Encoding of oscillations by axonal bursts in inferior olive neurons.
Inferior olive neurons regulate plasticity and timing in the cerebellar cortex via the climbing fiber pathway, but direct characterization of the output of this nucleus has remained elusive. We show that single somatic action potentials in olivary neurons are translated into a burst of axonal spikes. The number of spikes in the burst depends on the phase of subthreshold oscillations and, therefore, encodes the state of the olivary network. These bursts can be successfully transmitted to the cerebellar cortex in vivo, having a significant impact on Purkinje cells. They enhance dendritic spikes, modulate the complex spike pattern, and promote short-term and long-term plasticity at parallel fiber synapses in a manner dependent on the number of spikes in the burst. Our results challenge the view that the climbing fiber conveys an all-or-none signal to the cerebellar cortex and help to link learning and timing theories of olivocerebellar function.
Mathy
Alexandre
A
Wolfson Institute for Biomedical Research, Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK.
Ho
Sara S N
SS
Davie
Jenny T
JT
Duguid
Ian C
IC
Clark
Beverley A
BA
Häusser
Michael
M
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001369:Axons / Q000502:physiology; D001683:Biological Clocks / Q000502:physiology*; D002450:Cell Communication / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D009847:Olivary Nucleus / Q000166:cytology / Q000502:physiology*; D010507:Periodicity; D011689:Purkinje Cells / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012684:Sensory Thresholds / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology