ASSC16 Keynotes & Symposia
|Presidential Address : Victor Lamme (University of Amsterdam, Netherlands). BioSketch
18:00-19:00 Monday July 2
Title: You have Conscious Sensations without Knowing it
Summary: Consciousness has always been defined from introspective and behavioral intuitions. This has gotten us nowhere. What we need is a radical redefinition of what consciousness really is, from a convergence of introspective, behavioral and neural arguments. The criterion for success should be whether such a new definition explains what there is to explain about consciousness, not whether it fits our intuitive notions. From such an approach (Lamme, 2006; 2010), it emerges that it makes sense to acknowledge that we have conscious sensations (in the phenomenal, qualitative sense) without attention, without access, and hence also without thought. In this talk, I will present further arguments that impose such a far reaching conclusion.
Our latest experiments show that vision without attention is rich, detailed, precise, integrated, and - most importantly – shows perceptual inference i.e. goes beyond the retinal image towards a perceptual interpretation of that image. Moreover, we show a further dissociation between various forms of cognition (categorization, control) and consciousness, while the association between integration-segregation and conscious experience is strengthened.
In sum, there is now overwhelming evidence showing that neural representations outside the focus of attention, and outside the realm of access or thought possess all the key properties of conscious representations, except – of course – reportability. Moreover, these properties do all the explaining towards the phenomenal nature of conscious experience. The absence of access does little to explain that away. The proper conclusion is that we may have conscious sensations even when we don’t know it.
Lamme, V.A.F. (2006) Towards a true neural stance on consciousness. Trends Cogn Sci, 10: 494-501; Lamme, V.A.F. (2010) How neuroscience will change our view on consciousness. Cognitive Neuroscience, 1, 204-235
|Keynote Lecture 1: Tim Bayne, University of Oxford, Oxford, UK. BioSketch|
9:00-10:00 Tue July 3
Title: The Unity of Consciousness
Summary: Some theorists maintain that consciousness is necessarily unified; others maintain that although consciousness is typically unified, the unity of consciousness can break down on occasions; and still others argues that the apparent unity of consciousness is an illusion, and that consciousness is typically disunified. This talk provides an overview of the debate between these three approaches to consciousness. I distinguish different forms that the unity of consciousness can take, and I provide some tentative reasons for thinking that there is a sense in which consciousness is necessarily unified. I conclude with a discussion of how debates about the unity of consciousness might inform the development and evaluation of theories of consciousness.
Tim Bayne is a member of the Faculty of Philosophy at the University of Oxford and a Fellow of St. Catherine’s College. He received his undergraduate education at the University of Otago and his doctorate from the University of Arizona. He has published widely in the philosophy of mind and consciousness studies. Bayne has co-edited Delusion and Self-Deception: Affective and Motivational Influences on Belief Formation (Psychology Press, 2008), The Oxford Companion to Consciousness (2009, OUP), and most recently Cognitive Phenomenology (OUP, 2011). His own book, The Unity of Consciousness (OUP, 2010) draws on philosophy, psychology, psychopathology and cognitive neuroscience to provide a comprehensive treatment of the unity of consciousness. Writing in Notre Dame Philosophical Reviews, Sydney Shoemaker described it as "the most thorough discussion of the unity of consciousness there is, and anyone interested in the topic should read it."
|Keynote Lecture 2: Geraint Rees (University College London, UK). BioSketch|
9:00-10:00 Wed July 4
Title: Decoding Consciousness
Summary: Everything we know about the world comes to us through our brain. Yet for each of us our own conscious mental world of thoughts and feelings is isolated and private. Despite several centuries of research on the brain, communication through language or gesture remains the only way we can discover the conscious thoughts and experiences of others. This makes it difficult to compare our conscious experiences and discover whether we all experience the world in the same way. In this talk I will discuss recent work using non-invasive brain imaging showing that not only does our conscious perception of the world differ across individuals, but also that these individual differences are correlated with the structure and function of primary visual, parietal and prefrontal cortices. I will explore the implications of these findings for both neuroscience and society.
Geraint is Director of the UCL Institute of Cognitive Neuroscience and Deputy Head of the UCL Faculty of Brain Sciences. Funded by a Wellcome Trust Senior Clinical Fellowship, his work seeks to understand the neural basis of consciousness, and has resulted in over 160 papers including eight in Science or Nature. He has been awarded the Royal Society Francis Crick Medal, the Experimental Psychology Prize and the Young Investigator Medal of the Organisation for Human Brain Mapping. His work is widely covered in the print and broadcast media. He is passionately committed to developing clinical academic training in the UK and contributes widely to public policy and engagement with brain imaging technologies. In 2010 he was elected a Fellow of the Academy of Medical Sciences.
|Keynote Lecture 3: Tania Singer (Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany). BioSketch|
9:00-10:00 Thurs July 05
Title: Social Emotions from the Lens of Social Neuroscience: Modulation, Development and Plasticity
Summary: With the emergence of social neuroscience, researchers have started to investigate the underpinnings of our ability to share and understand feelings of others. After a definition of concepts, I will shortly revise the main results of neuroscientific studies investigating empathic brain responses elicited by the observation of others in pain and show how these empathic brain responses are modulated by several contextual and stimulus intrinsic factors such as perceived fairness or ingroup/outgroup membership. Furthermore, I will present data from a novel paradigm on empathy for pleasant and unpleasant touch allowing the investigation of the neural mechanisms underlying affective egocentric bias in adults. These data will be complemented with developmental findings showing age-differences in egocentric bias, social emotions such as envy and Schadenfreude as well as strategic decision making during childhood. Finally, I present evidence of affective brain plasticity based on mental training of social emotions. These data will be discussed in lights of their relevance for recent models of social cognition.
Tania Singer received her PhD in Psychology from Free University in Berlin in 2000. She became a Post-doctoral Fellow at the Max Planck Institute for Human Development in Berlin until 2002, then at the Wellcome Department of Imaging Neuroscience and later at the Institute of Cognitive Neuroscience in London, in 2005. She accepted a position as Assistant Professor at the University of Zurich in 2006 and later as Inaugural Chair of Social Neuroscience and Neuroeconomics as well as Co-Director of the Laboratory for Social and Neural Systems Research. Since 2010, she is the Director of the Department of Social Neuroscience at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, where she investigates the foundations of human social behavior and, social cognition and emotions (empathy, compassion, fairness), and social decision making.
|Keynote Lecture 4: Josef Perner (University of Salzburg, Austria). BioSketch|
09:00-10:00 Fri July 06
Title: Infants’ Sensitivity to Others’ Belief: Unconscious Theory of Mind?
Summary: At Sussex we (Clements & Perner 1994) discovered a dissociation. A majority of three year old children anticipate in their looking that an agent, who didn’t witness an object’s unexpected transfer to a new location will mistakenly return to the object’s original place. In contrast, when these children are asked where the agent will go to get the object, they adamantly claim that she will go to where the object actually is. Subsequent studies indicated that the dissociation is not one of explicit considerations between certain and uncertain possibilities (Ruffman et al 2001) and that not one between verbal and nonverbal measures. It also affects action responses that are given spontaneously and those that are given hesitantly. These results provided an analogy to the availability of unconscious (implicit) and conscious (explicit) knowledge in studies with blindsight patients and healthy adults with illusory stimuli and, thus, evidence for unconscious knowledge of a mistaken agent’s future action.This dissociation has gained new relevance with reports that infants as young as 14 months (Onishi & Baillargeon 2005, and many studies since) or even 7 months (Kovács et al 2010) show similar sensitivity to belief in their looking and other spontaneous responses. Although the dissociation between spontaneous and deliberate responding has affinity with the distinction between unconscious and conscious knowledge, we have no good understanding what leaves the one un- and makes the other conscious. I will elaborate the idea that spontaneous responding is based on abstraction of behavioural regularities, which may be causally shallow (behaviour rules) or deep (belief formation), while deliberate responding is based on understanding the agent’s reasons for acting.
JOSEF PERNER received his PhD in Psychology from the University of Toronto. He was Professor in Experimental Psychology at the University of Sussex and is now Professor of Psychology and member of the Centre for Neurocognitive Research at the University of Salzburg. He is author of "Understanding the Representational Mind" (MIT Press, 1991) and over 150 articles on cognitive development (theory of mind, executive control, episodic memory, logical reasoning), consciousness (perception versus action), simulation in decision making, and theoretical issues of mental representation and consciousness. He served as President of the European Society for Philosophy and Psychology, is a Fellow of the British Academy, the Academia Europaea, the Leopoldina, the Center for Advanced Studies in the Behavioral Sciences at Stanford, the Association for Psychological Sciences, and holds an honorary doctorate from the University of Basel.
|Special Lecture: Christof Koch (Caltech). BioSketch|
18:00-19:00 Wed July 04
Title: Studying the Murine Mind using Large Scale Observatories
Summary: Mice are a promising model system for studying the neuronal correlates of consciousness. Their brain structure is similar to that of the human, they display complex behavior, their underlying neuronal responses can be measured using optics and silicon probes at cellular level of resolution and the underlying neuronal networks can be modeled. In contrast to the blunt and edentate tools available to probe the human brain, optogenetics allows scientists to delicately, transiently, and reversibly control defined events in defined cell types at defined times in mice with millisecond resolution. That is, unlike the vast majority of human studies, experiments in mice move from correlation to causation, from observing that this circuit is activated whenever the subject is perceiving something to inferring that this circuit is necessary for a particular behavior or a conscious perception. I shall report on the ten year, large-scale (several hundred scientists and engineers) and high throughput efforts to build brain observatories to understand the mouse visual system that are ongoing at the Allen Institute.
Born in the American Midwest, Dr. Christof Koch grew up in Holland, Germany, Canada, and Morocco. He studied Physics and Philosophy at the University of Tübingen in Germany and was awarded his Ph.D. in Biophysics in 1982. After 4 years at MIT, he joined the California Institute of Technology, where he is the Lois and Victor Troendle Professor of Cognitive and Behavioral Biology. In 2011, he became the Chief Scientific Officer at the Allen Institute for Brain Science in Seattle, where he leads a ten year, large-scale, high through-put effort to build a series of brain observatories to analyze and understand the visual system of the mouse. He loves dogs, Apple Computers, climbing, biking and long-distance running.
SYMPOSIUM 1: Consciousness Fading
Chair: Andreas K. Engel (Dept. of Neurophysiology and Pathophysiology University Medical Center, Hamburg, Germany)
Manipulating consciousness by anesthetic agents is everyday clinical practice. However, the key mechanisms underlying pharmacologically induced breakdown of consciousness are still largely unresolved. Unraveling the neural determinants of loss of consciousness, apart from its obvious medical advances, may shed new light on brain processes relevant for the emergence of consciousness. The presentations of this symposium will discuss complementary findings that suggest convergent conclusions and highlight the implications of anesthesia research for understanding the neural mechanisms of consciousness. The first and the second presentation will focus on propofol anesthesia as a model of drug-induced loss of consciousness, and discuss recent experimental evidence suggesting that propofol anesthesia induces hypersynchronous ongoing activity leading to a brain state during which information processing is severely compromised, and functional integration across different areas is strongly reduced. The second presentation will also highlight potential similarities between the neurophysiological changes induced by propofol and those observed during sleep. The third presentation of the symposium will, in addition to discussing recent modeling work on the mechanisms of propofol anesthesia, provide a broader framework for understanding changes in neural dynamics under general anesthesia.
Andreas K. Engel (Dept. of Neurophysiology and Pathophysiology University Medical Center, Hamburg, Germany)
Talk 1: “Block of intracortical communication by propofol-induced neural hypersynchy”
Gernot Supp (Dept. of Neurophysiology and Pathophysiology University Medical Center, Hamburg, Germany)
Abstract: Manipulating consciousness by anesthetic agents is everyday clinical practice. However, the key mechanisms underlying pharmacologically induced breakdown of consciousness are still largely unresolved. Unraveling the neural determinants of loss of consciousness, apart from its obvious medical advances, may shed new light on brain processes relevant for the emergence of consciousness. The presentations of this symposium will discuss complementary findings that suggest convergent conclusions and highlight the implications of anesthesia research for understanding the neural mechanisms of consciousness. The first and the second presentation will focus on propofol anesthesia as a model of drug-induced loss of consciousness, and discuss recent experimental evidence suggesting that propofol anesthesia induces hypersynchronous ongoing activity leading to a brain state during which information processing is severely compromised, and functional integration across different areas is strongly reduced. The second presentation will also highlight potential similarities between the neurophysiological changes induced by propofol and those observed during sleep. The third presentation of the symposium will, in addition to discussing recent modeling work on the mechanisms of propofol anesthesia, provide a broader framework for understanding changes in neural dynamics under general anesthesia.
Talk 2: “Is propofol-induced loss of consciousness a sleep-like state?”
Melanie Boly (Coma Science Group, University of Liege, Belgium)
Abstract: Mechanisms of propofol-induced fading of consciousness, as well as the relationship between propofol anesthesia and sleep remains poorly understood. We will review recent neuroimaging studies investigating neural correlates of loss of consciousness during propofol sedation and non-REM sleep. We will then highlight some commonalities as well as observed differences in terms of spontaneous EEG, or functional and effective connectivity (using high-density EEG, functional MRI or TMS-EEG) between propofol and non-REM sleep. Finally, we will discuss the implications of these results for neural correlates of consciousness and for their use as clinical tools to detect awareness during anesthesia, and in other altered consciousness states.
Talk 3: “The neural dynamics of loss and recovery of consciousness under general anesthesia”
Emery Brown (Department of Anesthesia, Harvard Medical School, USA)
Abstract: General anesthesia is a drug-induced, reversible condition comprised of five behavioral states: unconsciousness, amnesia (loss of memory), analgesia (loss of pain sensation), akinesia (immobility), and hemodynamic stability with control of the stress response. The mechanisms by which anesthetic drugs induce the state of general anesthesia are considered one of the biggest mysteries of modern medicine. We have been using three experimental paradigms to study general anesthesia-induced loss of consciousness in humans: combined fMRI/EEG recordings, high-density EEG recordings and intracranial recordings. These studies are allowing us to establish precise neurophysiological, neuroanatomical and behavioral correlates of unconsciousness under general anesthesia. Combined with our mathematical modeling work on how anesthetics act on neural circuits to produce the state of general anesthesia we are able to offer specific hypotheses as to how changes in level of activity in specific circuits lead to the unconscious state. We will discuss the relation between our findings and two other important altered states of arousal: sleep and coma. Our findings suggest that the state of general anesthesia is not as mysterious as currently believed.
SYMPOSIUM 2: Bringing the in-depth body to the surface: interoception, awareness and prediction
Chair: Manos Tsakiris (Department of Psychology, University of London, UK)
Interoception is a ubiquitous information channel used for the central representation of internal bodily states. A renewed interest in the functional role of interoception has emphasized its primary role for the representation of an integrated sense of self. At the same time, current models of perception have been largely influenced by a Bayesian approach that underlines the role of internal predictive models for the processing and interpretation of incoming exteroceptive information. Could the functional role of interoception be understood in terms of predictive coding, and if yes what are the implications for interoceptive awareness? Interoceptive awareness (i.e. the awareness of the physiological state of one’s body) is assessed by quantifying interoceptive sensitivity (IS), usually in the context of heartbeat detection tasks. Behaviourally, the sensitivity to the perception of internal states of the body has been shown to modulate a range of cognitive, affective and sensory processes. The three talks of this symposium will focus on how sensitivity to internal bodily states comes to awareness and how it modulates emotional processes (Critchley), self-other representations (Tsakiris) and internal conflicts (Hopkins) via predictive internal models. Across three disciplines (e.g. neuroscience, psychology and philosophy), the three talks provide a timely debate of interoception as a model of predictive coding.
Talk 1: “Visceral afferent signaling, interoceptive awareness and predictive coding: Impact on emotional processes”
Hugo Critchley (Sackler Centre for Consciousness Science, Department of Psychiatry, Brighton and Sussex Medical School, UK)
Abstract: The experience of emotions as subjective feeling states arguably reflects the cognitive appraisal of information about changes in bodily state in conjunction with the inferences about the causes of those changes, consistent with a predictive coding framework. Moreover, individual differences in physiological responsivity influence the experience of emotions and people can be categorized according to their accuracy in judging physiological processes including heartbeats. Studies of good and bad 'heartbeat detectors' confirm a relationship between enhanced interoceptive ability and intensity of emotional experiences. Mechanistically, central signalling of cardiovascular arousal occurs via the activation of baroreceptors at cardiac systole that signals the occurrence and amplitude of individual heartbeats. We have shown this interoceptive stream differentially influences automatic processing and intentional evaluation of emotional stimuli including facial expressions. Nevertheless, cognitive and physiological dimensions of interoception can be dissociated experimentally, endorsing a model of interoceptive predictive coding which we have recently developed.
Talk 2: “Interoception and the Problem of Consciousness”
Jim Hopkins (Department of Philosophy, King’s College, UK)
Abstract: Recent studies have shown that “unconscious” processing can be surprisingly powerful (cf work in the labs of Lamme, Dijksterhuis, Mattler, Haynes, Dehaene, Bargh, myself, etc). I had taken these results to be a challenge to the notion that sensory awareness has special functional power. Here I criticize my previous arguments. A useful analogy: People without legs can move around (albeit poorly), but we all agree that legs are for locomotion. Likewise, although certain higher cognitive functions can be performed without awareness (just barely better than chance), it does not mean that awareness has no functional advantage. A different approach is to create conditions where subjects are equally good at detecting and discriminating the stimulus, but they report different subjective levels of awareness. Under these performance capacity‐matched cases, we observed functional advantage for awareness only in some specific tasks. These results give powerful constraints for theorizing about sensory awareness in general.
Talk 3: “Just a heartbeat away from one’s body: interoceptive sensitivity and malleability of self-representations”
Manos Tsakiris (University of London, UK)
Abstract: Body-awareness relies on the representation of both interoceptive and exteroceptive percepts coming from one’s body. However, the exact relationship and possible interaction of interoceptive and exteroceptive systems for body-awareness remain unknown. Based on recent models of self-awareness that consider the insula as a convergence zone linked to the representation of the bodily self, we examined the interaction between interoceptive and exteroceptive awareness of the body. Across three experiments, we combined measures of interoceptive sensitivity with experimental manipulations of body representations. Consistent results suggests that interoceptive sensitivity predicts the malleability of body representations, that is, people with low interoceptive sensitivity experience stronger illusions of embodiment (“rubber hand illusion”) and identification (“enfacement illusion”). In one final experiment, we manipulated interoceptive sensitivity by mirror self-observation. Overall these findings suggest that interoceptive sensitivity modulates the integration of multisensory information and predicts the strength of self-representations.
SYMPOSIUM 3: Perceptual consciousness and cognitive access
Chair: Ned Block (Departments of Philosophy, Psychology and Center for Neural Science, New York University, USA)
The most basic issue concerning the foundations of conscious perception is whether perceptual consciousness is rich or sparse. The overflow argument uses a form of iconic memory to argue that perceptual consciousness is rich, i.e. has a higher capacity than cognitive access: we are conscious of more than we can report or think about. However, there is also evidence that iconic memory is fragmentary and that it may involve “gists” or generic representations. These points have been used to argue that the informational resources that are the basis of “partial report superiority” in iconic memory experiments are really unconscious, and so the overflow argument is mistaken. A further alternative is that the debate between rich and sparse views of perception is not empirically decideable. This issue is one of the most thoroughly interdisciplinary of all theoretical issues concerning consciousness and accordingly this symposium has two philosophers and two scientists.
Talk1: “The fundamental methodological problem of consciousness research ”
Ned Block (Departments of Philosophy, Psychology and Center for Neural Science, New York University, USA)
Theories of consciousness are ultimately based on what we and other people report (or better: think) about their conscious states in various experimental paradigms. Some approaches—mine for example—claim that on the basis of such evidence we can conclude that cosciousness is richer than cognitive access and in particular there are experimental setups where inevitably reports and other cognitive processes will not reflect all of the specific details of conscious experience. But how can we know about the unaccessed conscious detail when being unaccessed would seem to preclude such knowledge? A similar problem arises in knowing about the conscious experience of unattended stimuli, since reporting requires attention to the stimuli or to memory traces of them, and attention is known to alter conscious experience. This talk proposes a solution to this problem.
Talk 2: “Kinds of access and phenomenality”
Jérôme Sackur (Department of Cognitive Studies, Ecole Normale Supérieure, France)
The science of consciousness seems to face a recurrent dilemma: either accept a non fully reportable phenomenal quality of conscious contents or repudiate phenomenality altogether. In this talk I will argue that this dilemma seems to arise only because of the delusive simplicity of the notion of cognitive access. I will show that access is more diverse than commonly acknowledged, and that it can be probed in many ways. Cognitive access is not uniform: for one given stimulus, it may vary in completeness, and also in regards to levels of processing. Therefore, any report of a conscious state must integrate an array of disparate fragments of accessed information, and take into account prior knowledge of the context. I argue that with this richer notion of access, we can aim for a functional construal of consciousness which obviates the need for a special kind of phenomenal consciousness.
Talk 3: “Making perceptual consciousness accessible”
Ilja Gabriël Sligte (Department of Psychology, University of Amsterdam, The Netherlands)
In recent years, we have published several papers showing the existence of a high-capacity (up to 15 objects) and long-lived (up to 4s) form of sensory memory that can be clearly dissociated from pure iconic memory (Sligte, Scholte, Lamme, 2008) and from working memory (Sligte, Wokke, Tesselaar, Scholte, & Lamme, 2010; Vandenbroucke, Sligte, & Lamme, 2011). However, all these results were based on partial-report experiments where subjects had to choose between change and no-change responses. This fact has triggered the criticism that subjects were just guessing (Phillips, 2011) on the basis of unconscious representations, as in blindsight. To explore this alternative explanation of our findings, we tested how subjects performed on a partial-report task with continuous response options (see Zhang & Luck, 2008; Bays & Husain, 2008 for examples of the task; we added retro-cues to this paradigm similar to Sligte, Scholte, & Lamme, 2008). We observed that subjects could report 7 objects (out of 10) with high precision on pure iconic memory conditions, about 6 on retro-cue (long-lasting and fragile form of iconic memory) conditions, and only 4 on postcue, working memory conditions. This suggests that all our previous studies validly make perceptual consciousness available for cognitive access.
Talk 4: “Indeterminate perceptual consciousness and cognitive access”
James Stazicker (Department of Philosophy, New York University, USA)
Does perceptual consciousness require cognitive access? Those who think it does often appeal to 'inattentional blindness' experiments to confirm their view. Those who think it doesn't often appeal to partial report experiments to confirm theirs. I'll argue that these experiments seem to provide this sort of evidence about perceptual consciousness and cognitive access, only because of an assumption about the determinacy of perceptual consciousness. To assess this assumption, we have to face up to a more ancient philosophical controversy about the difference between perception and cognition."
SYMPOSIUM 4: Balancing the self: Vestibular contributions to self-consciousness
Chair: Dr. Christophe Lopez (Centre National de la Recherche Scientifique, Université de Provence France)
Recent developments in cognitive neuroscience and philosophy of mind have highlighted some of the bodily foundations of the subjective experience of being a self (bodily self-consciousness). Yet, past research has focused on the convergence of visual, tactile and proprioceptive signals for aspects of bodily self-consciousness such as the sense of body ownership, self-identification, and self-location. However, recent work suggests a fundamental importance of vestibular signals for bodily self-consciousness. The fact that the vestibular system has been neglected until recently is surprising because this sensory system encodes one’s body position with respect to gravity as well as translations and rotations of the body in space. We will present data from cognitive neuroscience, neurology and neuroimaging showing the importance of the interactions of vestibular signals with visual and somatosensory signals to reflect bodily self-consciousness, including the first-person perspective. Bigna Lenggenhager will describe recent data on experimentally-induced changes in self-location and first-person perspective that were induced via visuo-vestibular and tactile conflicts. The importance of vestibular signals in perspective taking, self-other and self-environment distinctions will be discussed by Christophe Lopez. Gabriella Bottini will demonstrate the possibility to manipulate bodily consciousness, and various bodily deficits of neurological origin, using vestibular stimulation. The three speakers will discuss the convergence of vestibular signals in brain areas underpinning body representations. The convergence of the data presented during this symposium should stimulate the inclusion of vestibular signals into current models of body representations and pre-reflective forms of bodily self-consciousness.
Talk1: “Vestibular contribution to multisensory mechanisms underlying the sense of self”
Bigna Lenggenhager (Social and Cognitive Neuroscience Laboratory, Psychology Department, Sapienza University, Italy)
Abstract: Data in neurological patients with disturbances in the bodily self suggest an important role of vestibular processes in global aspects of the self such as self-location and first-person perspective. We used mental imagery and multisensory bodily illusions to simulate aspects of such neurological conditions in healthy participants to investigate underlying functional and neural mechanisms. In these experiments both vestibular stimulation as well as visuo-vestibular conflicts interfered with global aspects of the self, confirming a contribution of vestibular processing to a stable sense of self, localized at a specific position in space with a single perspective on the world. Functional magnetic resonance imaging revealed that temporo-parietal junction (TPJ) activity reflected experimental changes in self-location and first-person perspective due to multisensory conflicts. This finding relates again to data in neurological patients that suggest integration of vestibular, somatosensory and visual signals in the TPJ are crucial for a stable sense of self.
Talk 2: “Vestibular and multisensory foundations of self-location and self-other distinction”
Christophe Lopez (Laboratoire de Neurosciences Intégratives et Adaptatives Centre National de la Recherche Scientifique, Université de Provence, France)
Abstract: The vestibular system provides concurrent signals about gravity and one’s body position and motion in space. I will argue that vestibular signals play a crucial role in unifying bodily and extracorporeal signals necessary for self-location and self-other distinction. The core vestibular cortex overlaps with the temporo-parietal region, insula and intraparietal sulcus, three brain regions involved in self-processing. First, I will show that artificial stimulation of the vestibular system (caloric and galvanic vestibular stimulation) can interfere with these brain regions and modulate self-location and the conscious experience of the body (mental representation of the body shape and size, body ownership). Finally, I will present psychophysical data showing that, by distinguishing self-motion from other- and environment-motion, vestibular signals contribute to the subjective experience of being a self.
Talk 3: “Is there a vestibular-somatosensory interaction? Evidence from brain-damaged patients and healthy participants”
Gabriella Bottini (Psychology Department, University of Pavia, Italy)
Abstract: Signals from the vestibular system make a crucial contribution to everyday behaviours. No primary vestibular cortex has been identified, rather several multimodal areas integrate vestibular, visual and somatosensory signals. Functional imaging results revealed a clear anatomical overlap of vestibular and somatosensory projections in a number of parietal areas. Moreover, clinical evidence suggests a direct functional link between these sensory systems: a temporary remission of tactile imperception has been observed after left cold caloric vestibular stimulation in right and left brain-damaged patients. Further, psychophysical studies showed that vestibular stimulation improves detection of touch but, intriguingly, it also dramatically increases the threshold for detecting pain. These results lead to the suggestion that specific cross-modal perceptual interactions occur between vestibular and somatosensory systems. Successful interaction with the environment involves constant adjustment and updating of multisensory inputs. The vestibular system seems to play a crucial role in influencing processing within other individual sensory channels.