SHORT-TERM PLASTICITY AND SPATIAL ORGANIZATION OF EXCITATORY INPUTS IN THE CEREBELLAR NUCLEI

Recent studies have emphasized the role of the Cerebellar Nuclei (CN) as more than a simple relay of Purkinje Cell projections, but also as a behaviorally significant integration center. CN neurons receive direct excitatory collaterals from Mossy Fibers (MFs) and Climbing Fibers (CFs), as well as some CN-specific inputs. How these inputs shape CN neuron firing, and therefore the final motor output, strongly depends on synaptic strength and temporal dynamics (i.e., Short-Term Plasticity - STP), yet the diversity of these excitatory synaptic properties remains largely unexplored.
Our study aims to characterize the synaptic transmission properties of excitatory inputs in the Anterior Interposed Nucleus (IntA) of wild-type CD1 mice. Using whole-cell patch-clamp recordings in acute slices and stimulus trains (20-100 Hz), we found heterogeneous frequency-dependent excitatory transmission at these synapses.
Using acousto-optic lens two-photon 3D imaging, we employed arboreal scanning, a new technique enabling spatial mapping of inputs across an entire neuron during evoked stimulation, to visualize the dendritic locations of synaptic inputs. We aim to determine whether inputs with distinct STP profiles are clustered onto specific dendritic branches, potentially allowing for local nonlinear integration.
Future work will leverage these methods to decode input-specific activity patterns in vivo and determine how excitatory inputs in CN contribute to motor adaptation during motor behaviors.