Evolution, Development and Function of Motor Circuits
Movement is fundamental to nearly every animal behavior: to escape predators, to eat and breathe, animals must move. The Sweeney Group aims to define the molecular, cellular and neural circuit components that underlie differences in motor behavior, and to explore how such differences arise during an organism’s development.
The group uses the Xenopus frog to address these fundamental questions. The frog undergoes metamorphosis, transitioning from a swimming tadpole to a walking frog during development. The Sweeney Group exploits this transition and categorizes, compares and manipulates frog neurons at each stage. This allows the scientists to map variations in cellular properties and neural circuit structure onto differences in motor behavior.
Knowledge about such cell-circuit-behavior relationships in the frog will provide a basis for comparing motor circuits between tetrapods, understanding how motor circuits evolved from swimming to walking during evolution, and pinpointing how motor circuits break down in movement disorders.
On this site:
Single cell sequencing of tadpole versus frog neurons | Viral tracing of neural circuits for swimming and walking | Multiphoton imaging of calcium dynamics over metamorphosis
Sweeney LBJ, Bikoff JB, Gabitto MI, Brenner-Morton S, Baek M, Yang JH, Tabak EG, Dasen JS, Kintner CR, Jessell TM. 2018. Origin and segmental diversity of spinal inhibitory interneurons. Neuron. 97(2), 341–355.e3. View
Sweeney LBJ, Kelley DB. 2014. Harnessing vocal patterns for social communication. Current Opinion in Neurobiology. 28(10), 34–41. View
Joo WJ, Sweeney LBJ, Liang L, Luo L. 2013. Linking cell fate, trajectory choice, and target selection: Genetic analysis of sema-2b in olfactory axon targeting. Neuron. 78(4), 673–686. View
Sweeney LBJ, Chou Y-H, Wu Z, Joo W, Komiyama T, Potter CJ, Kolodkin AL, Garcia KC, Luo L. 2011. Secreted semaphorins from degenerating larval ORN axons direct adult projection neuron dendrite targeting. Neuron. 72(5), 734–747. View
Wu Z, Sweeney LBJ, Ayoob JC, Chak K, Andreone BJ, Ohyama T, Kerr R, Luo L, Zlatic M, Kolodkin AL. 2011. A combinatorial semaphorin code instructs the initial steps of sensory circuit assembly in the Drosophila CNS. Neuron. 70(2), 281–298. View
The Sweeney Group is looking for accomplished students and postdocs with experience in molecular/genetic, computational, anatomical and functional dissection of neural circuits and interest in motor circuits, frog metamorphosis, comparative studies between frog and mouse or motor circuit evolution. If interested, please email firstname.lastname@example.org with your CV, motivation letter and contact details of 2-3 referees.
Since 2020, Assistant Professor, IST Austria
2011-2020 Postdoc, Salk Institute for Biological Studies, USA
2011 PhD, Stanford University, USA
2019 Helmholtz Young Investigator Award, MDC Berlin and Helmholtz Foundation (declined)
2012 Damon Runyon HHMI Fellow
2012 Finalist, Larry Sandler Memorial Award
2011 Salk Pioneer Fund Post-doctoral Scholar Award
2009 Lieberman Fellowship, Stanford University