title: An analysis of current source density profiles activated by local stimulation in the mouse auditory cortex in vitro.
abstract: To examine local network properties of the mouse auditory cortex in vitro, we recorded extracellular spatiotemporal laminar profiles driven by short electric local stimulation on a planar multielectrode array substrate. The recorded local field potentials were subsequently evaluated using current source density (CSD) analysis to identify sources and sinks. Current sinks are thought to be an indicator of net synaptic current in the small volume of cortex surrounding the recording site. Thus, CSD analysis combined with multielectrode arrays enabled us to compare mean synaptic activity in response to small current stimuli on a layer-by-layer basis. We also used senescence-accelerated mice (SAM), some strains of which show earlier onset of age-related hearing loss, to examine the characteristic spatiotemporal CSD profiles stimulated by electrodes in specific cortical layers. Thus, the CSD patterns were classified into several clusters based on stimulation sites in the cortical layers. We also found some differences in CSD patterns between the two SAM strains in terms of aging according to principle component analysis with dimension reduction. For simultaneous two-site stimulation, we modeled the obtained CSD profiles as a linear superposition of the CSD profiles to individual single-site stimulation. The model analysis indicated the nonlinearity of spatiotemporal integration over stimulus-driven activity in a layer-specific manner. Finally, on the basis of these results, we discuss the auditory cortex local network properties and the effects of aging on these mouse strains.
authors.affiliation: Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo 060-0814, Japan. Electronic address: Yamamura_Daiki@ist.hokudai.ac.jp.
authors.forename: Daiki
authors.initials: D
authors.lastname: Yamamura
authors.affiliation: Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo 060-0814, Japan.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Sano
authors.affiliation: Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo 060-0814, Japan. Electronic address: tateno@ist.hokudai.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tateno
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D016000:Cluster Analysis; D004558:Electric Stimulation; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D016014:Linear Models; D008297:Male; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D008839:Microelectrodes; D025341:Principal Component Analysis; D012815:Signal Processing, Computer-Assisted; D046509:Tissue Culture Techniques
keywords: Auditory cortex; Current source density; Hierarchical clustering; Multielectrode array; Neural circuit; Principal component analysis; Senescence-accelerated mouse