The braincase of "Protoavis" is similar in some respects to "Troodon", with an enlarged cerebellum that shifted the optic lobes ventrolaterally, and also has a large floccular lobe. The inner ear is also pretty similar and bird-like in both taxa. The canalicular systems and the cochlear process differ in both taxa, and the vestibular region is relatively small and located in a ventral position to most of the anterior and posterior semicircular canals. The anterior semicircular canal is significantly longer than the others, and the cochlear process is a relatively long, vertically oriented tube. However, "Protoavis" is also remarkedly non-bird like in that it possess only a single exit for the trigeminal. However, these characters are not robust enough to identify "Protoavis" as a bird.