Learning & Brain @ Avon Old Farms

Blogging the Conference:

Kenneth LaRoque: Welcome
Bob Greenleaf, PhD. : Housekeeping
Begin at 8:00 am tomorrow
Sign-in for CEUs
Book purchasing @ registration
Thanks to 4 vendors: OR&L, Pexagon Technology, Wesleyan GLSP, My Hero Project
Smaller conference than usual

Introduce speaker: Laboratory for Perception, founder of center for law and the brain

end at 9:15

Ten Unsolved Questions of Neuroscience

David Eagleman, Ph.D
Department of Neuroscience
Department f Psychiatry
Baylor College of Medicine
Houston, TX

“pleasure to be here. I’m here to talk about the human brain, about 3 pounds, the most complicated device in the universe. 10 billion neurons – each as complicated as a city, having 10,000 of connections with its neighbors. In each cubic millimeter of the brain, there are more connections than there are stars in the Milky Way Galaxy.”

Different levels of neuroscience:
Molecules -> Neurons -> Networks -> Regions -> Behavior

Damage your pinky, doesn’t change you; change your brain even a little, and you change.

We’re here to construct a scaffolding of what we DON’T know about the brain.

1. How is information coded in neural activity?
The neurons are constantly popping with little spikes of voltage (up to +30 millivolts, where normally they operate at about -80 millivolts). These are neural alphabet, but we have no Rosetta Stone. The peripheral nervous system operates one way — spikes indicate muscular activity — but the deep brain codes information sloppily, and while there are some patterns, we have no idea what they mean. Different regions of the brain use different codes? How do we define information? What counts as informationally-relevant? Are neurons and spikes the basic units of informational code? The vast biochemical networks inside a cell, particularly a nerve cell, may be doing the informational storage, and not in electrical patterns at all.

2. How are memories stored and retrieved?
Short-term memory is one type; long-ter memory is divided between explicit and implicit or non-declarative memory. Explicit is things like facts or events in your life; implicit is stuff like walking or biking — skills, priming, classical and operant conditioning, and non-associative learning. You can damage some parts of your brain and shut off some parts of memory, but not others. Artificial neural nets can learn to recognize pictures and information, but other memories overwrite other memories. They don’t take account of relevance, unlike our human brains. If I tell you a joke and you tell your wife tonight using a slightly different set of words, you’ve translated it into your mentalese and then translated it back. Similarly, you seem to learn relationships between datapoints, not the datapoints themselves, unlike computer simulated Artificial neural nets.

3. What does the brain’s extensive baseline activity represent?
The brain uses 20% of your body’s energy but 2% of its mass. There’s a tremendous amount of energy being used for baseline functions, including heart, lungs, hormones, etc. It may be that it’s just housekeeping. But it’s also likely that it’s reminiscing, restructuring your knowledge, manipulating your memories, and running simulations of future states of life. There’s an assumption of an input layer, and an output layer… but that’s wrong. The brain is phenomenally active all the time; sensory inputs only anchor the brain in ‘reality’. you can have full visual experiences when you dream, which don’t involve the eyes at all. Alcatraz prisoners in solitary confinement in the dark experience full-blown hallucinations in very short order; so do folks in isolation tanks.

4. How do brains balance plasticity against retention?
Wildebeests come out of the womb ready to be a wildebeest in about a minute. Humans pursue a different strategy. We come out of the womb unfinished, and then respond to the environment. We learn how to be humans over a long period of time. The brain will assign all the functions it needs to whatever brain space it has available; an amputee will reassign the neurons for the missing arm to the face, body and other parts of the body. Kids with Rasmussen’s encephalitis can have a massive hemispherectomy – removal of one half of the brain – and the other half of the brain will begin performing the whole functions of the whole brain, as long as the kid is under eight years old. BUT… you’re not always plastic. The brain has the ability to be plastic when it wants to…

5. How should we neurally characterize emotions?
Happiness, sadness, anger love… how does this stuff get encoded? We don’t know. Distinctions between emotions – body’s physical response; Feelings are the attendant sensations – the sense of happiness, contentment, love, sadness. Darwin noticed that the same sets of facial reactions are remarkably conservative and specifically tagged across the globe. We understand a lot about where in the brain emotions are processed. The Amygdala – emergency ’emotional salience’ center. If you’re looking for “Where’s Waldo?” it’s hard to find Waldo. If it’s a snake, bear or giant spider, you process that discovery much, much faster.

6. What is intelligence?
This is more than learning and memory? What is intelligence from a biological point of view? When you’re watchign a murder mystery movie, and you figure out that it’s the unassuming wife an hour before the end, that’s intelligence. But how did you decide? What pieces of information did you process in order to discover that piece of truth? Google is a collection of text strings and facts, but there’s no manipulation of those facts. How do we study what intelligence is? It’s somehow a restructuring of information… a combination of learning and memory, and being able to model the world. It’s resolving cognitive conflicts in a larger working memory capacity, using stronger associations, and it’s FLEXIBLE.

7. How is time managed in the nervous system?
time ———————————^event———————–>

the brain is collecting information through its sensorium. But the auditory information is arriving later than the visual information, but the visual information is getting processed LAST. Different types of information is processed at different speeds and times, but the brain stitches many events together to create meaningful stories. there is physical time, and there’s also subjective time… our perception is running a little bit behind the actual timestream.

8. Why do brains sleep and dream? Why sleep?
We spend a third of our time asleep (newborns spend half of their time asleep). The brain is just as active asleep as it is awake. It may have a restorative function, but that’s not the only thing. It may have behavioral advantages. It may give you a chance to run neural programs (like aggression or flight-or-fight) that you don’t get to run normally. It may be about memory consolidation, forgetting, and restructuring. You can damage parts of your brain and permanently not sleep. Maybe it’s an offline practice session.

9. How do the brain’s highly specialized subsystems coordinate with one another?
this is the “binding problem”. If the brain has all these subsystems re-integrate all this information from the sensorium to make some useful picture of the world. Where’s the central processor? There isn’t one! The cortex may just be a data processor. It knows how to wrap itself around anything you feed it. The brain knows how to parallelize any data, but it should be celebrated for being able to re-serialize data.

10. What is consciousness?
It seems to be what flickers into existence when you wake up. Exercise: stare at an animation of 3 fixed yellow dots and 30+ moving blue dots. Focus on one spot, and the 3 yellow dots vanish – they’re not important compared with the movement. Is there a common mechanism. There’s been a change in the brain, but not on the screen. We can find correlates of consciousness, but not its identity.

6 comments

  1. Re: It’s been interesting…

    Ben here.

    Mmmm, Bob Greenleaf. Have you heard him yet?

    Interestingly enough, this is the topic for our middle school retreat next week. (Well, specifically, we’re going to talk about the differences between boys’ and girls’ learning styles.) I will peruse your notes so I can say something intelligent!

      • Re: It’s been interesting…

        Ben here.

        Mmmm, Bob Greenleaf. Have you heard him yet?

        Interestingly enough, this is the topic for our middle school retreat next week. (Well, specifically, we’re going to talk about the differences between boys’ and girls’ learning styles.) I will peruse your notes so I can say something intelligent!

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