Broadcast 2/28/2010 at 8:55 AM EST (62 Listens, 111 Downloads, 1144 Itunes)
Rob Kall Futurehealth Radio Show Podcast
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Earl K. Miller, Ph.D. may be one of the most widely covered neuroscientists, media-wise, with his work and wisdom covered by the Washington Post, NY Times, Scientific American, Harvard Business Review, ABC News, The Scientist, MSNBC, Boston Globe, Financial Times, Discover, USA Today and many more.
Earl Miller is the Picower professor of Neuroscience at MIT. His paper, "An Integrative Theory of Prefrontal Cortex Function", has been designated a Current Classic as among the most cited papers in Neuroscience and Behavior. He use fMRI and implanted microelectrodes in humans and monkeys.
We talked about top down and bottom up brain functions and how they apply to brain dysfunction and optimal fuctioning.
The is the Picower Professor of Neuroscience, Associate Director, The Picower Institute for Learning and Memory
The Miller Lab uses experimental and theoretical approaches to study the neural basis of cognition. We investigatehow categories, concepts, and rules are learned, mental flexibility, how attention is focused, and, more generally, how the brain coordinates goal-directed thought and action.
Our goal is toconstruct more detailed, mechanistic accounts of how executive control is implemented in the brain and its dysfunction in diseases such as autism, schizophrenia, and attention deficit disorder.
The Picower Institute for Learning and Memory and
Department of Brain and Cognitive Sciences at the
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Notes and some transcription from the interview:
Generally, when we talk about top down and bottom up in the brain, in a we're talking about raw sensory input-what's out there in the outside world-- that's bottom up.
And top Down, is the knowledge you use to decide what's important in the outside world, what decisions you make based on those sensory inputs.
deciding what's important to pay attention to.
In bottom up we're talking about the raw information in the outside world and in top down we're talking about the knowledge we have in our head in order to act on that information.
Study the electrical activity of the brain nd look at how the brain processes bottom up sensory inputs and then uses acquired knowledge to filter things out
Hierarchical signals that control sensory inputs come from the part of the brain called the pre-frontal cortex behind the forehead on the right side of your face-- executive part of the brain. processes.
Where top information comes from in the brain-- come from pre-frontal cortex. Synthesizes all the information coming into the brain and decides what's important.
Cure brain diseases where executive brain control-- where decision making is disfunctional.
On thing wehre there is Real interplay between top down and bottom up in the world today. 100 years ago there was a lot less distraction than there are now. It was relatively easy to decide what to pay attention to because there weren't many alternatives. IN todays day and age, we have all sorts of things vying for our attention. We have TV, the internet, our hand held devices
So it takes much more top-down control to deal with the complex, dynamic demanding world we're in now.
Many people have dysfucntions with that. Many people have trouble with focus and staying on task, filtering out distractions and getting side-tracked.
Our ultimate goal is to find out what parts of the brain are responsible for top down control and fix that in people who need it strengthened.
Rob What are some examples of disease or disfunction.
ADHD is a primary on-- people who have trouble staying keeping focused, people who are easily distractable. There also Decision making problems...
People who have normal cognition can keep goals on track. Some people with prefrontal cortex problems lose sightof the goals, the context, of the big picture and their minds are buffetted by the bottom up sensory inputs and they have very little top down control-- lose the forest-- the big picture, and get lost in the trees.
Rob: My experience with neuroscience, the way the mind works has taught me that there's a need for balancing taking place
Rob: So you need the bottom up. Are there also problems with the ways that information comes in from the bottom up?
Earl: Well you can have certain types of impairments-- blindness or deafness or more subtle examples where some people have trouble recognizing faces. And that's an example of a deficit in a bottom-up sensory input. The main thing we're hitting on is the balance, just as you described. THere's a balance in top down and bottom up. There's always an optimal way of balancing the two.
He describes a theory on balancing top down and bottom up considerations-- that there are two parts of the brain involved-- Pre-frontal cortex (PFC) largest part and most developed part in humans. for top down and it interacts with more primitve brain structures-- the basal ganglia-- are very primitive brain structures-- even reptiles have basal ganglia The basal ganglia are involved in learning important details about the outside world, assigning value to all the things around us. And they do so by assigning value to individual things, individual details of everyday experience. .
PFC takes all details learned by the more primitive basal ganglia and puts it together into the big picture-- the big idea about what's going on, so you have a better idea of what sort of goals are available out there, what sort of behaviors you have to engage in to attain those goals, botht the long term and shor term.
We think normal cognition is the balanace between these more detail oriented primitive structures of the brain that assign value to the details of the things around us and the PFC is involved in getting the big picture.
When the Bottom-up Brain goes out of whack; OCD, Autism
And in some case this system can go out of whack. If the basal ganglia becomes too strong relative to the PFC, if it does it's job too efficiently, then you have a brain that's oriented towards details and misses the big picture.
Rob: LIke OCD?
Earl: Exactly. OCD involves Dysfunction in the frontal lobes, the PFC and basal ganglia. And that's a case where the brain focuses on particular details and gets caught in a rut.
Now, other examples of the brain where imbalance is dysfunctional may be the autistic brain. In the brains of autistics, they figuratively cannot see the forest from the trees. They focus on every little detail of everyday life. So, for example, one thing that parents of autistic kids will report is that they'll painstakingly teach their kids to do things o their own, like brush their teeth. Then one day they'll come home with a new toothbrush that's a different color, like a blue toothbrush instead of a red toothbrush and the kid completely falls apart. It's almost as if they're learning things all over again just because a little, irrelevant details of the toothbrush have changed-- it's color. You and I know that the color of the toothbrush doesn't matter. It's what the toothbrush does. But in an autistic brain every little detail is equally important as every other detail, so if something new happens, they completely fall apart-- almost like they're seeing it for the very first time. If you have a brain like that, every time... you look at something from a new angle, ... it becomes like a new learning experience, instead of picking up where they left off and that's probably why you see such severe learning disabilities in a brain like that.
Rob: So an autistic has a predominance of the basal ganglia effect and the PFC is not up to doing the integration and interpretation?
Earl: Yes. THis is just a hypothesis based on data and tests done over the years-- and we're now doing a direct test of this hypothesis. And there's lots of supporting information. And the general idea is that , what we call plasticity mechanisms in the brain-- the mechanisma of the brain that allow for re-wiring-- are too strong in the basal ganglia. And the basal ganglia learn the details too well and the basal ganglia overwhelm the ability of the prefrontal cortex to get the big picture.
Normal cognition between more detail oriened, primitive structures.... and prefrontal cortex. In some cases the balance becomes out of whack.
Autistic Brain cannot see the forrest for the trees. Focus on all the details in everyday life.
Plasticity mechanisms are too strong in the basal ganglia
brain games-- for improvng attention, multitasking-- computer games to improve your brain.
with better understanding
the grassroots, the outside world, sort of form it's structure. 16:00
Overactive pre-frontal cortex-- some are more pre-frontal, more goal oriented. Others just live for the day. That's goign to be dysfunctional.
Personality disorders; too rigid, totalitarian, otherwise very driven and opinionated.
Stimulus bound behavior.... 23
Delusions, schizophrenia are top down disorders.
Using fMRI, micro-electrodes montior activity of individual neurons. with monkeys AND humans.
main difference in human and animal brain is size of prefrontal cortex 1/3 of cortex in humans 16% in monkeys, 4-5% in other animals.
Humans have a lot of folds in brain which add surface area.
Biggest difference between human mind and animal is human mind gets big picture easily.
brain synchrony "favored" 38:00 phase synchrony line up thoughts and organize them with different synchronies.
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