Tonic and spillover inhibition of granule cells control information flow through cerebellar cortex.
We show that information flow through the adult cerebellar cortex, from the mossy fiber input to the Purkinje cell output, is controlled by furosemide-sensitive, diazepam- and neurosteroid-insensitive GABA(A) receptors on granule cells, which are activated both tonically and by GABA spillover from synaptic release sites. Tonic activation of these receptors contributes a 3-fold larger mean inhibitory conductance than GABA released synaptically by high-frequency stimulation. Tonic and spillover inhibition reduce the fraction of granule cells activated by mossy fiber input, generating an increase of coding sparseness, which is predicted to improve the information storage capacity of the cerebellum.
Hamann
Martine
M
Department of Physiology, University College London, Gower Street, WC1E 6BT, London, United Kingdom.
Rossi
David J
DJ
Attwell
David
D
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002034:Bumetanide / Q000494:pharmacology; D002525:Cerebellar Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D003975:Diazepam / Q000494:pharmacology; D004558:Electric Stimulation; D005665:Furosemide / Q000494:pharmacology; D009412:Nerve Fibers / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism*; D013256:Steroids / Q000494:pharmacology; D027981:Symporters / Q000037:antagonists & inhibitors / Q000378:metabolism; D013569:Synapses / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*; D000096922:K Cl- Cotransporters
D001640:Bicuculline; D002034:Bumetanide; D003975:Diazepam; D005665:Furosemide; D011963:Receptors, GABA-A; D013256:Steroids; D027981:Symporters; D005680:gamma-Aminobutyric Acid; D000096922:K Cl- Cotransporters