Speaker of Workshop 1
Will talk about: The vertebrate midbrain: Cells, Circuits, Concepts
Harald Luksch studied biology in Bonn and Cologne (Germany) and received his Ph.D. degree from the University of Cologne in 1994. He worked as a PostDoc with Gerhard Roth at the University of Bremen and with Harvey J. Karten at the University of California at San Diego before joining Hermann Wagner at the Technical University of Aachen in Germany as an Assistant. In 2007, he was appointed Chair of Zoology at the Technische Universität München (TUM). He is head of the Department of Animal Sciences, faculty at the Graduate School for Systemic Neuroscience, and part of the Bernstein Center for Computational Neuroscience in Munich. In collaboration with Ralf Wessel (Washington University at Saint Louis), he has studied and modelled various aspects of midbrain circuits in birds.
The vertebrate dorsal midbrain (superior colliculus in mammals, optic tectum in all other vertebrate classes) is a central interface between sensory stimuli and behavioral motor patterns. It receives a strong retinal projection that forms a map of visual space in the upper layers. This map acts as a master coordinate system for other sensory afferents (auditory, somatosensory etc.), leading to a multimodal representation of the sensory environment. With a high degree of structural order, identifiable cell types and known input and output connectivity, the analysis of the tectum with a combined experimental-computational approach can provide a mechanistic understanding of sensory computation.
Recent advances have been made in the analysis of feedback loops formed between the optic tectum and a group of nuclei in the isthmic area in several bird species. The function of these circuits is considered to be a bottom-up attentional system that identifies the most salient object and allows for both orienting movements as well as fast motor responses in, for example, escape behaviours. These functions are not restricted to visual computation, but (taking into account the tectal role as a multisensory spatial center) deals predominantly with spatial coordinates to identify potential targets through a saliency-based process. I will present data from intracellular work, imaging studies and modelling and discuss the functional implications of the circuits.