Neurogenetics and Perception

Neurogenetics and Perception

The purpose of the present essay is a brief discussion of neurogenetics and sensation, perception and interpretation of sensory stimuli by the brain. Neurogenetics is a field that studies the genetics of the nervous system, and how genes might explain differences in genotypes, and resulting expressed phenotypes, in individuals. Naturally, the discipline draws on both genetics (the science of genes and related subjects) and neuroscience (the study of the nervous system).

Humans have colour vision. Image: Megan Jorgensen (Elena)

Other interesting subjects are the steps of sensation, perception and interpretation of the five senses. Of most interest would be vision and audition. For instance, there are parallels between seeing and hearing. Photoreceptors react to light wavelengths and are located in the retina, the lining at the back of the eye. Two types of these sensory receptors exist: rods and cones. Rods are located on the periphery and are better suited to night vision. Alternatively, cones are concentrated on the fovea (full Latin name fovea centralis), possess better acuity and can discern colours. Due to lack of receptors at the location where the optic nerve leaves the eye, a blind spot is formed, where no vision occurs.

Different wavelengths correspond to different colours. Image: Megan Jorgensen (Elena)

Further, in audition, there are likewise two types of receptors, or stereocilia: the inner and outer hair cells. The auditory receptors reside in the organ of Corti, and are thus sometimes called Corti’s cells. Signals thus obtained are similarly transmitted to the brain via a nerve bundle, namely the auditory nerve, auditory receptors are also vestibular. Finally, from there, the transduced energy is taken to the occipital lobe for vision, and the temporal lobe for hearing.