Minding the Brain
PRODUCERS: Larry Massett
Neuroscientists and philosophers alike are grappling with the interplay between the inner mind and the outer world, looking at how the brain we are born with changes in response to the cultural, social, personal and physical environments in which we live.
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Is the brain identical to the mind? And what do the genetics behind memory and learning tell us about the relationship between the two?
In this episode of The DNA Files, we turn to sea slugs, amnesiacs, and the ubiquitous fruit fly in search of the answer to this age-old question.
Does Changing Your Mind Physically Change Your Brain?
We all know that mind and brain are intertwined. Mind is what you experience—thoughts, feelings, desires, memories, hopes, and so on. Brain is that lump of grey matter plunked inside your skull, the physical stuff that seems both to drive and to contain your mind in some way.
Most scientists who study the brain believe that the sensations of the mind can be explained by the physical brain. And in recent decades they’ve learned a lot about how the brain learns and remembers. This program explores those discoveries. We’ll encounter experiments and theories that may surprise you. By the time we get to the end, you’ll have picked up some new ideas. In other words, your mind will have changed.
But that’s not all. This program is going to change your brain as well. We mean that literally: what you will hear will affect your physical brain, right down to the level of your brain cells, the neurons, and the genes that regulate them.
How does this happen? Because scientists can’t go around experimenting on people, most of our knowledge comes courtesy of other animals, and in brain science there is one animal that is very useful: Aplysia, the giant sea slug. It has no brain, but does have very large neurons, some so large that they’re visible to the naked eye—a quality that makes life much easier for brain researchers. On a cellular and molecular level, these giant sea slugs learn and create memories in a way very similar to humans.
Through a series of Pavlovian-like experiments using mild electric shocks, researchers are able show that even without a brain, the giant sea slug Aplysia can learn—that it has memory.
In a high-tech lab on Long Island, Dr. Tim Tully pushes the link between brain and memory one step further. His experiments with fruit flies show that learning not only creates memory, but that memories—long-term memories in particular—actually change the structure of the brain.
So learning influences memory, which actually alters the structure of the brain. But, even the concept of memory isn’t quite as simple as it seems.
What Amnesiacs Can Tell Us About Memory
Howard Eichenbaum, who directs the Center for Memory and Brain at Boston University, found out that the brain allows us to make and keep memories in more than one way. He’s worked with the famous amnesiac known by the initials H.M. H.M.’s amnesia is not the Hollywood cliche—his short-term memory is good enough to carry on a conversation with you or finish a crossword puzzle. What he can’t do is convert a short-term memory into a long-term one. But as we hear in the program, H.M. is able to learn some things, which tells us that memory and learning happen in multiple ways.
Scientists are also investigating the questions of memory and learning by looking at how the genes in our brains interact with environment. The idea is that what you do with your mind—your conscious attention—influences your brain at a molecular level, including how your genes are expressed.
Genes and ADHD
Geneticist Susan Smalley studies the effects of meditation on gene expression in the overactive minds of people diagnosed with ADHD. She believes that learning to influence gene expression may one day lead us to the ability to regulate our own biology—a literal triumph of mind over matter.
The mind and brain seem inextricably linked to each other. It is the very simple neurology of creatures like the giant sea slug, and the very complex neurology of the human brain, that has led UCLA neurobiologist, David Glanzman, to the idea that our minds evolved precisely because our physical brains evolved.
“They are very complicated questions,” says Glanzman. “I think of it as the Lifetime Employment Act for Neuroscientists, because they’re so complicated it’s going to take me the rest of my life to figure them out."