The Christie Lab endeavors to understand the neural-circuit-mechanisms that underlie the learning-dependent optimization of behavior. Our approach mainly focuses on the cerebellum, a brain region that guides adaptive updating of simple reflexive movements as well as experience-driven refinement of high-order brain function (e.g., thinking, planning, and decision making).
We employ a bottom-up approach using ex-vivo slice recording to first identify the principles allowing cerebellar neurons to accumulate and process information (e.g., properties of neurotransmission and/or intrinsic excitability) and alter their activity through associative plasticity. And second, we use in vivo measurements to examine how these processes unfold in awake, behaving animals to control action and encode memories of learning in both healthy subjects as well as in disease models (e.g., autism and intellectual disability).
To explore the links between cellular activity, neural computation, and behavior, we use a diverse toolkit employing electrophysiology, two-photon microscopy, optogenetics, and other cutting-edge techniques.
Bonnan A, Rowan MJR, Baker CA, Bolton MM, and Christie JM (2021) Autonomous Purkinje cell activation instructs bidirectional motor learning through evoked dendritic calcium signaling. Nat. Comm. 12:2153
Gaffield MA, Bonnan A, and Christie JM (2019) Conversion of graded presynaptic climbing fiber activity into graded postsynaptic Ca2+ signals by Purkinje cell dendrites. Neuron 102:762-769
Gaffield MA, Rowan MJM, Amat AB, Hirai H, and Christie JM (2018) Inhibition gates supralinear Ca2+ signaling in Purkinje cell dendrites during practiced movements. eLife 7:e36246
Rowan MJM*, Bonnan A*, Zhang K*, Amat AB, Kikuchi C, Taniguchi H, Augustine G, and Christie JM (2018) Graded control of climbing fiber-mediated plasticity and learning by inhibition in the cerebellum. Neuron 99: 999-1015
Gaffield MA and Christie JM (2017). Movement rate is encoded and influenced by widespread, coherent activity of molecular layer interneurons in the cerebellum. J. Neurosci. 37:4751-4765
Rowan MJM and Christie JM (2017) State-dependent alteration in Kv3 channel availability drives flexible synaptic signaling dependent on somatic subthreshold depolarization. Cell Reports. 18:2018-2029
Rowan MJM, DelCanto G, Kamasawa N, and Christie JM (2016) Synapse-level determination of action potential duration by K+ channel clustering in axons. Neuron. 91:370-383