ASSC9 Tutorial workshops

Tutorials will take place on Friday June 24. There will be one morning session of three tutorials and one afternoon session of four tutorials. Each tutorial will last three hours. The cost of tutorial attendance is $50 per single tutorial, $90 for two.

Morning Tutorials

Afternoon Tutorials

M1. EMOTION, FEELING, AND THE BRAIN

Ralph Adolphs
Division of Humanities and Social Sciences
Caltech
Email: radolphs@hss.caltech.edu

Syllabus:
Theories of emotion and feeling
Psychology of emotion
Cognitive Neuroscience of emotion: The Amygdala and orbitofrontal cortex
Cognitive Neuroscience of emotion: Somatosensory Cortices and simulation
Neural and functional basis of the experience of emotion

Summary:
Emotion and feeling figure prominently in everyday life, as well as in pathological states. Yet philosophical and psychological accounts have had difficulty providing explanations of these phenomena. In particular, they have had difficulty situating them within dominant accounts of representation and cognition. Recent findings from cognitive neuroscience provide a wealth of data that support a new view, according to which emotions and feelings represent the value of stimuli in a common currency of the survival and homeostasis-related states of our bodies. This new picture traces a common thread from writers such as William James to Antonio Damasio and Jesse Prinz. The workshop will sandwich a review of the current state of the neuroscience between the theoretical questions and accounts.

Short Bibliography:
Adolphs, R. (1999). "Social cognition and the human brain." Trends in Cognitive Sciences 3: 469-479.
Adolphs, R., F. Gosselin, et al. (2005). "A mechanism for impaired fear recognition after amygdala damage." Nature 433: 68-72.
Damasio, A. R. (1999). The Feeling of What Happens: Body and Emotion in the Making of Consciousness. New York, Harcourt Brace.
Russell, J. A. (2003). "Core affect and the psychological construction of emotion." Psychological Review 110: 145-172.
Scherer, K. R. (2000). Psychological models of emotion. The Neuropsychology of Emotion. J. C. Borod. New York, Oxford University Press: 137-162.

M2. INVESTIGATING NEURONAL CORRELATES OF CONSCIOUS VISUAL PERCEPTION

Alexander Maier & Melanie Wilke
Unit on Cognitive Neurophysiology and Imaging
National Institutes of Health
Email: maiera@mail.nih.gov

Recording the activity of individual cortical neurons during a sequence of multistable perceptual states has proven to be a fruitful approach for studying neuronal correlates of visual awareness. Focusing on the neurophysiological exploration of bistable perception in primates, this tutorial aims at providing an overview of basic techniques employed in isolating percept-related activity from general visual activation.

  1. First Hour: Psychophysical Findings on Multistable Perception, Binocular Rivalry and Visual Suppression

    We will give a brief introduction to multistable perception, including binocular rivalry and temporally triggered perceptual suppression (e.g.
    generalized flash suppression). We outline psychophysical results gathered with these paradigms, and discuss general commonalities of
    perceptual fluctuations during ambiguous visual stimulation. The advantages and disadvantages of these perceptual phenomena for
    neurophysiological studies will be evaluated and the scope of their applicability to neuroimaging assessed.
     

  2. Second Hour: Measuring Subjective Perception in Unreliable Subjects

    An important step for successful studies of subjective vision is to transform relevant psychophysical paradigms into meaningful neurophysiological experiments. One major obstacle for electrophysiological and neuroimaging studies of multistable perception is the degree of confidence that an experimenter can gain in a subject’s perceptual report. We will present various strategies that have been employed to test the reliability of subjects when their perception cannot be predicted from stimulation. These techniques include the use of statistical predictions, ongoing behavioral reinforcement as well as close observations of objective physiological markers such as involuntary eye movements. Covering differences between human and monkey approaches, we will demonstrate the application of each of these procedures based on practical examples.
     

  3. Recording Neuronal Correlates of Perception

    We will discuss several techniques used for measuring correlates of subjective perception on the level of single neurons and larger cell populations, and confer their benefits and problems. On the basis of recently collected data in monkey experiments, we will demonstrate how different neuronal signals (single unit firing rates, multiunit activity and local field potentials) can be related to varying aspects of visual awareness in early visual areas. Further, we will describe various statistical methods commonly used in these studies, generally dealing with a large variance within small sample numbers. The insight these studies have provided into neuronal mechanisms of perceptual organization and visual awareness will be discussed.

Short bibliography:
Leopold, D.A., Maier, A., Wilke, M. & Logothetis, N.K. (2004) Binocular rivalry and the illusion of monocular vision. In: D. Alais & R. Blake (eds.), Binocular rivalry, Cambridge, MA: MIT Press.
Gail A, Brinksmeyer HJ, Eckhorn R. (2004) Perception-related modulations of local field potential power and coherence in primary visual cortex of awake monkey during binocular rivalry. Cereb Cortex. 14(3):300-13.
Leopold, D.A., Maier, A. & Logothetis, N.K. (2003) Measuring subjective visual perception in the nonhuman primate. J. Consc. Stud. 10( 9-10): 115-130
Wilke M, Logothetis NK, Leopold DA. (2003) Generalized flash suppression of salient visual targets. Neuron. 39(6):1043-52.
Leopold, D.A., Wilke, M., Maier, A. & Logothetis, N.K. (2002) Stable perception of visually ambiguous patterns. Nat. Neurosci. 5(6): 605-609
Kreiman G, Fried I, Koch C. (2002) Single-neuron correlates of subjective vision in the human medial temporal lobe. PNAS 99(12):8378-83.
Leopold DA, Logothetis NK. Multistable phenomena: changing views in perception. TICS. 1999 3(7):254-264.
Logothetis, N.K. (1999) Vision: a window on consciousness. Sci. Am. 281(5):69-75
Crick, F. (1996) Visual perception: rivalry and consciousness. Nature 379(6565):485-6
Leopold DA, Logothetis NK. (1996) Activity changes in early visual cortex reflect monkeys' percepts during binocular rivalry. Nature. 379(6565):549-53.

 

M3. EMERGING ETHICAL ISSUES IN CONSCIOUSNESS RESEARACH FROM NEUROETHICS TO CONSCIOUSNESS ETHICS

Tutorial Presenters:
Thomas Metzinger
Director of the Theoretical Philosophy Group at the Department of
Philosophy of the Johannes Gutenberg-Universität Mainz
metzinger@uni-mainz.de

Stephan Schleim
Theoretical Philosophy Group at the Department of Philosophy of the
Johannes Gutenberg-Universität Mainz
schleim@students.uni-mainz.de

While there has been considerable scientific progress in consciousness research during the last two decades, the ethical reflection concerning research methods, technological consequences, social impact and the wider anthropological and cultural ramifications only began very recently. This development is interestingly paralleled be the emergence of the new field of "neuroethics" in cognitive neuroscience (for a recent review, see Farah 2005, in TICS 9(1): 34-40).

In this tutorial we will start out with a brief introduction into the different logical levels in philosophical ethics, and then proceed to the problem of domain-specific applied ethics. Do we need an applied ethics for consciousness research?
In the second half of session 1 we will complement with a general overview about the new field of neuroethics and its current status. It is interesting to note how, quite recently, a number of researchers in the neuro and cognitive sciences have started to develop domain-specific ethical investigations. An interesting question is if any of these investigations are relevant for consciousness as well. We think some of them are.

Therefore, we will then offer participants a catalogue of ethical issues in consciousness research, informing about those neuroethical issues that possess specific relevance in consciousness science. For instance, we will sketch ethical problems and solutions such as the availability and use of consciousness-altering drugs (legal as well as illegal), the experimental use of animals in consciousness research, military funding, neuropedagogics, or the individual scientists' responsibility implied by the impact of new scientific methods, for example, various brain-scanning techniques and the use of "brain
finger-printing" by legal authorities, on the life of individuals in society. The second session will try to define the current landscape of neuroethics for consciousness.

We will conclude the tutorial with a third session that then turns to more general issues: What could the social and cultural ramifications of progress in consciousness research be? How is the general image going to change, and how can the to-be-expected consequences of such a change be assessed in a timely manner? How can we intelligently minimize the price we will pay for scientific progress, and how can we ensure distributive justice with regard to the many positive benefits
consciousness research will offer in the decades to come?

Timetable:
Part 1: Introduction: Descriptive ethics, normative ethics, and metaethics (Metzinger, 30 minutes)
Part 2a: Introduction: Neuroethics, a general overview (Schleim, 30 minutes)
    Discussion (10 minutes)
Part 2b: Specific neuroethical issues in consciousness research (Schleim, 50 minutes)
    Discussion (10 minutes)
Part 3: "Consciousness ethics": General issues in the applied ethics of consciousness research (Metzinger, 40 minutes)
    Discussion (20 minutes) 

A1. PSYCHOPHYSICAL METHODS FOR RENDERING STIMULI INVISIBLE

Bruno Breitmeyer <Bruno.Breitmeyer@mail.uh.edu> and Vince di Lollo <vince_dilollo@sfu.ca>

In the past decade, the use of psychophysical techniques that render stimuli invisible or inaccessible to conscious report have become increasingly important in the study of visual cognition and in research on neural correlates of conscious and unconscious vision. The aim of the proposed tutorial is to introduce researchers interested in the study of conscious and unconscious visual processing to a range of psychophysical techniques and their effects on the visibility of stimuli. The techniques and phenomena to be covered and demonstrated in the tutorial will include:

  1. Standard methods of forward and backward pattern masking, including paracontrast and metacontrast;

  2. Temporal integration in vision and its relation to pattern masking;

  3. Target recovery (disinhibition),

  4. Object-substitution masking and the attentional blink.

These topics will be covered by two researchers, Bruno Breitmeyer and Vince Di Lollo, who are leaders in the above areas of study. Bruno Breitmeyer will cover Topics 1 and 3; and Vince Di Lollo, Topics 2 and 4. Below are brief descriptions of the material presented by each of the contributors.

B. Breitmeyer:
The first presentation and discussion topic will be standard masking procedures and phenomena.

These include:

  1. Forward and backward pattern masking, where the mask spatially overlaps the target;

  2. Para- and metacontrast, where the mask and target are spatially juxtaposed.

  3. Procedural/methodological aspects of these masking phenomena and the typical outcomes yielded by these procedures.

  4. Demonstrations of these procedures and outcomes will also be provided.

  5. Current theoretical accounts of these masking phenomena will also be briefly presented. The latter are important, since they, in turn, may contribute to our understanding of unconscious and conscious information processing by the visual system.

  6. Applications of standard masking to studies of unconscious and conscious processing
    of visual object attributes. The attributes include i) object location, ii) object surface properties, and iii) object contour/form properties.

The discussion will again be enriched by the “what/where” and “form/surface” distinctions made in several empirically and theoretically based accounts of visual object perception. 

V. Di Lollo:
The first topic to be presented and discussed will be the phenomenon of temporal integration in vision and its relation to
pattern masking. Temporal integration is commonly believed to be mediated by visible persistence (a brief period during which a stimulus remains visible after the physical display has been switched off).  Television images have provided the traditional example. Because of visible persistence, all parts of a TV image appear to be simultaneously present of the screen, even though the physical display consists of a single point of light displayed successively at every screen location, each of which continues to emit light for less than one millisecond. A series of demonstrations will be used to refute the
conventional belief that visible persistence is based on the contents of an iconic store that begins to decay when the stimulus is turned off. Instead, it will be shown that conscious awareness of a temporally-integrated display stems from ongoing neural processes time-locked to stimulus onset. A further series of demonstrations will illustrate the link between visible persistence and pattern masking by temporal integration.

B. Breitmeyer:
The second presentation and discussion topic will focus on target recovery (target disinhibition) produced by one of two procedures:

  1. The use of a secondary mask to weaken/eliminate the target-suppressive effect of the primary mask

  2. The use of binocular rivalry suppression to weaken/eliminate the target-suppressive effect of the primary mask.

  3. A demonstration of the first of these target recovery procedures also will be provided.

  4. Dissociations between visual cortical processes contributing to a stimulus’s effectiveness as a mask and to its visibility.

  5. Theoretical implications of these processes for theories of masking and for our understanding of functional hierarchies of unconscious and conscious visual processing also will be discussed.

V. Di Lollo:
The second topic concerns a new, non-standard form of visual masking procedure and phenomenon, viz., object-substitution masking. Besides outlining the

  1. Procedural/methodological aspects of  object-substitution masking and the typical outcomes yielded by these procedures

  2. Demonstrations of these procedures and outcomes will also be provided.

  3. Theoretical accounts of these masking phenomena, based on interactions between cortical feedforward
    and reentrant processes, will also be briefly presented. These again are important, since they may shed light on where and how unconscious and conscious information processing occurs in the visual system.

  4. Following this material, there will be a discussion of applications of object-substitution masking to studies of unconscious and conscious processing of visual object attributes. A final series of demonstrations will illustrate the link between object-substitution masking and a phenomenon known as the “attentional blink” in which conscious perception of the second of two rapidly sequential targets is impaired if it is presented within about 500 milliseconds from the first.

A2. The Feeling of Hurt: A Brain – Body Perspective on Pain

C. Richard Chapman
Director of the Pain Research Center
Department of Anesthesiology
University of Utah

Human pain is a complex somatic awareness involving sensation, emotion and cognition. It can fail to occur with tissue trauma and persist indefinitely in the absence of tissue trauma, causing disability. This workshop will provide a review of the basic neurophysiological mechanisms of pain, psychological aspects of pain, and pathological pain states including phantom limb pain. Discussion of mechanisms will include the effects of nociception on the central nervous system including limbic structures, the hypothalamo-pituitary-adrenocortical axis, and the immune system. These three systems share common chemical messengers and interact to produce negative somatic feeling states such as pain, fatigue, and sickness.

A3. COLOR & CONSCIOUSNESS

Robert Kentridge

Department of Psychology,
University of Durham, UK.

robert.kentridge@durham.ac.uk

Timetable:
What are the functions of colour vision (is there more than one)?
Seeing surfaces and the problem of colour-constancy.
Using colour in perception, attention and memory.
The anatomy and physiology of wavelength processing.
Neurological colour deficits and the loss of colour experience.
What are the neural and functional correlates of colour experience?

(each section approximately 30 minutes)


Summary:
Our experience of colour is so intense that it is probably the canonical example used in discussions of qualia. The transformation of wavelengths of light into our percepts of colour is, however, complex, as are the uses to which colour percepts are then put. The core question we address in this tutorial is whether specific aspects of these transformations and uses give rise to colour experience. In pursuit of an answer we provide tutorial reviews of the anatomy and physiology of wavelength processing, the psychology of colour-constancy and colour categorisation, and the neurology of colour-specific visual deficits (of which there are many). By tying together evidence from each of these areas we show when colour information does and does not give rise to experience and take some steps towards establishing anatomical distinctions between the loci of the covert use of colour and of colour experience.


Short Bibliography:

Foster, D. H. (2003). Does colour constancy exist? Trends in Cognitive Sciences, 7(10), 439-443.

Heywood, C.A. & Kentridge, R.W. (2003) Achromatopsia, color vision and cortex. Neurological Clinics of North America 21, 483-500.

Kentridge, R.W.; Heywood, C.A. & Davidoff, J. (2003) Color perception.
in M.A. Arbib (ed.) Handbook of brain theory and neural-networks (2nd
Edition) pp. 230-233. Cambridge MA: MIT Press.

Mollon, J.D. (1989) "Tho' she kneel'd in that place where they grew..."
The uses and origins of primate colour vision. Journal of Experimental Biology 146, 21-38.

Shapley, R. & Hawken, M. (2002) Neural mechanisms for color perception in the primary visual cortex. Current Opinion in Neurobiology 12, 426-432.

A.4 TEMPORAL AND SPATIAL ANALYSIS OF ELECTROENCEPHALOGRAPHIC SIGNALS

Walter Freeman
<drwjfiii@berkeley.edu>

Consciousness for most of us is realized in a rapid sequence of thoughts, feelings, perceptions and mental images, since few of us are Zen masters. Instead of seeking measures of the state or level of consciousness in subjects, as in evaluating surgical anesthesia or sleepiness, I propose to make images of the neural activity patterns in subjects who give verbal, instrumental or behavioral feedback on their mental states. Making such images is a challenging task that can be addressed with recent advances in EEG analysis. The objective of this tutorial is to describe these advanced methods of analysis of single and multichannel electroencephalographic (EEG) recordings. These new algorithms can be applied in any clinical facility with standard equipment at no great expense. They have applications to the study of intention, attention, expectancy, sensory processing, formation of meaning, learning, habituation, sensitization, epilepsy, etc.

In the first part of the tutorial I will review conventional as well as advanced methods of analysis of EEG in time series and in the temporal frequency domain. One of the most distinctive features of EEGs is the appearance of oscillations in different frequency bands, which reflect the synchronized activity of large groups of neurons. Brain oscillations are correlated with different brain processes and behaviors. Their power is usually quantified by means of the Fourier Transform. This is the most useful tool for analysis of EEGs, but it assumes linearity and stationarity of the signal, and it does not give time information. It is therefore not appropriate when frequency patterns change rapidly over time. For these cases, Ôtime-frequencyÕ representations such as the one given by the Short Time Fourier Transform are more suitable.

In particular, I will describe a relatively new time-frequency decomposition, namely, the Wavelet Transform, and stress its advantages in the analysis of EEG data. I will also describe reformulation of the output of the 1-D FFT by display in log-log coordinates. This display is useful to distinguish among various noise spectra and the Ò1/fÓ scaling that distinguishes EEGs from muscle potentials [electromyograms, EMGs]. As a complement to the Fourier Transform I will introduce the Hilbert Transform, which is needed to get high temporal resolution in order to document rapid changes in frequency and discontinuities in phase. I will include discussion of the criteria for the temporal and spatial filtering that are necessary for effective use of the Hilbert transform.

In the second part I will review recent advances in EEG spatial pattern imaging, with emphasis on techniques for analysis of multichannel scalp recordings from normal human volunteers. Brain processes involving large neuronal assemblies and/or interactions between distant sites are assayed by comparisons between pairs of EEG recordings and among multiple signals. I will describe recently proposed measures of synchronization and compare them to conventional approaches. I will introduce a form of nonstationarity in cortical dynamics, in which cortical states occur as brief stable EEG amplitude patterns, like frames in a movie film (ÒcinematographicÓ). Each window is bracketed by widespread yet simultaneous discontinuities in beta and gamma phase that recur at rates in the alpha and theta ranges.

I will compare two main uses of EEG (localization of modular signals vs. measurement of global spatial patterns) and describe the diametrically opposed methods that these two goals require. I will show the advantages of spatial analysis with 1-D arrays preparatory to 2-D recording. I will use the application of the 1-D FFT to EEGs from curvilinear scalp electrode arrays to exemplify temporal and spatial sampling, aliasing, the Nyquist frequencies, and the spectral features caused by the impedance barriers of the scalp and skull as well as by the sulci and gyri of cortex. I will review the subdivision of temporal EEG spectra into the classical ranges by use of temporal and spatial band pass filters, and introduce the subdivision of spatial EEG spectra. I will conclude with a brief description of some unsolved problems in correlation of EEG and behavior.