title: The cellular basis of GABA(B)-mediated interhemispheric inhibition.
abstract: Interhemispheric inhibition is thought to mediate cortical rivalry between the two hemispheres through callosal input. The long-lasting form of this inhibition is believed to operate via γ-aminobutyric acid type B (GABA(B)) receptors, but the process is poorly understood at the cellular level. We found that the firing of layer 5 pyramidal neurons in rat somatosensory cortex due to contralateral sensory stimulation was inhibited for hundreds of milliseconds when paired with ipsilateral stimulation. The inhibition acted directly on apical dendrites via layer 1 interneurons but was silent in the absence of pyramidal cell firing, relying on metabotropic inhibition of active dendritic currents recruited during neuronal activity. The results not only reveal the microcircuitry underlying interhemispheric inhibition but also demonstrate the importance of active dendritic properties for cortical output.
authors.affiliation: Physiologisches Institut, Universität Bern, Bühlplatz 5, CH-3012 Bern, Switzerland.
authors.forename: Lucy M
authors.initials: LM
authors.lastname: Palmer
authors.forename: Jan M
authors.initials: JM
authors.lastname: Schulz
authors.forename: Sean C
authors.initials: SC
authors.lastname: Murphy
authors.forename: Debora
authors.initials: D
authors.lastname: Ledergerber
authors.forename: Masanori
authors.initials: M
authors.lastname: Murayama
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Larkum
mesh_terms: D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000378:metabolism; D054022:Cerebrum / Q000502:physiology*; D003337:Corpus Callosum / Q000502:physiology; D003712:Dendrites / Q000502:physiology*; D004558:Electric Stimulation; D006614:Hindlimb; D007395:Interneurons / Q000502:physiology; D009433:Neural Inhibition; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D018080:Receptors, GABA-B / Q000378:metabolism*; D013003:Somatosensory Cortex / Q000166:cytology / Q000502:physiology*
chemical_list: D018080:Receptors, GABA-B; D002118:Calcium