensory neurons expressing the mI7 olfactory receptor is tagged with green fluorescent protein. Animals were continuously exposed to heptaldehyde, a cognate ligand of the mI7 receptor, from postnatal days 5-10. We hypothesized that continuous odorant exposure will induce changes in glomerular morphology, and that this can be recovered if the normal odorant environment is reestablished within the early postnatal period. We assessed changes in the distribution of mI7 axons in glomerular morphology, as well as possible changes in the number of the mI7 olfactory sensory neurons. Following odorant exposure the well-defined convergence of mI7 fibers into a single glomerulus was disrupted, producing numerous neighboring glomeruli partially innervated by mI7 fibers. After the normal odor environment was reestablished the number of glomeruli partially innervated by mI7 fibers decreased significantly. Moreover, we found that multiple supernumerary mI7 glomeruli were formed. Our results confirm the significant role of sensory input in glomerular formation and maintenance. Additionally, we show that the developing olfactory system actively maintains glomerular morphology, suggesting the importance of this for olfactory processing.

The body as constitutive element phenomenology and psychoanalysis on our view of ourselves and others.

The aim of this manuscript is to highlight that from the phenomenology and psychoanalysis point of view, the meaning of the notion of the body is different from the medical biologicist discourse. In psychoanalysis, the body is an erogenized body. It is constituted as an object for another self. Similarly, in phenomenology, the body is an own body in first instance. It is the body of a self, rather than a living body and a material body. Both positions enable us to understand how this conceptualization of the body is essential in any human field. Especially in the clinic, the position of the subject before the other will lead to a specific form of intervention. From this understanding of the human body, both phenomenology and psychoanalysis confirm that the biologicist understanding of the body, presumed by all psychological and medical practices, is insufficient.

Tendinitis of the temporalis muscle: differential diagnosis and treatment: a case report / Tendinitis del músculo temporal: diagnóstico diferencial y tratamiento: informe de caso

Abstract: introduction: The temporalis muscle plays an essential role in mastication and is actively involved in the mandibular closing movement. It is covered by a fibroelastic fascia that forms its tendon. Tendinitis is a degenerative and inflammatory process, which originates in the tendon-bone junction. Signs and symptoms such as swelling, pain, tenderness on palpation, limitation of movement and mouth opening are frequently associated with other temporomandibular disorders and not with tendinitis as a causal factor. Objective: To describe a clinical case identifying the diagnostic process and management of tendinitis of the temporalis muscle. Case report: A 30-year old male patient who sought treatment after continuous squeezing pain in the zygomatic and bilateral temporal regions with increased pain during mouth opening and mandibular function. The patient referred pain in the insertion region of the tendon of the temporalis muscle. Pain was removed after using anesthesia, consequently confirming the diagnosis of tendinitis of the temporalis muscle. Primary management measures were performed and then peritendinous corticosteroids were administered. The patient did not refer spontaneous or functional pain during check-up. Conclusion: Tendinitis of the temporalis muscle is a common condition, although frequently underdiagnosed. A good differential diagnosis must be performed to avoid confusion with other common conditions such as odontogenic pain, sinusitis, arthralgia, myofascial pain and migraine. Management depends on the type of tendinitis. It usually occurs in conjunction with other types of TMD or facial pain, so it is important to know the different clinical characteristics of pathologies with similar manifestations.

Resumen: introducción: El músculo temporal es fundamental en la masticación, participa activamente en los movimientos de cierre mandibular. Está recubierto por una fascia fibroelástica que conforma su tendón. La tendinitis es un proceso degenerativo e inflamatorio, que se origina en la unión tendón-hueso. Con frecuencia, signos y síntomas como inflamación, dolor a la palpación, limitación del movimiento y apertura, son asociados a otros trastornos temporomandibulares no considerando la tendinitis como un factor causal. Objetivo: Describir un caso clínico identificando el proceso diagnóstico y el manejo de una tendinitis del músculo temporal. Descripción del caso: Paciente sexo masculino de 30 años, acude por dolor opresivo continuo en la región cigomática y temporal bilateral con aumento del dolor en apertura y función mandibular. A la palpación presenta dolor en la zona de inserción del tendón del músculo temporal, el cual se elimina al anestesiar confirmando el diagnóstico de tendinitis del músculo temporal. Se realizan medidas primarias de manejo y luego se infiltra corticoides peritendineos. Al control el paciente no presenta dolor espontáneo ni en función. Conclusión: La tendinitis del músculo temporal es una patología frecuente, aunque subdiagnosticada. Debe realizarse el correcto diagnóstico diferencial con patologías frecuentes como dolor odontogénico, sinusitis, artralgia, dolor miofascial y migraña. El manejo dependerá del tipo de tendinitis. Habitualmente se presenta en conjunto con otros o dolores faciales, por lo que es importante conocer las distintas características clínicas de patologías con presentaciones similares.

Chromaffin cell transplants: from the lab to the clinic.

Chromaffin cell transplants have been explored since the early 1980s as a promising alternative in different pathological states, mainly Parkinson's disease and chronic pain. Advances are significant since transplants have been performed in humans. The general mechanism of these transplants relies in the capacity of chromaffin cells to act as mini-pumps that release amines and peptides. Different strategies are being used to improve the efficacy of transplants. However, a remaining hurdle is to determine the viability across time and the interaction with the microenvironment of the graft. We analyzed previous and current results finding that although there is a lot of positive evidence, there is also a lack of molecular studies that support behavioral results. The present review gives an update on recent advances of chromaffin cell transplants and their future in the clinic.

Rat psychomotor vigilance task with fast response times using a conditioned lick behavior.

Investigations into the physiological mechanisms of sleep control require an animal psychomotor vigilance task (PVT) with fast response times (<300 ms). Rats provide a good PVT model since whisker stimulation produces a rapid and robust cortical evoked response, and animals can be trained to lick following stimulation. Our prior experiments used deprivation-based approaches to maximize motivation for operant conditioned responses. However, deprivation can influence physiological and neurobehavioral effects. In order to maintain motivation without water deprivation, we conditioned rats for immobilization and head restraint, then trained them to lick for a 10% sucrose solution in response to whisker stimulation. After approximately 8 training sessions, animals produced greater than 80% correct hits to the stimulus. Over the course of training, reaction times became faster and correct hits increased. Performance in the PVT was examined after 3, 6 and 12 h of sleep deprivation achieved by gentle handling. A significant decrease in percent correct hits occurred following 6 and 12 h of sleep deprivation and reaction times increased significantly following 12 h of sleep deprivation. While behaviorally the animals appeared to be awake, we observed significant increases in EEG delta power prior to misses. The rat PVT with fast response times allows investigation of sleep deprivation effects, time-on-task and pharmacological agents. Fast response times also allow closer parallel studies to ongoing human protocols.

Precision rodent whisker stimulator with integrated servo-locked control and displacement measurement.

We developed a high speed voice coil based whisker stimulator that delivers precise deflections of a single whisker or group of whiskers in a repeatable manner. The device is miniature, quiet, and inexpensive to build. Multiple stimulators fit together for independent stimulation of four or more whiskers. The system can be used with animals under anesthesia as well as awake animals with head-restraint, and does not require trimming the whiskers. The system can deliver 1-2 mm deflections in 2 ms resulting in velocities up to 900 mm/s to attain a wide range of evoked responses. Since auditory artifacts can influence behavioral studies using whisker stimulation, we tested potential effects of auditory noise by recording somatosensory evoked potentials (SEP) with varying auditory click levels, and with/without 80 dBa background white noise. We found that auditory clicks as low as 40 dBa significantly influence the SEP. With background white noise, auditory clicks as low as 50 dBa were still detected in components of the SEP. For behavioral studies where animals must learn to respond to whisker stimulation, these sounds must be minimized. Together, the stimulator and data system can be used for psychometric vigilance tasks, mapping of the barrel cortex and other electrophysiological paradigms.