Parameters of biocytin injections.

Animal number, injection volume, diameter and laminar location of injection sites, number of labeled cell bodies and best frequency (BF) at each injection site are listed for each experimental animal. The diameter of each injection site was measured directly in each of the sections in which it was contained, and the mean diameter was calculated. BFs were determined either electrophysiologically or, in cases of stereotaxically guided injections (*), estimated by the locations of the injection sites relative to external and internal landmarks (see Materials and Methods).