Posts Tagged ‘cerebral cortex’

UNTHINKABLE

January 4, 2019

The title of this post is identical to the title of a book by Helen Thomson. The subtitle is “An Extraordinary Journey Through the World’s Strangest Brains.” In the opening chapter Ms. Thomson provides an overview of the brain. The most recognizable region of the human brain is the cerebral cortex. It forms the outside shell and is divided into two almost identical hemispheres. Each side of the cortex is divided into four lobes, which together are responsible for all our most impressive mental functions. If you touch your forehead, the lobe closest to your finger is called the frontal cortex and it allows us to make decisions, controls our emotions and helps us understand the actions of others. It gives us all sorts of aspects of our personality; our ambition, our foresight and our moral standards.

If you were to trace your finger around either side of your head toward your ear, you would find the temporal lobe, which helps us understand the meaning of words and speech and gives us the ability to recognize people’s faces.

Run you finger up toward the crown of your ear and you’ll reach the parietal lobe, which is involved in many of our senses, as well as certain aspects of language.

Low down toward the nape of the neck is the occipital lobe, whose primary concern is vision.

Hanging of the back of the brain we have a second “little brain,” a distinctive cauliflower-shaped mass. This is the cerebellum and it is vital for our balance, movement and posture. The vast majority of the cerebellum connects to regions of the cortex that are involved in cognition, perception, language and emotional processing.
A review of maps of the cerebellum built from functional MRI brain scans confirmed that all major cortical regions have loops of connections running to and from the cerebellum. The cerebellum has conversations with different areas of the cortex: taking information from them, transforming it and sending it back to where it came from. One of the more unexpected connections was with the prefrontal cortex, which lies far from the cerebellum at the front of the brain and has long been considered the most advanced part of the brain. This region is in charge of abilities such as planning, impulse control, and emotional intelligence. It is disproportionately large and complex in humans compared with our closest species. To learn more about the cerebellum see the healthy memory blog post “The Brain’s Secret Powerhouse That Makes Us Who We Are.”

If you were to pry open the two hemispheres, you would find the brain stem, the area that controls each breath and every heartbeat, as well as the thalamus, which acts as a grand central station, relaying information back and forth between all the other regions.
The brain is full of cells called neurons which are too small to be see with the naked eye. These cells pass messages from one side of the brain to the other in the form of electrical impulses. Neurons branch out forming connections with its neighbors. If you were to count one of these connections every second, it would take you three million years to finish.

Ms. Thomson writes, “We now know the mind arises from the precise physical state of these neurons at any one moment. It is from this chaotic activity that our emotions appear, our personalities are formed. and our imaginations are stirred. It is arguably one of the most impressive and complex phenomena known to man.

So it’s not surprising that sometimes it al goes wrong.”