166 research outputs found
Developmental Bootstrapping of AIs
Although some current AIs surpass human abilities in closed artificial worlds
such as board games, their abilities in the real world are limited. They make
strange mistakes and do not notice them. They cannot be instructed easily, fail
to use common sense, and lack curiosity. They do not make good collaborators.
Mainstream approaches for creating AIs are the traditional manually-constructed
symbolic AI approach and generative and deep learning AI approaches including
large language models (LLMs). These systems are not well suited for creating
robust and trustworthy AIs. Although it is outside of the mainstream, the
developmental bootstrapping approach has more potential. In developmental
bootstrapping, AIs develop competences like human children do. They start with
innate competences. They interact with the environment and learn from their
interactions. They incrementally extend their innate competences with
self-developed competences. They interact and learn from people and establish
perceptual, cognitive, and common grounding. They acquire the competences they
need through bootstrapping. However, developmental robotics has not yet
produced AIs with robust adult-level competences. Projects have typically
stopped at the Toddler Barrier corresponding to human infant development at
about two years of age, before their speech is fluent. They also do not bridge
the Reading Barrier, to skillfully and skeptically draw on the socially
developed information resources that power current LLMs. The next competences
in human cognitive development involve intrinsic motivation, imitation
learning, imagination, coordination, and communication. This position paper
lays out the logic, prospects, gaps, and challenges for extending the practice
of developmental bootstrapping to acquire further competences and create
robust, resilient, and human-compatible AIs.Comment: 102 pages, 29 figure
On the Road to 6G: Visions, Requirements, Key Technologies and Testbeds
Fifth generation (5G) mobile communication systems have entered the stage of commercial development, providing users with new services and improved user experiences as well as offering a host of novel opportunities to various industries. However, 5G still faces many challenges. To address these challenges, international industrial, academic, and standards organizations have commenced research on sixth generation (6G) wireless communication systems. A series of white papers and survey papers have been published, which aim to define 6G in terms of requirements, application scenarios, key technologies, etc. Although ITU-R has been working on the 6G vision and it is expected to reach a consensus on what 6G will be by mid-2023, the related global discussions are still wide open and the existing literature has identified numerous open issues. This paper first provides a comprehensive portrayal of the 6G vision, technical requirements, and application scenarios, covering the current common understanding of 6G. Then, a critical appraisal of the 6G network architecture and key technologies is presented. Furthermore, existing testbeds and advanced 6G verification platforms are detailed for the first time. In addition, future research directions and open challenges are identified for stimulating the on-going global debate. Finally, lessons learned to date concerning 6G networks are discussed
Social behaviours in rat models of autism
Neurodevelopmental disorders (NDDs) manifest during early childhood and have
deleterious effects on development, leading to lifelong conditions affecting attention,
cognition, motor abilities, communication and social domains, often alongside
physical ailments such as gastrointestinal issues and epilepsy. With a worldwide
reported prevalence of around 1%, NDDs either directly or indirectly affect a large
proportion of the population.
Rodent models of monogenic forms of NDD provide a means for unravelling
mechanisms and developing targeted therapeutics for debilitating aspects of NDDs.
However, modelling social and emotional facets of NDDs such as autism spectrum
disorder (ASD) remains a challenge. The rat makes a good model species for the
social and emotional facets of NDDs as rats are highly social, experience a sensitive
period of social and emotional development, and exhibit a behavioural repertoire
that is flexible and sensitive to context. The aim of this thesis was to develop a welfarefriendly,
robust assay of socio-emotional phenotype in rat models of NDD.
Play behaviour appears to be a critical aspect of the developmental process in many
highly social species, including both rats and humans. Children develop social skills
and emotional regulation through playful peer interactions. For individuals with
NDDs, including ASD, social challenges often emerge from a very young age and
impair playful interactions with peers. In juvenile rats, play experience is crucial for
social, emotional, and sensorimotor development. Therefore, disruptions in social
and emotional function in rat models of NDD may be observable in juvenile play
behaviour. While juvenile play has been well-characterised in wild-type (WT) rats, it
has not yet been thoroughly investigated in rat models of NDDs.
Some aspects of rat social play can be mimicked during playful interactions with
humans in which the rat is âpinnedâ by gently flipping onto the back and tickling using
fine-scale tickle movements of the fingers on the ventral surface. During tickle, rats
produce ultrasonic vocalisations (USVs) indicative of a positive affective state which
can be used as a proxy measure of tickle responsiveness. Number of successful pin
and tickle events per tickle session was used as a behavioural measure of
responsiveness as rats were only pinned if they engaged with the experimenterâs
hand. As an assay of social responsiveness, I investigated behavioural and USV
responses to tickle in three different rat models of NDD associated with ASD: Fragile
X Syndrome, SYGNAP1 haploinsufficiency, and CDKL5 Deficiency Disorder.
Tickle response varied between models of NDD. Tickle response in the Fragile X
Syndrome model (Fmr1-/y) was very similar to WT littermate controls, with high rates
of both USVs and pin/tickle events during tickle sessions in both genotypes. In
contrast, for models of SYNGAP1 haploinsufficiency (Syngap1+/DGAP and Syngap1+/-),
the tickle protocol was almost impossible to carry out due to climbing behaviour by
the SYNGAP1 model rats, and very few USVs were emitted during tickle sessions.
WTs were receptive to tickle and emitted USVs at high rates during tickle sessions. In
the CDKL5 Deficiency Disorder model (Cdkl5-/y), both WT and Cdkl5-/y rats emitted
very few USVs, and behavioural and USV responses were more variable in Cdkl5-/y
than in WTs. Because the tickle paradigm involves habituation to a novel environment
and experimenter handling, reduced tickle responsiveness may not be indicative of
playfulness or social responsiveness in general but could instead reflect an
impairment in habituation, since tickle response is highly sensitive to emotional state.
To address this possibility, I developed a novel paradigm which allows all
experimental manipulations and observations to be carried out in a spatially complex
home environment, minimising handling and exposure to novel experimental
environments. Play behaviour was observed for the first 2 hours of the dark phase
over a 4-week period following three experimental conditions: 24hr isolation, a
negative control condition, and an undisturbed condition.
In WT rats, brief isolation reliably elicits a transient increase in play, termed the
rebound effect. As isolation is stressful, the rebound effect is thought to reflect an
immediate benefit of play as a behavioural stress-reduction mechanism. I
hypothesised that Cdkl5-/y rats may not use this behavioural strategy to reduce stress
following isolation, or alternatively, that they would not find social isolation as stressful
as their WT littermates. I predicted that Cdkl5-/y pairs would show less of a play
rebound effect than their WT littermates.
Unexpectedly, my results suggest that both WT and Cdkl5-/y pairs exhibit the
expected rebound effect in response to brief (24hr) isolation. Further characterisation
of play behaviour revealed that pairs of Cdkl5-/y rats engage in more frequent play
bouts, but play for a similar amount of time as WT littermate pairs, and these
parameters were affected differently by treatment condition in WT and Cdkl5-/y pairs.
Detailed snapshot and longitudinal analysis of play behaviour indicates that the
temporal dynamics and sequencing of play in Cdkl5-/y pairs differs from WT
littermates, and that the developmental trajectory of play behaviour may diverge from
WT in Cdkl5-/y pairs.
Overall, this thesis provides evidence that rat models of NDD behave differently in
social contexts than WT animals and highlights the benefit of ethologically relevant
outcome measures and minimally invasive test environments for uncovering subtle
social and emotional phenotypes in rat models of NDD
Representations of girlhood trauma in Aotearoa, New Zealand literature written by women
In âRepresentations of Girlhood Trauma in Aotearoa New Zealand Literature Written by Womenâ, I investigate the way literary genres affect trauma-telling and how culturally sensitive forms of trauma-reading allow girl trauma-tellers to be heard and not re-traumatised by a patriarchal and colonial interpretation of their pain. I analyse about twenty texts by women writers of diverse ethnic descents, encompassing Aotearoaâs four main ethnic groups (PÄkehÄ [also called European New Zealanders], MÄori, Asian, and Pasifika), to illustrate New Zealandâs contemporary multiculturalism and multilingualism â an approach which contests a Western-imported, male-dominated, and Freudian-inspired reading of minoritiesâ cultural traumas. Following Dominick LaCapraâs theory, I argue that the signing of the Treaty of Waitangi on 6 February 1840 can be understood as a foundational trauma for the Indigenous people of Aotearoa. This document is at the root of their intergenerational cultural trauma as it led to massive land confiscation, the loss of their sovereignty, and their forced assimilation into a Western way of life. As New Zealand is still a settler colony today, women writers employ feminist and â especially when they are of non-PÄkehÄ descent â decolonial trauma-telling devices to formulate traumatic narratives which otherwise would remain unspeakable.
The five chapters of the thesis are each dedicated to a literary genre: life writing, poetry, fictional diaries and the epistolary mode, the female Bildungsroman, and young adult fiction. To analyse the interpersonal, intergenerational, transgenerational, and/or vicarious forms of girlhood trauma expressed in the corpus, I create a dialogue between the literary field of Trauma Studies founded at Yale University in the 1990s and four New Zealand-based trauma-reading traditions: Mason Durieâs theory of te whare tapa whÄ (the four-walled house) which is a holistic approach to MÄori health as physical, mental, spiritual, and familial health are intertwined; David Epstonâs and Michael Whiteâs research on Narrative Therapy; Charles Waldegraveâs and Kiwi Tamaseseâs work on Just Therapy; as well as Linda and Mark Kopuaâs storytelling practices during Mahi a atua (healing with ancestors) sessions
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Ruins and Remains: Performative Sculpture and the Politics of Touch in the 1970s
This dissertation investigates the materiality of performative sculpture in the Americas during the long 1970s through artists Beverly Buchanan (1940-2015) and Senga Nengudi (1943). United in their disenchantment with second-wave feminism, Buchanan and Nengudi are situated art-historically in the expanded fields of (post)minimalism, conceptualism, and the Black Arts Movement. These artists realize their objects by sourcing non-traditional artmaking materials within what this dissertation conjures as a haptic imaginaryâan intervening corrective to both the second-wave feminist and postmodern art imaginaries of the 1970s. Their materials expose the limitations of the visual and offer alternate models of knowing.
For Buchananâs frustulum series (1978-81), poured concrete, and later, tabby concrete, memorializes the textures of architectural sites to honor experiences of labor and displacement. Tabby concrete, a compound binding agent made of sand and lime, is a localized, inexpensive material that was often used by enslaved people in the southern United States, especially in coastal states like Georgia, which provide access to massive deposits of lime-rich oyster shells.
Nengudiâs R.S.V.P. series (1977) of pliable pantyhose and sand are anthropomorphic objects originally meant to be activated; they mimic bodily expansion, endurance, and fatigue. Pantyhose, made mostly of nylon, the worldâs first fully synthetic fiber, are the product of decades of scientific and economic development, whose intertwined history with World War II offers a springboard to understand the potency of Nengudiâs experiments with the garment.
The artistsâ materials become sites of investigation into memory, place, body, erotics, and precarity. By offering new epistemological methods of engagement that retaliate against the hegemony of the visual through their twinned interests in ruins for Buchanan, and remains for Nengudi, the artists realize a new womanist politic. Buchanan and Nengudi deploy, respectively, tabby concrete and pantyhose with sand to transmit historical and embodied knowledge. It is precisely through the activated sensorium of touchâimagined and physicalâthat the past is transmitted and materialized
Horses as Sentinels of Emerging Infectious Disease
Horses with illness consistent with Hendra virus (HeV) are routinely sampled and submitted with case descriptions, to government laboratories for timely testing. Extensive investigations for further infectious agents are rare, yet <1% of around 1000 horses test HeV positive annually. Most that test negative feature infectious-like signs such as acute, severe neurological or respiratory illness and pyrexia, yet do not receive causative diagnosis
HeV in horses and testing of suspect cases have highlighted challenges/ gaps in significant zoonotic disease investigation. Yet horses investigated for HeV-like disease present unique opportunities for improvements of broad profound biosecurity benefit. Horses are maintained in close association with other animals and humans, monitored thoroughly for disease and susceptible to agents transmitted by insects and wildlife such as bats
This research identified significant pathogens among horses with severe HeV-like illness beyond those currently recognised and considered disease significance
Fore-front diagnostic approaches integrated with information theoretical, epidemiological and virological analyses. Systematic pathologic-basis-interpretation of disease descriptions sensitively informed likelihood of infectious cause. Three innovative pillars were developed
âą purpose-built SQL database integrating bio-banked sample ID, sample event, subject and clinical details with parallel test results
âą explorative multiplex microbead immunoassay serological testing approach screening both IgG and IgM for emerging pathogens
âą explorative molecular methods targeting novel and emerging infectious agents, including high-throughput pan-PCR, metatranscriptomic sequencing and bioinformatical pipelines
Integrated application to suitably bio-banked clinical samples served proof-of-concept for proactive convergence research consideration of emerging infectious agents that could affect One health, livestock, trade and industry security and public healt
Etablierung und Validierung eines Meerschweinchenmodells fĂŒr die (humane) kongenitale Toxoplasmose
Die kongenitale Toxoplasmose kann zu schwerwiegenden Folgen fĂŒr einen Fötus fĂŒhren. In dieser Dissertation wird erstmals ein geeignetes Tierversuchsmodell in Form des Meerschweinchens etabliert. Anhand dessen konnten die pathologischen Alterationen als eine Folge von einer durch den Parasiten verursachte Reduktion von Neuronen und neuralen Stammzellen zurĂŒckgefĂŒhrt werden
Consciousness unbound: Social simulation theory of dreaming
Every night during sleep we experience an immersive world of dreams, woven together by our sleeping brain unbound by external stimulation. Despite considerable effort the question of why we dream has eluded a conclusive answer. Understanding dreams also arguably makes progress toward answering the broader question of consciousness: why do we experience anything at all? I attempt to illuminate these questions by concentrating on the quintessentially social nature of dreams. First, in Study I a novel theoretical account âthe Social Simulation Theory of dreaming (SST)âis proposed, together with the first outlines of a research program for its empirical study. SST suggests the world simulation form of dreams provides clues for its function by preferentially simulating certain kinds of scenariosnamely social interactions. Second, in Studies II and III specific hypotheses derived from the SST in Study I are empirically evaluated. These provide evidence for dreams to contain more social content than corresponding waking life and to remain so even when social interactions are removed from waking life (Sociality Bias). Furthermore, the Strengthening Hypothesis that suggests dreams serve to maintain and/or increase social bonding with close others gains partial support. The Practise and Preparation Hypothesis gained support as dreams simulated positive interactions in one fifth of dream interactions and overall simulate complex social behaviours. The Compensation Hypothesis suggests dreams simulations to increase when waking social contacts are abolished, but this was not supported in the data as dream sociality remained stable despite social seclusion. When excluded from others our dreams reconfigure to decrease simulations of interactions with strangers. However, dreams during normal day-to-day life do not preferentially simulate bond-strengthening interactions with close others. In opposition to previous findings, Study II found no differences in social dream contents between either stage of sleep or time of night. In Study III a short social seclusion showed not only differences in dream content, but also in sleep structure, with an increase in REM sleep. Third, methodological development was undertaken by, both, developing a content analysis method for extracting social episodes in narrative reports (Social Content Scale, SCS; Study II), and by assessing the validity of a novel home sleep monitor device, the Beddit Sleep Tracker (BST). While the SCS proved useful for categorizing the social features in both studies II and III, BST failed to provide accurate sleep data as measured against a polysomnogram. Overall, the development of SST and the initial empirical evidence for some of its hypotheses brings us closer to understanding the twin problems of dreaming and consciousness.</p
RĂȘves et rĂ©activation de la mĂ©moire : fenĂȘtre sur la consolidation de la mĂ©moire durant le sommeil
Le sommeil joue un rĂŽle important dans la consolidation de la mĂ©moire. Les expĂ©riences nouvellement acquises Ă lâĂ©veil sont rĂ©activĂ©es spontanĂ©ment durant le sommeil, un processus qui aiderait Ă consolider et intĂ©grer la mĂ©moire Ă plus long terme. Il a Ă©tĂ© suggĂ©rĂ© que ces rĂ©activations de mĂ©moire se reflĂ©taient, du moins partiellement, dans le contenu des rĂȘves et que les rĂȘves pouvaient jouer un rĂŽle actif dans la consolidation de la mĂ©moire. L'objectif gĂ©nĂ©ral de cette thĂšse de doctorat est ainsi d'Ă©valuer si et comment le rĂȘve est impliquĂ© dans le traitement de la mĂ©moire Ă©pisodique et procĂ©durale en utilisant de nouvelles technologies et approches expĂ©rimentales pour Ă©tudier ces relations.
La premiĂšre Ă©tude de cette thĂšse visait Ă influencer les rĂ©activations de mĂ©moire durant le sommeil afin de clarifier leurs liens avec les rĂȘves et la mĂ©moire procĂ©durale. Nous avons stimulĂ© ces rĂ©activations de mĂ©moire en rĂ©exposant des participants, durant leur sommeil, Ă un stimulus sonore prĂ©alablement associĂ© Ă un apprentissage moteur, une approche nommĂ©e « targeted memory reactivation » (TMR). Nous montrons que la TMR, lorsquâappliquĂ©e en stade de sommeil paradoxal, permet dâamĂ©liorer lâapprentissage dâune tĂąche motrice complexe, soit apprendre à « voler » en rĂ©alitĂ© virtuelle. De plus, le fait de rĂȘver Ă des Ă©lĂ©ments kinesthĂ©siques de la tĂąche motrice en sommeil paradoxal, mais pas en sommeil lent lĂ©ger, est associĂ© Ă une meilleure amĂ©lioration Ă cette tĂąche (article I). Ces rĂ©sultats appuient les modĂšles suggĂ©rant que le sommeil paradoxal joue un rĂŽle important dans la consolidation de la mĂ©moire procĂ©durale complexe et suggĂšrent en outre que la simulation de sensations sensorimotrices dans les rĂȘves pourrait contribuer Ă ce rĂŽle. Bien que la TMR nâait pas eu dâimpact direct sur les rĂȘves, nous montrons quâelle peut influencer le dĂ©cours temporel des incorporations de mĂ©moire dans les rĂȘves sur plusieurs jours. La TMR a amplifiĂ© les incorporations tardives de la tĂąche, soit 1-2 jours plus tard lorsquâappliquĂ©e en sommeil paradoxal, et 5-6 jours plus tard lorsquâappliquĂ©e en sommeil lent profond (article II). Nous suggĂ©rons que ces effets Ă plus long terme pourraient ĂȘtre dus Ă un mĂ©canisme de marquage (tagging) des traces de mĂ©moire, initiant ou amplifiant leur traitement subsĂ©quent au cours de plusieurs nuits de sommeil.
De plus, nous montrons que notre expĂ©rience immersive en rĂ©alitĂ© virtuelle a augmentĂ© lâincorporation de sensations de vol dans les rĂȘves, particuliĂšrement la nuit suivant lâexposition Ă celle-ci (article III). Nous identifions certains facteurs individuels qui sont associĂ©s Ă une plus grande incorporation de la tĂąche dans les rĂȘves, tels que le fait dâavoir dĂ©jĂ eu des rĂȘves de vols ou des rĂȘves lucides. Un examen plus approfondi des rĂȘves pendant 10 jours suivants l'expĂ©rience de rĂ©alitĂ© virtuelle montre que les sensations de vol sont progressivement dĂ©contextualisĂ©es du contexte de vol original au fil du temps. Les rĂȘves de vol aprĂšs lâexpĂ©rience en rĂ©alitĂ© virtuelle avaient Ă©galement des niveaux de contrĂŽle et d'intensitĂ© Ă©motionnelle plus Ă©levĂ©s que ceux ayant eu lieu avant lâexpĂ©rience. L'induction de rĂȘves de vol nous a permis de faire une analyse qualitative approfondie sur ceux-ci, menant Ă une nouvelle proposition de la maniĂšre dont les sensations de vol, ou les sensations de mouvement de maniĂšre plus gĂ©nĂ©rale, peuvent survenir dans les rĂȘves. Ces rĂ©sultats pourraient Ă leur tour faciliter le dĂ©veloppement de technologies pour mieux influencer et Ă©tudier les rĂȘves.
Une deuxiĂšme Ă©tude visait Ă Ă©valuer quand et comment une source de mĂ©moire Ă©pisodique commune Ă tous les participant â visiter le laboratoire de sommeil â est incorporĂ© dans les rĂȘves. Les rĂ©sultats montrent que prĂšs du tiers des rĂȘves incorporent des Ă©lĂ©ments du laboratoire, et ce, particuliĂšrement dans les rĂȘves en sommeil paradoxal lors dâune sieste matinale (article IV). Une Ă©tude qualitative de ces rĂȘves met de lâavant les maniĂšres typiques par lesquelles des Ă©lĂ©ments du laboratoire rĂ©apparaissent dans les narratifs de rĂȘve. Nous proposons lâexistence de diffĂ©rentes « pressions intĂ©gratives » qui structurent les fragments de mĂ©moire au sein de scĂ©narios de rĂȘves. Souvent, ces scĂ©narios impliquent une certaine pression de performance, sont de nature sociale, projettent le rĂȘveur dans le temps et dans lâespace, ou incorporent des sensations rĂ©elles du corps et de lâenvironnement de sommeil. Ătudier le phĂ©nomĂšne de « rĂȘver au laboratoire » aide ainsi Ă clarifier comment les rĂȘves sont façonnĂ©s autour de fragments de mĂ©moire et souligne Ă la fois les avantages et les limites mĂ©thodologiques de lâĂ©tude des rĂȘves et de la mĂ©moire en laboratoire.
Finalement, une troisiĂšme Ă©tude visait Ă suivre le dĂ©cours temporel des sources de mĂ©moire autobiographique des rĂȘves au cours dâune nuit de sommeil entiĂšre en utilisant un protocole de rĂ©veils en sĂ©rie. Nos rĂ©sultats montrent que les rĂȘves peuvent combiner plusieurs sources de mĂ©moire, en particulier lorsqu'ils se produisent en stade N1 ou en sommeil paradoxal, ce qui pourrait reflĂ©ter une plus grande richesse ou capacitĂ© intĂ©grative des rĂȘves ayant lieu en ces stades (article V). Nous reproduisons le rĂ©sultat voulant que les souvenirs rĂ©cents sont prĂ©fĂ©rentiellement rĂ©activĂ©s tĂŽt dans la nuit, tandis que les souvenirs plus lointains sont relativement plus reprĂ©sentĂ©s dans les rĂȘves de fin de nuit â nous prĂ©cisons que cet effet est indĂ©pendant des stades de sommeil. La co-activation de plusieurs sources de mĂ©moire dans un mĂȘme rĂ©cit de rĂȘve appuie la suggestion que lâune des fonctions du sommeil est d'intĂ©grer les nouvelles connaissances Ă nos rĂ©seaux de mĂ©moire prĂ©existants. Nos rĂ©sultats suggĂšrent que cette fonction pourrait ĂȘtre un processus cumulatif au cours d'une nuit de sommeil. Nous montrons entre autres qu'une seule source de mĂ©moire peut ĂȘtre rĂ©activĂ©e Ă plusieurs reprises dans plusieurs rĂȘves, et en diffĂ©rents stades de sommeil, ce qui pourrait permettre un traitement continu ou sĂ©quentiel de souvenirs Ă©pisodiques avec d'autres souvenirs tout au long de la nuit.
Dans lâensemble, nos Ă©tudes quantitatives et qualitatives des incorporations de mĂ©moire dans les rĂȘves permettent dâĂ©clairer les mĂ©canismes fondamentaux de la formation des rĂȘves ainsi que leurs associations avec le traitement et la consolidation des mĂ©moires Ă©pisodique et procĂ©durale. Nos rĂ©sultats suggĂšrent quâun rĂŽle potentiel du rĂȘve dans la mĂ©moire irait au-delĂ de sa simple rĂ©activation, soutenant des processus de transformation et dâintĂ©gration de la mĂ©moire. La crĂ©ation de scĂ©narios multisensoriels et immersifs basĂ©s sur des fragments mĂ©moire est possiblement centrale Ă ces processus et permettrait dâoptimiser lâutilisation de la mĂ©moire pour le futur.Sleep plays an important role in memory consolidation. New experiences acquired while awake are reactivated spontaneously during sleep, a process that is thought to facilitate their consolidation and integration into longer-term memory. It has been suggested that these memory reactivations are, at least partially, reflected in dream content and that dreams play an active role in memory consolidation. The general objective of this doctoral thesis is to assess these claims; I examine whether and how dreams are involved in episodic and procedural memory processes by using new technologies and experimental approaches to study relationships between memory and dreaming.
Our first study aimed to influence memory reactivations during sleep in order to clarify their relationships with dreams and procedural learning. We experimentally stimulated memory reactivations by re-exposing participants during their sleep to an auditory stimulus previously associated with motor learning, a process called targeted memory reactivation (TMR). We show that TMR, when applied during rapid eye movement (REM) sleep, improves performance of a complex motor task, i.e., learning how to "fly" in a virtual reality (VR) setting. Moreover, dreaming about kinesthetic elements of the motor task in REM sleep, but not in stage 2 sleep, is associated with better improvement on this task (article I). These results support previous models suggesting that REM sleep plays an important role in the consolidation of complex procedural memory and further suggest that the simulation of sensorimotor sensations in dreams contribute to this role. Although TMR did not directly impact dreams, we show that it can influence the time course of memory incorporations in dreams over multiple days. It amplified delayed incorporations of the task 1-2 days later when applied in REM sleep, and 5-6 days later when applied in slow-wave sleep (article II). We suggest that these longer-term effects could be due to a âtaggingâ mechanism of memory traces, which primes or amplifies their subsequent processing over several nights of sleep.
Furthermore, we show that our immersive VR task increased the incorporation of flying sensations in dreams, especially the night after exposure to it (article III). We identify individual factors that are associated with the incorporation of the flying task in dreams, such as previous experience with both flying and lucid dreams. A closer look at dreams over 10 days following the VR experience shows that flying sensations become progressively decontextualized from the original flying context over time. Flying dreams after VR exposure also had higher levels of control and emotional intensity compared to baseline flying dreams. The successful induction of flying dreams allowed us to do an in-depth qualitative analysis of them, based on which we propose a new mechanistic explanation of how flying sensations or movements may arise in dreams. These results could facilitate the development of technologies to better influence and study dreaming.
Our second study aimed to assess when and how an episodic memory source shared by all participants â visiting the sleep laboratory â is incorporated into dreams. The results show that almost a third of dreams incorporate elements of the laboratory, particularly REM dreams from a morning nap (article IV). A qualitative study of these dreams highlights the typical ways in which elements of the laboratory reappear in dream narratives. We suggest the existence of different âintegrative pressuresâ that structure memory fragments into these dream scenarios. These are often performative or social in nature, project the dreamer in time and space, or incorporate real sensations from the sleeping body or the sleep environment. Studying the phenomenon of dreaming about the laboratory helps clarify how dreams are shaped from memory fragments, and highlights the advantages and methodological limits of laboratory dream and memory studies.
Finally, our third study evaluated the time course of autobiographical dream memory sources during an entire night of sleep using a serial awakenings protocol. Our results show that dreams can combine multiple memory sources at once, especially when they occur at sleep onset or in REM sleep, which may reflect a greater dream richness or a more widespread associative memory activation in those stages (article V). We replicate the finding that recent memories are preferentially reactivated early in the night, while more distant memories are relatively more represented in late night dreams â we here clarify that this effect is independent of sleep stages. The coactivation of multiple memory sources in a dream narrative aligns with the suggestion that a function of sleep is to integrate new knowledge with existing knowledge. Our results further suggest that the latter may be a cumulative function of a night of sleep. We show that a single memory source can be repeatedly reactivated in multiple dreams in different sleep stages, which could allow a continuous or sequential processing of episodic memories with other memories across the night.
Overall, our quantitative and qualitative studies of memory incorporations in dreams shed light on fundamental mechanisms of dream formation and on their association with episodic and procedural memory processing and consolidation. Our results suggest that a potential role of dreams in memory goes beyond simple reactivation, supporting long-term processes of memory transformation and integration. The creation of immersive and multisensory dream scenarios built upon memory fragments may be key to these processes and to optimizing the use of these memories for the future
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