11e séminaire au Doctorat en informatique cognitive  

Friedemann PULVERMÜLLER – 3 décembre 2020 (ce séminaire sera en anglais)

(LIEN ZOOM - https://uqam.zoom.us/j/96780028011 )      

Titre : Constraining networks biologically to explain grounding

Résumé :

Meaningful use of symbols requires grounding in action and perception through learning. The mechanisms of this sensorimotor grounding, however, are rarely specified in mechanistic terms; and mathematically precise formal models of the relevant learning processes are scarce. As the brain is the device that is critical for mechanistically supporting and indeed implementing grounding, modelling needs to take into account realistic neuronal processes in the human brain. This makes it desirable to use not just ‘neural’ networks that are vaguely similar to some aspects of real networks of neurons, but models implementing constraints imposed by neuronal structure and function, that is, biologically realistic learning and brain structure along with local and global structural connectivity and functional interaction.

After discussing brain constraints for cognitive modelling, the talk will focus on the biological implementation of grounding, in order to address the following questions: Why do the brains of humans -- but not those of their closest relatives -- allow for verbal working memory and learning of huge vocabularies of symbols? Why do different word and concept types seem to depend on different parts of the brain (‘category-specific’ semantic mechanisms)? Why are there ‘semantic and conceptual hubs’ in the brain where general semantic knowledge is stored -- and why would these brain areas be different from those areas where grounding information is present (i.e., the sensory and motor cortices)? And why should sensory deprivation shift language and conceptual processing toward ‘grounding areas’ -- for example toward the visual cortex in the blind? I will argue that brain-constrained modelling is necessary to answer (some of) these questions and, more generally, to explain the mechanisms of grounding. 

Bio :

Friedemann Pulvermüller is a neuroscientist, psychologist and linguist whose research focuses on the neurobiological mechanisms of language, meaning and action. He got PhDs from the Universities of Tübingen and Konstanz, worked for many years as a Programme Leader at the MRC Cognition and Brain Sciences Unit, Cambridge University, and is now a professor in the neuroscience of language and pragmatics at the Freie Universität Berlin, where he also directs the ‘Brain Language Laboratory’. His honors include an Early Career Award of the Society for Psychophysiological Research and an ERC Advanced Grant and his publications ca 250 journal papers and 8 books.

Pulvermüller, F., Garagnani, M., & Wennekers, T. (2014). Thinking in circuits: Towards neurobiological explanation in cognitive neuroscience. Biological Cybernetics, 108(5), 573-593. doi: 10.1007/s00422-014-0603-9

Pulvermüller, F. (2018). Neural reuse of action perception circuits for language, concepts and communication. Progress in Neurobiology, 160, 1-44. doi: 10.1016/j.pneurobio.2017.07.001

Schomers, M. R., Garagnani, M., & Pulvermüller, F. (2017). Neurocomputational consequences of evolutionary connectivity changes in perisylvian language cortex. Journal of Neuroscience, 37(11), 3045-3055.

Tomasello, R., Wennekers, T., Garagnani, M., & Pulvermüller, F. (2019). Visual cortex recruitment during language processing in blind individuals is explained by Hebbian learning. Scientific Reports, 9(1), 1-16.