Este trabalho foi financiado por uma concessão do National Science Foundation suíço (CE: PBEZP3-131154)

1. Recrutamento Assunto <ol><li> Os assuntos são recrutados através de um banco de dados 5 on-line contendo uma lista de cerca de 3000 estudantes voluntários. A partir desta lista que só contactar mulheres que não tenham participado anteriormente em estudos similares e perguntar-lhes se estão interessados ​​em participar neste estudo. Nós o convidamos exclusivamente as mulheres como o curso de tempo dos efeitos neurofisiológicos após a administração de testosterona aguda está bem estabelecida entre as mulheres 6,7. Para os homens, este curso momento ainda não é muito bem compreendida. </li><li> Os sujeitos interessados ​​são, então, exibido em uma entrevista por telefone para excluir a ingestão de medicamentos, doenças somáticas, a contracepção hormonal ou quaisquer distúrbios neurológicos ou psiquiátricos. </li><li> Porque os níveis endógenos dos hormônios sexuais tendem a ser baixas e estáveis ​​dentro da primeira parte do ciclo menstrual feminino, realizamos uma entrevista por telefone segundo para obter informações sobre a estabilidade ea duração do ciclo. Assuntos são então convidados a vir para o experimento dentro de 10 dias desde o início do seu ciclo menstrual. Eles ainda são instruídos a abster-se de ingestão de álcool ou cafeína e fumo por 24 horas antes do experimento. </li><li> Sujeitos são convidados, em grupos de um tamanho médio de 12 para o laboratório experimental do Instituto de Pesquisa Empírica em Economia, em Zurique, na Suíça. </li></ol> 2. Procedimento Experimental <ol><li> Todas as sessões começam em 01:00 para controlar a variação circadiana dos níveis de hormônio esteróide. </li><li> Realizamos um teste de gravidez antes do início do experimento para impedir a gravidez. </li><li> Na preparação do experimento, a testosterona e pílulas placebo visualmente indistinguíveis são distribuídos aleatoriamente a doze estações de trabalho marcada 11:59 dentro da sala de laboratório por uma pessoa que não está envolvido na experiência de outra forma. </li><li> Na entrada para o laboratório, cada um dos sujeitos twelve tira uma carta com um número escondido nele. Os números variam 1-12. </li><li> Os assuntos são levados para a sala de laboratório, que é dotado de um total de 36 locais de trabalho do computador. Indivíduos são instruídos a procurar e sentar-se pelo local de trabalho marcados com o mesmo número indicado no cartão que tirou na entrada. </li><li> Todos os indivíduos ler e assinar o termo de consentimento informado. </li><li> Medimos testosterona basal e concentrações de cortisol salivar utilizando o Kit SaliCaps IBL (IBL-Hamburgo, Hamburgo, Alemanha) para a coleta de amostra de saliva. Indivíduos são convidados a transferir 1 mL de saliva em tubos de ensaio, que depois são imediatamente congeladas a -80 ° C. </li><li> Os sujeitos são convidados a tomar a pílula sublingual em sua boca, para mastigar e manter a substância se desintegrou na sua boca durante um minuto. Para conseguir contato máxima do complexo de inclusão HP-β-CD de testosterona com a mucosa oral, os sujeitos são instruídos a fazer movimentos circulares com a língua. Após um minuto, o restante da substância for ingerida com 100 mL de água. </li><li> Imediatamente após a administração de substâncias, os indivíduos são obrigados a preencher questionários diferentes. Medimos o humor e excitação por meio do Questionário Multidimensional Mood (MDBF) 8 e ansiedade e traços de raiva e estados, por meio do Inventário de Ansiedade Traço-Estado 9 eo Inventário Traço-Estado de Expressão e Raiva 10. Estes questionários têm a finalidade de controlar o possível efeito dos estados sujeitos incidental raiva humor e ansiedade, assim como para características de personalidade. Além disso, os indivíduos completa das versões validado alemã da Symptom Checklist 90 item (versão revista) 11 para medir a sua saúde psicológica. Aqueles que têm pontuações muito altas (de dois desvios-padrão acima da média, indicando a saúde psicológica pobres) são excluídos da análise de dados. Devido ao lapso de tempo estabelecido de quatro horas para o aparecimento de efeitos comportamentais após a aplicação sublingual de 0,5 mg de testosterona em mulheres jovens, saudáveis ​​6,7, um longo período de espera é parte integrante do nosso estudo. Durante este período, nossos sujeitos são obrigados a permanecer na sala de laboratório e manter-se silenciosamente ocupados. Isso é para garantir que nenhuma interação social fora do laboratório tem lugar que poderia dar lugar a medidas confundidos. </li></ol> 3. Jogo do Ultimato <ol><li> Assuntos, em seguida, receber as instruções para seu papel no jogo e as regras payoff no papel e são convidados a lê-los. Nós verificamos a sua compreensão da estrutura de recompensa por tê-los completos perguntas de controle diversas, no final das instruções. </li><li> Nós então resumir o procedimento experimental por via oral. A razão para isso é para garantir que as pessoas sabem que todo mundo tem as mesmas informações sobre a estrutura do jogo e como os retornos are determinada, que também é referido como &quot;conhecimento comum&quot;. O resumo é o seguinte: </li><li> &quot;O Jogo do Ultimato é jogado com dois tipos de jogadores, um proponente e um respondedor, que tem que concordar com a divisão de 10 unidades monetárias (MUS). O proponente pode decidir sobre a distribuição dos MUs 10. Neste experimento, os proponentes podem propor ofertas de 5, 3, 2, ou 0 MUs para a resposta. A resposta então tem que aceitar ou rejeitar esta proposta. Se a resposta aceita a oferta do proponente, a alocação proposta será executada e paga. No entanto, o responder também pode rejeitar a proposta, neste caso nenhuma das partes ganha nada &quot;. </li><li> Nós asseguramos uma separação clara entre uma oferta que é considerada como justa (5 MUS) e ofertas que são percebidos como injusto (3, 2 ou 0 UMs), restringindo as ofertas de 5, 3, 2 ou 0 MUs. Os sujeitos são aleatoriamente e de forma anônima atribuído à função, quer do proponente ou a resposta e depois permanecer neste papel para todo o experimento. Cada proponente faz três proposições sobre a distribuição de MUs enquanto emparelhado com três diferentes parceiros de interação selecionados aleatoriamente. Nenhum par de assuntos interage mais de uma vez. Eles nunca aprendem a identidade das pessoas com quem eles são comparados no experimento. O proponente não receber feedback sobre as escolhas que responderam &quot;até o final do experimento. Todas as decisões no jogo do ultimato são implementadas em software zTree e apresentado em telas de computador 12. </li><li> Porque a testosterona é um dos hormônios mais amplamente discutido na imprensa popular, é possível que os indivíduos têm uma crença pré-formadas (verdadeiro ou falso) sobre os seus efeitos 13. Além disso, por questões éticas requerem pesquisadores para informar as pessoas que eles nem receber um placebo ou a testosterona o conhecimento prévio sobre a testosterona podem poluir um possível impacto da testosterona sobre o comportamento. Portanto, avaliar o trabalho de grupo percebido por pedir os assuntos se eles pensam que receberam testosterona ou a pílula placebo. </li><li> O trabalho de grupo percebido é registrado no questionário final, juntamente com algumas características sócio-econômicas. Durante o último questionário nos preparamos pagamento sujeitos. </li></ol> 4. Pagamento sujeitos <ol><li> Voluntários recebem uma taxa base de cem francos suíços para a participação no experimento. O uso de incentivos monetários reais reduz um viés conveniência potencial social e tendenciosa auto-percepções. Portanto, cada indivíduo recebe um franco suíço (cerca de 1 $ EUA) para cada MU ganhou no jogo do ultimato. Cada sujeito recebe seu salário consiste na taxa de base mais o MUs ganhou em particular no final do experimento. </li></ol>

<ol>
	<li>Edwards, D. 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. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Behavioral game theory: experiments in strategic interaction. , (2003).</li><li>Henrich, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term="Economic+man"+in+cross-cultural+perspective:+Behavioral+experiments+in+15+small-scale+societies.">"Economic man" in cross-cultural perspective: Behavioral experiments in 15 small-scale societies.</a> Behavioral and Brain Sciences. 28, 795-855 (2005).</li><li>Bardsley, N., Cubitt, R. P., Loomes, G., Moffatt, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Experimental economics : rethinking the rules. , (2009).</li><li>Eisenegger, C., Naef, M., Snozzi, R., Heinrichs, M., Fehr, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prejudice+and+truth+about+the+effect+of+testosterone+on+human+bargaining+behaviour.">Prejudice and truth about the effect of testosterone on human bargaining behaviour.</a> Nature. 463, 356-359 (2010).</li></ol>

Não há conflitos de interesse declarados.

Uma indicação de que seus resultados são válidos se se as ofertas média observada é semelhante ao que outros estudos. Tipicamente, oferece médias são entre 30-40% do valor total e cerca de metade dos sujeitos oferecer a 14 partes iguais. Por outro lado, um indicador provável que indivíduos não entender as regras do jogo é se a oferta de mais de 50% são observados. É interessante notar, no entanto, que há considerável heterogeneidade na distribuição e oferece média observada em estudos em to...

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

Pesquisa endocrinológica comportamental em humanos, bem como em animais sugere que a testosterona tem um papel fundamental nas interações sociais. Estudos em roedores têm demonstrado uma relação directa entre a testosterona eo comportamento agressivo e uma sabedoria popular se adapta estas conclusões para os humanos, sugerindo que a testosterona induz comportamentos anti-sociais, egoístas ou até mesmo agressivo 2. No entanto, muitos pesquisadores dúvida um link de testosterona-agressão direta em humanos, argumentando que a testosterona é primariamente envolvidos na situação relacionada com o comportamento 3,4. Como um status elevado pode também ser obtida por meio agressivo e anti-social pode ser difícil distinguir entre anti-social e status comportamento de busca. Nós, portanto, criar um ambiente experimental, em que estado só pode ser alcançado por meio pró-social. Em um experimento duplo-cego e controlado com placebo, administrou uma dose única de 0,5 mg sublingual de testosterona (com um portador hidroxipropil-β-ciclodextrina) para 121 mulheres e investigou o comportamento de interação social em um paradigma de negociação econômica. Incentivos monetários reais estão em jogo neste paradigma, cada jogador recebe uma certa quantidade de dinheiro e tem que fazer uma oferta para outro jogador B sobre como dividir o dinheiro. Se B aceita, ela consegue o que foi oferecido e Um jogador mantém o resto. Se B se recusa a oferta, ninguém tem nada. Um status que procuram Um jogador é esperado para evitar ser rejeitado por se comportar de uma forma pró-social, ou seja, fazer ofertas mais elevadas. Os resultados mostram que se as expectativas sobre o hormônio são controlados, a administração de testosterona leva a um aumento significativo na negociação feira oferece em comparação com placebo. O papel das expectativas é refletida no fato de que os indivíduos que relatam que eles acreditam ter recebido testosterona fazer ofertas menores do que aqueles que dizem acreditar que eles foram tratados com um placebo. Estes achados sugerem que a abordagem economia experimental é sensível para a detecção de efeitos neurobiológicos tão sutil quanto os obtidos pela administração de hormônios. Além disso, os resultados apontam para a importância de ambos os fatores psicossociais, bem como neuroendócrino na determinação da influência da testosterona sobre o comportamento 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

O procedimento descrito neste protocolo mostra que a administração de testosterona e crenças populares sobre a testosterona pode estar associada diretamente oposta comportamentos sociais.

Combinando Behavioral Endocrinologia e Economia Experimental: Decisão da testosterona e Social Fazendo

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 visualizações.  University of Zurich. O procedimento descrito neste protocolo mostra que a administração de testosterona e crenças populares sobre a testosterona pode estar associada diretamente oposta comportamentos sociais.

Vídeo: 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.

Jogo computador baseado combinando experimentos comportamentais com alta densidade de rastreamento Gaze EEG e Infravermelho

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

Neurociência

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.

Investigação por imagem do cérebro os correlatos neurais da Observando Virtual Interações Sociais

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

Combining Lipophilic dye, in situ Hybridization, Immunohistochemistry, and Histology

Going beyond single gene function to cut deeper into gene regulatory networks requires multiple mutations combined in a single animal. Such analysis of two or more genes needs to be complemented with in situ hybridization of other genes, or immunohistochemistry of their proteins, both in whole mounted developing organs or sections for detailed resolution of the cellular and tissue expression alterations. Combining multiple gene alterations requires the use of cre or flipase to conditionally delete genes and avoid embryonic lethality. Required breeding schemes dramatically enhance effort and cost proportional to the number of genes mutated, with an outcome of very few animals with the full repertoire of genetic modifications desired. Amortizing the vast amount of effort and time to obtain these few precious specimens that are carrying multiple mutations necessitates tissue optimization. Moreover, investigating a single animal with multiple techniques makes it easier to correlate gene deletion defects with expression profiles. We have developed a technique to obtain a more thorough analysis of a given animal; with the ability to analyze several different histologically recognizable structures as well as gene and protein expression all from the same specimen in both whole mounted organs and sections. Although mice have been utilized to demonstrate the effectiveness of this technique it can be applied to a wide array of animals. To do this we combine lipophilic dye tracing, whole mount in situ hybridization, immunohistochemistry, and histology to extract the maximal possible amount of data.

Combining Lipophilic dye, in situ Hybridization, Immunohistochemistry, and Histology

A combination of different techniques to maximize data collection from mouse tissue is presented.

Combinando corante lipofílico, In situ Hibridação, imunohistoquímica e histologia

Going beyond single gene function to cut deeper into gene regulatory networks requires multiple mutations combined in a single animal.  Such analysis of ...

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.

Medir o valor subjetivo de Opções de risco e ambígua usando Economia Experimental e funcional métodos de ressonância 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 Acompanhamento e Medição do Comportamento

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.

A configuração de Baixo Custo para audiometria comportamental em 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.

Microinjeção insulina hipocampal e<em&gt; Em vivo</em&gt; Microdiálise Durante um teste de memória espacial

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

Simultaneous Detection of c-Fos Activation from Mesolimbic and Mesocortical Dopamine Reward Sites Following Naive Sugar and Fat Ingestion in Rats

This study uses cellular c-fos activation to assess effects of novel ingestion of fat and sugar on brain dopamine (DA) pathways in rats. Intakes of sugars and fats are mediated by their innate attractions as well as learned preferences. Brain dopamine, especially meso-limbic and meso-cortical projections from the ventral tegmental area (VTA), has been implicated in both of these unlearned and learned responses. The concept of distributed brain networks, wherein several sites and transmitter/peptide systems interact, has been proposed to mediate palatable food intake, but there is limited evidence empirically demonstrating such actions. Thus, sugar intake elicits DA release and increases c-fos-like immunoreactivity (FLI) from individual VTA DA projection zones including the nucleus accumbens (NAC), amygdala (AMY) and medial prefrontal cortex (mPFC) as well as the dorsal striatum. Further, central administration of selective DA receptor antagonists into these sites differentially reduce acquisition and expression of conditioned flavor preferences elicited by sugars or fats. One approach by which to determine whether these sites interacted as a distributed brain network in response to sugar or fat intake would be to simultaneous evaluate whether the VTA and its major mesotelencephalic DA projection zones (prelimbic and infralimbic mPFC, core and shell of the NAc, basolateral and central-cortico-medial AMY) as well as the dorsal striatum would display coordinated and simultaneous FLI activation after oral, unconditioned intake of corn oil (3.5%), glucose (8%), fructose (8%) and saccharin (0.2%) solutions. This approach is a successful first step in identifying the feasibility of using cellular c-fos activation simultaneously across relevant brain sites to study reward-related learning in ingestion of palatable food in rodents.

The goal of this study is to identify reward-related distributed brain networks by delineating a reliable immunohistological technique using cellular c-fos activation to measure simultaneous changes in dopamine pathways and terminal sites after novel ingestion of fat and sugar in rats.

Detecção simultânea de c-Fos Ativação de mesolímbico e mesocortical dopamina Sites Recompensa Após Naive açúcar e gordura ingestão em ratos

This study uses cellular c-fos activation to assess effects of novel ingestion of fat and sugar on brain dopamine (DA) pathways in rats. Intakes of sugars ...

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.

Efeitos da estimulação da corrente alternada transcraniana no córtex Motor primário por on-line abordagem combinada com estimulação magnética transcraniana

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 avaliar o custo-benefício durante a tomada de decisão reforçada 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 ...