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A distinct class of slow (⁓0.2-2 Hz) intrinsically bursting layer 5 pyramidal neurons determines UP/DOWN state dynamics in the neocortex
journal contribution
posted on 2023-05-20, 02:07 authored by Lorincz, ML, Gunner, D, Bao, Y, William ConnellyWilliam Connelly, Isaac, JT, Hughes, SW, Crunelli, VDuring sleep and anesthesia, neocortical neurons exhibit rhythmic UP/DOWN membrane potential states. Although UP states are maintained by synaptic activity, the mechanisms that underlie the initiation and robust rhythmicity of UP states are unknown. Using a physiologically validated model of UP/DOWN state generation in mouse neocortical slices whereby the cholinergic tone present in vivo is reinstated, we show that the regular initiation of UP states is driven by an electrophysiologically distinct subset of morphologically identified layer 5 neurons, which exhibit intrinsic rhythmic low-frequency burst firing at 0.2–2 Hz. This low-frequency bursting is resistant to block of glutamatergic and GABAergic transmission but is absent when slices are maintained in a low Ca 2 medium (an alternative, widely used model of cortical UP/DOWN states), thus explaining the lack of rhythmic UP states and abnormally prolonged DOWN states in this condition. We also characterized the activity of various other pyramidal and nonpyramidal neurons during UP/ DOWN states andfoundthat an electrophysiologically distinct subset of layer 5 regular spiking pyramidal neuronsfires earlier duringthe onset of network oscillations compared with all other types of neurons recorded. This study, therefore, identifies an important role for cell-type-specific neuronal activity in driving neocortical UP states.
History
Publication title
Journal of NeuroscienceVolume
35Issue
14Pagination
5442-5458ISSN
0270-6474Department/School
Tasmanian School of MedicinePublisher
Soc NeurosciencePlace of publication
11 Dupont Circle, Nw, Ste 500, Washington, USA, Dc, 20036Rights statement
Copyright 2015 Lo˝rincz et al. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/Repository Status
- Open