Ke Zhang, a PhD candidate in the Integrative Biology-Neuroscience program, has recently published a co-authored paper in the scientific journal Neuron. Zhang began the PhD program in the fall of 2016 and she is also a student in the International Max Planck Research School (IMPRS) for Brain and Behavior program. The IMPRS graduate program is jointly hosted between the University of Bonn (Germany), the Max Planck Florida Institute for Neuroscience (USA), the Max Planck Institute Caesar (Bonn, Germany) and Florida Atlantic University. She currently works under the direction of Dr. Jason Christie, Research Group Leader in Synaptic Signaling and Computation at the Max Planck Florida Institute for Neuroscience.
Her recent paper entitled Graded Control of Climbing-Fiber-Mediated Plasticity and Learning by Inhibition in the Cerebellum explores how Purkinje cells can alter neuronal plasticity and instruct adaptive behavior within the cerebellum. In addition to Zhang, the author list includes Dr. Matt Rowan, IB PhD alumnus who did his dissertation research under the direction of Dr. Wen Shen, and also worked as a postdoc in the Christie lab.
Purkinje cell dendrites convert excitatory climbing fiber input into signals that instruct plasticity and motor learning. Modulation of instructive signaling may increase the range in which learning is encoded, yet the mechanisms that allow for this are poorly understood. We found that optogenetic activation of molecular layer interneurons (MLIs) that inhibit Purkinje cells suppressed climbing fiber-evoked dendritic Ca 2+ spiking. Inhibitory suppression of Ca 2+ spiking depended on the level of MLI activation and influenced the induction of associative synaptic plasticity, converting climbing fiber-mediated potentiation of parallel fiber-evoked responses into depression. In awake mice, optogenetic activation of floccular climbing fibers in association with head rotation produced an adaptive increase in the vestibulo-ocular reflex (VOR). However, when climbing fibers were co-activated with MLIs, adaptation occurred in the opposite direction, decreasing the VOR. Thus, MLIs can direct a continuous spectrum of plasticity and learning through their influence on Purkinje cell dendritic Ca 2+ signaling.