Schizophrenic patients show difficulties in learning and representing behaviorally relevant percepts when the selection of relevant information is determined by previous experience. In this project, we aimed at determining how our knowledge of world,inferred from past experience is stored in the brain. While work on the influence of internal representations on sensory processing has been conducted from a cognitive or computational point-of-view, this study approaches the question at the brain circuit level.
Vision arises from a set of hierarchically-organized areas where neurons in early cortical stages represent simple attributes (such as orientation or direction of line elements) while areas higher in the hierarchy encode progressively more complex aspects of the world. The buildup of these increasingly complex representations is thought to depend on feedforward connections, those that link lower to higher order areas. However, a large number of feedback (FB) projections reciprocally link higher areas to lower areas. Given the complex attributes they represent, FB projections are ideally positioned to influence the sensory responses of lower-order areas carrying predictions based on the learned statistics of visual inputs. In this project, we investigated whether prior knowledge about the world is stored in the connectional specificity of FB axons.
By investigating the specificity of functional wiring of feedback loops in the brain, this project might also inspire the fields of computer science and information technology. Neuronal network-inspired structures could use the rules of feedback wiring established in this proposal – with wiring instructed by input statistics – to design better performing machine learning algorithms.
