We are interested in understanding computations in neural circuits of the mammalian brain. To attack this problem we work at the interface between cellular and systems neuroscience: we aim to understand the cellular toolkit that enables single neurons to perform computations, and in turn how single neurons and their patterns of connections contribute to the computations performed by neural circuits. Our lab has a special focus on neuronal dendrites, which actively transform synaptic inputs into specific neuronal output patterns. We use the cerebellum and neocortex as model systems, combining in vitro and in vivo imaging and electrophysiology approaches, and taking advantage of a range of high-tech approaches. These include two-photon microscopy, patch-clamp recordings from dendrites, recordings using Neuropixels probes, and most recently the development of 'all-optical' approaches for simultaneous readout and manipulation of neurons by combining two-photon imaging and two-photon optogenetics. Our experiments are complemented by computational models of single neurons and networks of neurons. At each stage of our work, our aim is to link different levels of brain function, in order to reveal how activity in single neurons and neural circuits drives behaviour and, importantly, what kinds of changes take place within these circuits during learning.