No obvious alterations in gross brain anatomy in the Kv3.1/Kv3.3 double mutant. A, Hematoxylin- and eosin-stained parasagittal sections (4 μm thick) of a wild type and a Kv3.1/Kv3.3 double mutant show no changes in gross brain anatomy. Cerebellar foliation is unchanged in the mutant brains.B, When examined at higher magnification, both brains display the same characteristic layering of the molecular (m), Purkinje (p), and granule (g) cell layers (top). Hippocampal cytoarchitecture also displays no obvious alterations (bottom).