Download Some words that are [inaudible] objects and animals, but listen

Some words that are [inaudible] objects and animals, but listen carefully and when I finish I want you to
say them back to me in the order of their physical size, so from smallest to largest. Waste basket, oven,
river, slipper, lemon.
>> Slipper, waste basket, oven, what was the third, the last one you said there. I forgot now already.
While only some of us suffer from strokes, all of us worry our minds may start to fail as we get older.
I would like you to point to the same blocks in the same order. Here is the first one.
This lab at the University of Michigan, studies how age affects mental performance. Its Director
Psychologist Denise Park is gathering evidence that presents a new view of brain aging.
Aging begins in your 20's, as soon as you reach maturity. Our data show clearly, absolutely clearly that as
you age from 20 to 30, you are a little bit slower. You process information not quite as fast, you can hold
a little bit less information and consciousness, and you recall a little tiny bit less from 20 to 30, and from
30 to 40 the same thing and so on, and so forth. Then suddenly you are 70 and you start really noticing
perhaps that these continuous declines have aggregated, and you may realize that you are not
cognitively what you used to be. Now, this is especially true of memory and the more unfamiliar the
information, the more trouble you are going to have. You are going to remember familiar stuff, but if I
bring you in my lab and ask you to remember a list of words, you are going to see that age related
decline.
Okay, this task is the free recall task. In this task I will read you a list of 12 words. You should listen
carefully to the words, and when I get to the end you should recall them back to me in any order that
you like, okay? Alright, line, honey, train, sky, puzzle, jury, garage, doll, wife, toast, bed, watch, recall.
>> Line, honey, train, sky, doll, honey. Watch, honey, train.
>> Watch, toast, doll, wife, honey, line.
Learning someone's name, remembering where you parked your car.
>> Jury comes to mind.
Why do these things get harder as we get older?
[ Music ]
One answer may lie in the way new memories are formed. For a memory to take shape, neurons must
forge electrical and chemical links that connect them into a stable circuit. For decades, scientists thought
that as the brain aged, millions of neurons died, making it harder for new circuits to form. But, in the
1990's, this long standing theory was found to be wrong.
One of the most remarkable things now that we understand it is how little nerves cell loss there is. How
much the brain stays full of cells that we need in order to function normally, and that is something that
we didn't used to know at all.
Now, this is interesting because it forces us then to look elsewhere for the changes in the brain that are
impacting function.
Hey guys, how's the cutting going?
> Great.
Now, this is the brains from Boston.
>> Yeah.
At Mount Sinai School of Medicine in New York, neurobiologist John Morrison is looking for clues in a
region of the brain where new memories are formed, the hippocampus. When we learn something new,
neurons in the hippocampus forge strong connections by sending electrochemical messages across the
tiny gaps between them, called synapses. Essential to the strength of the connection is the movement of
electrically charged particles of calcium drifting through the synapses. When the particle stream into a
neuron, they trigger chemical changes that make the connection more reliable. The calcium flows
through a molecule that is the gateway to the neuron, the NMDA receptor.
We know that the NMDA receptor is critically linked to memory, so one of the changes that this memory
decline in aging might be lower levels of NMDA receptor. So, we have looked for those kinds of changes.
When Morrison examined the hippocampus of monkeys, he found that in young animals a single
synapse had dozens of NMDA receptors, but in older monkeys the numbers of receptors dropped
sharply.
Well, it was really amazing because this decrease occurred in the circuit that leads to the ability to learn
and remember new things, the classic form of memory that is affected in aging.