Deacon+Reading

__**Glossary:**__ //Homology// - A fundamental similarity based on common descent. //Regressive// //-// Having a tendency to return or to revert to. //Anatomical -// Of or pertaining to anatomy (the structure of an animal or plant). //Irrespective -// Without regard to something else especially something specified. //Phylogeny -// The development or evolution of a particular group of organisms. //Topology -// The study of limits in sets considered as collections of points. //Axonal -// The appendage of the neuron that transmits impulses away from the cell body. //Analogous// - Corresponding in some particular (ex. a brain and computer are analogous) //Hodology// - Connection patterns. //NHDB// - Neuro Homology Database //Cortex -// The outer region of an organ or structure (the portion of a stem between the epidermis and the vascular tissure.) //Aphasia -// The loss of a previously held ability to speak or understand spoken or written language due to disease or injury to the brain. //Macaque -// Any monkey of the genus macaca (of Asia).


 * //(All definitions found on Dictionary.com )//**

__**//The Homology Puzzle//**__


 * Because comparisons of similar biological structures across species with a common genetic heritage (homology) are conducted by studying adult specimen, and
 * because these biological structures begin at cell differentiation (in utero), and
 * because cell differentiation happens differently in the brain than in other organs, in that
 * instead of receiving 'instructions' from adjacent cells,
 * brain cell differentiation is influenced by many other processes, so that
 * standard assumptions made in comparing biological structures are not necessarily relevant to comparing cognitive faculties and brain structure (cytoarchitechture) across species.


 * Axons (nerve fibers) are able to connect distant parts of the brain, therefore
 * communication between non-adjacent cells is possible, and
 * communication pathways between cells (connection topographies) which have no phylogenetic precedent (homo Sapiens is a member of the phylum Chordata, which includes all vertebrates and some invertebrates - a very long and wide history of brain topography to draw from) are possible, because of
 * changes in the direction of nerve signals (afferent changes) which alter which axons are more active (competitive interaction).
 * Changes in the connections between neurons as well as
 * changes in the relative size of the brain (allometry) are important considerations in the evolution of brain function, and
 * should be taken into account when considering comparisons between primate brains.

__//**Avoiding the 'fallacy of simple location'**//__


 * The processing of language by the brain is conducted across many more parts of the brain than previously thought, thus
 * it is unlikely that the study of monkey or primate brains will yield a clear 1-to-1 correspondence between human language processing centers and the brain structures from which they evolved (structure-by-structure homology).

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 * For a clearer discussion of brain structure and functional connectivity see:**