Assembly, function, and maintenance of brain circuits
Research in my group focuses on the following three questions:
- Brain circuits are formed combining genetic and sensory information. This process involves complex network interactions on various levels. What is the interplay of the different factors leading to the development of cortical circuits?
- Cortical circuits produce rich patterns of electrical activity, which are thought to underlay perception, behavior and reasoning. What are the relevant features of these patterns supporting such cognitive phenomena? What circuit components do they depend on?
- Brains are remarkably robust. The functionality of cortical circuits is maintained despite significant turnover on cellular, subcellular and molecular levels. How is this robustness achieved?
Data-driven theoretical neuroscience
In order to address these questions, my research employs mathematical, computational and machine learning techniques to study a variety of different systems, often in close collaboration with experimental neurobiologists. Ongoing projects include:
- The role of spontaneous activity and cortical network interactions in early cortical development. This is in collaboration with David Fitzpatrick at Max-Planck Florida Institute (MPFI), Jupiter, USA. In ferret visual cortex we study the role of spontaneous activity in the development of the orientation preference map. Read more
- Neural variability, perceptual learning and cortical development. With David Fitzpatrick, MPFI. Our recent study (Smith, Sederberg et al., Nat Neurosci, 2015) shows that responses to identical visual stimuli are highly variable in the immature ferret visual cortex and that this response variability declines with age; these changes contribute significantly to a marked improvement in direction discriminability over development. Read more
- Assessing the stability of sensory representations in cortical networks. This is in collaboration with Simon Rumpel at University Mainz. Our system of choice is the auditory cortex of habituated adult mice and we explore how robust sound responses are against ongoing fluctuations of neural connectivity that were observed in this system.
- Exploiting skin patterns of cuttlefish to obtain a precise and massively parallel readout of neural activity in a freely behaving organism. This is with Gilles Laurent at the Max-Planck Institute for Brain Research, Frankfurt, and involves image analysis and computational modeling. Read more
- Reorganization of neural response properties and the role of network interactions in the developing mouse visual cortex. This is with Kenichi Ohki at University of Tokyo, Japan.
- The influence of recurrent connections on visual perception. A computational model of primary visual cortex is devised and its functional properties studied using machine learning techniques.
- Understanding the fundamental difference between a visual cortex that has a functional columnar architecture (as in primates and carnivores) and one that lacks such an organization (as in rodent species), addressing both developmental and functional aspects. Read more
- The influence of cortical network interactions on visual perception. This is studied using a computational model combined with machine learning techniques.
Another branch of my research lies outside of neuroscience and focuses on morphogenesis, the process that transforms simple fertilized egg cells into complex animals or plants. Even though molecular biology has identified many genes and molecular pathways controlling central aspects of development, most of the dynamics and mechanisms operating across molecular, cellular and tissue levels to form a fully functional organism still remain elusive. In particular, how cell shape changes and cellular forces are coordinated across a tissue to achieve morphogenesis is an important unanswered question.
My research addresses this issue by developing precise quantitative characterizations of the complex phenotypes associated with the morphogenesis of cells and tissues. The central goal is to develop an integrated quantitative description of tissue morphogenesis across three different levels, from molecules to cells and to tissues, to shed new light on how tissues get sculpted, what molecular machineries are driving this process, and what interactions among cells are regulating it. Read more