Name: a low cost setup for behavioral audiometry in rodents
Uploaded: 2012-10-16T13:00:00
Description: Watch this Scientific Journal Video about A Low Cost Setup for Behavioral Audiometry in Rodents at JoVE.com

Questo lavoro è stato sostenuto dal Centro Interdisciplinare per la Ricerca Clinica (IZKF, progetto E7) presso l&#39;Ospedale Universitario dell&#39;Università di Erlangen-Norimberga.

1. Assemblaggio e installazione software di programmazione <ol><li> Installare un D / A carta in un Personal Computer (ad esempio: NI PCI 6229, National Instruments) e collegarlo a un breakout-box (ad esempio: BNC-2110, National Instruments), entrambi dovrebbero sostenere almeno un ingresso e un canale di uscita con una frequenza di campionamento di almeno 44,1 kHz ciascuno. </li><li> Collegare l&#39;uscita del breakout-box via cavo BNC ad una amplificazione del suono (ad esempio: AMP75 ampl...

<ol>
	<li>Brown, M., Irvine, D. R., Park, V. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perceptual+learning+on+an+auditory+frequency+discrimination+task+by+cats:+association+with+changes+in+primary+auditory+cortex.">Perceptual learning on an auditory frequency discrimination task by cats: association with changes in primary auditory cortex.</a> Cereb. Cortex. 14, 952-965 (2004).</li><li>Ohl, F. W., Scheich, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Learning-induced+plasticity+in+animal+and+human+auditory+cortex.">Learning-induced plasticity in animal and human auditory cortex.</a> Curr. Opin. Neurobiol. 15, 470-477 (2005).</li><li>Koch, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neurobiology+of+startle.">The neurobiology of startle.</a> Prog. Neurobiol. 59, 107-128 (1999).</li><li>Larrauri, J., Schmajuk, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prepulse+inhibition+mechanisms+and+cognitive+processes:+a+review+and+model.">Prepulse inhibition mechanisms and cognitive processes: a review and model.</a> EXS. 98, 245-278 (2006).</li><li>Walter, M., Tziridis, K., Ahlf, S., Schulze, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Context+dependent+auditory+thresholds+determined+by+brainstem+audiometry+and+prepulse+inhibition+in+Mongolian+gerbils.">Context dependent auditory thresholds determined by brainstem audiometry and prepulse inhibition in Mongolian gerbils.</a> Open Journal of Acoustics. 2, 34-49 (2012).</li><li>Gaese, B. H., Nowotny, M., Pilz, P. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acoustic+startle+and+prepulse+inhibition+in+the+Mongolian+gerbil.">Acoustic startle and prepulse inhibition in the Mongolian gerbil.</a> Physiol. Behav. 98, 460-466 (2009).</li><li>Fechter, L. D., Sheppard, L., Young, J. S., Zeger, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensory+threshold+estimation+from+a+continuously+graded+response+produced+by+reflex+modification+audiometry.">Sensory threshold estimation from a continuously graded response produced by reflex modification audiometry.</a> J. Acoust. Soc. Am. 84, 179-185 (1988).</li><li>Turner, J. G., Parrish, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gap+detection+methods+for+assessing+salicylate-induced+tinnitus+and+hyperacusis+in+rats.">Gap detection methods for assessing salicylate-induced tinnitus and hyperacusis in rats.</a> Am. J. Audiol. 17, 185-192 (2008).</li><li>Campeau, S., Davis, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fear+potentiation+of+the+acoustic+startle+reflex+using+noises+of+various+spectral+frequencies+as+conditioned+stimuli.">Fear potentiation of the acoustic startle reflex using noises of various spectral frequencies as conditioned stimuli.</a> Animal Learning &#38; Behavior. 20, 177-186 (1992).</li><li>Young, J. S., Fechter, L. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reflex+inhibition+procedures+for+animal+audiometry:+a+technique+for+assessing+ototoxicity.">Reflex inhibition procedures for animal audiometry: a technique for assessing ototoxicity.</a> J. Acoust. Soc. Am. 73, 1686-1693 (1983).</li><li>Turner, J. G., Brozoski, T. J., Bauer, C. A., Parrish, J. L., Myers, K., Hughes, L. F., Caspary, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gap+detection+deficits+in+rats+with+tinnitus:+a+potential+novel+screening+tool.">Gap detection deficits in rats with tinnitus: a potential novel screening tool.</a> Behav. Neurosci. 120, 188-195 (2006).</li><li>Turner, J., Larsen, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relationship+between+noise+exposure+stimulus+properties+and+tinnitus+in+rats:+Results+of+a+12-month+longitudinal+study.">Relationship between noise exposure stimulus properties and tinnitus in rats: Results of a 12-month longitudinal study.</a> ARO. Abs. 594, (2012).</li><li>Turner, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+measures+of+tinnitus+in+laboratory+animals.">Behavioral measures of tinnitus in laboratory animals.</a> Prog. Brain Res. 166, 147-156 (2007).</li><li>Engineer, N. D., Riley, J. R., Seale, J. D., Vrana, W. A., Shetake, J. A., Shetake, J. A., Sudanagunta, S. P., Borland, M. S., Kilgard, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversing+pathological+neural+activity+using+targeted+plasticity.">Reversing pathological neural activity using targeted plasticity.</a> Nature. 470, 101-104 (2011).</li></ol>

Vi presentiamo una configurazione a basso costo e facile da costruire per le misure audiometrici nei roditori sulla base di pre-impulso inibizione di risposte acustiche startle che possono essere utilizzati per determinare le soglie uditive comportamentali (= audiogrammi 10) e uditive percetti fantasma come tinnito soggettivo 11. In particolare le misure di questi ultimi sono al centro di alcuni recenti rapporti 8,12,13,14 e può essere visto come un prerequisito per le indagini elettrof...

a low cost setup for behavioral audiometry in rodents

Nella ricerca uditiva degli animali è fondamentale per avere informazioni precise sui parametri acustici fondamentali dei soggetti animali che sono coinvolti negli esperimenti. Tali parametri possono essere caratteristiche di risposta fisiologiche del percorso uditivo, ad esempio attraverso audiometria del tronco cerebrale (BERA). Ma questi metodi consentono estrapolazioni solo indirette e incerto circa la percezione uditiva che corrisponde a questi parametri fisiologici. Per valutare il livello percettivo dell&#39;udito, metodi comportamentali devono essere utilizzati. Un potenziale problema con l&#39;uso di metodi comportamentali per la descrizione della percezione in modelli animali è il fatto che la maggior parte di questi metodi comportano una qualche tipo di apprendimento paradigma prima che i soggetti possono essere testati comportamentale, per esempio animali possono imparare a premere una leva in risposta ad un suono. Dal momento che questi paradigmi di apprendimento cambiamento stessa percezione 1,2 che di conseguenza influenzano alcun risultato sulla percezione ottenuto conquesti metodi e quindi devono essere interpretati con cautela. Le eccezioni sono paradigmi che fanno uso di risposte riflesse, perché qui non paradigmi di apprendimento devono essere effettuate prima del test percettivo. Una tale risposta riflessa è la risposta agli stimoli acustici (ASR), che possono essere altamente riproducibile suscitato con inattesi suoni forti negli animali naïve. Questo ASR a sua volta può essere influenzato da precedenti suoni a seconda della percettibilità questo stimolo precedente: Suoni ben sopra soglia uditiva sarà inibire completamente l&#39;ampiezza della ASR, suoni vicino al limite solo leggermente inibire l&#39;ASR. Questo fenomeno è denominato pre-impulso inibizione (PPI) 3,4, e la quantità di PPI sul ASR dipende gradualmente sulla percettibilità della pre-impulso. PPI del ASR è quindi adatto per determinare audiogrammi comportamentali in ingenui, non addestrato gli animali, per determinare handicap dell&#39;udito o anche per individuare eventuali percezioni soggettive tinnito in questianimali. In questo articolo viene illustrato l&#39;utilizzo di questo metodo in un modello roditore (cfr. anche rif. 5), il gerbillo della Mongolia (Merione unguiculatus), che è un noto specie modello per la ricerca della risposta agli stimoli all&#39;interno della gamma normale udito umano (ad es 6).

Watch this Scientific Journal Video about A Low Cost Setup for Behavioral Audiometry in Rodents at JoVE.com

A Low Cost Setup for Behavioral Audiometry in Rodents

Un metodo veloce ed economico per la determinazione del comportamento di sentire parametri come soglie uditive, uditive o percezioni fantasma (tinnito soggettivo) è descritto. Esso utilizza pre-impulso di inibizione della risposta agli stimoli acustici e può essere facilmente implementato in un personal computer utilizzando un programmabile AD / DA-convertitore e un sensore piezoelettrico.

Un programma di installazione a basso costo per audiometria comportamentale nei roditori

In auditory animal research it is crucial to have precise information about basic hearing parameters of the animal subjects that are involved in the ...

a-low-cost-setup-for-behavioral-audiometry-in-rodents

Research

JoVE Journal

Neuroscience

A General Method for Evaluating Incubation of Sucrose Craving in Rats

For someone on a food-restricted diet, food craving in response to food-paired cues may serve as a key behavioral transition point between abstinence and relapse to food taking 1. Food craving conceptualized in this way is akin to drug craving in response to drug-paired cues. A rich literature has been developed around understanding the behavioral and neurobiological determinants of drug craving; we and others have been focusing recently on translating techniques from basic addiction research to better understand addiction-like behaviors related to food 2-4.
As done in previous studies of drug craving, we examine sucrose craving behavior by utilizing a rat model of relapse. In this model, rats self-administer either drug or food in sessions over several days. In a session, lever responding delivers the reward along with a tone+light stimulus. Craving behavior is then operationally defined as responding in a subsequent session where the reward is not available. Rats will reliably respond for the tone+light stimulus, likely due to its acquired conditioned reinforcing properties 5. This behavior is sometimes referred to as sucrose seeking or cue reactivity. In the present discussion we will use the term "sucrose craving" to subsume both of these constructs.
In the past decade, we have focused on how the length of time following reward self-administration influences reward craving. Interestingly, rats increase responding for the reward-paired cue over the course of several weeks of a period of forced-abstinence. This "incubation of craving" is observed in rats that have self-administered either food or drugs of abuse 4,6. This time-dependent increase in craving we have identified in the animal model may have great potential relevance to human drug and food addiction behaviors.
Here we present a protocol for assessing incubation of sucrose craving in rats. Variants of the procedure will be indicated where craving is assessed as responding for a discrete sucrose-paired cue following extinction of lever pressing within the sucrose self-administration context (Extinction without cues) or as responding for sucrose-paired cues in a general extinction context (Extinction with cues).

Responding for food or drug-paired cues increases over the course of a period of abstinence and this may relate to an increased susceptibility to relapse behaviors. Here we detail a procedure for evaluating this "incubation of craving" in rats that have self-administered sucrose.

Un metodo generale per la valutazione di incubazione della brama di saccarosio in ratti

For someone on a food-restricted diet, food craving in response to food-paired cues may serve as a key behavioral transition point between abstinence and ...

Ricerca

Neuroscienze

Large-scale Recording of Neurons by Movable Silicon Probes in Behaving Rodents

A major challenge in neuroscience is linking behavior to the collective activity of neural assemblies. Understanding of input-output relationships of neurons and circuits requires methods with the spatial selectivity and temporal resolution appropriate for mechanistic analysis of neural ensembles in the behaving animal, i.e. recording of representatively large samples of isolated single neurons. Ensemble monitoring of neuronal activity has progressed remarkably in the past decade in both small and large-brained animals, including human subjects1-11. Multiple-site recording with silicon-based devices are particularly effective because of their scalability, small volume and geometric design.
Here, we describe methods for recording multiple single neurons and local field potential in behaving rodents, using commercially available micro-machined silicon probes with custom-made accessory components. There are two basic options for interfacing silicon probes to preamplifiers: printed circuit boards and flexible cables. Probe supplying companies (<a href="http://www.neuronexustech.com/" >http://www.neuronexustech.com/</a>; <a href="http://www.sbmicrosystems.com/">http://www.sbmicrosystems.com/</a>; <a href="http://www.acreo.se/">http://www.acreo.se/</a>) usually provide the bonding service and deliver probes bonded to printed circuit boards or flexible cables. Here, we describe the implantation of a 4-shank, 32-site probe attached to flexible polyimide cable, and mounted on a movable microdrive. Each step of the probe preparation, microdrive construction and surgery is illustrated so that the end user can easily replicate the process.

We describe methods for large-scale recording of multiple single units and local field potential in behaving rodents with silicon probes. Drive fabrication, probe attachment to the drive and probe implantation processes are illustrated in sufficient details for easy replication.

Su larga scala di registrazione dei neuroni da sonde mobili in silicio Comportarsi Roditori

A major challenge in neuroscience is linking behavior to the collective activity of neural assemblies. Understanding of input-output relationships of ...

A Lightweight, Headphones-based System for Manipulating Auditory Feedback in Songbirds

Experimental manipulations of sensory feedback during complex behavior have provided valuable insights into the computations underlying motor control and sensorimotor plasticity1. Consistent sensory perturbations result in compensatory changes in motor output, reflecting changes in feedforward motor control that reduce the experienced feedback error. By quantifying how different sensory feedback errors affect human behavior, prior studies have explored how visual signals are used to recalibrate arm movements2,3 and auditory feedback is used to modify speech production4-7. The strength of this approach rests on the ability to mimic naturalistic errors in behavior, allowing the experimenter to observe how experienced errors in production are used to recalibrate motor output.
Songbirds provide an excellent animal model for investigating the neural basis of sensorimotor control and plasticity8,9. The songbird brain provides a well-defined circuit in which the areas necessary for song learning are spatially separated from those required for song production, and neural recording and lesion studies have made significant advances in understanding how different brain areas contribute to vocal behavior9-12. However, the lack of a naturalistic error-correction paradigm - in which a known acoustic parameter is perturbed by the experimenter and then corrected by the songbird - has made it difficult to understand the computations underlying vocal learning or how different elements of the neural circuit contribute to the correction of vocal errors13.
The technique described here gives the experimenter precise control over auditory feedback errors in singing birds, allowing the introduction of arbitrary sensory errors that can be used to drive vocal learning. Online sound-processing equipment is used to introduce a known perturbation to the acoustics of song, and a miniaturized headphones apparatus is used to replace a songbird's natural auditory feedback with the perturbed signal in real time. We have used this paradigm to perturb the fundamental frequency (pitch) of auditory feedback in adult songbirds, providing the first demonstration that adult birds maintain vocal performance using error correction14. The present protocol can be used to implement a wide range of sensory feedback perturbations (including but not limited to pitch shifts) to investigate the computational and neurophysiological basis of vocal learning.

We describe the design and assembly of miniaturized headphones suitable for replacing a songbird&#x2019;s natural auditory feedback with a manipulated acoustic signal. Online sound processing hardware is used to manipulate song output, introduce real-time errors in auditory feedback via the headphones, and drive vocal motor learning.

Un leggero, Cuffie-based per la gestione di sistema feedback uditivo in Songbirds

Experimental manipulations of sensory feedback during complex behavior have provided valuable insights into the computations underlying motor control and ...

Recording and Analysis of Circadian Rhythms in Running-wheel Activity in Rodents

When rodents have free access to a running wheel in their home cage, voluntary use of this wheel will depend on the time of day1-5. Nocturnal rodents, including rats, hamsters, and mice, are active during the night and relatively inactive during the day. Many other behavioral and physiological measures also exhibit daily rhythms, but in rodents, running-wheel activity serves as a particularly reliable and convenient measure of the output of the master circadian clock, the suprachiasmatic nucleus (SCN) of the hypothalamus. In general, through a process called entrainment, the daily pattern of running-wheel activity will naturally align with the environmental light-dark cycle (LD cycle; e.g. 12 hr-light:12 hr-dark). However circadian rhythms are endogenously generated patterns in behavior that exhibit a ~24 hr period, and persist in constant darkness. Thus, in the absence of an LD cycle, the recording and analysis of running-wheel activity can be used to determine the subjective time-of-day. Because these rhythms are directed by the circadian clock the subjective time-of-day is referred to as the circadian time (CT). In contrast, when an LD cycle is present, the time-of-day that is determined by the environmental LD cycle is called the zeitgeber time (ZT).
Although circadian rhythms in running-wheel activity are typically linked to the SCN clock6-8, circadian oscillators in many other regions of the brain and body9-14 could also be involved in the regulation of daily activity rhythms. For instance, daily rhythms in food-anticipatory activity do not require the SCN15,16 and instead, are correlated with changes in the activity of extra-SCN oscillators17-20. Thus, running-wheel activity recordings can provide important behavioral information not only about the output of the master SCN clock, but also on the activity of extra-SCN oscillators. Below we describe the equipment and methods used to record, analyze and display circadian locomotor activity rhythms in laboratory rodents.

Circadian rhythms in voluntary wheel-running activity in mammals are tightly coupled to the molecular oscillations of a master clock in the brain. As such, these daily rhythms in behavior can be used to study the influence of genetic, pharmacological, and environmental factors on the functioning of this circadian clock.

Registrazione e analisi dei ritmi circadiani in Running-ruota Attività nei roditori

When rodents have free access to a running wheel in their home cage, voluntary use of this wheel will depend on the time of day1-5. Nocturnal rodents, ...

A Low-cost Method for Analyzing Seizure-like Activity and Movement in Drosophila

Video tracking systems have been used widely to analyze Drosophila melanogaster movement and detect various abnormalities in locomotive behavior. While these systems can provide a wealth of behavioral information, the cost and complexity of these systems can be prohibitive for many labs. We have developed a low-cost assay for measuring locomotive behavior and seizure movement in D. melanogaster. The system uses a web-cam to capture images that can be processed using a combination of inexpensive and free software to track the distance moved, the average velocity of movement and the duration of movement during a specified time-span. To demonstrate the utility of this system, we examined a group of D. melanogaster mutants, the Bang-sensitive (BS) paralytics, which are 3-10 times more susceptible to seizure-like activity (SLA) than wild type flies. Using this novel system, we were able to detect that the BS mutant bang senseless (bss) exhibits lower levels of exploratory locomotion in a novel environment than wild type flies. In addition, the system was used to identify that the drug metformin, which is commonly used to treat type II diabetes, reduces the intensity of SLA in the BS mutants.

A Low-cost Method for Analyzing Seizure-like Activity and Movement in Drosophila

Using a webcam and a combination of free and inexpensive software programs, locomotive patterns in Drosophila melanogaster can be analyzed to detect differences in the speed, distance, and time of various motor activities.

Un metodo a basso costo per l&#39;analisi sequestro-come attività e il movimento in<em&gt; Drosophila</em

Video tracking systems have been used widely to analyze Drosophila melanogaster movement and detect various abnormalities in locomotive behavior. While ...

High-density Electroencephalographic Acquisition in a Rodent Model Using Low-cost and Open-source Resources

Advanced electroencephalographic analysis techniques requiring high spatial resolution, including electrical source imaging and measures of network connectivity, are applicable to an expanding variety of questions in neuroscience. Performing these kinds of analyses in a rodent model requires higher electrode density than traditional screw electrodes can accomplish. While higher-density electroencephalographic montages for rodents exist, they are of limited availability to most researchers, are not robust enough for repeated experiments over an extended period of time, or are limited to use in anesthetized rodents.1-3 A proposed low-cost method for constructing a durable, high-count, transcranial electrode array, consisting of bilaterally implantable headpieces is investigated as a means to perform advanced electroencephalogram analyses in mice or rats.

Procedures for headpiece fabrication and surgical implantation necessary to produce high signal to noise, low-impedance electroencephalographic and electromyographic signals are presented. While the methodology is useful in both rats and mice, this manuscript focuses on the more challenging implementation for the smaller mouse skull. Freely moving mice are only tethered to cables via a common adapter during recording. One version of this electrode system that includes 26 electroencephalographic channels and 4 electromyographic channels is described below.

Instructions for the low-cost construction and surgical implantation of a chronic transcranial high-density electroencephalographic montage into mice are provided. Signal recording, extraction, and processing techniques are also described.

Ad alta densità elettroencefalografico Acquisizione in un modello di roditore Utilizzando risorse a basso costo e open-source

Advanced electroencephalographic analysis techniques requiring high spatial resolution, including electrical source imaging and measures of network ...

The Power of Interstimulus Interval for the Assessment of Temporal Processing in Rodents

Temporal processing deficits have been implicated as a potential elemental dimension of higher-level cognitive processes, commonly observed in neurocognitive disorders. Despite the popularization of prepulse inhibition (PPI) in recent years, many current protocols promote using a percent of control measure, thereby precluding the assessment of temporal processing. The present study used cross-modal PPI and gap prepulse inhibition (gap-PPI) to demonstrate the benefits of employing a range of interstimulus intervals (ISIs) to delineate effects of sensory modality, psychostimulant exposure, and age. Assessment of sensory modality, psychostimulant exposure, and age reveals the utility of an approach varying the interstimulus interval (ISI) to establish the shape of the ISI function, including increases (sharper curve inflections) or decreases (flattening of the response amplitude curve) in startle amplitude. Additionally, shifts in peak response inhibition, suggestive of a differential sensitivity to the manipulation of ISI, are often revealed. Thus, the systematic manipulation of ISI affords a critical opportunity to evaluate temporal processing, which may reveal the underlying neural mechanisms involved in neurocognitive disorders.

Temporal processing, a preattentive process, may underlie deficits in higher-level cognitive processes, including attention, commonly observed in neurocognitive disorders. Using prepulse inhibition as an exemplar paradigm, we present a protocol for manipulating interstimulus interval (ISI) to establish the shape of the ISI function to provide an assessment of temporal processing.

Il potere di Interstimulus intervallo per la valutazione di elaborazione temporale in roditori

Temporal processing deficits have been implicated as a potential elemental dimension of higher-level cognitive processes, commonly observed in ...

Data Acquisition and Analysis In Brainstem Evoked Response Audiometry In Mice

Brainstem evoked response audiometry (BERA) is of central relevance in the clinical neurophysiology. As other evoked potential (EP) techniques, such as visually evoked potentials (VEPs) or somatosensory evoked potentials (SEPs), the auditory evoked potentials (AEPs) are triggered by the repetitive presentation of identical stimuli, the electroencephalographic (EEG) response of which is subsequently averaged resulting in distinct positive (p) and negative (n) deflections. In humans, both the amplitude and the latency of individual peaks can be used to characterize alterations in synchronization and conduction velocity in the underlying neuronal circuitries. Importantly, AEPs are also applied in basic and preclinical science to identify and characterize the auditory function in pharmacological and genetic animal models. Even more, animal models in combination with pharmacological testing are utilized to investigate for potential benefits in the treatment of sensorineural hearing loss (e.g., age- or noise-induced hearing deficits). Here we provide a detailed and integrative description of how to record auditory brainstem-evoked responses (ABRs) in mice using click and tone-burst application. A specific focus of this protocol is on pre-experimental animal housing, anesthesia, ABR recording, ABR filtering processes, automated wavelet-based amplitude growth function analysis, and latency detection.

Brainstem evoked response audiometry is an important tool in clinical neurophysiology. Nowadays, brainstem evoked response audiometry is also applied in the basic science and preclinical studies involving both pharmacological and genetic animal models. Here we provide a detailed description of how auditory brainstem responses can be successfully recorded and analyzed in mice.

Acquisizione e analisi dei dati nel cervello evocato Audiometria di risposta nei topi

Brainstem evoked response audiometry (BERA) is of central relevance in the clinical neurophysiology. As other evoked potential (EP) techniques, such as ...

A Hydrophobic Tissue Clearing Method for Rat Brain Tissue

Hydrophobic tissue clearing methods are easily adjustable, fast, and low-cost procedures that allows for the study of a molecule of interest in unaltered tissue samples. Traditional immunolabeling procedures require cutting the sample into thin sections, which restricts the ability to label and examine intact structures. However, if brain tissue can remain intact during processing, structures and circuits can remain intact for the analysis. Previously established clearing methods take significant time to completely clear the tissue, and the harsh chemicals can often damage sensitive antibodies. The iDISCO method quickly and completely clears tissue, is compatible with many antibodies, and requires no special lab equipment. This technique was initially validated for the use in mice tissue, but the current protocol adapts this method to image hemispheres of control and transgenic rat brains. In addition to this, the present protocol also makes several adjustments to preexisting protocol to provide clearer images with less background staining. Antibodies for Iba-1 and tyrosine hydroxylase were validated in the HIV-1 transgenic rat and in F344/N control rats using the present hydrophobic tissue clearing method. The brain is an interwoven network, where structures work together more often than separately of one another. Analyzing the brain as a whole system as opposed to a combination of individual pieces is the greatest benefit of this whole brain clearing method.

Here we present a hydrophobic tissue clearing method that allows for the viewing of target molecules as part of intact brain structures. This technique has now been validated for F344/N control and HIV-1 transgenic rats of both sexes.

Un metodo di compensazione del tessuto idrofobico per il tessuto cerebrale del ratto

Hydrophobic tissue clearing methods are easily adjustable, fast, and low-cost procedures that allows for the study of a molecule of interest in unaltered ...

A Rat Model of EcoHIV Brain Infection

It has been well studied that the EcoHIV infected mouse model is of significant utility in investigating HIV associated neurological complications. Establishment of the EcoHIV infected rat model for studies of drug abuse and neurocognitive disorders, would be beneficial in the study of neuroHIV and HIV-1 associated neurocognitive disorders (HAND). In the present study, we demonstrate the successful creation of a rat model of active HIV infection using chimeric HIV (EcoHIV). First, the lentiviral construct of EcoHIV was packaged in cultured 293 FT cells for 48 hours. Then, the conditional medium was concentrated and titered. Next, we performed bilateral stereotaxic injections of the EcoHIV-EGFP into F344/N rat brain tissue. One week after infection, EGFP fluorescence signals were detected in the infected brain tissue, indicating that EcoHIV successfully induces an active HIV infection in rats. In addition, immunostaining for the microglial cell marker, Iba1, was performed. The results indicated that microglia were the predominant cell type harboring EcoHIV. Furthermore, EcoHIV rats exhibited alterations in temporal processing, a potential underlying neurobehavioral mechanism of HAND as well as synaptic dysfunction eight weeks after infection. Collectively, the present study extends the EcoHIV model of HIV-1 infection to the rat offering a valuable biological system to study HIV-1 viral reservoirs in the brain as well as HAND and associated comorbidities such as drug abuse.

Here, we present a protocol to establish a new rat model of active HIV infection using chimeric HIV (EcoHIV), which is critical for enhancing our understanding of HIV-1 viral reservoirs in the brain and offering a system to study HIV-associated neurocognitive disorders and associated comorbidities (i.e., drug abuse).

Un modello di ratto di infezione cerebrale EcoHIV

It has been well studied that the EcoHIV infected mouse model is of significant utility in investigating HIV associated neurological complications. ...