Ce travail a été soutenu par une subvention du Fonds national suisse (CE: PBEZP3-131154)

1. Le recrutement des sujets <ol><li> Les sujets sont recrutés via une base de données 5 en ligne contenant une liste d&#39;environ 3000 étudiants bénévoles. De cette liste, nous communiquerons uniquement avec les femmes qui n&#39;ont pas déjà participé à des études similaires et leur demander s&#39;ils sont intéressés à participer à cette étude. Nous invitons exclusivement des femmes que le cours du temps des effets neurophysiologiques après l&#39;administration de testostérone aiguë est bien établi chez les femmes 6,7. Pour les hommes, ce cours du temps n&#39;est pas encore très bien compris. </li><li> Les sujets intéressés sont ensuite criblées dans un entretien téléphonique afin d&#39;exclure la prise du médicament, les maladies somatiques, la contraception hormonale ou des troubles neurologiques ou psychiatriques. </li><li> Parce que les niveaux endogènes des hormones sexuelles ont tendance à être faible et stable dans la première partie du cycle menstruel féminin nous effectuons un entretien téléphonique secondes pour obtenir des informations sur la stabilité et la durée du cycle. Les sujets sont ensuite invités à venir à l&#39;expérience dans les 10 jours depuis le début de leur cycle menstruel. Ils sont en outre demandé de s&#39;abstenir de la consommation d&#39;alcool ou de caféine et le tabagisme pendant 24 heures avant l&#39;expérience. </li><li> Les sujets sont invités à des groupes d&#39;une taille moyenne de 12 à le laboratoire expérimental de l&#39;Institut de recherche empirique en économie, à Zurich, en Suisse. </li></ol> 2. Procédure expérimentale <ol><li> Toutes les séances commencent à 13h00 pour contrôler la variation circadienne des niveaux d&#39;hormones stéroïdes. </li><li> Nous effectuons un test de grossesse avant le début de l&#39;expérience pour empêcher la grossesse. </li><li> En préparation de l&#39;expérience, la testostérone et un placebo sont impossibles à distinguer visuellement réparties de façon aléatoire à douze postes de travail a marqué une à douze dans la salle de laboratoire par une personne qui n&#39;est pas impliqué dans l&#39;expérience autrement. </li><li> A l&#39;entrée du laboratoire, chacun des douze le sujet tire une carte avec un numéro caché sur elle. Les chiffres vont de un à douze. </li><li> Les sujets sont alors pris à la salle de laboratoire qui est doté d&#39;un total de 36 lieux de travail informatique. Les sujets sont chargés de rechercher et d&#39;asseoir par le milieu de travail portant le même numéro, comme indiqué sur la carte ils ont attiré à l&#39;entrée. </li><li> Tous les sujets lire et signer le formulaire de consentement éclairé. </li><li> Nous mesurons la testostérone de base salivaires et les concentrations de cortisol en utilisant l&#39;IBL SaliCaps Kit (IBL-Hamburg, Hambourg, Allemagne) pour la collecte des échantillons de salive. Les sujets sont invités à transférer 1 ml de salive dans les tubes à essai, qui sont ensuite immédiatement congelés à -80 ° C. </li><li> Les sujets sont invités à prendre la pilule sublinguale dans leur bouche, de le mâcher et de garder la substance désintégré dans leur bouche pendant une minute. Pour parvenir à un contact maximal du complexe HP-β-CD testostérone inclusion avec la muqueuse buccale, les sujets ont pour instruction de faire des mouvements encerclant avec leur langue. Après une minute, le reste de la substance est avalée en utilisant 100 ml d&#39;eau. </li><li> Immédiatement après l&#39;administration de la substance, les sujets sont tenus de remplir différents questionnaires. Nous mesurons l&#39;humeur et l&#39;excitation au moyen du questionnaire d&#39;humeur (Multidimensional MDBF) 8 et de l&#39;anxiété et les traits de la colère et déclare, par le biais de l&#39;Inventaire State-Trait Anxiety Inventory 9 et le State-Trait Anger Expression 10. Ces questionnaires ont pour but de contrôler les éventuels effets des états sujets d&#39;humeur, la colère et l&#39;anxiété accessoires ainsi que pour les caractéristiques de la personnalité. Par ailleurs, les sujets complète les versions validées allemande de la Symptom Checklist-90 article (version révisée) 11 afin de mesurer leur santé psychologique. Ceux qui ont des scores très élevés (deux écarts-types au-dessus de la moyenne, indiquant une mauvaise santé psychologique) sont exclus de l&#39;analyse des données. En raison du décalage créé de quatre heures de l&#39;apparition des effets comportementaux après l&#39;application sublinguale de 0,5 mg de testostérone chez les jeunes, les femmes en santé 6,7, une longue période d&#39;attente est une partie intégrante de notre étude. Durant cette période, nos sujets sont tenus de rester dans la salle de laboratoire et de se tenir tranquillement occupés. Ceci est pour s&#39;assurer qu&#39;aucune interaction sociale en dehors du laboratoire a lieu ce qui pourrait donner lieu à des mesures confondues. </li></ol> 3. Jeu de l&#39;ultimatum <ol><li> Les sujets ont alors reçu des instructions pour leur rôle dans le jeu et les règles de gain sur le papier et sont invités à les lire. Nous vérifier leur compréhension de la structure de gain en leur faisant remplir des questions de contrôle de plusieurs à la fin des instructions. </li><li> Nous résumons ensuite la procédure expérimentale par voie orale. La raison pour cela est de s&#39;assurer que les sujets savent que tout le monde a la même information sur la structure du jeu et comment les gains are déterminé, qui est aussi appelée la «connaissance commune». Le sommaire est le suivant: </li><li> «Le jeu de l&#39;ultimatum est joué avec deux types de joueurs, un auteur et un répondeur, qui ont à s&#39;entendre sur la répartition des 10 unités monétaires (UM). L&#39;auteur du projet peut décider de la répartition de l&#39;UM 10. Dans cette expérience, le proposants peuvent proposer des offres de 5, 3, 2, ou 0 UM au répondeur. Le répondeur doit alors accepter ou rejeter cette proposition. Si le répondeur accepte l&#39;offre du proposant, l&#39;allocation proposée sera mise en œuvre et payés. Cependant, le répondeur peut aussi rejeter la proposition, dans ce cas aucune des parties ne gagne rien &quot;. </li><li> Nous assurons une séparation claire entre une offre qui est considéré comme juste (5 UM) et les offres qui sont perçues comme injustes (3, 2 ou 0 UM) en limitant l&#39;offre à 5, 3, 2 ou 0 UM. Les sujets sont assignés au hasard et de façon anonyme au rôle de l&#39;auteur soit ou le répondeur, puis reste dans ce rôle pour l&#39;expérience entière. Chaque auteur fait trois propositions sur la répartition des UM alors jumelé avec trois différents partenaires d&#39;interaction sélectionnées au hasard. Aucune paire de sujets interagit plus d&#39;une fois. Ils n&#39;apprennent jamais l&#39;identité des personnes avec qui ils sont jumelés à l&#39;expérience. L&#39;auteur ne reçoit pas de commentaires sur les choix de l&#39;répondeurs »jusqu&#39;à la fin de l&#39;expérience. Toutes les décisions dans le jeu de l&#39;ultimatum sont mises en œuvre dans les logiciels zTree et présentés sur des écrans d&#39;ordinateur 12. </li><li> Parce que la testostérone est l&#39;une des hormones les plus débattus dans la presse populaire, il est possible que les sujets ont une croyance préformés (vrai ou faux) sur ses effets 13. Par ailleurs, en raison des préoccupations éthiques obligent les chercheurs à informer les personnes qu&#39;elles reçoivent soit un placebo ou de testostérone de la connaissance préalable de la testostérone peut polluer un impact possible de la testostérone sur le comportement. Par conséquent, nous évaluons l&#39;affectation de groupe perçu en demandant aux sujets s&#39;ils pensent qu&#39;ils ont reçu la testostérone ou la pilule placebo. </li><li> L&#39;affectation de groupe perçu est enregistrée dans le questionnaire final, accompagné de quelques caractéristiques socio-économiques. Au cours du dernier questionnaire nous préparons le paiement des sujets. </li></ol> 4. Paiement Sujet <ol><li> Sujets de recevoir une redevance de base d&#39;une centaine de francs suisses pour la participation à l&#39;expérience. L&#39;utilisation de réelles incitations monétaires réduit grandement une biais de désirabilité sociale potentielle et biaisé la perception de soi. Par conséquent, chaque sujet reçoit un franc suisse (environ 1 $ US) pour chaque MU gagné dans le jeu de l&#39;ultimatum. Chaque sujet reçoit son salaire composé de la taxe de base plus le UM gagné en privé, à la fin de l&#39;expérience. </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. 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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. 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Une indication que vos résultats sont valables si l&#39;offre est moyenne observée est similaire à ce que d&#39;autres études trouvées. Typiquement, vous propose en moyenne entre 30 - 40% du montant total et environ la moitié des sujets offrent les 14 parts égales. D&#39;autre part, un indicateur probable que les sujets n&#39;ont pas compris les règles du jeu est de savoir si les offres de plus de 50% sont observées. Il est à noter, cependant, qu&#39;il existe une hétérogénéité considérable da...

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

Comportementale des recherches endocrinologiques chez les êtres humains ainsi que chez les animaux suggèrent que la testostérone joue un rôle clé dans les interactions sociales. Des études sur des rongeurs ont montré un lien direct entre la testostérone et le comportement agressif et une sagesse populaire adapte ces résultats aux humains, ce qui suggère que la testostérone induit un comportement antisocial, égoïste, voire agressive 2. Toutefois, de nombreux chercheurs doute un directs testostérone-agression lien chez les humains, mais soutient plutôt que la testostérone est principalement impliquée dans le statut comportements liés à 3,4. Comme un statut élevé peut également être obtenu par des moyens agressifs et antisociaux il peut être difficile de distinguer entre les anti-sociaux et le statut comportement de recherche. Nous avons donc mis en place un environnement expérimental, dans lequel le statut ne peut être atteint par des moyens prosociaux. Dans une expérience en double aveugle et contrôlée contre placebo, nous avons administré une dose unique par voie sublinguale de 0,5 mg de testostérone (avec un transporteur hydroxypropyl-β-cyclodextrine) à 121 femmes et étudié leur comportement d&#39;interaction sociale dans un paradigme de négociation économique. Immobilier incitations monétaires sont en jeu dans ce paradigme, chaque joueur A reçoit une certaine somme d&#39;argent et a faire une offre à un autre joueur B sur la façon de partager l&#39;argent. Si B accepte, elle reçoit ce qui était offert et le joueur A garde le reste. Si B refuse l&#39;offre, personne ne se rien. Un statut chercher le joueur A est prévu pour éviter d&#39;être rejeté par comporté d&#39;une façon prosociale, c&#39;est à dire en faisant des offres plus élevées. Les résultats montrent que si les attentes concernant l&#39;hormone sont contrôlés, l&#39;administration de testostérone conduit à une augmentation significative de la négociation équitable offre par rapport au placebo. Le rôle des attentes se reflète dans le fait que les sujets qui déclarent qu&#39;ils croient avoir reçu la testostérone font des offres plus basses que celles qui disent qu&#39;ils croient qu&#39;ils ont été traités avec un placebo. Ces résultats suggèrent que l&#39;approche d&#39;économie expérimentale est sensible pour détecter les effets neurobiologiques aussi subtils que ceux obtenus par l&#39;administration d&#39;hormones. Par ailleurs, les résultats pointent vers l&#39;importance des deux facteurs psychosociaux ainsi que neuroendocrines de déterminer l&#39;influence de la testostérone sur le comportement social humain.

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

La procédure décrite dans ce protocole montre que l&#39;administration de testostérone et les croyances populaires au sujet de testostérone peut être associée à des comportements sociaux directement opposés.

Combinant endocrinologie du comportement et l&#39;économie expérimentale: Décision de la testostérone et social Rendre

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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SCIENTISTS IN ACTION

15.0K vues.  University of Zurich. La procédure décrite dans ce protocole montre que l'administration de testostérone et les croyances populaires au sujet de testostérone peut être associée à des comportements sociaux directement opposés.

Vidéo: 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.

Jeu-Based Computer combinant les expériences comportementales à haute densité Suivi Gaze EEG et infrarouge

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.

Investigation d&#39;imagerie cérébrale de les corrélats neuraux de l&#39;observation virtuelle Interactions sociales

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.

Mesurer la valeur subjective des options risquées et ambiguës l&#39;aide de l&#39;économie expérimentale et fonctionnels des méthodes d&#39;IRM

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 Suivi et évaluation comportementale

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.

Une configuration à faible coût pour l&#39;audiométrie comportementale chez les rongeurs

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.

La micro-injection d&#39;insuline de l&#39;hippocampe et<em&gt; In vivo</emMicrodialyse&gt; Test de la mémoire spatiale cours

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.

Effets de la Stimulation transcrânienne courant alternatif sur le Cortex moteur primaire par en ligne approche combinée avec la Stimulation magnétique transcrânienne

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.

Opérante protocoles d’évaluation de l’analyse coûts-avantages au cours de la prise de décision renforcée par les rongeurs

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.

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.

Post-Movie Subliminal Measurement (PMSM), pour enquêter sur les biais sociaux implicites

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