title: Boosting of action potential backpropagation by neocortical network activity in vivo.
abstract: Action potentials backpropagate into the dendritic trees of pyramidal neurons, reporting output activity to the sites of synaptic input and provoking long-lasting changes in synaptic strength. It is unclear how this retrograde signal is modified by neural network activity. Using whole-cell recordings from somata, apical trunks, and dendritic tuft branches of layer 2/3 pyramidal neurons in vivo, we show that network-driven subthreshold membrane depolarizations ("up states") occur simultaneously throughout the apical dendritic tree. This spontaneous synaptic activity enhances action potential-evoked calcium influx into the distal apical dendrite by promoting action potential backpropagation. Hence, somatic feedback to the dendrites becomes stronger with increasing network activity.
authors.affiliation: Abteilung Zellphysiologie, Max-Planck-Institut für medizinische Forschung, 69120 Heidelberg, Germany. jwaters@mpimf-heidelberg.mpg.de
authors.forename: Jack
authors.initials: J
authors.lastname: Waters
authors.forename: Fritjof
authors.initials: F
authors.lastname: Helmchen
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000502:physiology; D003712:Dendrites / Q000502:physiology*; D004569:Electroencephalography; D019579:Neocortex / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D017966:Pyramidal Cells / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012815:Signal Processing, Computer-Assisted; D013569:Synapses / Q000502:physiology
chemical_list: D002118:Calcium