FIG. 1.
Extracellular field recording of compound action potentials (CAPs) for evaluating axonal function in cortical slices of sham and controlled cortical impact (CCI)-injured mice. (A) For CAP recording, a tungsten bipolar electrode (right, “Stim”) was placed in the corpus callosum of one hemisphere of a coronal slice (400 μm thick), and a glass pipette (left, “Rec”) was placed in the corpus callosum of the other hemisphere, ∼1 mm from the stimulating electrode. (B) A CAP waveform evoked in the corpus callosum usually consisted of two sequential negative peaks (N1 and N2), which were generated by myelinated and unmyelinated axons, respectively. The time of electrical stimulation is marked with a black dot. (C,D) Two-photon images of fluorescence Nissl staining of coronal cortical slices from a sham-injured mouse (C) and a CCI-injured mouse at 2 days after injury (D). Note the impact site and lost cortical tissue of the injured slice. Scale bar: 250 μm.