Scientific Program
Download the preliminary program here!
Download the detailed schedule here!
Keynote lectures
Optogenetics: development and application
Evaluating the strengths and limitations of birdsong as a model for speech and language
Discussion panels
The neural architecture of semantic memory
The visual word form area: selective for words?
Slide sessions
Poster sessions
Keynote lectures
Karl Deisseroth
Stanford University, USA
Title: Optogenetics: development and application
Abstract: Coming soon!
Daniel Margoliash
The University of Chicago, USA
Title: Evaluating the strengths and limitations of birdsong as a model for speech and language
Abstract: Coming soon!
Discussion panels
Panel A: The neural architecture of semantic memory
Featuring Alex Martin and Karalyn Patterson
Alex Martin is a NIH Senior Investigator and Chief of Section on Cognitive Neuropsychology, NIMH, Bethesda MD.
'Semantic memory' covers a vast terrain of cognition, ranging from information about historical and scientific facts, details of public events and mathematical equations to the information that allows us to identify objects and understand words. Functional neuroimaging and neuropsychological investigations have established a number of findings about this division of memory, especially with regard to the neural substrate underpinning perceiving and knowing about concrete objects. First, object information is not stored in a single place but rather is distributed throughout the brain. Second, the location of this information in the brain is not random. Information about specific properties of objects - such as what they look like, how they move, how they are manipulated, and our emotional response to them - is stored in our perceptual, action, and affective processing systems. Third, these property-based regions are organized into distinct circuits; some of which underpin knowing about broadly defined object categories such as animate entities (living things that move on their own) and manmade manipulable objects designed to perform specific functions ('tools'). Integration of object property-based information is a characteristic of the circuits themselves, accomplish via the dynamic interaction among the nodes. As a result of this co-dependence, damage to one node could potentially cause widespread disruption and even a catastrophic collapse of the circuit, resulting in a domain-specific category disorder. Generalization across concepts, as well individualization of specific concepts is a function of these circuits, perhaps in unison with frontal cortices. These circuits serve as a foundation or scaffolding upon which we can build our rich store of conceptual knowledge, much of which is dependent on, and stored in, the language system. The idea of a single hub in the anterior temporal lobe(s) for integration of information to support generalization and other conceptual functions is unnecessary. A single hub architecture for conceptual processing remains largely unsupported by a variety of measures, including a spate of recent studies on the large-scale functional connectivity of the human brain. More likely roles for the anterior temporal lobes in conceptual processing include representation of individuals or a more general role in social processing, and/or experience-dependent sharpening of representations stored elsewhere.
Karalyn Patterson is a senior scientist at the Department of Clinical Neurosciences, University of Cambridge UK and Medical Research Council Cognition & Brain Sciences Unit, Cambridge UK
Essentially all current views about semantic memory share the idea that much of the content of our semantic memory relates to perception and action and is represented in brain regions that overlap with, or possibly even correspond to, the regions responsible for perceiving and acting. This view about semantic memory therefore entails commitment to the idea that semantic memory is a widely distributed neural network, with its individual components taking 'responsibility' for different modality-specific aspects of conceptual knowledge (visual, auditory, tactile, etc) and also perhaps for different categories of knowledge (e.g. living things vs. manmade objects). Theoretical positions differ, however, on the following question: are these distributed brain regions, plus connections between them, the entire neural basis of semantic memory? Many researchers offer a positive answer to this question (the 'distributed-only' view). My position (the distributed-plus-hub view) is that the sensory-, motor- and language-specific aspects of conceptual knowledge are necessary but not sufficient, and that the functions of semantic memory also require a central component or hub that supports the interactive activation of representations in all modalities, for all semantic categories. There are two principal reasons for this view, one empirical and one theoretical:
Empirical: From the distributed-only perspective, no form of focal brain damage would be expected to yield a semantic impairment that is independent of the modality of input (objects, pictures, words, sounds, tastes, etc.), of the modality of output (naming an object, drawing it, using it correctly, etc.) and of the category to which the concept belongs. Yet precisely such an impairment is observed in semantic dementia (SD), characterized primarily by atrophy of the bilateral anterior-inferior temporal lobes. Although critics of this position argue that the damage in SD extends beyond this circumscribed region, there is accruing evidence not only that this is the major site of abnormality but also that it is the only region to correlate significantly with the patients' semantic deficit. Furthermore, the proposal that the semantic deficit in SD might arise from damage to multiple brain regions offers no explanation for the identical nature of the deficit across all modalities/categories, with strong modulation by the factors of frequency and typicality.
Theoretical: A central function of semantic memory is to generalize across concepts that have similar semantic significance, but do not necessarily have similar specific attributes. If semantic memory consisted only of the modality-specific content of objects (and the links between them), it is not clear that we could ever achieve the higher-order generalizations on which so much of our semantic processing relies.
Panel B: The visual word form area: selective for words?
Featuring Cathy Price and Stanislas Dehaene
Cathy Price is a professor at the Wellcome Trust Department of NeuroImaging, University College London (UCL).
Although we all agree that visual word form processing activates the left ventral occipito-temporal cortex (vOT), there is disagreement over the following:
1)Evidence for whether this region is selective for words. Stan and Lauren Cohen have argued for word selective responses relative to picture processing. Joe Devlin and I argue that it depends on the task and the processing computations, not the stimulus. Consequently, activation is higher for pictures in some tasks and higher for words in other tasks. During naming tasks, it is invariably higher for pictures than words. Likewise, damage to the left ventral occipito-temporal cortex impairs object naming more than reading.
2)Terminology. Given that there is no evidence that the area is specialized for word stimuli, is it useful to refer to it as the visual word form area? There are pros and cons. The term VWFA is easy to remember. It also makes it easy to remember the wrong function of the area. We believe that an area should be named by anatomy not its function, particularly since nobody yet knows what the exact computations of the area are.
3)Structure-function mapping at the cognitive level. Is it ever possible to assign cognitive functions to a single region? We don't think so because the function of an area depends on the regions that it is interacting with. Cognitive functions therefore arise at the level of distributed rather than modular processing.
Stanislas Dehaene is a Professor at the College de France, chair of Experimental Cognitive Psychology, and Director of the INSERM-CEA Cognitive Neuroimaging Unit, Paris, France.
My argument is that we already have much evidence that the visual word form area hosts computations specialized for reading. Cathy and I agree the VWFA is a major site of change associated with literacy. Lesion to that site, its afferents or its efferents can create a specific reading deficit. We both also agree that reading activates only a small subset of the areas involved in object recognition. I argue that this finding suggests functional specialization at this cortical location.
The VWFA responds identically to objects and words only when the comparison is uncontrolled for visual features. With better controls, we now find a significantly greater response to words.
The VWFA responds to words and pictures with distinct patterns of invariance (e.g. case invariance) and selectivity (e.g. greater response to frequent bigrams) that forcefully indicate specialization for reading in a specific script.
In particular, the VWFA hosts a mirror-invariant representation of objects, but distinguishes mirror images of words and even single letters of matched complexity (e.g. b and d), again indicating functional specialization of two different circuits within the same voxel.
The overall pattern of results is compatible with the "neuronal recycling" hypothesis, according to which we acquire novel cultural abilities through the pre-emption and minimal reconfiguration of evolutionarily older circuits. The VWFA is not a region "evolved for reading". Rather, it inherits from primate evolution a propensity for the detection of line junctions, which are non-accidental features useful for both scene and object recognition – and these features are then used in the shapes of our letters.
Neuronal recycling explains the partial similarities between word and picture recognition, while at the same time leaving room for increasing cortical specialization with increasingly expert reading, thus dissolving much of the debate between Cathy and I.
Slide sessions
Coming soon!
Poster sessions
Coming soon!