The Evolution Of The Neocortex In The Brain

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It is overtly known that the humans’ brain is the most complex in respect to any other species. Since the emergence of the first species in our Homo habilis about 2 million years ago, the brain doubled in size, and compared to our earlier ancestors from about 4 million years ago it is now three times larger. The average size of the modern human adult brain is about 1350 cc. The brain of the walking ape/man of 4.5 million years ago, was about 400 cc in size, and the first human brain about 2 million years ago was about 575 cc. Ascending from lower life forms, the human brain emerged through the natural selection process from randomly occurring changes to make the brain in which we have today. Three separate brains, the reptilian, mammalian brain, and the neocortex brain all work together to form the “triune” structure of the brain and formed a piece called the neocortex that allow us as humans to have sophisticated cognitive abilities. Paul D. MacLean introduces his evolutionary view of the brain in three stages. The reptilian brain, the primitive is the innermost core that consists of the upper brain stem, basal ganglia and the reticular system, the mammalian brain, which is characterized by the limbic system added new functions and ways in which we control the body, and lastly the neo-cortex brain, with the development of the neocortex, the grey matter is the bulk of the brain introduced by the two symmetrical hemispheres, the left and right (Miller, E. 1974; Reardon, M. 1998). This allows and enables us to act as human beings. Through these three interconnected brain parts we are better able to understand the functions and evolution of each individual brain, which subsequently helps to understand human behavior. The Reptilian Brain, also known as the sensory motor brain, is not only the oldest part of our brain, but it controls all voluntary and involuntary
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