title: Activity-dependent changes in the firing properties of neocortical fast-spiking interneurons in the absence of large changes in gene expression.
abstract: The diverse cell types that comprise neocortical circuits each have characteristic integrative and firing properties that are specialized to perform specific functions within the network. Parvalbumin-positive fast-spiking (FS) interneurons are a particularly specialized cortical cell-type that controls the dynamics of ongoing activity and prevents runaway excitation by virtue of remarkably high firing rates, a feature that is permitted by narrow action potentials and the absence of spike-frequency adaptation. Although several neuronal intrinsic membrane properties undergo activity-dependent plasticity, the role of network activity in shaping and maintaining specialized, cell-type-specific firing properties is unknown. We tested whether the specialized firing properties of mature FS interneurons are sensitive to activity perturbations by inactivating a portion of motor cortex in vivo for 48 h and measuring resulting plasticity of FS intrinsic and firing properties with whole-cell recording in acute slices. Many of the characteristic properties of FS interneurons, including nonadapting high-frequency spiking and narrow action potentials, were profoundly affected by activity deprivation both at an age just after maturation of FS firing properties and also a week after their maturation. Using microarray screening, we determined that although normal maturation of FS electrophysiological specializations is accompanied by large-scale transcriptional changes, the effects of deprivation on the same specializations involve more modest transcriptional changes, and may instead be primarily mediated by post-transcriptional mechanisms.
authors.affiliation: Department of Biology, Brandeis University, Waltham, Massachusetts 02453, USA.
authors.forename: Mark N
authors.initials: MN
authors.lastname: Miller
authors.forename: Benjamin W
authors.initials: BW
authors.lastname: Okaty
authors.forename: Saori
authors.initials: S
authors.lastname: Kato
authors.forename: Sacha B
authors.initials: SB
authors.lastname: Nelson
mesh_terms: D000200:Action Potentials / Q000235:genetics* / Q000502:physiology; D000818:Animals; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007395:Interneurons / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D019579:Neocortex / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D009924:Organ Culture Techniques