Model organismA model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms. Model organisms are widely used to research human disease when human experimentation would be unfeasible or unethical. This strategy is made possible by the common descent of all living organisms, and the conservation of metabolic and developmental pathways and genetic material over the course of evolution.
Cortical columnA cortical column is a group of neurons forming a cylindrical structure through the cerebral cortex of the brain perpendicular to the cortical surface. The structure was first identified by Mountcastle in 1957. He later identified minicolumns as the basic units of the neocortex which were arranged into columns. Each contains the same types of neurons, connectivity, and firing properties. Columns are also called hypercolumn, macrocolumn, functional column or sometimes cortical module.
DeafnessDeafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written with a lower case d. It later came to be used in a cultural context to refer to those who primarily communicate through sign language regardless of hearing ability, often capitalized as Deaf and referred to as "big D Deaf" in speech and sign.
Human–animal hybridA human–animal hybrid and animal–human hybrid is an organism that incorporates elements from both humans and non-human animals. Technically, in a human–animal hybrid, each cell has both human and non-human genetic material. It is in contrast to an individual where some cells are human and some are derived from a different organism, called a human-animal chimera. Examples of human–animal hybrids mainly include humanized mice that have been genetically modified by xenotransplantation of human genes.
