Purkinje Cells Directly Inhibit Granule Cells in Specialized Regions of the Cerebellar Cortex.
Inhibition of granule cells plays a key role in gating the flow of signals into the cerebellum, and it is thought that Golgi cells are the only interneurons that inhibit granule cells. Here we show that Purkinje cells, the sole output neurons of the cerebellar cortex, also directly inhibit granule cells via their axon collaterals. Anatomical and optogenetic studies indicate that this non-canonical feedback is region specific: it is most prominent in lobules that regulate eye movement and process vestibular information. Collaterals provide fast, slow, and tonic inhibition to granule cells, and thus allow Purkinje cells to regulate granule cell excitability on multiple timescales. We propose that this feedback mechanism could regulate excitability of the input layer, contribute to sparse coding, and mediate temporal integration.
Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
Chong
C
Guo
Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
Laurens
L
Witter
Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
Stephanie
S
Rudolph
Image and Data Analysis Core, Harvard Medical School, Boston, MA 02115, USA.
Hunter L
HL
Elliott
Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
Katelin A
KA
Ennis
Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA. Electronic address: wade_regehr@hms.harvard.edu.
Wade G
WG
Regehr
D000818:Animals; D002525:Cerebellar Cortex / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D009433:Neural Inhibition; D009474:Neurons / Q000502:physiology*; D011689:Purkinje Cells / Q000502:physiology*; D013569:Synapses / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D005680:gamma-Aminobutyric Acid