Neurobiology concepts and applications

Neurobiology

Binocular Vision

One of the most significant achievements made in the evolution of certain mammals is binocular vision, which allows for much greater precision, depth perception, and non-movement-based differentiation of objects when compared to monocular vision (Howard & Rogers, 1995). Part of this development has to do with the physical structures of the skull and specifically the placements of the eyes, which lead to a coordination of visual fields that simply does not occur in monocular vision, but there is also a great deal of responsibility for this phenomenon found in the internal structures of the eye, the parts of the nervous system connecting the eye to the brain, and alterations in the visual processing centers of the brain (Howard & Rogers, 1995). The timing of transmissions from the two eyes of binocular versioned organisms is a matter of great interest and importance.

Information from both eyes is ultimately communicated to a single area and often to a single cell used for processing the information and sending it further along towards the brain for ongoing analysis and processing (Howard & Rogers, 1995). The fact that there are not two separate pathways to the visual areas of the brain for the transmission of light information taken in by the two eyes and translated into neural impulses means that there must be another mechanism by which the information received and transmitted by each eye is differentiated. The timing by which the ganglia at the end of the retinal neurons receive chemical messengers from each eye determines how the brain will eventually interpret these signals and create binocular vision (Howard & Rogers, 1995).

Synapse Competition and Elimination

Throughout the growth and life of vertebrates and many animals, beginning even in the embryonic stages of development and continuing throughout adult life, a process known as synaptic competition takes place that eliminates certain underperforming synapses and neurons and leads to the dominance of a single motor neuron bringing even in embryonic stages (Wyatt & Balice-Gordon, 2003). This begins with the innervation of musculature during embryonic development by a single motor neuron that remains dominant and leads to the ongoing elimination of other motor neurons throughout life (Wyatt & Balice-Gordon, 2003). Though the mechanisms by which synaptic competition and the resulting synaptic eliminations occur are not precisely known, there has been some research into this area and the beginnings of reasonable theory explaining this phenomenon have been developed.