Nipkow confocal imaging from deep brain tissues.

One of the problems in imaging from brain tissues is light-scattering. Thus, multiphoton laser scanning microscopy is widely used to optically access fluorescent signals located deeply in tissues. Here we report that Nipkow-type spinning-disk one-photon confocal microscopy, which embodies high temporal resolution and slow photobleaching, is also capable of imaging tissues to a depth of up to 150 μm. Using a Nipkow-disk microscope, we conducted functional multi-cell calcium imaging of CA3 neurons from in toto intact hippocampal preparations and astrocytes from in vivo neocortical layer 1. This novel application of Nipkow-disk microscopy expands the potential usefulness of this type of microscopy and will contribute to our understanding of natural neuronal microcircuitry.