Figure 2.

Parallel thalamocortical pathways in the adult pallid bat auditory system. I (A–F) An example of injection made in the HFR. (A) Fluorogold (FG) injection site. (B) Frequency selectivity of injection site. The injection was made near neurons tuned ∼42 kHz and selective for downward FM sweeps. (C–F) Photomicrographs of increasingly more rostral locations of the MGB show that labeled neurons were found in the SG, MGBm, and MGGd, but not in the MGBv. II (G–P) An example of injections made in the LFR. (G) FG injection site (H) Fluororuby (FR) injection site. (I) FG was injected near neurons tuned ∼26 kHz. FR was injected near neurons tuned ∼15 kHz. (J–N) Schematics of increasingly rostral sections through the MGB showing that labeled neurons were found in the MGBv, MGBm, and MGBd, but not the SG. (O,P) Photomicrographs showing FG and FR labeled cells near the rostrocaudal center of the MGB. III (Q–S) An experiment in which FG was injected in the LFR and FR was injected in the HFR. (Q) Schematic of injection sites. (R) Schematic of a section at the rostrocaudal center of the MGB showing that FG labeled neurons were present in MGBv, but not the SG, and that FR labeled cells were found in the SG, but not the MGBv. (S) Photomicrograph of the section shown in (R).