Similarities Between Songbirds And Parod

Throughout all vertebrates, most species are able to produce sounds (Elemans, 2014). Not all of them, however, are capable of vocal learning, which is referred to as being able to learn vocalizations by imitating rather than by instinctive behavior, or auditory learning, which is the ability to associate sounds heard to a certain behavioral response (Jarvis, 2009). Whereas many species accomplish auditory learning, such as dogs reacting to “Sit!” with sitting down, relatively few species additionally possess the aptitude of vocal learning. In the class of birds, this specifically applies to songbirds, parrots and hummingbirds, forming a subgroup of vocal learning birds (Jarvis, 2009). Most notably, parrots such as the African gray parrot, are
(Elemans, 2014) Songbirds and parrots share a very similar arrangement of a total of seven nuclei that constitute two bilateral vocal pathways. Firstly, the posterior vocal pathway consists of four nuclei that project from the telencephalon to the brainstem and ultimately innervate the vocal organ syrinx (Elemans, 2014; Jarvis, 2009). As this pathway is obviously crucial for movements of the syrinx, that produces sounds by causing exhaled air to vibrate, this pathway is also known as the vocal (or song) motor pathway (Elemans, 2014). The second, the anterior vocal pathway loop (or less specifically: anterior forebrain pathway) (Elemans, 2014; Jarvis, 2009) is composed of three nuclei, constituting a loop from the telencephalon via striatum and thalamus back to the telencephalon. Both pathways are connected to each other at several points as well as to the auditory system (Matsunaga & Kazuo, 2009). Important organs for bird song in the peripheral nervous system are the respiratory system, the vocal tract and the vocal organ syrinx, a skeletal structure affected by 10 muscle pairs containing two pairs of labia with the ability to produce each one tone at a time, ranging from 100-12,000 Hz (compared to 80-1,100 Hz in humans). Those muscles are obviously not directly innervated by originating nuclei in the forebrain and it is therefore plausible that on a higher level, movement patterns rather than specific muscular movements are represented (Elemans, 2014) and hence assembly of song structures may be hierarchical (Matsunaga & Kazuo, 2009). As mentioned before, auditory learning is found in all animals that demonstrate vocal learning, whereas auditory learning can occur independently, suggesting that it is a requirement for vocal learning (Jarvis, 2009). In the brain, the loop pathway is possibly responsible for integrating auditory feedback and somatosensory