[The Svedberg seminar] – Brain-wide hierarchical and multiplexed encoding of behaviour in C. elegans
November 27 @ 15:15 – 16:15 CET
Manuel Zimmer
Professor
Department of Neuroscience and Developmental Biology, The University of Vienna
Bio
Manuel Zimmer studied biochemistry at the Free University of Berlin and performed his undergraduate thesis in 1998 on neuromuscular synapse formation with Steve Burden at the Skirball Institute of Biomolecular Medicine, New York University Medical School, New York. Afterward, he moved back to Germany to perform his Ph.D. work with Rüdiger Klein at the European Molecular Biology Laboratory in Heidelberg and the Max Planck Institute of Neurobiology in Munich, until 2003. Here, he focused on the molecular mechanisms that wire up the nervous system during development. From 2004 to 2010, he performed his postdoctoral studies with Cori Bargmann at the University of California, San Francisco, and Rockefeller University, New York. Here, he developed lab-on-a-chip and calcium-imaging techniques to investigate the chemosensory mechanisms by which animals sense oxygen in the environment. Since 2010, he has lived in Austria, where he works as an independent group leader at the Research Institute of Molecular Pathology in Vienna. Dr. Zimmer’s current research is focused on how neuronal network dynamics in the brain of C. elegans arise from sleep to wakefulness to engage in processing the sensory world and to produce competent behaviors, like foraging and navigation.
Brain-wide hierarchical and multiplexed encoding of behaviour in C. elegans
Large-scale neuronal recordings in the brains of different species have revealed brain-wide, highly coordinated patterns of neuronal activity associated with the animals’ ongoing behaviours. It is not known why behaviour is represented in the brain on such a global scale. In the nematode C. elegans, the activity of such neuronal populations recorded from immobilised animals was suggested to correlate with brain-wide motor commands orchestrating a major action sequence. Direct confirmation of this conclusion in freely crawling animals has been lacking. I will present unpublished data from a new imaging pipeline to record brain-wide activity at single cell resolution in freely crawling animals performing a variety of motor behaviours.
Extending our previous findings, we observe population-wide neural activity in the form of a structured low-dimensional manifold from which the major motor programmes, arranged as an action sequence, can be decoded. However, the brain-wide activity appears to be much richer than just encoding the identity of the main actions: while all behaviourally relevant neuronal activity patterns we detect in our recordings are modulated by the global population modes, many individual neurons show multiplexed activity, i.e. they carry additional residual signals. These can represent a variety of behaviourally relevant information, such as graded movement metrics, the animal’s undulatory gate, or even re-afferent sensation of movement-triggered external signals.
In summary, we discover a brain-wide hierarchical organisation of behaviour in which information about the current slow time-scale behavioural state is broadcast across the brain via a low-dimensional population mode, providing a context for the encoding of fine-tuned fast movement patterns and even sensory perception. We propose this as an organising principle that may apply to animals with larger brains.
https://neurodevbio.univie.ac.at/zimmer-research/
Host: Klas Kullander, UU
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