Le sens du goût chez l'aveugle congénital

Thèse réalisée en collaboration avec le Département de neurosciences et pharmacologie de l'Université de Copenhague, Danemark.La vision est cruciale dans la recherche et l’identification de nourriture. Non seulement elle déclenche le réflexe céphalique de la digestion mais, combinée à l’expérience alimentaire, elle aide à raffiner nos prévisions par rapport aux aliments. En un simple clin d’œil, la vue renseigne sur la disponibilité, l’identité, la comestibilité, les saveurs, les textures et les contenus nutritionnel, calorique et toxique des aliments qui nous entourent. Étant donnée l’importance de la vue dans l’expérience gustative, il est judicieux de se poser la question suivante : Qu’arrive-t-il au goût en absence de vision? Cette thèse répond à cette question par l’étude de cette modalité chez l’aveugle de naissance grâce aux techniques de psychophysique et d’imagerie cérébrale. De plus, les conséquences gustatives de la cécité sont comparées à celles suivant la perte d’un autre sens important dans l’appréciation des aliments, soit l’odorat (anosmie). Les résultats comportementaux démontrent premièrement que l’absence de vision depuis la naissance abaisse la sensibilité gustative, reflétée par des seuils élevés de détection et d’identification des cinq goûts de base (sucré, salé, acide, amer, umami). Deuxièmement, bien que les aveugles congénitaux aient plus de facilité à identifier les odeurs comestibles par leurs narines (voie olfactive orthonasale), ceux-ci perdent leur avantage par rapport aux voyants quand ils doivent identifier ces stimuli placés sur la langue (voie olfactive rétronasale). Les résultats d’imagerie indiquent en outre que les aveugles congénitaux activent moins leur cortex gustatif primaire (insula/opercule) et leur hypothalamus par rapport aux voyants durant une tâche gustative. De plus, l’absence d’activation dans le cortex (« visuel ») occipital chez l’aveugle pointe vers le manque de plasticité intermodale en gustation. Chez les anosmiques congénitaux d’autre part, non seulement l’absence d’odorat diminue l’habileté à reconnaître les goûts mais elle abaisse également la force du signal dans les aires olfactives (ex : cortex orbitofrontal médial) durant une tâche gustative. Les résultats chez l’aveugle contrastent grandement avec les études antérieures soulignant l’amélioration de leurs sens extéroceptifs tels que l’audition, l’olfaction (orthonasale) et le toucher qui font tous intervenir la plasticité intermodale. Par ailleurs, les données chez l’anosmique concordent avec ceux de la littérature indiquant une diminution similaire de la chémosensation trigéminale, laquelle est également associée à un affaiblissement du circuit neural des saveurs. Ceci suggère que le sens du goût ne soit pas utile aux handicapés visuels pour percevoir l’environnement extérieur et ainsi compenser leur perte de vision. De plus, bien que l’odorat participe à l’appréciation de la nourriture en bouche, sa perte n’entraîne pas de compensation sensorielle chez l’anosmique. Prises ensemble, ces données indiquent différents mécanismes d’adaptation suivant la cécité et l’anosmie. Elles soutiennent également le point de vue selon lequel la perception unifiée de goûts et de saveurs inclut non seulement les sens chimiques et le toucher mais également la vision. Considérant l’importance du goût et de l’alimentation dans la qualité de vie, ces résultats encouragent la société tout comme les professionnels de la réadaptation à faciliter l’accès à la nourriture ainsi qu’à l’enseignement culinaire chez les handicapés sensoriels.Vision is crucial for seeking and identifying food. Not only does it trigger the cephalic digestion reflex but, when combined with the experience of eating, it helps to refine expectations about foods. In a single eye blink, sight informs us about the availability, identity, palatability, flavours, textures as well as nutritional, caloric and toxic contents of foods surrounding us. Given the importance of sight in the gustatory experience, one may therefore ask the following question: What happens to gustation without vision? This thesis answers this question by studying this modality in congenitally blind subjects using psychophysical and brain imaging techniques. Additionally, the gustatory consequences of blindness are compared to those following the loss of another important modality involved in the appreciation of food, i.e. the sense of smell (anosmia). Behavioural results first show that the absence of vision from birth reduces the gustatory sensitivity, as reflected by higher detection and identification thresholds of the five basic tastes (sweet, salty, acid, bitter, umami). Second, although congenitally blind subjects are better at identifying palatable odorant stimuli through their nostrils (orthonasal olfactory route), they lose this advantage over sighted people when identifying these stimuli placed on their tongue (retronasal olfactory route). Neuroimaging results also reveal that congenitally blind subjects activate the primary gustatory cortex (insula/operculum) and the hypothalamus less compared to blindfolded sighted participants. Moreover, the absence of occipital (“visual”) cortex activity in the blind points towards the lack of crossmodal plasticity in gustation. In congenitally anosmics, on the other hand, not only does the absence of smell lower the ability to recognize tastes but it also lowers the strength of the signal in olfactory areas (e.g. medial orbitofrontal cortex) during a gustatory task. The results in the blind greatly contrast with previous studies highlighting the enhancement of their exteroceptive senses such as audition, (orthonasal) olfaction and touch, all of which involve crossmodal plasticity. Moreover, data in the anosmic group are consistent with previous literature describing similar decrease of trigeminal chemosensation that is also associated with a weakening of the flavour neural network. This suggests that the sense of taste is not useful to the visually impaired to perceive their exterior environment and compensate for their lack of vision. Furthermore, although olfaction contributes to the appreciation of foods in the mouth, the lack of this modality does not drive sensory compensation in anosmic subjects. Taken together, these data indicate different adaptation mechanisms following blindness and anosmia. They also support the view according to which the unified perception of tastes and flavours includes not only the chemical senses (taste, smell and trigeminal chemosensation) and touch but also vision. Given the importance of taste and eating experience in quality of life, these results encourage society as well as rehabilitation professionals to facilitate access to foods and culinary lessons in sensory deprived subjects

Homing in on consciousness in the nervous system: An action-based synthesis

Abstract: The primary function of consciousness in the nervous system remains mysterious. Passive frame theory, a synthesis of empirically supported hypotheses from diverse fields of investigation, reveals that consciousness serves as a frame that constrains and directs skeletal muscle output, thereby yielding adaptive behavior. How consciousness achieves this is more counterintuitive, “low level, ” and passive than the kinds of functions that theorists have attributed to consciousness. From this unique, action-based perspective, consciousness is in the service of the somatic nervous system. The framework begins to isolate the neuroanatomical, cognitive-mechanistic, and representational processes associated with consciousness.

Neurolaw, transhumanism, posthumanism

Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Faculdade de Direito, 2021.O presente trabalho visa explorar as intersecções entre Direito, Tecnologias, Neurociência, Transhumanismo e Pós-Humanismo, com foco em Neurotecnologias e Robótica. Para atingir esse objetivo, muitas abordagens científicas serão abordadas, como Direito, Neurociência, Sociologia, Psicologia, Ética, Biodireito e Filosofia. Como está o estado da arte das neurotecnologias e como elas transformarão os humanos? Qual é o nosso futuro com tecnologias hiper-avançadas? O que a neurociência, a física e a matemática têm a nos dizer sobre nossa natureza, cérebro, mente e comportamento humano? Os humanos estão dominando tecnologias super-avançadas que realizam as aspirações escatológicas das religiões tradicionais. Por meio dessas realizações e evolução, novas espécies nascerão ou serão fabricadas, como ciborgues, robôs e pós-humanos, rompendo com a condição humana. Muitos cenários distópicos e disruptivos emergirão dos mundos trans- e pós-humanistas. Certos sistemas de controle serão criados e podem ser letais para nós. O Direito deve ser extremamente proativo contra a transgressão de direitos. As tecnologias atuais, como a internet e redes sociais, podem ser usadas contra a nossa liberdade e privacidade. Imagine quando as neurotecnologias terão amplo uso na sociedade, tecnologias com conexões diretas cérebro-cérebro, conexões diretas cérebro-internet. A internet será substituída pela brainet, provocando profundas mudanças de paradigma. Além das questões de direitos humanos, as neurotecnologias e nanotecnologias transformarão a nós e ao mundo. Dia-a-dia somos mais Homo Digitalis, mais algo entre humanos, máquinas e deuses: transhumanos e pós-humanos. O transhumanismo está crescendo muito. É a transformação humana a partir de tecnologias, mudando nosso cérebro, corpo e mente. O transhumanismo colocará a humanidade na pós-humanidade, acabando com a condição humana. Em meio a essa jornada, dominaremos doutrinas religiosas perigosas, como o poder da Criação e da Perfeição. Relações entre civilizações de Robôs e (Pós)Humanos serão comuns, mas essas relações são um mistério completo, embora algumas possibilidades estejam sendo reveladas. A ideia deste trabalho é a seguinte: o Capítulo 1 é uma introdução ao Neurodireito e ao Transhumanismo fazendo considerações gerais sobre o cérebro; O Capítulo 2 é uma exploração do cérebro, consciência, comportamento humano, processo de aprendizagem e características neuropsicológicas abordando questões como valores humanos - empatia, egoísmo, etc; O Capítulo 3 é uma consideração sobre muitos tipos de neurotecnologias e suas questões legais e implicações sobre os seres humanos; O Capítulo 4 é uma abordagem de questões filosóficas, jurídicas e morais concernentes aos mundos do conhecimento, do transhumanismo e pós- humanismo, com visões escatológicas através da perspectiva tecnológica, como robótica, deificação, e as perspectivas científico-religiosas da natureza de Deus; O Capítulo 5 aborda a doutrina da imortalidade por meio do ponto de vista do mind- uploading.The current work aims to explore the intersections among Law, Technologies, Neuroscience, Transhumanism, and Posthumanism, focusing on Neurotechnologies and Robotics. To accomplish this purpose, many scientific approaches will be addressed such as Law, Neuroscience, Sociology, Psychology, Ethics, Biolaw, and Philosophy. How is the state of the art of neurotechnologies and how they will transform humans? What is our future with hyper-advanced technologies? What do neuroscience, physics, and mathematics have to tell us about our nature, brain, mind, and human behavior? Humans are mastering super-advanced technologies accomplishing eschatological aspirations of traditional religions. Through these fulfillments and evolution, new species will be born or fabricated, such as cyborgs, robots, and posthumans breaking with the human condition. Many dystopian and disruptive scenarios will emerge from the trans- and posthumanist worlds. Certain systems of control will be created and can be lethal for us. The law must be extremely proactive against transgression of rights. Current technologies such as the internet and social networks can be used against our freedom and privacy. Imagine when neurotechnologies will have wide use in society, technologies with direct brain-to-brain connections, direct brain-internet connections. The internet will be replaced by the brainet provoking profound paradigm shifts. Beyond human rights issues, neurotechnologies and nanotechnologies will transform us and the world. Day to day we are more Homo Digitalis, more something among humans, machines, and gods: transhumans and posthumans. Transhumanism is growing a lot. It is the human transformation from technologies, changing our brain, body, and mind. Transhumanism will place humanity into the posthumanity, finishing with the human condition. Amid this journey, we will master dangerous religious doctrines, such as the power of Creation and Perfection. Relations between civilizations of Robots and (Post)Humans will be commonplace, but those relations are a complete mystery, although some possibilities are been unveiled. The idea of this work is as follows: Chapter 1 is an introduction of Neurolaw and Transhumanism making general considerations of the brain; Chapter 2 is an exploration of the brain, consciousness, human behaviors, learning process, and neuropsychological features approaching issues like human values - empathy, selfishness, etc; Chapter 3 is a consideration about many kinds of neurotechnologies and their legal issues and implications on human beings; Chapter 4 is an approach of philosophical, legal, and moral questions concerning to the knowledge, the transhumanism and posthumanism worlds, with eschatological visions through the technological perspective, such as robotics, deification, and the scientific-religious perspectives of nature of God; Chapter 5 addresses the doctrine of immortality through the mind-uploading’s viewpoint

Neurobiology, empathy and social cognition: the potential benefits of theatre in traumatised communities

Includes abstract.Includes bibliographical references.The ubiquity of technology enables unprecedented contact between people, yet it neglects essential face-to-face communion; e-mail, text-messaging and even social media strip away the metadata of our interpersonal communications; the emotional cues and clues that are a necessary part of everyday social interaction. At the same time, the relentless densification of urban populations enforces proximity among strangers, with routine encounters increasingly bereft of emotional nourishment. The affective numbing that ensues shares many characteristics of post-traumatic stress disorder. The current study explores how exposure to theatre may help to maintain the emotional health of individuals alienated by the stresses of 21st century urban living; moreover, it examines how performance is able to facilitate emotional and social healing in post-conflict communities

Investigating Middle Stone Age foraging behaviour in the Karoo, South Africa

The Middle Stone Age (MSA) in Africa ~500- 50 kyr is recognised as a key time-period associated with important developments in hominin evolution, including the appearance of earliest genetic markers for Homo sapiens. Despite advances, our knowledge of the behaviour of hominins during this period is limited, especially for the early MSA (EMSA) pre-160ka. This study presents new data on animal bones recovered at the Bundu Farm site, in the upper Karoo region of the Northern Cape, South Africa, dated to circa ~300ka and found in association with EMSA type lithic facies, burning and hearth-like features. Previous analysis of the Bundu fauna compared the site to a G/wi hunter-gatherer 'biltong' processing locale, implying primary access to animal carcasses and socially complex hunting behaviour, circa 400-300 ka. An interpretation at odds with other interpretations of the EMSA data that suggest limited hunting and social complexity, and which would therefore have significant implications for MSA archaeology. To test the biltong hypothesis my study presents new data on the fracture characteristics of non-fresh animal bone broken by hammerstone and new environmental data for the site from an analysis of ostrich eggshell isotopes. Experimental and environmental data are used to provide a new interpretation of the Bundu fauna and my conclusion is that the data while not supporting the biltong model, does indicate evidence of delayed communal food consumption, use of fire and the transformation of foodstuffs into meals presaging and echoing social and ecological adaptations seen in the later MSA and LSA. The data also highlights a greater role for carnivores in the accumulation of the faunal assemblage and expedient hominin foraging similar to the preceding ESA and brings attention to the ecological relationships between hominins and carnivores in a Pleistocene Karoo environment that was markedly different from that of today. The study therefore rejects the biltong hypothesis for Bundu Farm as both inconsistent with likely EMSA social structures and ecology and instead proposes the site as evidence for novel behaviour indicative of a transition from ESA to MSA lifeways. The Bundu Farm site reflecting a rare archaeological occurrence where the shift in the behavioural trajectory that led to our species is observed

How input modality and visual experience affect the representation of categories in the brain

The general aim of the present dissertation was to participate in the progress of our understanding of how sensory input and sensory experience impact on how the human brain implements categorical knowledge. The goal was twofold: (1) understand whether there are brain regions that encode information about different categories regardless of input modality and sensory experience (study 1); (2) deepen the investigation of the mechanisms that drive cross-modal and intra-modal plasticity following early blindness and the way they express during the processing of different categories presented as real-world sounds (study 2). To address these fundamental questions, we used fMRI to characterize the brain responses to different conceptual categories presented acoustically in sighted and early blind individuals, and visually in a separate sighted group. In study 1, we observed that the right posterior middle temporal gyrus (rpMTG) is the region that most reliably decoded categories and selectively correlated with conceptual models of our stimuli space independently of input modality and visual experience. However, this region maintains separate the representational format from the different modalities, revealing a multimodal rather than an amodal nature. In addition, we observed that VOTC showed distinct functional profiles according to the hemispheric side. The left VOTC showed an involvement in the acoustical categorization processing at the same degree in sighted and in blind individuals. We propose that this involvement might reflect an engagement of the left VOTC in more semantic/linguistic processing of the stimuli potentially supported by its enhanced connection with the language system. However, paralleling our observation in rpMTG, the representations from different modalities are maintained segregated in VOTC, showing little evidence for sensory-abstraction. On the other side, the right VOTC emerged as a sensory-related visual region in sighted with the ability to rewires itself toward acoustical stimulation in case of early visual deprivation. In study 2, we observed opposite effects of early visual deprivation on auditory decoding in occipital and temporal regions. While occipital regions contained more information about sound categories in the blind, the temporal cortex showed higher decoding in the sighted. This unbalance effect was stronger in the right hemisphere where we, also, observed a negative correlation between occipital and temporal decoding of sound categories in EB. These last results suggest that the intramodal and crossmodal reorganizations might be inter-connected. We therefore propose that the extension of non-visual functions in the occipital cortex of EB may trigger a network-level reorganization that reduce the computational load of the regions typically coding for the remaining senses due to the extension of such computation in occipital regions

An Introduction to Zooarchaeology

zooarchaeology is a self-reproducing field taught in many university departments of anthropology or archaeology. As archaeologists have literally taken faunal analysis into their own hands, they have debated how best to use animal remains to study everything from early hominin hunting or scavenging to animal production in ancient market economies. Animal remains from archaeological sites have been used to infer three kinds of information: the age of deposits (chronology); paleoenvironment and paleoecological relations among humans and other species; human choices and actions related to use of animals as food and raw materials. Methods for reconstructing human diet and behavior have undergone the greatest growth over the last four decades, and most of this book addresses the second and third areas. This book deals with what I know best: vertebrate zooarchaeology, and within that, analysis of mammalian bones and teeth