As teorias mais influentes acerca do funcionamento do córtex pré-frontal (PFC) tomam essa estrutura como um córtex de associação e de integração de informações oriundas de outras estruturas nervosas. Isso implicaria na participação direta do PFC nos processos de memória operacional e em processo atencionais. Estudos hodológicos e neurofisiológicos sugerem, que o córtex orbitofrontal (OFC) seria responsável pela integração de informações de caráter sensorial, motivacional e afetivo, enquanto o córtex pré-frontal ventromedial (vmPFC) seria diretamente ligado ao OFC, tendo um papel crucial na codificação de estímulos emocionais oriundos da amígdala. Nesse contexto, é aceito que a integração das informações feita por essas estruturas seja essencial para o processo de tomada de decisões, uma vez que esse comportamento necessita de uma avaliação do ambiente em termos de comparações de situações novas a experiências prévias armazenadas na memória, assim como um balanço entre custos, benefícios e cálculo de possíveis valores da recompensa. Para testar essas hipóteses, ratos com danos seletivos no vmPFC foram submetidos testes de avaliação de ansiedade e medo condicionado no paradigma de teste e reteste no labirinto em cruz elevado (LCE), assim como a testes de memória de referência espacial e memória operacional no labirinto aquático de Morris. Outro grupo de animais teve matrizes de multi-eletrodos implantadas no OFC para a avaliação da atividade neuronal dessa estrutura em um teste envolvendo tomada de decisões, no qual devem escolher entre ganhar 1 pellet de chocolate imediatamente ou 4 pellets envolvendo atrasos variados. No teste no LCE, animais com lesão no vmPFC diferem dos animais controle por apresentarem uma diminuição do tempo de avaliação de risco sem apresentar alterações nos parâmetros que aferem memória, atividade locomotora e ansiedade. No teste de memória de referência espacial após treinamento extensivo de busca pela plataforma em um mesmo local no labirinto aquático, animais com lesão persistem no local quando se retira a plataforma (probe test). Já no teste de memória operacional, no qual a localização da plataforma é alterada diariamente, esses animais não diferem do grupo controle. Na tarefa envolvendo tomada de decisões, observou-se uma atividade eletrofisiológica de neurônios do OFC relacionada ao momento crítico no qual o animal deve realizar uma escolha. Em conjunto, esses resultados mostram que o vmPFC está relacionado à flexibilidade comportamental e tomada de decisões, possivelmente em conjunto com o OFC, cuja atividade neuronal sugere uma participação nos processos de tomada de decisões e de elaboração de estratégias / The most influential theories on the function of the prefrontal cortex (PFC) suggest that this structure is an association cortex, responsible for integration of information received from other parts of the brain. This would implicate in direct participation of the PFC in working memory and attentional processes. Given this context, hodological and neurophysiological studies suggest that the orbitofrontal cortex (OFC) would be responsible for the integration of sensory, motivational and affective aspects, while the ventromedial prefrontal cortex (vmPFC), which is directly connected to the OFC, would have a key role in encoding emotional stimuli from the amygdala. It is well accepted that the processing of these aspects of information is crucial for decision-making processes, given the fact that this expression of behavior requires an evaluation of the environment in terms of comparing novel situation to previous experiences, as well as processing the balance between costs, outcomes and reward values. In order to test these hypotheses, rats with selective lesions to the vmPFC were subjected to the elevated plus maze (EPM) to evaluate anxiety and conditioned fear in the test retest paradigm. Animal were also tested in a spatial reference memory and a working memory tasks in the Morris water maze. Another group of rats had multi-electrode arrays chronically implanted in the OFC for the evaluation of the neuronal activity during a decision-making task, in which the animals had to choose between a small reward of one chocolate pellet immediately and a large reward of four chocolate pellets after varying delays. The results of the EPM show that animals with lesion to the vmPFC differ from control animals by showing diminished time evaluating risk in the second exposure to the EPM, without damage to locomotor activity, memory and anxiety levels. In the reference spatial memory task in the water maze, after extensive training searching for the hidden platform in the same location, lesioned animals persisted searching for the platform in that particular location after it was removed (probe test). However, in the working memory task, in which the platform is presented in a different location each day, lesioned animals did not differ from control animals. In the decision-making task, differential electrophysiological activity in OFC neurons was observed, particularly in the moment of the task in which the animal was required to perform the choice between rewards. Together, these results suggest that the vmPFC is related to behavioral flexibility and decision-making, possibly acting together with the OFC, which neuronal activity suggests participation in decision-making processes

Previous research has suggested that viewing of another’s averted eye gaze causes automatic orienting of attention and eye movements in observers due to the importance of eye gaze for effective social interaction. Other types of visual cues with no social or biological relevance, such as arrows, are claimed not to produce such a direct effect on orienting behaviour. The finding that processing of eye gaze is reduced in individuals with Autistic Spectrum Disorders as well as following damage to the orbitofrontal cortex of the brain, suggests that gaze processing is indeed critical for effective social behaviour and therefore eye gaze may constitute a “special” directional cue. This thesis tested these ideas by examining the influence of socio-biological (eye gaze and finger pointing) and non-social cues (arrows and words) on eye movement responses in both healthy control participants and those with damage to the frontal lobes of the brain. It further investigated the relationship between orienting to gaze and arrow cues and autistic traits in a healthy population. Important differences between the effects of socio-biological and non-social cues were found on saccadic eye movements. Although in the pro-saccade tasks, arrow cues caused a similar facilitation of responses in the cued direction as eye gaze and pointing cues, in the anti-saccade tasks (in which participants have to respond away from the location of a peripheral onset), arrows had a greatly reduced effect on oculomotor programming relative to the biologically relevant cues. Importantly, although the socio-biological cues continued to influence saccadic responses, the facilitation was in the opposite direction to the cues. This finding suggests that the cues were being processed within the same "anti-response" task set (i.e. "go opposite") as the target stimulus. Word cues had almost no effects on saccadic orienting in either pro- or anti-saccade tasks. Schematicised eye gaze cues had a smaller magnitude effect than photographic gaze cues suggesting that ecological validity ("biological-ness") is an important factor in influencing oculomotor responses to social cues. No relationship was found between autistic traits and orienting to gaze or arrow cues in a large sample of males. However, findings from the neurological patients point to a possible double-dissociation between the neural mechanisms subserving processing of socio-biological and non-social cues, with the former reliant on the orbitofrontal cortex, and the latter on lateral frontal cortex. Taken together, these results suggest that biologically relevant cues have privileged access to the oculomotor system. The findings are interpreted in terms of a neurocognitive model of saccadic orienting to socio-biological and non-social cues, and an extension to an existing model of saccade generation is proposed. Finally, limitations of the research, its wider impact and directions for future work are discussed.

O córtex orbitofrontal é apontado como uma estrutura fundamental para a tomada de decisão baseada em valor. Acredita-se que sua função envolva a valoração de recompensas a partir da integração de informações sensoriais e memória, a fim de comparar custos e benefícios. Resultados conflitantes sobre os efeitos da lesão do córtex orbitofrontal em tarefas de escolha intertemporal geram questionamentos sobre o nível de especialização de sua função. O presente estudo almeja testar a hipótese de que a participação do córtex orbitofrontal no desempenho de tarefa de escolha intertemporal depende da experiência dos animais com a tarefa em relação ao momento da lesão. Para isto foi utilizada uma tarefa de escolha intertemporal em que os animais deveriam escolher entre dois reforços distintos, um deles menor e entregue imediatamente após a resposta, e o outro maior porém entregue após um determinado tempo de espera após a resposta. Foram incluídos quatro grupos, dois experimentais envolvendo lesão neurotóxica do córtex orbitofrontal e dois controle-operados submetidos a procedimentos idênticos, exceto pela indução de lesão (os grupos controle foram, posteriormente a análises dos resultados comportamentais e constatada ausência de diferença, fundidos num único grupo controle). Um grupo experimental e um correspondente grupo controle foram submetidos a neurocirurgia antes da exposição a 15 sessões de treino na tarefa. Um outro grupo experimental e seu correspondente controle foram submetidos a treinamento similar, porém, depois da neurocirurgia. Posteriormente, todos os animais foram submetidos a 10 sessões adicionais de treino na mesma tarefa e, a seguir, a outras 10 sessões de treino de reversão, em que os locais previamente associados aos esquemas de reforço foram invertidos. Os resultados revelaram que todos os grupos se comportaram de maneira semelhante nas diferentes fases experimentais, independente do momento de realização da lesão ou mesmo da própria lesão, indicando que o córtex orbitofrontal intacto não é necessário para a aquisição e o desempenho da tarefa de escolha intertemporal. Esses resultados levam a conclusão de que danos seletivos do córtex orbitofrontal não geram prejuízos no desempenho de escolhas intertemporais / The orbifrontal cortex is pointed out as a fundamental structure for value-based decision making. It is believed that its function involves the valuation of rewards from the integration of sensory information and memory in order to compare costs and benefits. Conflicting results on the effects of the orbifrontal cortex lesion on tasks of intertemporal choice bring about questions on the level of specialization of its function. The purpose of the present study is to test the hypothesis that the participation of the orbifrontal cortex in the task performance of intertemporal choice depends on the experience of the animal with the task in relation to the moment of injury. For this, an intertemporal choice task was used in which the animals had to choose between two distinct reinforcements, one smaller and delivered immediately after the response and the other larger but delivered after a certain waiting time after the response. Four groups were included, two experimental groups involving neurotoxic injury and two control groups, submitted to identical procedures, except for the induction of lesion (the control groups were, after an analysis of behavioral results and found no difference, merged into a single group control) an experimental group and a corresponding control group underwent neurosurgery before being exposed to 15 training tasks sessions. Another experimental group and its corresponding control underwent similar training, yet, after neurosurgery. Afterward, all the animals were submitted to 10 additional training sessions on the same task and later to another 10 reversal sessions, in which the sites previously associated to the reinforcement schemes were inverted. The results revelead that all groups behaved similarly in the different experimental phases regardless the time of injury or even the lesion itself, showing that the intact orbifrontal cortex is not necessary for the acquisition and performance of the task of intertemporal choice. These results lead to the conclusion that selective orbifrontal cortex damages do not generate losses in the performance of intertemporal choices

Previous research indicates that many important changes in executive functions, or higher cognitive capacities, occur between the ages of three and five years. Additionally, a distinction can be made between the cognitive functions associated with two different cortical regions. The functions of the dorsolateral prefrontal cortex (DL-PFC) are assessed using 'cool' tasks that are abstract and decontextualised. In contrast, the functions of the orbitofrontal cortex (OFC) are assessed using 'hot' tasks that require flexible appraisal of the affective significance of stimuli (Zelazo & Müller, 2002). Different clinical populations have been hypothesized to differ in terms of their impairment on tasks associated with each area of functioning. Current research conclusions regarding the primacy of hot versus cool executive function impairments are limited, however, as they have not taken complexity into account. That is, tasks currently used in investigations of hot and cool executive functions might differ in terms of the complexity of the cognitive processes that the tasks require. Therefore, comparisons across tasks may be misleading because these tasks vary in terms of the demands they place on participants as well as their hot versus cool status. While complexity theories have been applied to a number of cool tasks, only one hot task, those measuring theory-of-mind abilities, have been analysed in terms of complexity. One aim of the current research was to modify several tasks presumed to measure OFC performance to include a complexity manipulation. Tasks from three hot domains (conditional discrimination, the Children's Gambling Task, and future-oriented decision-making) were analysed in terms of their relational complexity, that is, the number of related entities or arguments inherent in a task or concept (Halford, 1993). Based on these complexity analyses, binary-relational and ternary-relational items of each of these tasks were developed or existing tasks were selected and/or modified. The binary-relational items were closely matched to the ternary-relational items in terms of stimuli and procedure, however, they were lower in complexity. After pilot testing, the three new measures of hot executive functioning were included in a larger test battery that was administered to a sample of 120 normally developing 3-, 4-, 5- and 6-year-old children. Existing binary- and ternary-relational items assessing theory-of-mind (a hot task) and three cool measures (transitivity, class inclusion and the Dimensional Change Card Sort test) were also included. The inclusion of measures of both hot and cool executive functions, each with complexity manipulated, allowed for the examination of a possible differential age of emergence of executive abilities associated with the DL-PFC versus the OFC. In support of the relational complexity approach, significant complexity effects were found across all seven tasks. Items at a higher level of complexity were experienced as relatively more difficult by children of all ages. Significant effects of age were also observed, with performance across all tasks increasing with age. The age effects were strongest on the ternary-relational items. The pass-fail data indicated that the majority of children in all age groups succeeded on the binary-relational items. However, it was not until a median of five years of age that children were able to process ternary relations. Consequently, the ternary-relational items produce the greatest differences in performance between the four age groups. The overall pattern of the results also suggested that a distinction can be made between the ages of emergence of abilities associated with the OFC versus the DL-PFC. The results of the pass-fail percentages, patterns of age-related change and age effects on domain factor scores all suggested that while hot executive functions may begin to develop around four years of age, similar levels of improvement are not seen in cool executive functions until five years of age. Thus, the ability to succeed on ternary-relational items of hot executive function tasks appeared to emerge slightly earlier than the cool executive function tasks. Complexity appears to be a critical factor underlying children's performance on executive function tasks, and future assessment regarding the development of executive abilities will benefit from keeping this in mind. While some refinement of new task items may be beneficial, the current test battery may have utility in further examinations of the executive profiles underlying clinical groups, such as children with autism and ADHD.

Drug addiction is a complex behavioral disorder that has been extensively studied in an attempt to uncover its underlying biological mechanisms. This paper contributes to the literature on addiction by demonstrating that addiction is a result of an improperly functioning decision making process. The areas of the brain that are most implicated in decision making demonstrate significant overlap with those areas most affected by addiction. Specifically, the limbic structures of the brain (amygdala, basal ganglia, and mesolimbic reward pathway) and the prefrontal cortices (orbitofrontal cortex, dorsolateral prefrontal cortex, and ventromedial prefrontal cortex) are discussed in relation to their involvement in prominent theories of decision making such as Prospect Theory and the Somatic Marker Hypothesis. This paper will then use the above knowledge regarding the specific brain mechanisms that control decision making and apply it to neurobiological theories of addiction. The view that addiction is a behavioral disorder that results primarily from a degradation of the brain mechanisms involved in decision making processes is important to consider because it can help provide a concrete approach to developing more individualized and effective treatment programs in the future.

Decades of research have demonstrated that people sometimes provide self-evaluations that emphasize their most flattering qualities. Different theoretical accounts have been offered to explain the mechanisms underlying positively-biased self-evaluation. Some researchers theorize that positively-biased self-evaluations arise from a self-protection motivation because positivity biases increase in situations of heightened self-esteem threat. Alternative views question whether self-protection motivation is a necessary or even dominant source of positivity bias by demonstrating that positively-biased self-evaluations occur even when threat is not heightened, and that a general judgment approach leads to positivity biases in some domains but also to negativity biases in other domains. One reason for this gap in knowledge is that behavioral measures are limited in their ability to resolve whether the processes underlying positively-biased self-evaluation are the same or different depending on contextual motivators. Neuroimaging methods are well suited to examine whether different mechanisms underlie similar behaviors, specifically similar positively-biased responses in different contexts. The four studies presented here explore the neural mechanisms of positively-biased self-evaluation by first identifying a core set of neural regions associated with positivity bias (Study 1A and 1sB), examining whether a heightened self-protection motivation changes the engagement of those neural systems (Study 2), and specifying the precise mechanisms supported by those regions (Study 3). Studies 1A and 1B revealed evidence for a neural system comprised of medial and lateral orbitofrontal cortex (OFC) and, to a lesser extent dorsal anterior cingulate (dACC) that was modulated by positivity bias. Study 2 found that a heightened self-protection motivation changes the engagement of medial OFC in positively-biased self-evaluation. Finally, Study 3 found evidence that medial OFC may support a common mechanism in positively-biased judgment that is implemented differently as a function of the motivational context. Taken together, these studies represent a first step toward developing a neural model of positively-biased self-evaluation. The findings provide some preliminary evidence that positivity biases may represent distinct processes in different motivational contexts. This dissertation sets the stage for future work to examine how specific positively-biased cognitive mechanisms may be supported by specific neural systems and computations as a function of motivational contexts. / text

The ability to recognise an individual's affective state from their facial expression is crucial to human social interaction. However, understanding of facial expression recognition processes is limited because mounting evidence has revealed important differences between posed and genuine facial expressions of emotion. Most previous studies of facial expression recognition have used only posed or simulated facial expressions as stimuli, but posed expressions do not reflect underlying affective state unlike genuine expressions. The current study compared behavioural responses and Evoked Response Potentials (ERPs) to neutral expressions, posed smiles and genuine smiles, during three different tasks. In the first task, no behavioural judgment was required, whereas participants were required to judge whether the person was showing happiness in the second task or feeling happiness in the third task. Behavioural results indicated that participants exhibited a high degree of sensitivity in detecting the emotional state of expressions. Genuine smiles were usually labelled as both showing and feeling happiness, but posed smiles were far less likely to be labelled as feeling happiness than as showing happiness. Analysis of P1 and N170 components, and later orbitofrontal activity, revealed differential activity levels in response to neutral expressions as compared to posed and genuine smiles. This differential activity occurred as early as 135ms at occipital locations and from 450ms at orbitofrontal locations. There were significant interactions between participant behavioural sensitivity to emotional state and P1 and N170 amplitudes. However, no significant difference in ERP activity between posed smiles and genuine smiles was observed until 850ms at orbitofrontal locations. An additional finding was greater right temporal and left orbitofrontal activation suggesting hemispheric asymmetry of facial expression processing systems.

Pleasure is part of hedonic well-being, with roots back to Epicurus 2000 years ago. With the new evolving neuroscientific methods of the late 20th and beginning of the 21st century, we are now able to study the biological components of pleasure. This thesis aims to review empirical studies on the neural correlates of pleasure, which can have important implications for well-being, and treatment of addiction and affective disorders. Recent studies have suggested that pleasure can be separated into coding and causing. Discoveries show that causing of pleasure is created in so called hedonic hot spots, areas of the brain that intensely creates pleasure in the shell of nucleus accumbens and in the ventral pallidum. Areas that codes pleasure on the other hand is represented into more cortical areas of the brain, including orbitofrontal cortex, anterior cingulate cortex and anterior insular cortex. There has been a growing understanding about how pleasure is represented in the brain, and a discussion on interpretations and limitations are provided followed by future research suggestions in the final section.

This essay is about the somatosensory system, which is divided into different kinds of touch. Described briefly are the proprioceptive touch, which is transported to the brain via A-alfa fibers and transmits information about e. g. limb position and movement. The cutaneous touch is the main focus and it is divided into discriminative touch and affective touch. The first corresponds to stimuli such as vibration and pressure and is transported via A-beta axons. The second, affective touch, corresponds to e.g. painful and pleasant stimuli which are transported to the brain via A-delta and C-fibers. The aim of the essay is to give an overview of the sense of touch, by doing a literature search, including a discussion of relevant neuronal correlates focusing particularly on affective touch. Moreover, the physiological aspects of touch will be presented. The sources that are used are review and original articles taken from databases such as ScienceDirect, and some articles send by the author. Some books have also been used to find more general knowledge. The conclusion for the essay is that touch is important for humans to function in everyday life. Additional, a specific receptor called C- tactile (CT) is identified to correspond to gentle touch and is suggested to have a vital role for humans in maintaining and forming social bounds. Moreover, discriminative touch is associated with activation in the primary and secondary somatosensory cortex, whereas affective touch seems to be associated with activity in the orbitofrontal cortex, cingulate cortex and the insula cortex, as well as the prefrontal cortex, which is suggested to be activated during interpersonal touch. Further, the sense touch needs to be more researched in order to understand its functions and benefits deeper.

O córtex orbitofrontal é apontado como uma estrutura fundamental para a tomada de decisão baseada em valor. Acredita-se que sua função envolva a valoração de recompensas a partir da integração de informações sensoriais e memória, a fim de comparar custos e benefícios. Resultados conflitantes sobre os efeitos da lesão do córtex orbitofrontal em tarefas de escolha intertemporal geram questionamentos sobre o nível de especialização de sua função. O presente estudo almeja testar a hipótese de que a participação do córtex orbitofrontal no desempenho de tarefa de escolha intertemporal depende da experiência dos animais com a tarefa em relação ao momento da lesão. Para isto foi utilizada uma tarefa de escolha intertemporal em que os animais deveriam escolher entre dois reforços distintos, um deles menor e entregue imediatamente após a resposta, e o outro maior porém entregue após um determinado tempo de espera após a resposta. Foram incluídos quatro grupos, dois experimentais envolvendo lesão neurotóxica do córtex orbitofrontal e dois controle-operados submetidos a procedimentos idênticos, exceto pela indução de lesão (os grupos controle foram, posteriormente a análises dos resultados comportamentais e constatada ausência de diferença, fundidos num único grupo controle). Um grupo experimental e um correspondente grupo controle foram submetidos a neurocirurgia antes da exposição a 15 sessões de treino na tarefa. Um outro grupo experimental e seu correspondente controle foram submetidos a treinamento similar, porém, depois da neurocirurgia. Posteriormente, todos os animais foram submetidos a 10 sessões adicionais de treino na mesma tarefa e, a seguir, a outras 10 sessões de treino de reversão, em que os locais previamente associados aos esquemas de reforço foram invertidos. Os resultados revelaram que todos os grupos se comportaram de maneira semelhante nas diferentes fases experimentais, independente do momento de realização da lesão ou mesmo da própria lesão, indicando que o córtex orbitofrontal intacto não é necessário para a aquisição e o desempenho da tarefa de escolha intertemporal. Esses resultados levam a conclusão de que danos seletivos do córtex orbitofrontal não geram prejuízos no desempenho de escolhas intertemporais / The orbifrontal cortex is pointed out as a fundamental structure for value-based decision making. It is believed that its function involves the valuation of rewards from the integration of sensory information and memory in order to compare costs and benefits. Conflicting results on the effects of the orbifrontal cortex lesion on tasks of intertemporal choice bring about questions on the level of specialization of its function. The purpose of the present study is to test the hypothesis that the participation of the orbifrontal cortex in the task performance of intertemporal choice depends on the experience of the animal with the task in relation to the moment of injury. For this, an intertemporal choice task was used in which the animals had to choose between two distinct reinforcements, one smaller and delivered immediately after the response and the other larger but delivered after a certain waiting time after the response. Four groups were included, two experimental groups involving neurotoxic injury and two control groups, submitted to identical procedures, except for the induction of lesion (the control groups were, after an analysis of behavioral results and found no difference, merged into a single group control) an experimental group and a corresponding control group underwent neurosurgery before being exposed to 15 training tasks sessions. Another experimental group and its corresponding control underwent similar training, yet, after neurosurgery. Afterward, all the animals were submitted to 10 additional training sessions on the same task and later to another 10 reversal sessions, in which the sites previously associated to the reinforcement schemes were inverted. The results revelead that all groups behaved similarly in the different experimental phases regardless the time of injury or even the lesion itself, showing that the intact orbifrontal cortex is not necessary for the acquisition and performance of the task of intertemporal choice. These results lead to the conclusion that selective orbifrontal cortex damages do not generate losses in the performance of intertemporal choices