Evolution of the Human Brain, Essay Example

In the ‘Theory of Evolution’ by Charles Darwin he proposed that those animals that survive adapted to their environment. The ability to pass on their traits through genes enabled the development and evolution of the human brain. Those animals that cannot adapt will ultimately perish.  The human’s success on Earth has been the remarkable ability to adapt to the different environmental conditions on Earth.

The brain cells of all animals are essentially made up of the same building blocks. That is to say they comprise of brain cells, neurotransmitters, molecules and synapses.  The brains have adapted in animal species in order to meet specific needs. A crocodile has a large part of its brain oriented to smell. Birds are more oriented to vision and smell.  Human brains have evolved over some 3-4 million years to reach an average size of 1.4 kgms.  The human brain has evolved beyond that of animals in order to have a consciousness or awareness of existence. This aspect is still somewhat of a mystery to scientists today.  The main factors in the development of the brain are considered to be : Adaptability to environment, passing of genes between generations increases development potential,  gaining consciousness,  learning to survive.

Myelinated Axon

It is the myelin sheath that provides layers of insulation around vertebrate axons. The myelin is heavy in lipid substances that do not conduct electricity well. Owing to the insulation action potentials have greater capacity to travel down these myelination axons than the unmylinated ones. This action essentially prevents the brain from having a short circuit within the nerve signals contained within the central nervous system. The actual nervous system comprises billions of cells which we call neurons. It is these which provide the conduit for information transmitted from the brain to other parts of the body.  This process of neurotransmitter release can essentially be broken down into four key steps : (1) The neurotransmitter is released, synthesized and stored in receptors that provide a relay of passed on information between the neurons (2) When the action arrives at the terminal it has to develop a quick release mechanism so as to deposit in the synaptic cleft  (3) The neurotransmitter then obtains recognition by certain receptors on the postsynaptic cell in order to initiate and pass along the signals (4) The inactivation of the neurotransmitter in order to prevent constant stimulation of the postsynaptic cell. (Zucker, R.S. 1989).

Brains Electrical Activity

Electroencephalogram (EEG) is the main process used by researchers, Scientists and Doctors in order to measure the brains electrical activity.  This is used to both study function and equally detect any neurological disorders. It still however remains somewhat of a mystery in terms of whether the electrodes placed on the head can provide a precise functional diagnostic of what is happing in the brain. (Max-Planck-Gesellschaft., 2012).

Neuroimaging is another recent method used to map the functioning of the brain. A form of CT Scanning that enables a photo image of the brain.  There have been issues with this method concerning accuracy and false discovery methods. “effective thresholds for voxelwise statistics derived from neuroimaging data has been a long-standing problem” (Christopher R. Genovesea, 2002).

Works Cited

Christopher R. Genovesea. (2002). Thresholding of Statistical Maps in Functional Neuroimaging Using the False Discovery Rate . NeuroImage Volo 15(4), 870–878.

Max-Planck-Gesellschaft. (2012, 10 11). How to Read Brain Activity With an EEG. Retrieved from Science Daily: http://www.sciencedaily.com/releases/2009/12/091204103751.htm

Zucker, R. S. (1989). Short-Term Synaptic Plasticity. Annual Review of Neuroscience Vol 12 (31), 13-31.