Ralf’s primary research interest is understanding the contributions of subcortical brain circuits to higher order cognitive functions such as attention and decision-making across different species. More specifically, he is combing in vivo electrophysiological recordings, optogenetics as well as behavioral testing to study thalamic function during cognitive tasks across mice and tree shrews (Tupaia).
Ralf did his MSc with Chris Pryce at the Federal Institute of Technology in Zurich (ETH), where he acquired a strong background in behavioral neuroscience. He discovered quickly that in order to understand the neural mechanisms underlying behavior he would need to combine behavioral observations with a more cellular oriented approach. During his PhD he trained with Anita Luthi and Paul Franken at the University of Lausanne where he obtained the skills to look both at single cell neuronal activity in vitro as well as in vivo brain activity using EEG recordings. He applied those skills to interrogate the functions of the thalamic reticular nucleus (TRN) during sleep. For his ultimate goal, to understand neural circuit function underlying behavior, he then joined for his post doc Mike Halassa at the Massachusetts Institute of Technology (MIT) where he sharpened his skills in design of behavioral testing and learned how to perform in vivo single unit electrophysiology in combination with opto-genetic manipulations.
Capitalizing on the genetic accessibility in mice, he interrogated brain circuits underlying basic building blocks of attention, distractor suppression and task switching. Together with Mike he developed a novel attentional task which allowed the discovery that the mediodorsal thalamus, in addition to the prefrontal cortex, plays a key role in cognition (Wimmer et al., Nature 2015, Schmitt et al., Nature, 2017). However, to what degree the thalamocortical circuits identified in the mouse generalize to other species and how they may be even utilized in higher-level cognitive function in humans and non-human primates is currently unclear. To begin to address these questions, he has recently started using the tree shrew (Tupaia), a rat sized species that is phylogenetically closer related to humans than rodents, to probe thalamic function in more complex cognitive tasks. Outside of the lab, whenever the weather permits, it is most likely to find Ralf in a State or National Park camping and/or hiking in the mountains with his family or friends.
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