Size does matter: generation of intrinsic network rhythms in thick mouse hippocampal slices.
Rodent hippocampal slices of < or = 0.5 mm thickness have been widely used as a convenient in vitro model since the 1970s. However, spontaneous population rhythmic activities do not consistently occur in this preparation due to limited network connectivity. To overcome this limitation, we develop a novel slice preparation of 1 mm thickness from adult mouse hippocampus by separating dentate gyrus from CA3/CA1 areas but preserving dentate-CA3-CA1 connectivity. While superfused in vitro at 32 or 37 degrees C, the thick slice exhibits robust spontaneous network rhythms of 1-4 Hz that originate from the CA3 area. Via assessing tissue O2, K+, pH, synaptic, and single-cell activities of superfused thick slices, we verify that these spontaneous rhythms are not a consequence of hypoxia and nonspecific experimental artifacts. We suggest that the thick slice contains a unitary circuitry sufficient to generate intrinsic hippocampal network rhythms and this preparation is suitable for exploring the fundamental properties and plasticity of a functionally defined hippocampal "lamella" in vitro.
Wu
Chiping
C
Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada.
Luk
Wah Ping
WP
Gillis
Jesse
J
Skinner
Frances
F
Zhang
Liang
L
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D048429:Cell Size; D006624:Hippocampus / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009415:Nerve Net / Q000502:physiology*; D009924:Organ Culture Techniques / Q000379:methods; D010507:Periodicity