The thing that should not be: predictive coding and the uncanny valley in perceiving human and humanoid robot actions

Using functional magnetic resonance imaging (fMRI) repetition suppression, we explored the selectivity of the human action perception system (APS), which consists of temporal, parietal and frontal areas, for the appearance and/or motion of the perceived agent. Participants watched body movements of a human (biological appearance and movement), a robot (mechanical appearance and movement) or an android (biological appearance, mechanical movement). With the exception of extrastriate body area, which showed more suppression for human like appearance, the APS was not selective for appearance or motion per se. Instead, distinctive responses were found to the mismatch between appearance and motion: whereas suppression effects for the human and robot were similar to each other, they were stronger for the android, notably in bilateral anterior intraparietal sulcus, a key node in the APS. These results could reflect increased prediction error as the brain negotiates an agent that appears human, but does not move biologically, and help explain the ‘uncanny valley’ phenomenon

Valuation of socially relevant facial expressions and gestures: fMRI and clinical investigations

Prochnow D. Valuation of socially relevant facial expressions and gestures: fMRI and clinical investigations. Bielefeld: Universitätsbibliothek Bielefeld; 2013.As people are social beings, they are inclined to infer the emotions and intentions of their counterpart in order to adapt their behavior. This capacity, which is often referred to as forming a cognitive and emotional theory of mind (ToM), can consolidate social relations and also helps protecting people’s well-being. In this process, body language, such as facial expressions and gestures, is an important source of information, in particular, since it develops beyond voluntary control. Based on current research, this dissertation aimed at exploring the brain activation patterns related to different aspects of nonverbal body language used as a source of empathic evaluation such as dynamics, ambiguity, subjective relevance and accessibility to conscious evaluation. Based on reports of a ToM deficit associated with older age, empathic reasoning based on affective states seen in photographs was compared in young and old adults. Taken together, our experiments highlight the role of the inferior frontal cortex, the adjacent anterior insula cortex and the dorsomedial frontal cortex in empathic evaluation based on facial expressions and gestures. Brain areas associated with the putative human mirror neuron system were recruited regardless whether the seen emotional expression was ambiguous due to its dynamics or its low degree of emotional expressiveness, not consciously accessible or of varying degree of social impact. Within correspondence to previous research on emotional contagion, empathy and ToM, this finding highlights the relevance of perception-action-coupling in social life. In addition, parts of the DMFC became activated either with or without an explicit instruction to empathize. The DMFC has been implicated in affective ToM, primarily with a self-referential component. Areas in the DMFC, as well as parts of the hMNS were shown to be recruited in young, as well as in old adults but at different time points. In contrast to the young adults who accurately inferred the origin of an emotional state seen in a face, the old adults’ deficit in efficiently forming a ToM was related to a too early engagement of anterior prefrontal higher order control areas. This was likely to bind cognitive resources due to upregulation of other top-down modulated ToM associated areas at a time point when not all relevant information for efficient reasoning was available. Finally, we consistently found activation within the DLFC supporting the notion that it is not only crucially involved in social decision-making but that there is some degree of functional specialization within this large frontal area. While activation in posterior parts of the DLFC became activated during the preparatory stage of the decision when some but not all decision-relevant information were present, the actual decision was reflected by activation of a more anterior portion of the DLFC being interconnected with premotor, and dorsomedial frontal areas

Hearing in the mind\u27s ear: A PET investigation of musical imagery and perception

Neuropsychological studies have suggested that imagery processes may be mediated by neuronal mechanisms similar to those used in perception. To test this hypothesis, and to explore the neural basis for song imagery, 12 normal subjects were scanned using the water bolus method to measure cerebral blood flow (CBF) during the performance of three tasks. In the control condition subjects saw pairs of words on each trial and judged which word was longer. In the perceptual condition subjects also viewed pairs of words, this time drawn from a familiar song; simultaneously they heard the corresponding song, and their task was to judge the change in pitch of the two cued words within the song. In the imagery condition, subjects performed precisely the same judgment as in the perceptual condition, but with no auditory input. Thus, to perform the imagery task correctly an internal auditory representation must be accessed. Paired-image subtraction of the resulting pattern of CBF, together with matched MRI for anatomical localization, revealed that both perceptual and imagery. tasks produced similar patterns of CBF changes, as compared to the control condition, in keeping with the hypothesis. More specifically, both perceiving and imagining songs are associated with bilateral neuronal activity in the secondary auditory cortices, suggesting that processes within these regions underlie the phenomenological impression of imagined sounds. Other CBF foci elicited in both tasks include areas in the left and right frontal lobes and in the left parietal lobe, as well as the supplementary motor area. This latter region implicates covert vocalization as one component of musical imagery. Direct comparison of imagery and perceptual tasks revealed CBF increases in the inferior frontal polar cortex and right thalamus. We speculate that this network of regions may be specifically associated with retrieval and/or generation of auditory information from memory

Systems Biology Determinants of Motor Behavior in Humans

Motor skills are mediated by a dynamic and finely regulated interplay of the primary motor cortex (M1) with various cortical and subcortical regions engaged in movement preparation and execution. Several neuroimaging studies already demonstrated that increasing motor performance in simple motor tasks is associated with higher activation levels in the motor system. Additional to the extrinsic modulation of motor performance, neural activity is also influenced by intrinsic factors such as handedness. Handedness – defined as the preference to use one hand over the other – is associated with differences in activation levels in various motor tasks performed with the dominant or non-dominant hand. However, motor actions are implemented in a distributed network of motor regions rather than a single cortical area. For that reason, it is important to consider the neural processes underlying motor behavior from a network perspective that is offered by connectivity analyses. Models of effective connectivity allow the estimation of the influence that areas exert over each other while functional connectivity is defined as temporal coherence between remote, segregated neurophysiological events. The present thesis aimed to investigate how the dynamic modulation of motor performance and connectivity is mediated by extrinsic and intrinsic factors in the human motor system. In the first study, we used functional magnetic resonance imaging (fMRI) and dynamic causal modeling (DCM) to investigate effective connectivity of key motor areas at different movement frequencies performed by right-handed subjects (n=36) with the left or right hand. The network of interest consisted of motor regions in both hemispheres including M1, supplementary motor area (SMA), ventral premotor cortex (PMv), motor putamen, and motor cerebellum. The connectivity analysis showed that performing hand movements at higher frequencies was associated with a linear increase in neural coupling strength from premotor areas (SMA, PMv) contralateral to the moving hand and ipsilateral cerebellum towards contralateral, active M1. In addition, we found hemispheric differences in the amount by which the coupling of premotor areas and M1 was modulated, depending on which hand was moved. Other connections were not modulated by changes in motor performance. The results suggest that a stronger coupling, especially between contralateral premotor areas and M1, enables increased motor performance of simple unilateral hand movements. In the second study, we used fMRI and DCM to investigate effective connectivity between key motor areas during fist closures of the dominant or non-dominant hand performed by 18 right- and 18 left-handers. Handedness was assessed employing the Edinburgh-Handedness-Inventory (EHI). The network of interest consisted of key motor regions in both hemispheres including M1, SMA, PMv, motor putamen and motor cerebellum. The connectivity analysis revealed that in right-handed subjects movements of the dominant hand were associated with significantly stronger coupling of contralateral (left, i.e., dominant) SMA with ipsilateral SMA, ipsilateral PMv, contralateral motor putamen and contralateral M1 compared to equivalent connections in left-handers. The degree of handedness as indexed by the individual EHI scores also correlated with coupling parameters of these connections. In contrast, we found no differences between right- and left-handers when testing for the effect of movement speed on effective connectivity. In conclusion, the data show that handedness is associated with differences in effective connectivity within the human motor network with a prominent role of SMA in right-handers. Left-handers featured less asymmetry in effective connectivity implying different hemispheric mechanisms underlying hand motor control compared to right-handers. However, differences in task performance are inherent putative confounds for all task based fMRI studies. For example, performing a standard motor task might be less demanding when using the dominant hand compared to the non-dominant hand, which may also affect neural activation levels, e.g., in frontoparietal areas. Thus, resting-state fMRI seems an attractive approach to overcome these putative confounds as it allows investigating networks independent from performance. In the third study, we, therefore, scanned 18 right- and 18 left-handers with resting-state fMRI. Handedness was assessed by the EHI. We computed whole-brain functional connectivity maps of the left and right M1. To test for the effect of handedness, we computed differential contrasts and regression analyses including EHI as a covariate. We further used a multivariate linear support vector machine (SVM) classifier algorithm to reveal the individual specificity of brain regions showing differences between the resting-state maps of right- and left-handers. Using left M1 as a seed region revealed stronger interhemispheric functional connectivity between M1 and dorsolateral premotor cortex (PMd) in right-handers as compared to left-handers. Furthermore, this individual cluster in right PMd classified right- and left-handers with 86.2% accuracy. Control analyses using non-motor resting-state networks, including the (Broca) speech and the visual network, revealed no significant differences in functional connectivity related to handedness. Higher connectivity in right-handers might, therefore, reflect a systematic impact of handedness on an intrinsic functional level and might explain the observation that right-handedness is usually more lateralised than left-handedness. Furthermore, enhanced connectivity between M1 and PMd serves as an individual marker / endophenotype of handedness. In summary, the present thesis demonstrates that the dynamic modulation of the motor system during motor performance is mediated by a specific set of brain regions in both rightand left-handers. Furthermore, the results indicate that differences in coupling strength between right- and left-handers reflect the impact of handedness on both functional and effective connectivity

Neuroscience in marketing : an FMRI-Based Perspective on brands

Doutoramento em GestãoAlthough somewhat outdated, the American Marketing Association definition of brand still is largely accepted. In this case, brands are signs for product differentiation. The present research, instead, finds brands and their logos as meaningful signs that belong to the human communicative lexicon. Logos are ideograms, i.e. graphic representations that convey meanings. These meanings are transferred from one mind to other minds through brands, establishing communication between humans, and which is also used to self-monitoring in a self-reflexive process, i.e., reading the reactions of others to the ideographic messages once sent to them. Brands are intimately connected to meta-representational processes, whether they are seen as the repository of human attributes, whether themselves are perceived as interlocutors, in a quasi-human level. It also finds that the human emotion system is used to perceive, interpret, and classify brands. Founding in the neuro-based model of emotions developed by Damásio, the present research reveals that brands systematically recruits the emotion system when stimulate brains, which leads to posit that brands are felt in order to be perceived. It is also largely relying in the brain structures that support emotion processing, but also based in other regions that support self-relatedness processing, that is trained an artificial neural network that yields predictions of subjects' choices at a level much higher than mere chance. This procedure allows a coarse but promising consumers' "mind reading".Apesar de algo ultrapassada, a definição de marca da American Marketing Association ainda é largamente aceite. Assim, as marcas são sinais usados na diferenciação de produtos. A investigação presente, pelo contrário, sugere que as marcas e os seus logotipos são sinais com significado que pertencem ao léxico comunicativo humano. Os logotipos são ideogramas, i.e. representações gráficas que transmitem significados. Tais significados transferem-se de uma mente para outra através das marcas, estabelecendo uma comunicação entre humanos, e que também é usada na auto-monitorização num processo auto-reflexivo, i.e. lendo as reacções que os outros têm às mensagens ideográficas que lhes foram enviadas. As marcas estão intimamente ligadas aos processos meta-representacionais, seja por elas serem consideradas um repositório de atributos humanos, seja por elas próprias serem consideradas como interlocutores, a um nível quase-humano. Este estudo também constata que o sistema emocional humano é usado para perceber, interpretar, e classificar as marcas. Baseado no modelo neuronal das emoções de Damásio, verifica-se que as marcas recrutam sistematicamente o sistema das emoções sempre que elas estimulam um cérebro, o que leva a avançar que as marcas são sentidas de forma a serem percebidas. É com base em estruturas cerebrais que sustentam o processamento das emoções, mas também com base em outras regiões ligadas a processamentos da auto-reflexão, que é treinada uma rede neuronal artificial, da qual resultam previsões das escolhas dos sujeitos participantes, as quais estão a um nível muito superior ao mero acaso. Este procedimento permite uma "leitura da mente" algo grosseira, mas muito promissora

Dark Control: The Default Mode Network as a Reinforcement Learning Agent

International audienceThe default mode network (DMN) is believed to subserve the baseline mental activity in humans. Its higher energy consumption compared to other brain networks and its intimate coupling with conscious awareness are both pointing to an unknown overarching function. Many research streams speak in favor of an evolutionarily adaptive role in envisioning experience to anticipate the future. In the present work, we propose a process model that tries to explain how the DMN may implement continuous evaluation and prediction of the environment to guide behavior. The main purpose of DMN activity, we argue, may be described by Markov Decision Processes that optimize action policies via value estimates based through vicarious trial and error. Our formal perspective on DMN function naturally accommodates as special cases previous interpretations based on (1) predictive coding, (2) semantic associations, and (3) a sentinel role. Moreover, this process model for the neural optimization of complex behavior in the DMN offers parsimonious explanations for recent experimental findings in animals and humans

Anterior Cingulate Cortex: Contributions to Social Cognition

It has been suggested that the Anterior Cingulate Cortex (ACC) plays an important role in decision-making. Activity in this area reflects processing related to two principles of Reinforcement Learning Theory (RLT): (i) signalling the predicted value of actions at the time they are instructed and (ii) signalling prediction errors at the time of the outcomes of actions. It has been suggested that neurons in the gyrus of the ACC (ACCg) process information about others’ decisions and not one’s own. An important aim of this thesis is to investigate whether the ACCg processes others’ decisions in a manner that conforms to the principles of RLT. Four fMRI experiments investigate activity in the ACCg at the time of cues that signal either the predicted value of others’ actions or that signal another’s predictions are erroneous. • Experiment 1: Activity in the ACCg occurred when the outcome of another’s decision was unexpectedly positive. • Experiment 2: Activity in the ACCg varied parametrically with the discrepancy between another’s prediction of an outcome and the actual outcome known by the subject, in a manner that conformed to the computational principles of RLT. • Experiment 3: Activity in the ACCg varied with the predicted value of a reward, discounted by the amount of effort required to obtain it. • Experiment 4: Activity in the ACCg varied with the value of delayed rewards that were discounted in a manner that conformed to a social norm. These results support the hypothesis that the ACCg processes the predicted value of others’ actions and also signals when others’ predictions about the value of their actions are erroneous, in a manner that conforms to the principles of RLT