By David Coppage

Recent discoveries about the brain and the mind reveal the wonders inside our skulls and pose deep philosophical questions.

Switchboard operator:  How does your brain keep track of the constant stream of input coming in from the senses without getting lost in the stimuli?  Science Daily says you have a switchboard operator called the pulvinar.  It “regulates communication between clusters of brain cells as our brain focuses on the people and objects that need our attention.”  For instance, when crossing a street, you need to be able to focus on the oncoming bus without worrying about all the other sights and sounds.  An orchestra musician needs to focus on his or her part amidst all the rest of the players.  A mother wants to hear her daughter’s voice coming off the train amidst all the other voices.  “The transmission of behaviorally relevant information between various parts of the brain is tightly synchronized,” the article said.  “When we pay attention to important visual information, the pulvinar makes sure that information passing between clusters of neurons is consistent and relevant to our behavior.”  This makes it sound like attention is a choice, and the pulvinar is a servant of our choices.

Cleaning crew:  A whole plumbing system in the brain has been overlooked till now.  Like other organs, brains generate garbage that needs to be taken out, but the blood-brain barrier isolates the brain from the rest of the circulatory system, thus protecting it from viruses and microbes.  The mystery has been solved, according to National Geographic News.  A pump and plumbing system that circulates cerebrospinal fluid was undiscovered before now because opening the skull makes it stop.  For this reason, neuroscientists thought cerebrospinal fluid moved by passive diffusion throughout the brain.  Now, researchers at University of Rochester Medical Center have found a system that is “on the order of a thousand times faster than diffusion” – a “glymphatic system” as named by Maiken Nedergard.  The article describes how it works:

Glial cells do this by growing their “feet” around vessels and veins that carry blood, forming a sort of pipe around a pipe.  Tiny pores in this outer pipe then suck nutrient-rich cerebrospinal fluid from the blood vessels into channels dense with nerve cells, and pores at other locations pump the fluid out….

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