Este trabajo fue apoyado por una beca de la Swiss National Science Foundation (CE: PBEZP3-131154)

1. El reclutamiento de sujetos <ol><li> Los sujetos son reclutados a través de una base de datos de 5 en línea que contiene una lista de cerca de 3.000 estudiantes voluntarios. De esta lista, sólo póngase en contacto con mujeres que no han participado anteriormente en estudios similares y preguntarles si están interesados ​​en participar en este estudio. Te invitamos en exclusiva a las mujeres como el curso temporal de los efectos neurofisiológicos de la administración de testosterona aguda está bien establecida entre las mujeres 6,7. Para los hombres, este curso el tiempo aún no se entiende muy bien. </li><li> Los sujetos interesados ​​son entonces examinados en una entrevista telefónica para excluir el consumo de medicamentos, las enfermedades somáticas, los anticonceptivos hormonales o cualquier otro trastorno neurológico o psiquiátrico. </li><li> Debido a que los niveles endógenos de hormonas sexuales tienden a ser baja y estable dentro de la primera parte del ciclo menstrual femenino que llevamos a cabo una segunda entrevista telefónica para obtener información sobre la estabilidad y la duración del ciclo. Los sujetos son invitados a venir a la experiencia dentro de 10 días desde el comienzo de su ciclo menstrual. Además, se les ordenó abstenerse de la ingesta de alcohol o la cafeína y el tabaco durante 24 horas antes del experimento. </li><li> Los sujetos se invita a grupos de un tamaño medio de entre 12 y el laboratorio experimental del Instituto de Investigación Empírica en Economía, en Zurich, Suiza. </li></ol> 2. Procedimiento experimental <ol><li> Todas las sesiones empiezan a las 13:00 en el control de la variación circadiana de los niveles de las hormonas esteroides. </li><li> Llevamos a cabo una prueba de embarazo antes del inicio del experimento para evitar el embarazo. </li><li> En la preparación del experimento, la testosterona y pastillas de placebo distinguen visualmente se distribuyen al azar a doce estaciones de trabajo marcado once y cincuenta y nueve dentro de la sala de laboratorio por una persona que no está involucrado en el experimento de otra manera. </li><li> En la entrada al laboratorio, cada uno de los doce sujetos roba una carta con un número oculto en él. Las cifras van de uno a doce. </li><li> Los sujetos son llevados a la sala de laboratorio que está dotado con un total de 36 puestos de trabajo informáticos. Los sujetos son instruidos para buscar y sentarse en el lugar de trabajo marcado con el número que se indica en la tarjeta que sacó a la entrada. </li><li> Todos los sujetos leer y firmar el formulario de consentimiento informado. </li><li> Medimos la testosterona basal y las concentraciones de cortisol salival con el IBL SaliCaps Kit (IBL-Hamburg, de Hamburgo, Alemania) para la recogida de saliva de la muestra. Se pide a los temas de transferencia de 1 mL de saliva en los tubos de ensayo, que luego se congeló inmediatamente a -80 ° C. </li><li> Los sujetos deberán tomar la pastilla sublingual en la boca, a masticar y guardar la sustancia se desintegró en la boca durante un minuto. Para lograr el máximo contacto del complejo de testosterona HP-β-CD de inclusión con la mucosa oral, los sujetos se les instruye para hacer movimientos circulares con la lengua. Después de un minuto, el resto de la sustancia se ingiere con 100 ml de agua. </li><li> Inmediatamente después de la administración de la sustancia, los sujetos son requeridos para completar los cuestionarios diferentes. Nosotros medimos el estado de ánimo y la excitación por medio del cuestionario Mood multidimensionales (MDBF) 8 y la ansiedad y los rasgos de ira y los estados, mediante el Inventario de Ansiedad Estado-Rasgo 9 y el Inventario de Ira Estado-Rasgo de Expresión 10. Estos cuestionarios tienen el propósito de controlar los posibles efectos de los estados sujetos incidental estado de ánimo, la ira y la ansiedad, así como de las características de personalidad. Además, los sujetos completa de las versiones validadas alemana de la Symptom Checklist-90 artículo (versión revisada) 11 para medir su salud psicológica. Los que tienen puntuaciones muy altas (dos desviaciones estándar por encima de la media, lo que indica la salud psicológica de los pobres) están excluidos del análisis de datos. Debido a la demora de tiempo establecido de cuatro horas de la aparición de efectos en el comportamiento después de la aplicación sublingual de 0,5 mg de testosterona en mujeres jóvenes y sanas 6,7, un largo período de espera es una parte integral de nuestro estudio. Durante este período, los sujetos están obligados a permanecer en la sala de laboratorio y se mantienen bastante ocupados. Esto es para asegurar que no la interacción social fuera del laboratorio se lleva a cabo lo que podría dar lugar a medidas confundido. </li></ol> 3. Ultimatum Juego <ol><li> Los sujetos luego recibir las instrucciones para su papel en el juego y las reglas de pago en papel y se les pide que lea. Comprobamos su comprensión de la estructura de pagos haciendo que completar varias preguntas de control al final de las instrucciones. </li><li> A continuación, un resumen del procedimiento experimental por vía oral. La razón de esto es asegurar que los participantes saben que todos los demás tienen la misma información sobre la estructura del juego y de cómo las recompensas are determinado, que también se conoce como &quot;conocimiento común&quot;. El resumen es el siguiente: </li><li> &quot;El juego del ultimátum se juega con dos tipos de jugadores, una propuesta y una respuesta, que tienen que ponerse de acuerdo sobre la división de 10 unidades monetarias (UM). El proponente puede decidir sobre la distribución de la UM 10. En este experimento, el proponente puede proponer ofertas de 5, 3, 2, o UM 0 a la respuesta. La respuesta entonces tiene que aceptar o rechazar esta propuesta. Si la respuesta acepta la oferta del proponente, la propuesta de aplicación se llevará a cabo y de pago. Sin embargo, el de respuesta también puede rechazar la propuesta, en este caso ninguna de las partes gana nada &quot;. </li><li> Nos aseguramos de una clara separación entre una oferta que se considere justo (5 UM) y ofertas que se perciben como injustas (3, 2 o UM 0) mediante la restricción de la oferta a 5, 3, 2 ó UM 0. Los sujetos son al azar y de forma anónima asignado a la función ya sea de la proponente o el contestador y luego permanecer en este papel para todo el experimento. Cada proponente hace tres proposiciones sobre la distribución de las UM, mientras que se combina con tres socios diferentes interacción seleccionados al azar. Ningún par de temas interactúa más de una vez. Nunca aprenden de la identidad de las personas con las que se corresponden en el experimento. El proponente no recibir comentarios sobre las opciones de la respuesta &#39;hasta el final del experimento. Todas las decisiones en el juego del ultimátum se implementan en software zTree y presentados en pantallas de ordenador 12. </li><li> Como la testosterona es una de las hormonas más discutido en la prensa popular, es posible que las personas tienen la creencia de preformada (verdadera o falsa) acerca de sus efectos 13. Además, debido a las preocupaciones éticas exigen a los investigadores para informar a los sujetos que, o bien recibirá un placebo o la testosterona del conocimiento previo acerca de la testosterona puede contaminar un posible impacto de la testosterona en el comportamiento. Por lo tanto, evaluar la asignación a los grupos percibidos por preguntar a los sujetos si ellos piensan que han recibido la testosterona o la píldora de placebo. </li><li> La asignación a los grupos que se percibe es registrada en el cuestionario final, con las características socioeconómicas de una pocas. Durante el último cuestionario que prepare el pago de los sujetos. </li></ol> 4. Pago tema <ol><li> Los sujetos reciben una cuota base de cien francos suizos para la participación en el experimento. El uso de incentivos monetarios reales reduce un posible sesgo de deseabilidad social y parcial percepciones de sí mismo. Por lo tanto, cada uno de los sujetos recibe un franco suizo (aproximadamente 1 $ EE.UU.) por cada mu ganado en el juego del ultimátum. Cada sujeto recibe sus ganancias que consiste en la tarifa básica más la UM obtuvo en privado al final del experimento. </li></ol>

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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+Androgen+Stimulation+and+Aggressive+Behavior+in+Male+and+Female+Mice.">Early Androgen Stimulation and Aggressive Behavior in Male and Female Mice.</a> Physiology &#38; Behav. 4, 333-338 (1969).</li><li>Archer, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Testosterone+and+human+aggression:+an+evaluation+of+the+challenge+hypothesis.">Testosterone and human aggression: an evaluation of the challenge hypothesis.</a> Neurosci Biobehav R. 30, 319-345 (2006).</li><li>Mazur, A., Booth, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Testosterone+and+dominance+in+men.">Testosterone and dominance in men.</a> Behav Brain Sci. 21, 353-363 (1998).</li><li>Josephs, R. A., Newman, M. L., Brown, R. P., Beer, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Status,+testosterone,+and+human+intellectual+performance:+stereotype+threat+as+status+concern.">Status, testosterone, and human intellectual performance: stereotype threat as status concern.</a> Psychol Sci. 14, 158-163 (2003).</li><li>Greiner, B., Kremer, K., Macho, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Forschung und wissenschaftliches Rechnen: GWDG Bericht 63. , 79-93 (2004).</li><li>van Honk, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+single+administration+of+testosterone+induces+cardiac+accelerative+responses+to+angry+faces+in+healthy+young+women.">A single administration of testosterone induces cardiac accelerative responses to angry faces in healthy young women.</a> Behav Neurosci. 115, 238-242 (2001).</li><li>van Honk, J., Peper, J. S., Schutter, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Testosterone+reduces+unconscious+fear+but+not+consciously+experienced+anxiety:+implications+for+the+disorders+of+fear+and+anxiety.">Testosterone reduces unconscious fear but not consciously experienced anxiety: implications for the disorders of fear and anxiety.</a> Biol Psychiatry. 58, 218-225 (2005).</li><li>Steyer, R., Schwenkmezger, P., Notz, P., Eid, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Der Mehrdimensionale Befindlichkeitsfragebogen (MDBF) [Multidimensional Mood Questionnaire. , (1997).</li><li>Laux, L., Glanzmann, P., Schaffner, P., Spielberger, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Das State-Trait-Angstinventar (Manual for the State-Trait Anxiety Inventory. , (1981).</li><li>Schwenkmezger, P., Hodapp, V., Spielberger, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Das State-Trait-Aergerausdruck-Inventar STAXI [The State-Trait Anger Expression Inventory (STAXI)]. , (1992).</li><li>Derogatis, L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> SCL-90-R, administration, scoring &amp;amp; procedures manual-I for the R(evised) version. , (1977).</li><li>Fischbacher, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=z-Tree:+Zurich+toolbox+for+ready-made+economic+experiments.">z-Tree: Zurich toolbox for ready-made economic experiments.</a> Experimental Economics. 10, 171-178 (2007).</li><li>Bjorkqvist, K., Nygren, T., Bjorklund, A. C., Bjorkqvist, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Testosterone+Intake+and+Aggressiveness+-+Real+Effect+or+Anticipation.">Testosterone Intake and Aggressiveness - Real Effect or Anticipation.</a> Aggressive Behav. 20, 17-26 (1994).</li><li>Camerer, C. 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Una indicación de que los resultados son válidos si se la ofrece media observada es similar a lo encontrado en otros estudios. Por lo general, ofrece promedio son entre 30 - 40% del importe total y aproximadamente la mitad de las asignaturas ofrecen las 14 partes iguales. Por otro lado, un indicador de probable que los sujetos no entender las reglas del juego es si las ofertas de más del 50% se observan. Vale la pena señalar, sin embargo, que existe una heterogeneidad considerable en la distribución y el...

combining behavioral endocrinology and experimental economics: testosterone and social decision making

La investigación del comportamiento endocrinológico en los seres humanos, así como en animales sugiere que la testosterona juega un papel clave en las interacciones sociales. Los estudios en roedores han mostrado una relación directa entre la testosterona y el comportamiento agresivo y una sabiduría popular se adapta estos hallazgos en humanos, lo que sugiere que la testosterona induce un comportamiento antisocial, egoísta o agresiva, incluso dos. Sin embargo, muchos investigadores duda una directa relación testosterona-la agresión en los seres humanos, argumentando que la testosterona está principalmente involucrado en el estado de comportamiento relacionado con 3,4. Como un estado de alta también se puede lograr por medios agresivos y antisociales que pueden ser difíciles de distinguir entre los anti-sociales y el estado de la conducta de búsqueda. Por lo tanto, establecer un entorno experimental, en el que el estado sólo puede lograrse por medio prosocial. En un experimento de doble ciego y controlado con placebo, se administró una sola dosis sublingual de 0,5 mg de testosterona (con un portador de hidroxipropil-β-ciclodextrina) a 121 mujeres e investigar su comportamiento interacción social en un paradigma de negociación económica. Incentivos monetarios reales están en juego en este paradigma, cada jugador recibe una cierta cantidad de dinero y tiene que hacer una oferta a otro jugador B sobre cómo compartir el dinero. Si B acepta, ella consigue lo que se ofrecía y el jugador A mantiene el resto. Si B rechaza la oferta, nadie recibe nada. Un estado buscando un jugador que se espera para evitar ser rechazados por comportarse de una manera prosocial, es decir, haciendo ofertas más altas. Los resultados muestran que si las expectativas acerca de la hormona son controlados, la administración de testosterona produce un aumento significativo en la negociación feria ofrece en comparación con placebo. El papel de las expectativas se refleja en el hecho de que los sujetos que expresan que creen haber recibido la testosterona hacer ofertas más bajas que aquellos que dicen que creen que fueron tratados con un placebo. Estos hallazgos sugieren que el enfoque de la economía experimental es sensible para la detección de efectos neurobiológicos tan sutil como los alcanzados por la administración de hormonas. Por otra parte, los resultados apuntan hacia la importancia de ambos factores psicosociales, así como neuroendocrino en la determinación de la influencia de la testosterona en el comportamiento social humano.

Watch this Scientific Journal Video about Combining Behavioral Endocrinology and Experimental Economics: Testosterone and Social Decision Making at JoVE.com

Combining Behavioral Endocrinology and Experimental Economics: Testosterone and Social Decision Making

El procedimiento descrito en este protocolo muestra que la administración de testosterona y las creencias populares acerca de la testosterona puede estar asociada con opone directamente a las conductas sociales.

La combinación del comportamiento de Endocrinología Experimental y Economía: Decisión de la testosterona y sociales que

Behavioral endocrinological research in humans as well as in animals suggests that testosterone plays a key role in social interactions. Studies in ...

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15.0K vistas.  University of Zurich. El procedimiento descrito en este protocolo muestra que la administración de testosterona y las creencias populares acerca de la testosterona puede estar asociada con opone directamente a las conductas sociales.

Video: Combining Behavioral Endocrinology and Experimental Economics: Testosterone and Social Decision Making

Combining Computer Game-Based Behavioural Experiments With High-Density EEG and Infrared Gaze Tracking

Experimental paradigms are valuable insofar as the timing and other parameters of their stimuli are well specified and controlled, and insofar as they yield data relevant to the cognitive processing that occurs under ecologically valid conditions. These two goals often are at odds, since well controlled stimuli often are too repetitive to sustain subjects' motivation. Studies employing electroencephalography (EEG) are often especially sensitive to this dilemma between ecological validity and experimental control: attaining sufficient signal-to-noise in physiological averages demands large numbers of repeated trials within lengthy recording sessions, limiting the subject pool to individuals with the ability and patience to perform a set task over and over again. This constraint severely limits researchers' ability to investigate younger populations as well as clinical populations associated with heightened anxiety or attentional abnormalities. Even adult, non-clinical subjects may not be able to achieve their typical levels of performance or cognitive engagement: an unmotivated subject for whom an experimental task is little more than a chore is not the same, behaviourally, cognitively, or neurally, as a subject who is intrinsically motivated and engaged with the task. A growing body of literature demonstrates that embedding experiments within video games may provide a way between the horns of this dilemma between experimental control and ecological validity. The narrative of a game provides a more realistic context in which tasks occur, enhancing their ecological validity (Chaytor &amp; Schmitter-Edgecombe, 2003). Moreover, this context provides motivation to complete tasks. In our game, subjects perform various missions to collect resources, fend off pirates, intercept communications or facilitate diplomatic relations. In so doing, they also perform an array of cognitive tasks, including a Posner attention-shifting paradigm (Posner, 1980), a go/no-go test of motor inhibition, a psychophysical motion coherence threshold task, the Embedded Figures Test (Witkin, 1950, 1954) and a theory-of-mind (Wimmer &amp; Perner, 1983) task. The game software automatically registers game stimuli and subjects' actions and responses in a log file, and sends event codes to synchronise with physiological data recorders. Thus the game can be combined with physiological measures such as EEG or fMRI, and with moment-to-moment tracking of gaze. Gaze tracking can verify subjects' compliance with behavioural tasks (e.g. fixation) and overt attention to experimental stimuli, and also physiological arousal as reflected in pupil dilation (Bradley et al., 2008). At great enough sampling frequencies, gaze tracking may also help assess covert attention as reflected in microsaccades - eye movements that are too small to foveate a new object, but are as rapid in onset and have the same relationship between angular distance and peak velocity as do saccades that traverse greater distances. The distribution of directions of microsaccades correlates with the (otherwise) covert direction of attention (Hafed &amp; Clark, 2002).

Procedures for recording high-density EEG and gaze data during computer game-based cognitive tasks are described. Using a video game to present cognitive tasks enhances ecological validity without sacrificing experimental control.

La combinación de PC del juego basado en experimentos del comportamiento de alta densidad de seguimiento de mirada EEG e infrarrojo

Experimental paradigms are valuable insofar as the timing and other parameters of their stimuli are well specified and controlled, and insofar as they ...

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Brain Imaging Investigation of the Neural Correlates of Observing Virtual Social Interactions

The ability to gauge social interactions is crucial in the assessment of others&#x2019; intentions. Factors such as facial expressions and body language affect our decisions in personal and professional life alike 1. These "friend or foe" judgements are often based on first impressions, which in turn may affect our decisions to "approach or avoid". Previous studies investigating the neural correlates of social cognition tended to use static facial stimuli 2. Here, we illustrate an experimental design in which whole-body animated characters were used in conjunction with functional magnetic resonance imaging (fMRI) recordings. Fifteen participants were presented with short movie-clips of guest-host interactions in a business setting, while fMRI data were recorded; at the end of each movie, participants also provided ratings of the host behaviour. This design mimics more closely real-life situations, and hence may contribute to better understanding of the neural mechanisms of social interactions in healthy behaviour, and to gaining insight into possible causes of deficits in social behaviour in such clinical conditions as social anxiety and autism 3.

This article demonstrates an experimental design in which whole-body animated characters are used in conjunction with functional magnetic resonance imaging (fMRI) to investigate the neural correlates of observing virtual social interactions.

La investigación del cerebro imágenes de los correlatos neurales de Observación de las interacciones sociales virtuales

The ability to gauge social interactions is crucial in the assessment of others&#x2019; intentions. Factors such as facial expressions and body language ...

Measuring the Subjective Value of Risky and Ambiguous Options using Experimental Economics and Functional MRI Methods

Most of the choices we make have uncertain consequences. In some cases the probabilities for different possible outcomes are precisely known, a condition termed "risky". In other cases when probabilities cannot be estimated, this is a condition described as "ambiguous". While most people are averse to both risk and ambiguity1,2, the degree of those aversions vary substantially across individuals, such that the subjective value of the same risky or ambiguous option can be very different for different individuals. We combine functional MRI (fMRI) with an experimental economics-based method3 to assess the neural representation of the subjective values of risky and ambiguous options4. This technique can be now used to study these neural representations in different populations, such as different age groups and different patient populations.
In our experiment, subjects make consequential choices between two alternatives while their neural activation is tracked using fMRI. On each trial subjects choose between lotteries that vary in their monetary amount and in either the probability of winning that amount or the ambiguity level associated with winning. Our parametric design allows us to use each individual's choice behavior to estimate their attitudes towards risk and ambiguity, and thus to estimate the subjective values that each option held for them. Another important feature of the design is that the outcome of the chosen lottery is not revealed during the experiment, so that no learning can take place, and thus the ambiguous options remain ambiguous and risk attitudes are stable. Instead, at the end of the scanning session one or few trials are randomly selected and played for real money. Since subjects do not know beforehand which trials will be selected, they must treat each and every trial as if it and it alone was the one trial on which they will be paid. This design ensures that we can estimate the true subjective value of each option to each subject. We then look for areas in the brain whose activation is correlated with the subjective value of risky options and for areas whose activation is correlated with the subjective value of ambiguous options.

Using functional MRI and behavioral methods to determine the neural representation of the subjective value of risky and ambiguous options in the human brain.

La medición del valor subjetivo de las opciones arriesgado y ambiguo utilizando Economía Experimental y Métodos funcionales de resonancia magnética

Most of the choices we make have uncertain consequences. In some cases the probabilities for different possible outcomes are precisely known, a condition ...

C. elegans Tracking and Behavioral Measurement

We have developed instrumentation, image processing, and data analysis techniques to quantify the locomotory behavior of C. elegans as it crawls on the surface of an agar plate. For the study of the genetic, biochemical, and neuronal basis of behavior, C. elegans is an ideal organism because it is genetically tractable, amenable to microscopy, and shows a number of complex behaviors, including taxis, learning, and social interaction1,2. Behavioral analysis based on tracking the movements of worms as they crawl on agar plates have been particularly useful in the study of sensory behavior3, locomotion4, and general mutational phenotyping5. Our system works by moving the camera and illumination system as the worms crawls on a stationary agar plate, which ensures no mechanical stimulus is transmitted to the worm. Our tracking system is easy to use and includes a semi-automatic calibration feature. A challenge of all video tracking systems is that it generates an enormous amount of data that is intrinsically high dimensional. Our image processing and data analysis programs deal with this challenge by reducing the worms shape into a set of independent components, which comprehensively reconstruct the worms behavior as a function of only 3-4 dimensions6,7. As an example of the process we show that the worm enters and exits its reversal state in a phase specific manner.

C. elegans Tracking and Behavioral Measurement

We have developed a video-rate tracking microscope system that can record and quantify C. elegans behavior at high resolution and high speeds. We have also developed computational methods to reduce the dimensionality of the worm images to a fundamental set of measurements that completely describe the shape of the worm.

C. elegans Seguimiento y Medición del Comportamiento

We have developed instrumentation, image processing, and data analysis techniques to quantify the locomotory behavior of C. elegans as it crawls on the ...

A Low Cost Setup for Behavioral Audiometry in Rodents

In auditory animal research it is crucial to have precise information about basic hearing parameters of the animal subjects that are involved in the experiments. Such parameters may be physiological response characteristics of the auditory pathway, e.g. via brainstem audiometry (BERA). But these methods allow only indirect and uncertain extrapolations about the auditory percept that corresponds to these physiological parameters. To assess the perceptual level of hearing, behavioral methods have to be used. A potential problem with the use of behavioral methods for the description of perception in animal models is the fact that most of these methods involve some kind of learning paradigm before the subjects can be behaviorally tested, e.g. animals may have to learn to press a lever in response to a sound. As these learning paradigms change perception itself 1,2 they consequently will influence any result about perception obtained with these methods and therefore have to be interpreted with caution. Exceptions are paradigms that make use of reflex responses, because here no learning paradigms have to be carried out prior to perceptual testing. One such reflex response is the acoustic startle response (ASR) that can highly reproducibly be elicited with unexpected loud sounds in na&iuml;ve animals. This ASR in turn can be influenced by preceding sounds depending on the perceptibility of this preceding stimulus: Sounds well above hearing threshold will completely inhibit the amplitude of the ASR; sounds close to threshold will only slightly inhibit the ASR. This phenomenon is called pre-pulse inhibition (PPI) 3,4, and the amount of PPI on the ASR gradually depends on the perceptibility of the pre-pulse. PPI of the ASR is therefore well suited to determine behavioral audiograms in na&iuml;ve, non-trained animals, to determine hearing impairments or even to detect possible subjective tinnitus percepts in these animals. In this paper we demonstrate the use of this method in a rodent model (cf. also ref. 5), the Mongolian gerbil (Meriones unguiculatus), which is a well know model species for startle response research within the normal human hearing range (e.g. 6).

A fast and inexpensive method for the behavioral determination of hearing parameters like hearing thresholds, hearing impairments or phantom perceptions (subjective tinnitus) is described. It uses pre-pulse inhibition of the acoustic startle response and can be easily implemented in a personal computer using a programmable AD/DA-converter and a piezo sensor.

Una instalación de Bajo Costo para audiometría conductual en roedores

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

Hippocampal Insulin Microinjection and In vivo Microdialysis During Spatial Memory Testing

Glucose metabolism is a useful marker for local neural activity, forming the basis of methods such as 2-deoxyglucose and functional magnetic resonance imaging. However, use of such methods in animal models requires anesthesia and hence both alters the brain state and prevents behavioral measures. An alternative method is the use of in vivo microdialysis to take continuous measurement of brain extracellular fluid concentrations of glucose, lactate, and related metabolites in awake, unrestrained animals. This technique is especially useful when combined with tasks designed to rely on specific brain regions and/or acute pharmacological manipulation; for example, hippocampal measurements during a spatial working memory task (spontaneous alternation) show a dip in extracellular glucose and rise in lactate that are suggestive of enhanced glycolysis1-3,4-5, and intrahippocampal insulin administration both improves memory and increases hippocampal glycolysis6. Substances such as insulin can be delivered to the hippocampus via the same microdialysis probe used to measure metabolites. The use of spontaneous alternation as a measure of hippocampal function is designed to avoid any confound from stressful motivators (e.g. footshock), restraint, or rewards (e.g. food), all of which can alter both task performance and metabolism; this task also provides a measure of motor activity that permits control for nonspecific effects of treatment. Combined, these methods permit direct measurement of the neurochemical and metabolic variables regulating behavior.

Hippocampal Insulin Microinjection and In vivo Microdialysis During Spatial Memory Testing

Modulation of hippocampally-dependent spatial working memory by direct intrahippocampal microinjection, accompanied and followed by in vivo microdialysis for metabolites in conscious, behaving animals.

Microinyección insulina hipocampo y<em&gt; En vivo</em&gt; Microdiálisis durante la prueba de memoria espacial

Glucose metabolism is a useful marker for local neural activity, forming the basis of methods such as 2-deoxyglucose and functional magnetic resonance ...

Effects of Transcranial Alternating Current Stimulation on the Primary Motor Cortex by Online Combined Approach with Transcranial Magnetic Stimulation

Transcranial Alternating Current Stimulation (tACS) is a neuromodulatory technique able to act through sinusoidal electrical waveforms in a specific frequency and in turn modulate ongoing cortical oscillatory activity. This neurotool allows the establishment of a causal link between endogenous oscillatory activity and behavior. Most of the tACS studies have shown online effects of tACS. However, little is known about the underlying action mechanisms of this technique because of the AC-induced artifacts on Electroencephalography (EEG) signals. Here we show a unique approach to investigate online physiological frequency-specific effects of tACS of the primary motor cortex (M1) by using single pulse Transcranial Magnetic Stimulation (TMS) to probe cortical excitability changes. In our setup, the TMS coil is placed over the tACS electrode while Motor Evoked Potentials (MEPs) are collected to test the effects of the ongoing M1-tACS. So far, this approach has mainly been used to study the visual and motor systems. However, the current tACS-TMS setup can pave the way for future investigations of cognitive functions. Therefore, we provide a step-by-step manual and video guidelines for the procedure.

Transcranial Alternating Current Stimulation (tACS) allows the modulation of cortical excitability in a frequency-specific fashion. Here we show a unique approach which combines online tACS with single pulse Transcranial Magnetic Stimulation (TMS) in order to "probe" cortical excitability by means of Motor Evoked Potentials.

Efectos de la corriente alterna la estimulación transcraneal en la corteza de Motor primaria por Online enfoque combinado con la estimulación magnética transcraneal

Transcranial Alternating Current Stimulation (tACS) is a neuromodulatory technique able to act through sinusoidal electrical waveforms in a specific ...

Operant Protocols for Assessing the Cost-benefit Analysis During Reinforced Decision Making by Rodents

Reinforcement-guided decision making is the ability to choose between competing courses of action based on the relative value of the benefits and their consequences. This process is integral to the normal human behavior and has been shown to be disrupted by neurological and psychiatric disorders such as addiction, schizophrenia, and depression. Rodents have long been used to uncover the neurobiology of human cognition. To this end, several behavioral tasks have been developed; however, most are non-automated and are labor-intensive. The recent development of the open-source microcontroller has enabled researchers to automate operant-based tasks for assessing a variety of cognitive tasks, standardizing the stimulus presentation, improving the data recording and consequently, improving the research output. Here, we describe an automated delay-based reinforcement-guided decision-making task, using an operant T-maze controlled by custom-written software programs. Using these decision-making tasks, we show the changes in the local field potential activities in the anterior cingulate cortex of a rat whilst it performs a delay-based cost-and-benefit decision-making task.

A cost-benefit analysis is a weighing-scale approach that the brain performs during the course of decision making. Here, we propose a protocol to train rats on an operant-based decision-making paradigm where rats choose higher rewards at the expense of waiting for 15 s to receive them.

Operante protocolos para evaluar el análisis de costo-beneficio en decisiones reforzadas por roedores

Reinforcement-guided decision making is the ability to choose between competing courses of action based on the relative value of the benefits and their ...

Abbiategrasso Brain Bank Protocol for Collecting, Processing and Characterizing Aging Brains

In a constantly aging population, the prevalence of neurodegenerative disorders is expected to rise. Understanding disease mechanisms is the key to find preventive and curative measures. The most effective way to achieve this is through direct examination of diseased and healthy brain tissue. The authors present a protocol to obtain, process, characterize and store good quality brain tissue donated by individuals registered in an antemortem brain donation program. The donation program includes a face-to-face empathic approach to people, a collection of complementary clinical, biological, social and lifestyle information and serial multi-dimensional assessments over time to track individual trajectories of normal aging and cognitive decline. Since many neurological diseases are asymmetrical, our brain bank offers a unique protocol for slicing fresh specimens. Brain sections of both hemispheres are alternately frozen (at -80 &#176;C) or fixed in formalin; a fixed slice on one hemisphere corresponds to a frozen one on the other hemisphere. With this approach, a complete histological characterization of all frozen material can be obtained, and omics studies can be performed on histologically well-defined tissues from both hemispheres thus offering a more complete assessment of neurodegenerative disease mechanisms. Correct and definite diagnosis of these diseases can only be achieved by combining the clinical syndrome with the neuropathological evaluation, which often adds important etiological clues necessary to interpret the pathogenesis. This method can be time consuming, expensive and limited as it only covers a limited geographical area. Regardless of its limitations, the high degree of characterization it provides can be rewarding. Our ultimate goal is to establish the first Italian Brain Bank, all the while emphasizing the importance of neuropathologically verified epidemiological studies.

This protocol describes a method to track individual brain-aging trajectories through a brain donation program and proper characterization of brains. Brain donors are involved in a long-term longitudinal study including serial multi-dimensional assessments. The protocol contains a detailed description of brain processing and an accurate diagnostic methodology.

Protocolo del Banco Cerebral Abbiategrasso para Recopilar, Procesar y Caracterizar Cerebros De Envejecimiento

In a constantly aging population, the prevalence of neurodegenerative disorders is expected to rise. Understanding disease mechanisms is the key to find ...

Post-Movie Subliminal Measurement (PMSM), for Investigating Implicit Social Bias

New knowledge is continuously gained from a social environment that can influence how people respond to each other. Such responses often occur implicitly, at a subliminal perceptual level, and related brain mechanisms can be experimentally isolated by presenting the stimuli quickly. Subliminal presentation of faces that belong to different ethnicity groups, races, or gender has been shown to be successful in investigating social implicit responses. However, many implicit responses are based on knowledge previously gained about the faces (e.g., sexual orientation, political views, and socioeconomic status) and not solely on physical appearance. Here, a novel method called post-movie subliminal measurement (PMSM) is presented. When watching a socially engaging movie, a spectator gains knowledge about the protagonist and becomes familiar with his/her identity and world views. When the face of the protagonist is presented subliminally after the movie, it evokes an implicit neural response depending on what is learned about the protagonist. With a vast number of movies available, each depicting a variety of people with different identities, the PMSM method enables investigation of the brain&#39;s complex implicit biases in a manner that resembles real-life social perceptions.

Post-Movie Subliminal Measurement PMSM, for Investigating Implicit Social Bias

This protocol describes the use of movies to investigate brain mechanisms underlying implicit social biases during functional magnetic resonance imaging. When the face of a protagonist is presented after a movie subliminally, it evokes an implicit response based on knowledge of the protagonist gained during the movie.

Medición Subliminal Post-Película (PMSM), para investigar el sesgo social implícito

New knowledge is continuously gained from a social environment that can influence how people respond to each other. Such responses often occur implicitly, ...