For comparison, see brain dissections of a ferret, a fox, and a tree shrew.

BRAIN AND CRANIAL NERVES DISSECTION

To remove the brain, we first detached the temporalis muscle from the skull and completely removed it. We detached the neck muscles close to the skull so that the dorsal braincase was completely exposed. Using small, sharp scissors carefully we carefully perforated the occipital bone. Note that it is important to not cut too deeply in order to protect the brain from damage during the dissection. We cut around the parietal and temporal bones laterally making sure to cut above the orbits to leave the eyes intact. We were able to remove parts of the temporal and parietal bones to expose the brain inside. Most of the dura mater adhered to the skull and was removed with the bone.

Points of Note:

The parietal and frontal bones of Tadarida braziliensis are about the thickness of a fingernail, but more brittle. When we were trying to remove the skull covering of the brain, it broke into several pieces.

The brain of our specimen measured 10 mm in length and 7 mm in width. Our specimen has enlarged olfactory bulbs of the brain, which look like extra lobes protruding anteriorly to the frontal lobes. This suggests a high dependence upon the sense of smell.

The brain of Tadarida braziliensis does not have sulci (or fissures) on the surface of the brain except for the median sagittal fissure, which the dura mater folds into. Otherwise, the surface of the cerebral hemispheres is relatively smooth..

Tadarida braziliensis is a microchiropteran bat. All 800 species of Microchiroptera use echolocation as a tool for locomotion and hunting prey. Several studies have shown an enlarged auditory cortex in the cerebrum, due to use of different frequencies to produce mental maps. [1]

References

1. Suga, N. 1990. Biosonar and neural computation in Bats. In Scientific American 262:60-68.

Links

to Comparative Mammalian Anatomy home

to mammalian brains

to bat facial and head muscles