Morning tutorial descriptions
Tutorial 1: The Scope and Limits of Brain Imaging in Consciousness ResearchHakwan Lau Department of Experimental Psychology, Oxford University Wellcome Department of Imaging Neuroscience, University College London
Brain imaging has gained a lot of attention within the consciousness research community. The aim of this workshop is to give a non-technical (i.e. no equations) introduction to brain imaging, allowing non-experts to be able to read and understand experimental reports critically. First I explain the basic procedures and mechanisms of how a typical fMRI or PET study is done, and how the data are analyzed. I then focus on the methodological problems that are often found in published articles, such as statistical errors and anatomical mis-localization. The results in imaging often depend on how the data were analyzed, and therefore a cautious reading of the methodology is necessary. I then move on to discuss issues of interpretation using examples from the consciousness research literature. I particularly pick out cases where theoretical interpretations of brain imaging results were misguided, and explain why some forms of arguments are fallacious. For example, the fact that two tasks reveal similar activations in the same brain region does not necessarily mean that they are fundamentally related; there are only so many brain regions defined by conventional labels. I then describe some more advanced methods that bypass the problems discussed. These include repetitional priming, connectivity analyses, high-resolution imaging and multivariate approaches. Finally I also describe other relatively new techniques such as MEG and fMRI-guided TMS and discuss how they might contribute to consciousness research in the future.
Tutorial 2: Representing and misrepresenting the bodyFrederique de Vignemont Institut of Cognitive Science Roblin Meeks Princeton University
What neural subsystems are implicated in representing one’s body? Do we
draw upon the same subsystem to represent the bodies of others? How
sensitive are such representations to input from different sensory
modalities? What underwrites or constitutes our sense of bodily
ownership, the feeling we have that we experience a particular body
“from the inside”? In this workshop we investigate the central
questions surrounding the ways in which we represent and misrepresent
our bodies in thought and action. We canvas recent work in both
philosophy and psychology, paying particular attention to
neuropsychological data concerning disruptions in body representations
such as asomatognosia and autotopagnosia and the susceptibility of
normal subjects to illusions of limb ownership. We end with
considerations as to how philosophical theories of conscious experience
of our bodies can both inform and be informed by empirical data.
Tutorial 3: Reading conscious and unconscious mental states from human brain activity
John-Dylan Haynes Bernstein Center for Computational Neuroscience Berlin
Recent advances in human neuroimaging have shown that it is possible to
accurately “read” or “decode” a person's conscious experience from
non-invasive measurements of their brain activity. Such decoding is
based on the idea that each thought is associated with a unique spatial
pattern of brain activity. By training a computer to recognize these
unique patterns it is possible to reliably read many different thoughts
from a person’s brain activity. This tutorial will give a broad
overview of the emerging field of “brain reading”, as well as an
in-depth discussion of its implications for research on consciousness.
The first section will provide a historical overview of brain reading
with a special focus on EEG. The second section will concisely present
the main brain imaging techniques used for brain reading (EEG, single-
and multi-cell recordings, fMRI). The third section will introduce the
key concepts of information theory and pattern recognition in an easily
accessible form. The fourth section will present an overview of the
current “state of the art” in the field including many examples. The
fifth section will show in-depth all steps involved in a typical
brain-reading study. For this purpose a study will be presented
step-by-step that tracks a dynamically changing “stream of
consciousness” using fMRI. A sixth section will demonstrate how
decoding-based research can provide important clues about conscious and
unconscious information processing, and how it is a useful framework
for studying neural “representation” in general. Finally, the current
challenges and limitations of brain reading techniques will be
discussed along with perspectives for future research.
Tutorial 4: Can inner experience be faithfully described?
Russell T. HurlburtPsychology,University of Nevada, Las VegasEric SchwitzgebelPhilosophy, University of California, Riverside
Psychologist Russell Hurlburt is known for his innovative methods of exploring inner experience. Philosopher Eric Schwitzgebel is known for his skepticism about such methods. Hurlburt and Schwitzgebel will team up (perhaps “square off” would be a better term) and interview two subjects selected from the ASSC membership about the details of their inner experience. That interview will follow Hurlburt’s Descriptive Experience Sampling (DES) method: the subjects will have taken DES random beepers into their natural environments and paid attention to whatever experiences were ongoing at the moments of a half-dozen random beeps. Hurlburt, Schwitzgebel, and the tutorial attendees will question the subjects about those beeps during what DES calls the “expositional interview.” During these interviews, we (all tutorial participants) will conduct “sidebar” discussions about: what are the characteristics of good and bad questions; how believable are the subjects’ reports; to what extent do we “lead the witness”; etc.
Tutorial 4 attendees: Would you like be a subject in this demonstration? If so, visit http://www.nevada.edu/~russ/assc-demo-participants.html
Afternoon Tutorial Descriptions
Tutorial 5: The Pharmacology of Perception
Olivia Carter Vision Sciences Lab, Psychology Dept,Harvard UniversityMichael SilverHelen Wills Neuroscience Institute and School of Optometry,University of California, Berkeley
studies have proven to be invaluable to molecular, cellular, and
systems neuroscientists in the study of neurons and neural networks.
The benefits of being able to experimentally manipulate complex systems
in a biochemically-specific manner are well-established in these
fields. However, pharmacology has rarely been employed in the study of
perception, cognition, or consciousness. This tutorial will show how
pharmacological research can provide critical information regarding the
neurotransmitters that modulate consciousness as well as providing
insights into the neural correlates of consciousness itself.
Specifically, we will explore the pharmacology of perception in three
sections that will be accessible to nonscientists but also be detailed
enough to give the most experienced neuroscientist plenty to think
about. The three sections will include 1) Introduction to
neuropharmacology, from receptor biochemistry to the cognitive
functions of the major neurotransmitter systems. 2) The role of
serotonin (5-HT) in visual perception. We will review a number of
experiments indicating a special role for the cortical 5 HT2A receptor
in the action of hallucinogenic drugs. Data will also be presented from
human behavioral studies examining the effects of psilocybin (the
5-HT2A activating drug found in magic mushrooms) on visual perception
and attention. 3) The role of acetylcholine in cognition, including
learning, memory, and attention. Behavioral and neuroimaging results
from cholinergic pharmacology studies in humans will be discussed,
including studies of attention and visual perception.
Tutorial 6: What is self-specific? A tutorial questioning the cerebral correlates of the self
Dorothée Legrand (Chair)CREA, Centre de Recherche en Epistémologie Appliquée.Perrine Ruby (Chair)Centre hospitalier Le Vinatier
The self is increasingly investigated empirically. However, reviews show that the self still lacks both consensual definition and specific cerebral correlates. This tutorial intends to better understand and overcome this critical situation.
First (Dorothée Legrand), two criteria for self-specificity will be determined: Exclusivity (X applies only to the self) and Collinearity (Any change of X entails a change of the self). These criteria are met neither by evaluative processing nor by self-attributed contents, but by first-person perspective. The latter relates represented objects to the representing subject without depending on any representation of the self. It is proposed that such relation is made possible at a basic level thanks to a sensori-motor integration i.e. the matching of efference with re-afference (afference issuing from the subject's own action) Self-specificity will thus be accounted for in functional terms, in a framework integrating a dynamic sensorimotor approach and a phenomenological account of bodily self-consciousness.
Second (Perrine Ruby), a review of the neuroimaging literature will
come in support to this theoretical proposal. A synthesis of a wide
range of neuroimaging studies tackling self, mind reading, memory,
reasoning and resting state issues will serve to demonstrate that the
cerebral activations repeatedly reported in self-related studies are
also recruited for others-related tasks. It is argued that such common
cerebral network can thus not subserve any self-specific component, but
would rather subserve a general cognitive processing of evaluation
using information recalled from memory, which would explain its
recruitment in all the aforementionned tasks. The search of the self is
thus re-oriented toward the self-specific first-person perspective.
Results of the literature showing increased activity in
somatosensory-related corticies for first (vs third) person perspective
coheres with the theoretical proposal that the first-person perspective
is grounded on
sensorimotor integration and encourage further invesigations in this direction.
Tutorial 7: The relationship between top-down attention and consciousness
Naotsugu Tsuchiya and Christof Koch California Institute of Technology
Historically, the pervading assumption among sensory psychologists is that what a subject attends to is what she is conscious of. That is, attention and consciousness are very closely related, if not identical, processes. However, a number of recent authors have argued that these are two distinct processes, with different neuronal mechanisms. While the neuronal correlates of consciousness remain elusive, significant progress has been made in studying the neuronal correlates of “unconscious” processing; a multitude of techniques---such as masking, crowding, attentional blink, motion-induced blindness, continuous flash-suppression, and binocular rivalry---permit visual scenes to be presented to subjects without subjects becoming aware of them. Such experiments, coupled to fMRI in humans and single-cell recordings in behaving monkeys, show that vigorous hemodynamic and spiking activity in cortex is often not associated with conscious perception.
Building upon the successful tutorial at ASSC10, we review and update the recent evidence showing 1) that invisible stimuli can be attended with top-down attention and can influence subsequent behavior, 2) that to observe some behavioral evidence of unconscious processing, top-down attention to invisible stimuli is necessary and 3) that under some conditions top-down attention and consciousness can result in opposite effects.
The philosopher Ned Block has argued on conceptual grounds for two forms of consciousness, access (A) and phenomenal (P) consciousness. Given the data, it may be possible that A is equivalent to top-down attention and read-out (which usually, but not always, goes hand-in-hand with P) while P can occur with or without top-down attention.
Tutorial 8: “Measuring consciousness”: Combining objective and subjective data, and what it may all mean
Axel Cleeremans Cognitive Science Research Unit, Department of Psychology, Université Libre de Bruxelles
Morten Overgaard Neuropsychological Laboratory,Hammel Neurorehabilitation and Research Center
Andreas K. EngelDept. of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf
Can we measure consciousness? Does the question even make sense? On the one hand, any empirical approach to consciousness would seem to require that the concept be sufficiently well defined that we can indeed measure it, just as we can measure energy, mass, or reaction time. On the other, many would disagree with the very idea that consciousness is something that one can “measure”, as we have no direct way of assessing its presence in others In light of this quandary, it has been pointed out that consciousness presents unique methodological challenges for its study requires that one combines subjective (“first-person”) and objective (“third-person”) data. While some of these methods are familiar, many others have been proposed recently, and some have not been thoroughly explored yet. The main goal of this tutorial is to overview the different methods one can deploy to contrast information processing with and without consciousness. Many such methods are inherently interdisciplinary, and the tutorial will therefore highlight complementary methods ranging (1) from neuroimaging to introspection, (2) from methods appropriate to study normal cognition to methods best applied to patients, (3) from methods aimed at characterizing states or levels of consciousness to methods aimed at appreciating its contents and dynamics. In all three cases, we will focus specifically on how to best combine subjective and objective data, as well as on metatheoretical issues, such as the problem of bias in subjective methods or the problem of spurious correlations between performance and consciousness in imaging studies. The tutorial will be illustrated with recent experimental data.