Plenary Symposia

2006 Tom Slick Research Award in Consciousness

- Saturday, June 23. 8:30AM - 10:30 AM -


“Who Am I? Where Am I? – Neurobiological and Philosophical Concepts of the Self”

Mind Science Foundation – “Distinguished Debates in Consciousness”

Daniel C. Dennett
Tufts University. Massachusetts, USA
Michael Gazzaniga
University of California, Santa Barbara. California, USA

Cross-modal Plasticity

Melissa Saenz
California Institute of Technology. California, USA

Much of the human brain cortex is devoted to visual processing, leading to the question of what happens to the visual cortex in people who are blind? Brain imaging studies have shown that the visual cortex of people who became blind early in life responds to a variety of non-visual auditory, tactile, and verbal tasks. This sensory reorganization is called cross-modal plasticity. It is still unknown how the cross-modal responses map onto the normal functional subdivisions of the visual cortex. I am currently conducting neuroimaging (fMRI) experiments to address this question. My experiments also study the long-term effects of cross-modal plasticity in formerly blind individuals with sight recovery.


Development and Application of Real-Time fMRI

Fumiko Hoeft
Stanford University, California, USA

One of the applications we are currently focusing on is to provide feedback of fMRI signal in real-time from a specific brain region (e.g. anterior cingulate) to healthy individuals and patients with chronic pain and anxiety disorders to investigate whether people can learn to control the activation of a localized brain region and whether there is a corresponding change in cognition and behavior. In addition, in patients, we are investigating whether there is a resultant change in their symptoms (e.g. pain).
ACKNOWLEDGEMENT: This ongoing project is funded by NIH/NINDS 9R44NS050642-03, NIH/NIDA N43DA-4-7748, and NIH/NIDA N44DA and the Mind Science Foundation.

 

Cortical Networks and Conscious Awareness


Faces, Cortical Networks and Effective Connectivity

Alumit Ishai (Chair)
University of Zurich. Zurich, Switzerland

- Sunday, June 24. 2:30PM - 3:00 PM -

Face perception elicits activation within a distributed cortical network that includes visual (‘core’) regions, as well as limbic and prefrontal (‘extended’) regions, which process invariant and changeable facial features, respectively. Using fMRI and Dynamic Causal Modeling, we investigated effective connectivity and functional organization between and within the core and the extended systems. We found that the core system is hierarchically organized in a predominantly feed-forward fashion, and that the fusiform gyrus exerts the dominant influence on the extended system. Moreover, emotional faces increased the coupling between the fusiform gyrus and the amygdala, whereas famous faces increased the connectivity between the fusiform gyrus and the orbitofrontal cortex. Implications of these findings will be discussed in the context of conscious awareness, mental imagery, and face recognition deficits in prosopagnosic patients.


Fundamental antagonistic networks in the human cortex: implication to neuronal models of subjective awareness.

Rafi Malach
Weizmann Institute of Science. Rehovot, Israel

- Sunday, June 24. 3:00PM - 3:30 PM -

Could it be that activity in a small, isolated cortical network is sufficient for perceptual awareness? It may seem that besides being extremely counter-intuitive this conjecture can never be tested experimentally. Indeed how can we ever find out if some cortical network in our brain develops a subjective awareness of its own? Fortunately, there is at least one mental stat that may allow us to ‘peak’ into such an independent cortical activity. This mental state is paradoxically associated with moments of a particularly heightened perception, where we have the intuitive sense of ‘losing our selves’. I will review data, obtained from fMRI research, showing that during such intense moments, cortical regions associated with introspection are shut-off, leaving sensory cortex to be active on its own. Furthermore, this behavior reflects a more fundamental antagonistic relationship between ‘extrinsic’ networks engaged in perception, and more ‘intrinsically’ oriented cortical systems. While these experiments are far from proving that isolated network activity suffices for perceptual awareness- they provide a first step in this direction, and illustrate that such ‘minimal’ models of awareness are experimentally tractable.


Consciousness and effective connectivity in wakefulness and sleep

Giulio Tononi
University of Wisconsin. Madison, USA

- Sunday, June 24. 3:30PM - 3:30 PM -

According to a theoretical prediction (Tononi, 2004), consciousness depends critically not so much on firing rates, synchronization at specific frequency bands, or sensory input per se, but rather on the brain's ability to integrate information. This is contingent on the effective connectivity among functionally specialized regions of the thalamocortical system. In a series of experiments we used a combination of TMS and EEG to measure directly the changes in effective connectivity that occurs in the human brain when consciousness fluctuates across the sleep-wake cycle. We observed that, as vigilance drops, from light drowsiness to deep NREM sleep, the response of the brain to a direct cortical perturbation becomes larger and larger, while specific patterns of long-range activation are progressively impaired. During REM sleep, effective connectivity partially recovers. Further experiments suggested that the breakdown of effective connectivity observed during NREM sleep may be due to intrinsic bistability in thalamocortical networks between up- and down states.

 

The Cognitive Basis of Intuitions about Consciousness

Philosophers have long taken an interest in intuitions about consciousness. This symposium would offer a new twist on that familiar approach. Each of the researchers presenting talks would report experimental data on the nature of people’s ordinary intuitions. The speakers then draw on these data to offer specific hypotheses about the cognitive basis of intuitions about consciousness. The symposium would bring together researchers from a number of disciplines, including philosophy, neuroscience and social psychology.

Intuitions about Consciousness: Experimental Studies

Joshua Knobe (Chair) and Jesse Prinz
University of North Carolina. North Carolina, USA

- Monday, June 25. 8:30AM - 9:00 AM -

People's understanding of an entity's mental states can be influenced both by functional considerations and by strictly physical considerations. We conducted a series of studies to determine how each of these kinds of considerations impact people’s mental state ascriptions. The results point to a striking difference between two kinds of states — those that involve phenomenal consciousness and those that do not. Specifically, it appears that ascriptions of states that involve phenomenal consciousness show a special sort of sensitivity to purely physical factors.


Dimensions of Mind Perception

Heather M. Gray, Kurt Gray and Daniel M. Wegner
Harvard University. Massachusetts, USA

- Monday, June 25. 9:00AM - 9:30 AM -

How do people decide what sorts of entities have minds? To date, it has generally been assumed that mind perception occurs on one dimension--things simply have more or less mind--and the dimensions of mind perception have remained unexamined. We studied the structure of mind perception through 2,399 completed online surveys. Participants were asked to compare the mental capacities of various human and non-human characters and to respond to hypothetical moral situations. Factor analyses revealed two dimensions of mind perception: Experience (e.g., capacity for hunger, fear, and pain), and Agency (e.g., capacity for self-control, morality, and memory). In other words, from a perceiver's perspective, there exists a broad distinction between phenomenal consciousness (our Experience factor) and the capacity to exert control. In addition, these dimensions were differentially related to ethical questions; only perceptions of Experience were correlated with a desire to provide protection from harm.

The genuine problem of consciousness

Philip Robbins and Anthony Jack
Washington University. Missouri, USA

- Monday, June 25. 9:30AM - 10:00 AM -

Those who are optimistic about the prospects of a science of consciousness, and those who believe that it lies beyond the reach of standard scientific methods, have something in common: both groups see consciousness as posing a special challenge for science. In this talk, we view this challenge through the lens of social neuroscience. We show that popular conceptions of the problem of consciousness, epitomized by David Chalmers' formulation of the "hard problem", can be best explained as a cognitive illusion, which arises as a by-product of our cognitive architecture. We present evidence from numerous sources to support our claim that we have a specialized system for thinking about phenomenal states, and that an inhibitory relationship exists between this system and the system we use to think about physical mechanisms. Even though the hard problem is an illusion, unfortunately it appears that our cognitive architecture forces a closely related problem upon us. The "genuine problem" of consciousness shares many features with the hard problem, and it also represents a special challenge for psychology.

 

Animal Consciousness:
Towards a Scientific Description and Natural History

David Edelman and Anil Seth (Co-Chairs)
The Neurosciences Institute. California, USA and University of Sussex. Brighton, UK

The majority of investigations of human consciousness have relied on “accurate reports”, supplied by healthy or brain-damaged individuals, of what they experienced during experimental trials. In species without natural language, however, acquisition of accurate reports of conscious contents presents a major challenge. But now, timely advances in functional neuroanatomy, neurophysiology, and genetics offer the possibility of exploring consciousness substantively and systematically in non-human mammals, birds, and possibly other species as well. In this symposium, recent research in animal cognition relevant to consciousness will be highlighted by three invited speakers whose efforts extend the state of the art. The co-organizers will describe a methodological framework for the investigation of animal consciousness that incorporates the speakers’ findings; finally, a speculative phylogeny of animal consciousness will be proposed with the aim of stimulating future investigations of consciousness in species far removed from the human, mammalian, or even vertebrate, lines.


Cognition and Communication in Grey Parrots

Irene Pepperberg
Harvard University. Massachusetts, USA

- Monday, June 25. 10:30AM - 11:00 AM -

For almost 30 years I have studied cognitive and communicative abilities of Grey parrots. Although I do not examine consciousness directly, my research seeks to answer questions related to consciousness: (1) To what extent can a nonhuman, nonprimate (with a brain the size of a shelled walnut) share mental capacities, representations, and comprehension with humans? (2) To what extent, and at what level, do mechanisms of cognition and communication exhibited by this avian species resemble those operating in humans? (3) To what extent, and for what innate purpose, have such avian abilities been developed? (4) Can the study of mechanisms for vocal learning in the laboratory help us understand human vocal learning; that is, can an avian subject be a model for human processes? My data, showing that, on some tasks, Grey parrot abilities match those of young children, suggest that these birds are viable candidates for more advanced study.


Is there a vertebrate mechanism of consciousness, and how would we recognize it if we saw it?

Björn Merker
Royal University College of Music. Stockholm, Sweden

- Monday, June 25. 11:00AM - 11:30 AM -

The general plan of the vertebrate brain is highly conserved in
phylogeny, such that its principal subdivisions and fiber tract circuitry can be homologized across widely different species throughout the vertebrate clade. An issue of fundamental importance for our understanding of animal consciousness is accordingly whether a “mechanism of consciousness” might be implemented as part of this conserved circuitry – which would mean that all vertebrates are conscious creatures – or whether consciousness is a matter of specializations added to this circuitry in some species – say the mammalian novelty of a neocortex – but absent in others. In my presentation I will outline conceptual approaches to this question drawing on a characterization of minimal requirements for conscious function on the one hand, and on conjectures regarding the role and organization of such a functional mode within the over-all economy of brain macrosystems on the other. Implications of this perspective for the larger issue of the possibility of consciousness in invertebrate animals will also be considered.

 


The 'octopus' cognition: reality or dreams of scientists

Graziano Fiorito
Stazione Zoologica Anton Dohrn. Naples, Italy

- Monday, June 25. 11:30AM - 12:00 AM -

The cephalopod mollusc, Octopus vulgaris, an invertebrate, has been long considered a learning animal exhibiting an enriched behavioral repertoire of comparable complexity with the one recognizable in higher vertebrates up to humans. I will review briefly almost a century of research effort dedicated to the understanding of its learning capabilities and the underlying neural correlates. In reviewing this history we will be faced with limits in the capabilities of octopuses such as the lack of kinaesthetics. I will try to show that these "limits" are weak and that the octopus should be considered a model to test properties such as parallel processing, sensorial independence and hierarchical organization of motor control, "self perception".
This with the aim to show that the octopus, an invertebrate, is an experiment in the phylogeny that may allow us to ask questions on consciousness in animals.