Delay Discounting im Sinne eines Abwertens zukünftiger Belohnungen ist ein weit verbreitetes Phänomen. Es zeigt sich z. B. in persönlichen Angelegenheiten, wie der Entscheidung für den kurzfristigen Genuss von Süßigkeiten und gegen die langfristigen, durchaus größeren Vorteile einer schlanken Figur. Auch internationale wirtschaftliche und politische Diskussionen zum Klimaschutz oder der Finanzkrise werden von der Präferenz für sofortige, kleinere Belohnungen über verzögerte, größere Belohnungen getrieben. In der Psychologie wird Delay Discounting als Maß für Impulsivität bzw. Selbstkontrolle mit dem Auftreten von Aufmerksamkeitsdefizit-Hyperaktivitäts-Syndromen und von Abhängigkeitserkrankungen in Verbindung gebracht. Bezüglich der neuronalen Grundlagen von Delay Discouting ist mithilfe von sogenannten Intertemporal Choice Tasks bereits herausgefunden worden, dass die Entscheidung für eine sofortige Belohnung stärkere neuronale Aktivierung in belohnungsspezifischen Gehirnregionen evoziert als die Entscheidung für eine verzögerte Belohnung. Außerdem wurden sowohl theoretisch wie auch empirisch ein impulsives und ein reflektives System als Grundlage des Delay Discounting beschrieben, deren Existenz jedoch von manchen Wissenschaftlern angezweifelt wird. Ebenso wird angezweifelt, ob Delay Discounting unabhängig vom Einsatz von Intertemporal Choice Tasks und der damit verbundenen Entscheidung zwischen zwei Alternativen überhaupt besteht. Da die neuronalen Grundlagen des Delay Discounting und des impulsiven und reflektiven Systems bisher nicht unabhängig von einer Entscheidungsaufgabe erfasst wurden, konnten diese Zweifel nicht ausgeräumt werden. Ebenso ist zurzeit unbekannt, ob sich die neuronalen Korrelate des Delay Discounting bei Personen mit unterschiedlichen Persönlichkeitseigenschaften, bei Männern und Frauen, bei Rauchern und Nichtrauchern und in Abhängigkeit von verschiedenen Genvarianten unterscheiden. Um diese Lücke zu schließen, ist im Rahmen der vorliegenden Arbeit ein neuartiges Delay Discounting Paradigma zum Einsatz im Magnetresonanztomographen entwickelt worden. Dieses Paradigma ähnelt einem Monetary Incentive Delay Task und ermöglicht es, neuronale Aktivierung bei der Antizipation und bei dem Erhalt einer einzelnen Belohnung zu einem Zeitpunkt zu erfassen. Außerdem kann nach der Antizipation einer Belohnung, die sich durch eine bestimmte Höhe (0,05 €, 0,50 €, 1,00 €) und eine bestimmte Auszahlungsverzögerung (0 Tage, 10 Tage, 100 Tage) auszeichnet, in einer einfachen visuellen Diskriminationsaufgabe eine Reaktionszeit erfasst werden, die als behaviorales Maß für die inzentive Motivation fungiert. Zusammen mit einer Erfassung verschiedener Persönlichkeitseigenschaften und einer Genotypisierung für den COMT Val 158 Met Polymorphismus, den DRD2 Taq 1 A Polymorphismus und den DAT 1 Polymorphismus ist das Delay Discounting Paradigma an insgesamt 90 Probanden im Magnetresonanztomographen eingesetzt worden, so dass 84 auswertbare Datensätze gewonnen werden konnten. Diese 84 Datensätze stammten insgesamt von 42 Frauen und 42 Männern bzw. von 43 strikten Nichtrauchern, 38 starken Rauchern und drei Gelegenheitsrauchern. Anhand der Auswertung der Gesamtstichprobe konnte bestätigt werden, dass das Delay Discounting Paradigma belohnungs- und verzögerungsspezifisch unterschiedliche Reaktionszeiten und unterschiedliche neuronale Aktivierung hervorruft. In belohnungsverarbeitenden Gehirnregionen wie dem ventralen Striatum zeigte sich sowohl stärkere Aktivierung für größere Belohnungen als auch für Belohnungen, die früher ausgezahlt wurden. Damit steht fest, dass Delay Discounting unabhängig von der Entscheidung zwischen zwei Alternativen auftritt. Außerdem konnte erstmalig ein Interaktionseffekt zwischen Belohnungshöhe und Belohnungsverzögerung aufgedeckt werden: Es zeigte sich eine Abnahme der Differenzen in der neuronalen Aktivierung zwischen größter und kleinster Belohnung über die Zeit, was auf eine Indifferenz gegenüber der Höhe verzögerter Belohnung hindeutet. Ein Einfluss der Belohnungsverzögerung wurde allerdings nur beim Erhalt von Belohnungen messbar, bei der Antizipation von Belohnungen zeigte sich kein Delay Discounting Effekt. Bezüglich der Kontroverse zur Existenz eines impulsiven und reflektiven Systems konnten Ergebnisse gewonnen werden, die beide Positionen integrieren. So wurde zwar die Beteiligung von zwei distinkten neuronalen Systemen beim Abwerten zukünftiger Belohnungen bestätigt, allerdings zeigte sich auch, dass beide Systeme – in einem unterschiedlichen Ausmaß – verzögerte Belohnungen abwerten. Trotzdem wird von den vorliegenden Ergebnissen die Annahme, dass sich aus der Interaktion von impulsivem und reflektivem System impulsives und selbstkontrolliertes Verhalten ergeben kann, gestützt. Im Hinblick auf die interindividuellen Unterschiede, die in der vorliegenden Arbeit aufgedeckt werden sollten, haben sich vor allem Zusammenhänge zwischen dem subjektiv berichteten allgemeinen Stress der Versuchspersonen (operationalisiert über das Selbststeuerungsinventar) und der neuronalen Aktivität von Gehirnregionen, die dem impulsiven und reflektiven System zugeordnet werden, gezeigt. So ist bei niedrigem Stress das impulsive System signifikant weniger aktiviert als das reflektive System, während sich bei hohem Stress dieser Zusammenhang umkehrt. Die relative Hyperaktivierung des impulsiven Systems bei Stress könnte erklären, warum unter Stress vermehrt Rückfälle bei abhängigkeitserkrankten Probanden beobachtet werden. Außerdem ging starkes neuronales Delay Discounting in medial präfrontalen Gehirnregionen mit hohem Stress, ebenso wie mit hoher nichtplanender Impulsivität (gemessen anhand der Barratt Impulsivitätsskala) und mit geringer Selbstkontrolle (gemäß des Selbststeuerungsinventars) einher. Dieses Ergebnis belegt unter anderem, dass das neu entwickelte Delay Discounting Paradigma neuronale Prozesse abbildet, die mit Impulsivität und Selbstkontrolle in Verbindung stehen. Darüber hinaus konnte kongruent mit entsprechenden Vorbefunden ein Einfluss des COMT Val 158 Met Polymorphismus auf das neuronale Delay Discounting im ventralen Striatum und erstmalig ein Zusammenhang zwischen dem DRD2 Taq 1 A A1-Allel und neuronalem Delay Discounting im posterioren Cingulum aufgedeckt werden. Damit ist die Bedeutung des Neurotransmitters Dopamin, der durch die untersuchten Polymorphismen beeinflusst wird, für die neuronalen Grundlagen des Delay Discounting bestätigt worden. Zusammengenommen deuten sowohl die beschriebenen Befunde als auch die sonstigen Ergebnisse der Arbeit darauf hin, dass sich neuronales Delay Discounting interindividuell unterscheidet. Im Hinblick auf Pathologien, die mit diesem Phänomen in Verbindung stehen, sollte daher weitere Forschung zu interindividuellen Unterschieden und zu spezifischen Behandlungsmethoden erfolgen.

The aim of this study was to examine associations between biases in decision-making (delay discounting [DD], opportunity cost neglect [OCN], status quo bias [SQB]), educational attainment, and use of cigarettes and other tobacco and nicotine delivery products among women of reproductive age. Women of reproductive age are of special interest because of the additional risks that cigarette smoking or use of these other products represents should they become pregnant. Data were collected anonymously online in survey format using Amazon Mechanical Turk [AMT]. Participants were 800 women of reproductive age (24-44 years) from across the US. Half (n = 400) were smokers who reported current, daily smoking and half (n = 400) were never smokers who reported smoking less than 100 cigarettes in their lifetime. Participants reported smoking characteristics, plans to quit smoking, use of nicotine replacement therapies, use of other tobacco and nicotine delivery products, alcohol and drug use histories, and the Fagerström Test for Nicotine Dependence. Participants completed two measures for each of the three biases in decision-making, the Barratt Impulsiveness Scale [BIS-11], and two scales measuring short- and long-term propensity to plan for money expenditures [PPMS and PPML]. Educational attainment analyses compared three education groups: high school or less vs. some college (e.g. some college/A.A.) vs. B.A. or higher. DD was steeper among current vs. never smokers and for women with lower vs. higher levels of education, with no significant interaction between smoking and education. Modifying the instructions of the DD measure to make the zero option explicit reduced DD similarly across levels of smoking status and education. OCN was worse at lower vs. higher educational attainment on one OCN measure, with no significant effect of smoking status or interaction between opportunity cost neglect and educational attainment on either measure. No evidence was found for stronger SQB by smoking status or education. Smoking status was related to BIS Total, BIS Motor and Nonplanning subscales and to PPML in initial models but remained significant after adjusting for baseline differences in participant characteristics only for BIS Motor subscale and educational attainment was related only to BIS Nonplanning subscale. Preliminary comparisons of e-cigarette users to non-users suggest smokers using e-cigarettes only differ from smokers not using e-cigarettes on measures related to quitting smoking whereas within never smokers e-cigarette users demonstrated a pattern of riskier decision-making compared to non-users. Results confirm that DD and education are important to understanding the use of tobacco and nicotine products in women of reproductive age, and suggest that smoking and educational attainment are independently related to discounting rates. The observed explicit-zero framing effect suggests making alternatives more explicit when presenting choices may help reduce DD and lead to better decision-making, which has possible treatment implications. Results identify OCN as an additional decision-making bias to consider in understanding how low educational attainment might relate to smoking vulnerabilities. The preliminary examination of e-cigarette use suggests for women of reproductive age above age 24 years, e-cigarette use among current smokers may reflect desire or attempts to quit or cut back on smoking whereas e-cigarette use among non-smokers may be a marker of a more impulsive, riskier repertoire, although additional study of this question is needed.

Tomadas de decisões intertemporais envolvem escolhas entre opções, cujas consequências ocorrem em diferentes intervalos. Os tomadores de decisões tendem a preferir recompensas menores e mais cedo sobre recompensas maiores e tardias, refletindo em descontos de resultados atrasados. Dentre os vários fatores motivacionais, que podem influenciar nas Escolhas Intertemporais, pode ser considerado o papel moral como relevante. O modelo do Jogo do Ultimato é usado, especialmente, para examinar a interferência das ações éticas sobre o comportamento econômico. Entende-se a rejeição de uma oferta baixa nesse jogo como uma punição altruísta, aplicada como estratégia de recuperar uma cooperação justa. Os fatores psicológicos que motivam essa \"punição altruísta\" não são totalmente compreendidos. Para alguns, a punição altruísta é um ato ético de aplicação da norma de justiça, que requer autocontrole, enquanto outros afirmam que é um ato impulsivo, dirigido principalmente pela emoção. Nosso objetivo foi avaliar se a punição altruísta de participantes apontados no contexto do Jogo do Ultimato tem relação com o autocontrole nas distribuições de Escolhas Intertemporais. Um total de 100 participantes realizou o procedimento, individualmente. O software PAJUEI usado contém uma série de 27 ofertas no formato do Jogo do Ultimato e 130 séries de Escolhas Intertemporais. No Jogo do Ultimato, foram ofertados nove níveis de porcentagens entre 3-50% de três recompensas fixas (R$50,00; 100,00 e 150,00), em que o participante tinha duas opções de resposta: aceitar ou recusar. Na fase seguinte das Escolhas Intertemporais, foram apresentadas duas opções: uma de tempo de recebimento imediato e menor valor monetário e a outra com um tempo de recebimento tardio e maior valor monetário. Foram empregados cinco diferentes atrasos de recebimento vinculados a duas recompensas fixas (R$500,00 e 100.000,00); cada recompensa imediata variou em 13 valores entre 5% e 95% do valor fixo tardio. As punições altruístas foram determinadas pela taxa de rejeição das ofertas do Jogo do Ultimato. A partir das decisões feitas nas Escolhas Intertemporais, foram determinados os descontos temporais e categorizados os grupos com baixas, médias e altas escolhas imediatas. Descobrimos que os indivíduos que esperaram por recompensas maiores também rejeitaram ofertas menores, mesmo que positivas, por uma percepção de injustas. Esses indícios indicam que os participantes do estudo exerceram a punição altruísta em resposta à falta de cooperação, como uma reação de autocontrole. / Temporal decision making are choices between options which the consequences occur at different intervals. Decision makers tend to prefer smaller and earlier rewards over larger and later rewards, discounting on later results. Among the several motivational factors that may influence the delay-discounting task, the moral role can be considered relevant. The Ultimatum Game model is especially used to examine the interference of ethical actions on economic behavior. The rejection of a low offer in this game is known as an altruistic punishment, applied as a strategy to recover a fair cooperation. The psychological factors that motivate this \"altruistic punishment\" are not fully understood. For some, altruistic punishment is the ethical act of applying the rule of justice, which requires self-control. On the other hand, others claim that it is an impulsive act, driven primarily by emotion. Our objective was to evaluate if the altruistic punishment of participants pointed out in the context of the ultimatum game is related to the self-control in the distributions of the delay-discounting task. A total of 100 participants performed the procedure individually. The PAJUEI software contains a series of 27 offers in the format of the Ultimatum Game and 130 series of the delay-discounting task. In the Ultimatum Game, nine levels of percentages were offered between 3-50% of three fixed rewards (R $ 50,00, 100,00 and 150,00), in which the participant had two options to choose from: to accept or to refuse. At the next phase of the the delay-discounting task, two options were presented: one of immediate receiving time and smaller monetary value and the other with a late receiving time and greater monetary value. Five different collection delays were applied to two fixed rewards (R$ 500,00 and 100.000,00); each immediate reward varied in 13 values between 5% and 95% of the late fixed value. The altruistic punishments were determined by the rejection rate of the Ultimatum Game offerings. From the decisions made at the delay-discounting task, the temporary discounts were determined and the groups with low, medium and high immediate choices were categorized. We found that individuals who waited for larger rewards also rejected smaller offers, five positive ones, due to a perception of unfairness. These findings indicate that the studied participants exercised altruistic punishment in response to a lack of cooperation, such as a reaction to self-control.

Submitted by Noeme Timbo (noeme.timbo@metodista.br) on 2016-09-01T16:54:41Z No. of bitstreams: 1 André Tonin Ferrari.pdf: 1426729 bytes, checksum: e1d8ae95c5a67d05a964335a9463dec0 (MD5) / Made available in DSpace on 2016-09-01T16:54:41Z (GMT). No. of bitstreams: 1 André Tonin Ferrari.pdf: 1426729 bytes, checksum: e1d8ae95c5a67d05a964335a9463dec0 (MD5) Previous issue date: 2016-06-22 / Studies have been conducted on the delay discouting, which seek to demonstrate the existence of factors that influence financial decision making considering an aversive scenario. Some of these factors with impulsive behavior and the procrastinator behavior, can be critical for the individual to accept or not to devalue certain value. This study analyzed the impulsive behavior and procrastinator that may influence financial decision making. Through a quantitative research approach, data were collected through a survey tool to obtain 410 questionnaires response. The results of this research confirm the influence of procrastination in making the individual financial decision. It concludes that the procrastinator behavior affects decision making, leading the individual to not devalue the delay. But it was found that impulsive behavior was not observed in this study as a component that can impact the financial decision of the individual aversive scenarios. / Estudos tem sido realizados sobre a desvalorização por atraso que buscam demonstrar a existência de fatores que influenciam a tomada de decisão financeira considerando um cenário aversivo. Alguns destes fatores como o comportamento impulsivo e o comportamento procrastinador, podem ser fundamentais para que o indivíduo aceite ou não desvalorizar determinado valor. Este estudo analisou os comportamentos impulsivo e procrastinador que podem influenciar na tomada de decisão financeira. Através de uma abordagem de investigação quantitativa, os dados foram coletados por meio de um instrumento de pesquisa com obtenção da resposta de 410 questionários. Os resultados obtidos por esta pesquisa confirmam a influência da procrastinação no processo de tomada da decisão financeira individual. Conclui-se que o comportamento procrastinador afeta a tomada de decisão, conduzindo o indivíduo a não desvalorizar o atraso. Porém constatou-se que o comportamento impulsivo não ficou evidenciado neste estudo como componente que possa impactar na decisão financeira do indivíduo em cenários aversivos

Fatores como o tempo de espera ou o risco a ser enfrentado por uma recompensa maior têm um efeito importante e, por vezes, paradoxal no processo de tomada de decisão. O Capítulo I apresenta uma discussão teórica sobre a tomada de decisão mediada por esses dois fatores, bem como sua interligação com o conceito de impulsividade e o Transtorno de Déficit de Atenção e Hiperatividade (TDAH). O Capítulo II oferece uma aplicação desses conceitos em um modelo animal do espectro da Síndrome Alcoólica Fetal, condição que apresenta algumas características semelhantes ao TDAH. Utilizando ratos expostos ao álcool no período pré-natal, duas tarefas de tomada de decisão mediada por tempo ou probabilidade foram usadas para testar se esses animais apresentam diferenças em seus padrões de escolha. Não foram encontradas diferenças significativas entre grupos controle e experimentais. Futuros estudos com outros protocolos, espécies e/ou linhagens são desejáveis. / Factors such as the time to wait, or the risk to be faced for a bigger reward have an important and, sometimes, paradoxical effect on the decision making process. Chapter I presents a theoretical discussion about decision making mediated by these two factors, as well as how they relate to the concept of impulsivity and the Attention-Deficit Hyperactivity Disorder (ADHD). Chapter II offers a practical application of these concepts in an animal model of the spectrum of Fetal Alcohol Syndrome, a condition that presents some similar characterstics in comparison to ADHD. Using rats prenatally exposed to ethanol, two decision making tasks, mediated by time or probability, were used to test if these animals show any difference in their patterns of choice. No significant differences were found between control and experimental groups. Future studies with other protocols, species and/or strains are desirable.

Fatores como o tempo de espera ou o risco a ser enfrentado por uma recompensa maior têm um efeito importante e, por vezes, paradoxal no processo de tomada de decisão. O Capítulo I apresenta uma discussão teórica sobre a tomada de decisão mediada por esses dois fatores, bem como sua interligação com o conceito de impulsividade e o Transtorno de Déficit de Atenção e Hiperatividade (TDAH). O Capítulo II oferece uma aplicação desses conceitos em um modelo animal do espectro da Síndrome Alcoólica Fetal, condição que apresenta algumas características semelhantes ao TDAH. Utilizando ratos expostos ao álcool no período pré-natal, duas tarefas de tomada de decisão mediada por tempo ou probabilidade foram usadas para testar se esses animais apresentam diferenças em seus padrões de escolha. Não foram encontradas diferenças significativas entre grupos controle e experimentais. Futuros estudos com outros protocolos, espécies e/ou linhagens são desejáveis. / Factors such as the time to wait, or the risk to be faced for a bigger reward have an important and, sometimes, paradoxical effect on the decision making process. Chapter I presents a theoretical discussion about decision making mediated by these two factors, as well as how they relate to the concept of impulsivity and the Attention-Deficit Hyperactivity Disorder (ADHD). Chapter II offers a practical application of these concepts in an animal model of the spectrum of Fetal Alcohol Syndrome, a condition that presents some similar characterstics in comparison to ADHD. Using rats prenatally exposed to ethanol, two decision making tasks, mediated by time or probability, were used to test if these animals show any difference in their patterns of choice. No significant differences were found between control and experimental groups. Future studies with other protocols, species and/or strains are desirable.

Fatores como o tempo de espera ou o risco a ser enfrentado por uma recompensa maior têm um efeito importante e, por vezes, paradoxal no processo de tomada de decisão. O Capítulo I apresenta uma discussão teórica sobre a tomada de decisão mediada por esses dois fatores, bem como sua interligação com o conceito de impulsividade e o Transtorno de Déficit de Atenção e Hiperatividade (TDAH). O Capítulo II oferece uma aplicação desses conceitos em um modelo animal do espectro da Síndrome Alcoólica Fetal, condição que apresenta algumas características semelhantes ao TDAH. Utilizando ratos expostos ao álcool no período pré-natal, duas tarefas de tomada de decisão mediada por tempo ou probabilidade foram usadas para testar se esses animais apresentam diferenças em seus padrões de escolha. Não foram encontradas diferenças significativas entre grupos controle e experimentais. Futuros estudos com outros protocolos, espécies e/ou linhagens são desejáveis. / Factors such as the time to wait, or the risk to be faced for a bigger reward have an important and, sometimes, paradoxical effect on the decision making process. Chapter I presents a theoretical discussion about decision making mediated by these two factors, as well as how they relate to the concept of impulsivity and the Attention-Deficit Hyperactivity Disorder (ADHD). Chapter II offers a practical application of these concepts in an animal model of the spectrum of Fetal Alcohol Syndrome, a condition that presents some similar characterstics in comparison to ADHD. Using rats prenatally exposed to ethanol, two decision making tasks, mediated by time or probability, were used to test if these animals show any difference in their patterns of choice. No significant differences were found between control and experimental groups. Future studies with other protocols, species and/or strains are desirable.

Indiana University-Purdue University Indianapolis (IUPUI) / Impulsivity, or the tendency to act prematurely without foresight, has been linked to a diverse range of pathological conditions. Foresight refers to the ability to envision future rewards and events (i.e. prospectively sample) and has been associated with decreased impulsivity. One form of impulsivity is measured by the ability to delay gratification and is often studied in the framework of Delay Discounting (DD). DD provides the means to study impulsivity in a number of pathological conditions. However, whether impulsivity precedes the development of pathological states or results from the pathological state itself is not fully understood. This necessitates an understanding of neurobiological mechanisms contributing to decision making in both non-impulsive as well as impulsive populations of individuals. Animal models allow invasive techniques to be used to dissect the neurocircuitry involved in decision making. Given that the decision-making process is an ongoing process rather than an isolated event, optogenetics provide the temporal and spatial specificity necessary for evaluating brain region specific contributions to decision making in DD. In the present study, optogenetics were used to assess the contribution of the medial Prefrontal Cortex (mPFC), a brain region involved in ‘goal-directed’ behavior, in the planning of future choices (i.e. prospective plans) and subsequent measures of impulsivity in an adjusting amount DD procedure. Optogenetic inhibition of mPFC was conducted in Wistar rats during different epochs of a DD task in order to assess how mPFC affects planning behavior in a population of rat not considered to be highly impulsive. Although no direct effects on planning behavior (e.g. consistency) were observed, inhibiting mPFC after a trial has been initiated and directly before a choice was made (Epoch 2) was observed to increase measures of impulsivity in comparison to days where no optogenetic manipulation occurred in a delay-specific manner. This suggests that mPFC differentially contributes to decision making at different delays. A pattern of associations between choice latency, impulsivity, and consistency began to emerge for inactivation occurring in Epoch 2, suggesting that mPFC contributes to some aspect of planning choices during this epoch. Moreover, these results indicate that mPFC is involved in decision making in Wistar Rats. Understanding the direct role that mPFC plays in promoting choices of delayed rewards provides a neurobiological target for treatment aimed at reducing impulsivity in the clinical population.

Humans and other animals systematically discount the value of future rewards as a function of their delay, and individual differences in the steepness of this ``delay discounting'' are predictive of a range of important real-world outcomes. Episodic future thinking, the mental simulation of episodes in the personal future, is one means by which to curb delay discounting. This thesis seeks to contribute to our understanding of how this effect occurs. The account that predominates in the literature is that episodic future thinking simulates the experience of future rewards, enabling their undiscounted value to be appreciated in the present. This thesis takes this account as a starting point, formalizing it in a mathematical model and carrying out several experimental studies to test its predictions. We find that key predictions are not borne out and develop an alternative account in which simulated experience plays a less central role. / Thesis / Doctor of Philosophy (PhD) / Pursuing our goals for the future usually means sacrificing immediate gratification, yet we often make decisions that are not in our best interest over the long term. This is because we assign lower subjective value to future rewards the further they are from the present. Individuals differ in how much they devalue future rewards, and these differences are related to many real-world outcomes. Our tendency to devalue future rewards is reduced when we vividly imagine the future in a process called ``episodic future thinking,'' and this thesis seeks to understand how this effect occurs. The most obvious explanation would seem to be that episodic future thinking ``simulates'' the experience of future rewards and allows us to recognize their value in the present. However, using results from several experimental studies, I argue that this may not be the best explanation after all, and I develop an alternative.

<p> <i>Impulsivity</i>, or the tendency to act prematurely without foresight, has been linked to a diverse range of pathological conditions. Foresight refers to the ability to envision future rewards and events (i.e. prospectively sample) and has been associated with decreased impulsivity. One form of impulsivity is measured by the ability to delay gratification and is often studied in the framework of Delay Discounting (DD). DD provides the means to study impulsivity in a number of pathological conditions. However, whether impulsivity precedes the development of pathological states or results from the pathological state itself is not fully understood. This necessitates an understanding of neurobiological mechanisms contributing to decision making in both non-impulsive as well as impulsive populations of individuals. </p> <p> Animal models allow invasive techniques to be used to dissect the neurocircuitry involved in decision making. Given that the decision-making process is an ongoing process rather than an isolated event, optogenetics provide the temporal and spatial specificity necessary for evaluating brain region specific contributions to decision making in DD. In the present study, optogenetics were used to assess the contribution of the medial Prefrontal Cortex (mPFC), a brain region involved in ‘goal-directed’ behavior, in the planning of future choices (i.e. prospective plans) and subsequent measures of impulsivity in an adjusting amount DD procedure. Optogenetic inhibition of mPFC was conducted in Wistar rats during different epochs of a DD task in order to assess how mPFC affects planning behavior in a population of rat not considered to be highly impulsive. Although no direct effects on planning behavior (e.g. consistency) were observed, inhibiting mPFC after a trial has been initiated and directly before a choice was made (Epoch 2) was observed to increase measures of impulsivity in comparison to days where no optogenetic manipulation occurred in a delay-specific manner. This suggests that mPFC differentially contributes to decision making at different delays. A pattern of associations between choice latency, impulsivity, and consistency began to emerge for inactivation occurring in Epoch 2, suggesting that mPFC contributes to some aspect of planning choices during this epoch. Moreover, these results indicate that mPFC is involved in decision making in Wistar Rats. Understanding the direct role that mPFC plays in promoting choices of delayed rewards provides a neurobiological target for treatment aimed at reducing impulsivity in the clinical population.</p>