Enforcement of temporal fidelity in pyramidal cells by somatic feed-forward inhibition.
The temporal resolution of neuronal integration depends on the time window within which excitatory inputs summate to reach the threshold for spike generation. Here, we show that in rat hippocampal pyramidal cells this window is very narrow (less than 2 milliseconds). This narrowness results from the short delay with which disynaptic feed-forward inhibition follows monosynaptic excitation. Simultaneous somatic and dendritic recordings indicate that feed-forward inhibition is much stronger in the soma than in the dendrites, resulting in a broader integration window in the latter compartment. Thus, the subcellular partitioning of feed-forward inhibition enforces precise coincidence detection in the soma, while allowing dendrites to sum incoming activity over broader time windows.
Pouille
F
F
Brain Research Institute, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
Scanziani
M
M
D000200:Action Potentials; D000818:Animals; D001369:Axons / Q000502:physiology; D001640:Bicuculline / Q000494:pharmacology; D003712:Dendrites / Q000502:physiology; D004558:Electric Stimulation; D005071:Evoked Potentials; D019706:Excitatory Postsynaptic Potentials; D018756:GABA Antagonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D066298:In Vitro Techniques; D007395:Interneurons / Q000502:physiology; D009433:Neural Inhibition; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000502:physiology*; D011724:Pyridazines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000378:metabolism; D009435:Synaptic Transmission; D013997:Time Factors
D018756:GABA Antagonists; D058787:GABA-A Receptor Antagonists; D011724:Pyridazines; D011963:Receptors, GABA-A; C049853:gabazine; D001640:Bicuculline