title: Properties of basal dendrites of layer 5 pyramidal neurons: a direct patch-clamp recording study.
abstract: Basal dendrites receive the majority of synapses that contact neocortical pyramidal neurons, yet our knowledge of synaptic processing in these dendrites has been hampered by their inaccessibility for electrical recordings. A new approach to patch-clamp recordings enabled us to characterize the integrative properties of these cells. Despite the short physical length of rat basal dendrites, synaptic inputs were electrotonically remote from the soma (>30-fold excitatory postsynaptic potential (EPSP) attenuation) and back-propagating action potentials were significantly attenuated. Unitary EPSPs were location dependent, reaching large amplitudes distally (>8 mV), yet their somatic contribution was relatively location independent. Basal dendrites support sodium and NMDA spikes, but not calcium spikes, for 75% of their length. This suggests that basal dendrites, despite their proximity to the site of action potential initiation, do not form a single basal-somatic region but rather should be considered as a separate integrative compartment favoring two integration modes: subthreshold, location-independent summation versus local amplification of incoming spatiotemporally clustered information.
authors.affiliation: Department of Physiology, University of Berne, Bühlplatz 5, 3012 Berne, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nevian
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Larkum
authors.forename: Alon
authors.initials: A
authors.lastname: Polsky
authors.forename: Jackie
authors.initials: J
authors.lastname: Schiller
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D002540:Cerebral Cortex / Q000166:cytology* / Q000502:physiology*; D003712:Dendrites / Q000502:physiology* / Q000648:ultrastructure*; D049229:Dendritic Spines / Q000502:physiology / Q000648:ultrastructure; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D009924:Organ Culture Techniques; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000166:cytology* / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D013569:Synapses / Q000502:physiology / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D012964:Sodium