title: Purkinje Cell Collaterals Enable Output Signals from the Cerebellar Cortex to Feed Back to Purkinje Cells and Interneurons.
abstract: Purkinje cells (PCs) provide the sole output from the cerebellar cortex. Although PCs are well characterized on many levels, surprisingly little is known about their axon collaterals and their target neurons within the cerebellar cortex. It has been proposed that PC collaterals transiently control circuit assembly in early development, but it is thought that PC-to-PC connections are subsequently pruned. Here, we find that all PCs have collaterals in young, juvenile, and adult mice. Collaterals are restricted to the parasagittal plane, and most synapses are located in close proximity to PCs. Using optogenetics and electrophysiology, we find that in juveniles and adults, PCs make synapses onto other PCs, molecular layer interneurons, and Lugaro cells, but not onto Golgi cells. These findings establish that PC output can feed back and regulate numerous circuit elements within the cerebellar cortex and is well suited to contribute to processing in parasagittal zones.
authors.affiliation: Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Laurens
authors.initials: L
authors.lastname: Witter
authors.affiliation: Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Rudolph
authors.affiliation: Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: R Todd
authors.initials: RT
authors.lastname: Pressler
authors.affiliation: Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Safiya I
authors.initials: SI
authors.lastname: Lahlaf
authors.affiliation: Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA. Electronic address: wade_regehr@hms.harvard.edu.
authors.forename: Wade G
authors.initials: WG
authors.lastname: Regehr
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D002525:Cerebellar Cortex / Q000502:physiology*; D002529:Cerebellar Nuclei / Q000502:physiology; D005246:Feedback; D007395:Interneurons / Q000502:physiology*; D011689:Purkinje Cells / Q000502:physiology*; D013569:Synapses / Q000502:physiology*