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From Amoeba to Cognition Frankfurt Institute of Advanced Studies April 16, 2003. Christoph von der Malsburg Institut für Neuroinformatik und Fakult ät für Physik und Astronomie Ruhr-University Bochum, Germany and Computer Science Department and Program in Neuroscience
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From Amoeba to CognitionFrankfurt Institute of Advanced StudiesApril 16, 2003 Christoph von der Malsburg Institut für Neuroinformatik und Fakultät für Physik und Astronomie Ruhr-University Bochum, Germany and Computer Science Department and Program in Neuroscience University of Southern California Los Angeles
Repertoire of single-celled animals 1 • Metabolism • Production, transformation and breakdown of molecules • Synthesis of molecules under genetic control • Regulation, e.g., of ionic concentrations • Transport of molecules, inside, in and out of cell • Electrical “behavior” • Circadian rhythm • Reproduction
Repertoire of single-celled animals 2 • Behavior • Sensing (light, sound, chemical milieu) • Self-shaping (pseudopodia, mitosis) • Motility, esp. chemotaxis • Feeding: ingestion and digestion • Aggression, flight • Signalling • Collaboration (e.g., slime mold, biofilms)
The Ontogenetic “Riddle” • Information content of the genome: 109 bits • Information content of the brain’s wiring: 1016 bits • (1010 neurons, hence ld 1010 = 33 bits per connection, • times 1015 synapses = 1016 bits of information) • Solution: genetically controlled self-organization
Rettec anatomical schema • A Model for the Ontogenesis of Retinotopy • (Willshaw and Malsburg, 1976)
Rettec functional schma • Chemotaxis • Synaptic plasticity controlled by electrical signals
Hebbian Plasticity Correlation-controlled Synaptic Plasticity (“Hebbian Plasticity”) Time 10 sec
Meister (Prenatal ferret retina, M. Meister et al.)
Network Self-Organization Network Signals Signal Dynamic Synaptic Plasticity
Binoc 1 A Model for the Ontogenesis of Ocularity Domains (Biol. Cybernetics, 1977)
73 projection A model for the development of orientation-specific neurons (Kybernetik, 1973) Connection Strength Cortex Retina
73 stimuli Retinal Stimuli
Meister (Prenatal ferret retina, M. Meister et al.)
73 cell 70 Re-organization of a cortical receptive field
Olshausen-and Field: Schema Natural images • Development of connections strengths Φi(x,y) under 2 constraints: • Preservation of information (ability to reconstruct) • Sparsity
Points of Conclusion: • Retinotopy, orientation specificity as paradigms • of network self-organization and CNS ontogenesis • Ontogenesis of CNS and cellular repertoire • Amount of genetic information
image model Invariant object Recognition(As paradigm of a cognitive function)
Rubfig 1 Objectrecognition Image Domain Model Domain Model Window
Rubfig 2 Objection recognition 2 Image Domain Model Domain Model Window
Temporal binding Rapid, Reversible Synaptic Plasticity Time 10 msec Temporal binding
Network Self-Organization Network Signals Signal Dynamic Synaptic Plasticity
Face recognition rates * After 3 iterations
Points of Conclusion: • Evolution as a game of varying the eurkaryote’s repertoire • Ontogenesis as a refinement of old cellular behavioral patterns • reproduction, differentiation • cellular migration, chemotaxis • chemical signalling, reaction-diffusion patterns • putting out of “pseudopodia” • Brain function as a fast version of the same game again • Network Self-Organization the central process
Outlook • The flexibility of the human brain shows that fundamental • principles are at work • Similar conclusions may be drawn from the rapid • development of human society • Elucidating the general principles of organization is the • challenge of our times • This issue has at present no academic home