Cytoarchitecture of the Medial Geniculate Body of Three Species of Bats: Noctilio leporinus, Phyllostomus hastatus and Carollia perspicillata

The aim of the present study is to document cytoarchitectural details of Medial Geniculate Body (MGB) of the brain in three species of echolocating bats with different forage behavior. The brains were collected from six male adult bats of each species: Noctilio leporinus (fish-eating), Phyllostomus hastatus(carnivorous/ omnivorous) and Carollia perspicillata (fruit-eating) and were double-embedded and transverse serial sections were cut and stained with cresyl fast violet. The results showed that the mean length of the medial geniculate body was 1330 ± 115 µm in N. leporinus, 1210 ± 90 µm in P.hastatus and 790 ± 68 µm in C. perspicillata. The MGB of all three bats appeared to be divided into three divisions: dorsal (MGBd), ventral (MGBv) and medial (MGBm). These divisions were most distinct in the N. leporinus bat and least apparent in the C. perspicillata. In the N. leporinus, both dense-staining multipolar cells and light-staining round cells were located throughout the MGB. In the P. hastatus, the dense-staining multipolar cells were predominantly present in the ventral division of the middle third of the MGB, whereas light-staining round cells predominated at the rostral end of the MGB. Only light-staining round cells were seen throughout the MGB of the C. perspicillata. The large sized MGB and its clear subdivisions in N. leporinussuggests that it relies heavily on echolocation whereas P.hastatus and C. perspicillata use echolocation as well but also rely on hearing, smell and vision.