[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:12.32,0:00:17.41,Default,,0000,0000,0000,,Isn't it amazing how the face of an old friend can seem so familiar even if you haven't seen
Dialogue: 0,0:00:17.41,0:00:22.75,Default,,0000,0000,0000,,them in years or even decades? On the other hand, the names of some of your old classmates
Dialogue: 0,0:00:22.75,0:00:28.43,Default,,0000,0000,0000,,may have been forgotten. Have you ever wondered whats going on in here to support these successes
Dialogue: 0,0:00:28.43,0:00:33.76,Default,,0000,0000,0000,,or failures of learning and memory? Well this is the subject of the research in my laboratory.
Dialogue: 0,0:00:33.76,0:00:38.24,Default,,0000,0000,0000,,We're trying to understand exactly what changes in your brain when you learn and how those
Dialogue: 0,0:00:38.24,0:00:43.38,Default,,0000,0000,0000,,changes persist over time to support memory. And one thing that we know which helps explain
Dialogue: 0,0:00:43.38,0:00:48.56,Default,,0000,0000,0000,,why some things are easier to remember than other is that learning is not a unitary process.
Dialogue: 0,0:00:48.56,0:00:53.50,Default,,0000,0000,0000,,There is no single mechanism of learning in the brain but Instead there are distinct kinds
Dialogue: 0,0:00:53.50,0:00:58.74,Default,,0000,0000,0000,,of learning that depend on distinct brain regions. A brain structure called the hippocampus
Dialogue: 0,0:00:58.74,0:01:02.66,Default,,0000,0000,0000,,supports memory for facts and events in your life. This is what you rely on to remember
Dialogue: 0,0:01:02.66,0:01:07.24,Default,,0000,0000,0000,,someones name or what you had for breakfast. Where as another structure called the amygdala
Dialogue: 0,0:01:07.24,0:01:13.09,Default,,0000,0000,0000,,supports emotional memory. You can have a fear of dogs even if you've lost the explicit
Dialogue: 0,0:01:13.09,0:01:19.42,Default,,0000,0000,0000,,hippocampus dependent memory of being bitten by one as a child. So these memory systems
Dialogue: 0,0:01:19.42,0:01:23.14,Default,,0000,0000,0000,,are fairly independent. The basal ganglia supports habit memory. This is what you're
Dialogue: 0,0:01:23.14,0:01:28.25,Default,,0000,0000,0000,,using when you brush your teeth or drive to work when your mind is elsewhere. The cerebral
Dialogue: 0,0:01:28.25,0:01:34.09,Default,,0000,0000,0000,,cortex supports perceptual learning. Even basic functions like being able to see depend
Dialogue: 0,0:01:34.09,0:01:39.49,Default,,0000,0000,0000,,on experience and learning. And this structure down there is called the cerebellum. It supports
Dialogue: 0,0:01:39.49,0:01:44.61,Default,,0000,0000,0000,,motor learning. This is the process by which you acquire skilled movements. If we were
Dialogue: 0,0:01:44.61,0:01:49.26,Default,,0000,0000,0000,,to zoom in on any one of these brain areas we'd find that they are made up of the same
Dialogue: 0,0:01:49.26,0:01:56.55,Default,,0000,0000,0000,,basic building blocks. Neurons which are specialized cells of the nervous system and synapses which
Dialogue: 0,0:01:56.55,0:02:01.04,Default,,0000,0000,0000,,are the connections between neurons that allow for one to signal to the next. But unlike
Dialogue: 0,0:02:01.04,0:02:07.05,Default,,0000,0000,0000,,wires synapses are not static and can change with experience. The electrical and chemical
Dialogue: 0,0:02:07.05,0:02:11.81,Default,,0000,0000,0000,,signals that flow through your synapses as they process information can induce long lasting
Dialogue: 0,0:02:11.81,0:02:15.60,Default,,0000,0000,0000,,changes. So on the one hand we know a lot about how learning and memory are organized
Dialogue: 0,0:02:15.60,0:02:20.28,Default,,0000,0000,0000,,at the functional whole brain level. On the other hand we know a lot about its implementation
Dialogue: 0,0:02:20.28,0:02:25.67,Default,,0000,0000,0000,,at the cellular level with neurons and synapses. The next great challenge and the one that
Dialogue: 0,0:02:25.67,0:02:30.89,Default,,0000,0000,0000,,my lab is tackling is to try to bridge the gap between these very different levels of
Dialogue: 0,0:02:30.89,0:02:34.89,Default,,0000,0000,0000,,organization and understand how learning works at the level of the neural circuit. Because
Dialogue: 0,0:02:34.89,0:02:41.04,Default,,0000,0000,0000,,it is the circuit level organization that causes changes in synapses in the hippocampus
Dialogue: 0,0:02:41.04,0:02:45.85,Default,,0000,0000,0000,,to be able to encode the name of someone whereas changes in the synapses of the cerebellum
Dialogue: 0,0:02:45.85,0:02:52.44,Default,,0000,0000,0000,,improve your tennis game. A lot of the magic occurs at this intermediate circuit level
Dialogue: 0,0:02:52.44,0:02:57.35,Default,,0000,0000,0000,,of organization. And of course thats true not just for brains but for many things its
Dialogue: 0,0:02:57.35,0:03:02.72,Default,,0000,0000,0000,,that intermediate level of organization that is really critical for how that thing works.
Dialogue: 0,0:03:02.72,0:03:08.07,Default,,0000,0000,0000,,So if for example you wanted to understand how a car works so you can fix it you might
Dialogue: 0,0:03:08.07,0:03:13.69,Default,,0000,0000,0000,,go down to your auto parts store and carefully examine spark plugs and belts and gaskets
Dialogue: 0,0:03:13.69,0:03:18.54,Default,,0000,0000,0000,,and hoses and things like that. And you might also draw on your experience as a driver to
Dialogue: 0,0:03:18.54,0:03:23.45,Default,,0000,0000,0000,,know that there is a power system that makes the car go and a steering system that makes
Dialogue: 0,0:03:23.45,0:03:29.51,Default,,0000,0000,0000,,it turn and a braking system. But thats not enough right? If you want to fix your car
Dialogue: 0,0:03:29.51,0:03:35.47,Default,,0000,0000,0000,,the critical thing is to understand how all those parts interact to give rise to the engine
Dialogue: 0,0:03:35.47,0:03:39.56,Default,,0000,0000,0000,,that makes the car go and how all the parts fit together to make the steering system that
Dialogue: 0,0:03:39.56,0:03:44.82,Default,,0000,0000,0000,,makes it turn. Its this critical intermediate level of organization that is necessary if
Dialogue: 0,0:03:44.82,0:03:51.00,Default,,0000,0000,0000,,you want to fix your car. Of course for the car, we have things like engineering drawings
Dialogue: 0,0:03:51.00,0:03:55.90,Default,,0000,0000,0000,,and auto mechanics repair manuals that give us that information about how the parts work
Dialogue: 0,0:03:55.90,0:03:59.88,Default,,0000,0000,0000,,together but we have no such thing for the brain. And so thats what my lab is working
Dialogue: 0,0:03:59.88,0:04:05.04,Default,,0000,0000,0000,,to produce because thats what we need if we want to be able to fix it. And of course we
Dialogue: 0,0:04:05.04,0:04:11.83,Default,,0000,0000,0000,,do want to fix it. One in twenty kids has a learning disability. One in seven people
Dialogue: 0,0:04:11.83,0:04:19.35,Default,,0000,0000,0000,,over the age of 70 and half of the people over 85 have alzheimer's disease or a related
Dialogue: 0,0:04:19.35,0:04:22.94,Default,,0000,0000,0000,,dementia. And the treatments available at this point are not as effective as we'd like.
Dialogue: 0,0:04:22.94,0:04:28.00,Default,,0000,0000,0000,,They are mainly pharmaceutical. And for most drugs we have some idea how they act at the
Dialogue: 0,0:04:28.00,0:04:33.19,Default,,0000,0000,0000,,level of individual neurons or synapses. But we don't know much about how the effects at
Dialogue: 0,0:04:33.19,0:04:39.08,Default,,0000,0000,0000,,that level then effect the next level up, the neural circuit and its ability to process
Dialogue: 0,0:04:39.08,0:04:43.77,Default,,0000,0000,0000,,and store information. So sometimes the drugs work and sometimes they don't and often we
Dialogue: 0,0:04:43.77,0:04:49.31,Default,,0000,0000,0000,,don't really understand why. Some really new and exciting technologies are being developed
Dialogue: 0,0:04:49.31,0:04:54.35,Default,,0000,0000,0000,,that will allow us to manipulate the brain with a precision thats not possible with drugs.
Dialogue: 0,0:04:54.35,0:05:00.51,Default,,0000,0000,0000,,Even if tomorrow someone were to hand doctors a magic new technology that would enable to
Dialogue: 0,0:05:00.51,0:05:06.19,Default,,0000,0000,0000,,control neurons and synapses with whatever precision they want safely inexpensively.
Dialogue: 0,0:05:06.19,0:05:10.97,Default,,0000,0000,0000,,Those doctors would still not be able to improve school performance of the kids with learning
Dialogue: 0,0:05:10.97,0:05:16.19,Default,,0000,0000,0000,,disabilities and they would still not be able to prevent cognitive impairment and loss of
Dialogue: 0,0:05:16.19,0:05:20.16,Default,,0000,0000,0000,,memory in older adults because at this point we really don't understand enough about learning
Dialogue: 0,0:05:20.16,0:05:25.06,Default,,0000,0000,0000,,to know which neurons and synapses within a circuit would need to be tinkered with.
Dialogue: 0,0:05:25.06,0:05:30.71,Default,,0000,0000,0000,,So at this point giving doctors this magic tool would be like giving me some fancy wrenches
Dialogue: 0,0:05:30.71,0:05:36.75,Default,,0000,0000,0000,,but no repair manual and asking me to fix your car. I could go in there and make some
Dialogue: 0,0:05:36.75,0:05:41.55,Default,,0000,0000,0000,,changes and I might get lucky but if it was my car or my brain I would like to have the
Dialogue: 0,0:05:41.55,0:05:46.50,Default,,0000,0000,0000,,detailed repair manual available. So thats what my lab is working to produce. We're trying
Dialogue: 0,0:05:46.50,0:05:52.99,Default,,0000,0000,0000,,to understand how neurons and synapses work together in circuits to support learning and
Dialogue: 0,0:05:52.99,0:05:57.96,Default,,0000,0000,0000,,memory. So what do we know about neural circuits? The function of a circuit is to compute. To
Dialogue: 0,0:05:57.96,0:06:04.72,Default,,0000,0000,0000,,take an input and generate an output. And this transformation of input into output is
Dialogue: 0,0:06:04.72,0:06:09.90,Default,,0000,0000,0000,,accomplished and shaped by the very precise patterns of interconnections synaptic connections
Dialogue: 0,0:06:09.90,0:06:15.11,Default,,0000,0000,0000,,between neurons and your neural circuits. And this is really how information is processed
Dialogue: 0,0:06:15.11,0:06:20.77,Default,,0000,0000,0000,,in the brain. Information is processed and transformed and used to make decisions through
Dialogue: 0,0:06:20.77,0:06:26.20,Default,,0000,0000,0000,,the many individual synaptic signaling events that occur in a neural circuit. So for example
Dialogue: 0,0:06:26.20,0:06:32.96,Default,,0000,0000,0000,,your driving down the road and see a yellow light. That input will activate neurons in
Dialogue: 0,0:06:32.96,0:06:37.70,Default,,0000,0000,0000,,the visual parts of your brain and when they're activated they'll send signals to the neurons
Dialogue: 0,0:06:37.70,0:06:43.03,Default,,0000,0000,0000,,on which they make synapses. A typical neuron has connections with thousands of other neurons.
Dialogue: 0,0:06:43.03,0:06:46.42,Default,,0000,0000,0000,,If some of those neurons get enough input they will then become activated and they will
Dialogue: 0,0:06:46.42,0:06:51.34,Default,,0000,0000,0000,,signal to the next neurons which will signal to the next neurons until eventually an output
Dialogue: 0,0:06:51.34,0:06:58.31,Default,,0000,0000,0000,,is generated, a movement of your foot to the
Dialogue: 0,0:06:58.31,0:07:03.76,Default,,0000,0000,0000,,accelerator.
Dialogue: 0,0:07:03.76,0:07:05.30,Default,,0000,0000,0000,,A lot of you are nodding but
Dialogue: 0,0:07:05.30,0:07:12.70,Default,,0000,0000,0000,,a few of you are frowning disapprovingly. But to those of you frowning never fear because
Dialogue: 0,0:07:12.70,0:07:18.55,Default,,0000,0000,0000,,those synapses that define our neural circuits as I said are not static but can change with
Dialogue: 0,0:07:18.55,0:07:22.48,Default,,0000,0000,0000,,experience. So for example
Dialogue: 0,0:07:22.48,0:07:28.87,Default,,0000,0000,0000,,If you get a ticket for running a red light
Dialogue: 0,0:07:28.87,0:07:35.61,Default,,0000,0000,0000,,this is likely to induce changes in your brain. Some synapses might get stronger, others could
Dialogue: 0,0:07:35.61,0:07:37.13,Default,,0000,0000,0000,,get weaker
Dialogue: 0,0:07:37.13,0:07:42.32,Default,,0000,0000,0000,,and this will cause this circuit to process information differently the next time it is
Dialogue: 0,0:07:42.32,0:07:46.30,Default,,0000,0000,0000,,activated. So the next time you see that yellow light the output of your circuits could be
Dialogue: 0,0:07:46.30,0:07:51.79,Default,,0000,0000,0000,,quite different and you might move your foot to the brake. This is just one simple example
Dialogue: 0,0:07:51.79,0:07:57.23,Default,,0000,0000,0000,,of the kind of computation that your brain is performing every day. And we think that
Dialogue: 0,0:07:57.23,0:08:01.64,Default,,0000,0000,0000,,virtually all of the computations that the brain performs are powerfully influenced by
Dialogue: 0,0:08:01.64,0:08:05.69,Default,,0000,0000,0000,,experience and learning. My lab focuses on the effects of learning on the computations
Dialogue: 0,0:08:05.69,0:08:10.81,Default,,0000,0000,0000,,performed by this brain region, the cerebellum. And the cerebellum has some cognitive functions
Dialogue: 0,0:08:10.81,0:08:14.74,Default,,0000,0000,0000,,and also as I mentioned earlier it plays a key role in motor learning, the process by
Dialogue: 0,0:08:14.74,0:08:21.18,Default,,0000,0000,0000,,which motions become smooth and accurate with practice. And you might think first of musicians,
Dialogue: 0,0:08:21.18,0:08:25.68,Default,,0000,0000,0000,,athletes, and dancers, but if you've ever observed a small child then you probably realize
Dialogue: 0,0:08:25.68,0:08:30.84,Default,,0000,0000,0000,,that most movements are learned. Even mundane acts like walking or reaching accurately for
Dialogue: 0,0:08:30.84,0:08:36.92,Default,,0000,0000,0000,,something without knocking it over are gradually learned through a lot of repetition and practice.
Dialogue: 0,0:08:36.92,0:08:42.29,Default,,0000,0000,0000,,And even once we acquire those skillful movements the circuits that produce those movements
Dialogue: 0,0:08:42.29,0:08:48.37,Default,,0000,0000,0000,,need to be recalibrated as the body changes, as it grows and then ages we need to make
Dialogue: 0,0:08:48.37,0:08:52.79,Default,,0000,0000,0000,,those recalibrations or our movements will again become clumsy like those of a child.
Dialogue: 0,0:08:52.79,0:08:57.22,Default,,0000,0000,0000,,And this is in fact what is seen with damages to this brain area. So the cerebellum has
Dialogue: 0,0:08:57.22,0:09:04.15,Default,,0000,0000,0000,,some important functions but the main reason my lab focuses on this structure its the brain
Dialogue: 0,0:09:04.15,0:09:07.88,Default,,0000,0000,0000,,region where we have the very best chance of understanding how learning works at the
Dialogue: 0,0:09:07.88,0:09:13.07,Default,,0000,0000,0000,,level of the circuit. Why is that? Well, one of the very first things that you need if
Dialogue: 0,0:09:13.07,0:09:17.59,Default,,0000,0000,0000,,you want to analyze the circuit is the wiring diagram. We need to know which neurons are
Dialogue: 0,0:09:17.59,0:09:21.93,Default,,0000,0000,0000,,connected to which and how signals flow through the pathways, through the circuit. And for
Dialogue: 0,0:09:21.93,0:09:26.34,Default,,0000,0000,0000,,most learning tasks we do not have that but we do have it for several learning tasks that
Dialogue: 0,0:09:26.34,0:09:32.17,Default,,0000,0000,0000,,depend on the cerebellum and the heart of that is shown here. So now with this wiring
Dialogue: 0,0:09:32.17,0:09:37.57,Default,,0000,0000,0000,,diagram in hand we are able to go on and ask the next level of questions about how the
Dialogue: 0,0:09:37.57,0:09:43.17,Default,,0000,0000,0000,,circuit computes and how learning affects that computation. And my lab is asking three
Dialogue: 0,0:09:43.17,0:09:48.60,Default,,0000,0000,0000,,very fundamental questions about this process. The first is where in the circuit do changes
Dialogue: 0,0:09:48.60,0:09:54.48,Default,,0000,0000,0000,,occur when you learn? If you go out and practice your golf swing this weekend, which synapses
Dialogue: 0,0:09:54.48,0:09:58.97,Default,,0000,0000,0000,,in your cerebellum will get strengthened and which will get weakened. Will it be the connections
Dialogue: 0,0:09:58.97,0:10:02.83,Default,,0000,0000,0000,,from the green neuron to the red or from the green to the purple? Are particular types
Dialogue: 0,0:10:02.83,0:10:08.70,Default,,0000,0000,0000,,of synapses more likely to go under changes than others? And are all the changes happening
Dialogue: 0,0:10:08.70,0:10:14.39,Default,,0000,0000,0000,,at one stage in the signal processing pathway or are there multiple serial changes? These
Dialogue: 0,0:10:14.39,0:10:19.89,Default,,0000,0000,0000,,are the kinds of issues that we are looking at. A second very fundamental question is
Dialogue: 0,0:10:19.89,0:10:26.73,Default,,0000,0000,0000,,how are changes induced in the circuit. Which neurons in your cerebellum are monitoring
Dialogue: 0,0:10:26.73,0:10:30.79,Default,,0000,0000,0000,,the accuracy of your swing and deciding when the circuit that produces that movement needs
Dialogue: 0,0:10:30.79,0:10:36.27,Default,,0000,0000,0000,,to be updated? Which neurons know when you made a mistake? And the third fundamental
Dialogue: 0,0:10:36.27,0:10:41.35,Default,,0000,0000,0000,,question is how are synaptic changes in the circuit read out? How do particular changes
Dialogue: 0,0:10:41.35,0:10:46.71,Default,,0000,0000,0000,,in the circuit alter the way that it processes information the next time that it is activated?
Dialogue: 0,0:10:46.71,0:10:51.04,Default,,0000,0000,0000,,And we don't have all the answers to these questions but what we've found so far by studying
Dialogue: 0,0:10:51.04,0:10:53.51,Default,,0000,0000,0000,,the cerebellum parallels in many ways what has been seen at the whole brain level. We
Dialogue: 0,0:10:53.51,0:10:58.63,Default,,0000,0000,0000,,know that there are distinct kinds of learning and memory that depend on distinct brain regions.
Dialogue: 0,0:10:58.63,0:11:02.88,Default,,0000,0000,0000,,But until very recently it was thought that within the brain region there was one main
Dialogue: 0,0:11:02.88,0:11:07.11,Default,,0000,0000,0000,,learning mechanism. So that every time that that brain region learned it did it in very
Dialogue: 0,0:11:07.11,0:11:12.61,Default,,0000,0000,0000,,much the same way. In contrast what we found out is that the cerebellum contains within
Dialogue: 0,0:11:12.61,0:11:19.11,Default,,0000,0000,0000,,it multiple learning mechanisms. So if your golf swing needs a particular type of adjustment
Dialogue: 0,0:11:19.11,0:11:24.31,Default,,0000,0000,0000,,you may be able to accomplish that through different combinations of changes in the circuits
Dialogue: 0,0:11:24.31,0:11:29.55,Default,,0000,0000,0000,,of your cerebellum. We find that individual training sessions can engage more than one
Dialogue: 0,0:11:29.55,0:11:33.45,Default,,0000,0000,0000,,learning mechanism and fairly subtle changes in the way that we do the training or the
Dialogue: 0,0:11:33.45,0:11:38.94,Default,,0000,0000,0000,,way we practice can determine which mechanism are recruited or not recruited, which synapses
Dialogue: 0,0:11:38.94,0:11:43.90,Default,,0000,0000,0000,,change or do not change. And this has some really important implications because we think
Dialogue: 0,0:11:43.90,0:11:49.20,Default,,0000,0000,0000,,that the recruitment of different learning mechanisms will affect factors like how long
Dialogue: 0,0:11:49.20,0:11:55.40,Default,,0000,0000,0000,,the learning is retained, whether what you learn in one context will generalize to other
Dialogue: 0,0:11:55.40,0:11:59.38,Default,,0000,0000,0000,,contexts, and we think that it will affect the ability for learning to be reversed if
Dialogue: 0,0:11:59.38,0:12:05.93,Default,,0000,0000,0000,,circumstances change. And this is important not just for your golf swing but for other
Dialogue: 0,0:12:05.93,0:12:14.84,Default,,0000,0000,0000,,things like developing rehabilitation strategies for patients that have had a stroke and developing
Dialogue: 0,0:12:14.84,0:12:19.13,Default,,0000,0000,0000,,education strategies for our kids. But of course along the way if we do find something
Dialogue: 0,0:12:19.13,9:59:59.99,Default,,0000,0000,0000,,that will improve your golf swing that will be ok too. Thank you for your time.