title: NMDA receptors are the basis for persistent network activity in neocortex slices.
abstract: During behavioral quiescence the neocortex generates spontaneous slow oscillations that consist of Up and Down states. Up states are short epochs of persistent activity, but their underlying source is unclear. In neocortex slices of adult mice, we monitored several cellular and network variables during the transition between a traditional buffer, which does not cause Up states, and a lower-divalent cation buffer, which leads to the generation of Up states. We found that the resting membrane potential and input resistance of cortical cells did not change with the development of Up states. The synaptic efficacy of excitatory postsynaptic potentials mediated by non-NMDA receptors was slightly reduced, but this is unlikely to facilitate the generation of Up states. On the other hand, we identified two variables that are associated with the generation of Up states: an enhancement of the intrinsic firing excitability of cortical cells and an enhancement of NMDA-mediated responses evoked by electrical or optogenetic stimulation. The fact that blocking NMDA receptors abolishes Up states indicates that the enhancement in intrinsic firing excitability alone is insufficient to generate Up states. NMDA receptors have a crucial role in the generation of Up states in neocortex slices.
authors: Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania.
authors: Manuel A
authors: MA
authors: Castro-Alamancos
authors: Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania.
authors: Morgana
authors: M
authors: Favero
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001703:Biophysics; D000075402:Channelrhodopsins; D004558:Electric Stimulation; D018683:Excitatory Amino Acid Agents / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics; D016202:N-Methylaspartate / Q000494:pharmacology; D019579:Neocortex / Q000166:cytology* / Q000502:physiology*; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology*; D062308:Optogenetics; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D016704:Synapsins / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D000075402:Channelrhodopsins; D018683:Excitatory Amino Acid Agents; D008164:Luminescent Proteins; D016194:Receptors, N-Methyl-D-Aspartate; D016704:Synapsins; C054562:yellow fluorescent protein, Bacteria; D016202:N-Methylaspartate
keywords: Down state; Up state; arousal; cortex; slice; slow oscillation