Hanse Lectures in Neurosciences am Hanse-Wissenschaftskolleg mit Prof. Jochen Braun

Prof. Dr. Jochen Braun speaks about “Illuminating the hierarchical dynamics of visual inference” Professor Jochen Braun’s talk on hierarchical processes of visual inference. The speaker is Professor for Cognitive Biology at the Otto-von-Guericke University, Magdeburg, Germany.

Abstract:
The visual environment is noisy, variable, and ambiguous.  In the face of unknown prior statistics, optimal inference is computationally challenging even in simplified settings.  However, optimal inference can be approximated by accumulating and comparing evidence in stochastic dynamical systems, an approach which also suggests plausible neural implementations (Bogacz et al., 2006; Deneve, 2007; Veliz-Cuba, Kirkpatrick, 2016).   But what kind of stochastic dynamics governs visual perception in human observers and how suitable is this dynamics for performing inference? 
The perceptual dynamics engendered by multi-stable visual displays appears to comprehensively illuminate these issues.  Specifically, some well-established and generic characteristics -- abrupt onset of perception & gradual adaptation/recovery of input representations, stereotypical shape of dominance distribution (“scaling property”), bimodal dependence on input strength (“Levelt’s propositions”) -- suffice to fully constrain an underlying stochastic dynamics with (at least) three hierarchical levels: bistable assemblies biased by stimulation (cortical columns?), uncoupled populations of assemblies to accumulate evidence, coupled populations to represent perception, with reciprocal interactions between all levels.   
With suitable input weights, this empirically identified dynamical system accumulates noisy evidence to make nearly optimal categorical discriminations.   Accelerated discounting of evidence that has already been discriminated may serve to balance stability and sensitivity of inference in a volatile world.

Lecture and discussion from 7:00 pm until approximately 8:00 pm
followed by dinner and informal discussion in the HWK Bistro.

The lecture is open to everybody, but registration is required for this event (by replying to mdaniel@h-w-k.de )