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Have you heard about gray and white matter? Gray matter is mainly located in the cortex, this is where we find the cell bodies which make the matter look darker. White matter is primarily a wiring carrying information from the cell's core to the rest of the body. The wiring is called axons, and these are long cords traveling from the cell's core. The white comes from the fatty tissue that covers the axons called myelin. Thanks to the myelin sheath, the nerve impulse can travel a whopping 119 meters per second.

Tomorrow we will zoom in and have a look at this process.

The cortex has four specific spheres, each specialized in certain processes:



  • The frontal lobe takes care of what most people think of as "thinking". This includes planning, reasoning and executing functions. In the front part of the frontal lobe, you'll find the prefrontal cortex. This is the part that takes care of rational thinking. Remember Phineas Gage from yesterday's lesson? Yes, this is the part he lost in the accident.


  • The parietal lobe takes care of sensory sensations, such as touch, but also deals with central aspects of our language processing. 


  • The occipital lobe is where visual processing takes place.



  • The temporal lobe derives meaning from sensory input by retaining appropriate visual memories, language comprehension and emotion association. One area, named Wernicke's area, takes care of speech comprehension. Damaging this area wouldn't affect your ability to speak, but your ability to speak anything besides jibberish.