Full transcript
0:02our brains are so complicated
0:04neuroscientists are still only at the
0:06beginning of understanding how that gray
0:08matter inside our skull works for
0:11centuries the brain was completely
0:14misunderstood then as we started to
0:16unlock the myriad regions and elements
0:18of the brain a wide range of theories
0:21emerged about how it worked most of
0:24those have been set aside especially
0:26since the introduction of functional
0:27magnetic resonance imaging to map our
0:30brains over the past 25 years F MRIs
0:34have reshaped our understanding of the
0:36brain one important discovery has been
0:39how flexible and adaptable it is dr.
0:42Norman Doidge has been at the forefront
0:44of discovering the power of the brain to
0:47adapt and change because of its plastic
0:49nature neuroplasticity in other words is
0:52the ability to form and reorganize
0:55synaptic connections in response to
0:57learning experience disease and
1:00following injury we asked dr. Deutsch to
1:03join us for a conversation that matters
1:04about our remarkably adaptable brains
1:09conversations that matter is a partner
1:12program for the Center for dialogue at
1:13Simon Fraser University the production
1:16of this program is made possible thanks
1:18to the support of the following and
1:19viewers like you
1:25dr. Deutsch welcome to conversations
1:27that matter thanks for having me let's
1:30start with just a brief definition of
1:32what no plasticity is and then we'll go
1:35from there and how we can apply it to
1:36our lives sure it's the property of the
1:39brain that allows it to change its
1:41structure its physical structure and its
1:44function in response to mental
1:46experience and mental experience can be
1:49perceiving sensing thinking imagining
1:52moving any of those things insofar as
1:55they create a subjective mental
1:57experience actually changes the
2:00structure of the brain
2:01it changes the connections between the
2:03cells mm-hmm physical exercise can
2:07trigger all sorts of growth factors that
2:10allow certain parts of the brain in fact
2:12to grow new cells and so on so it's it's
2:16a big change from this old machine model
2:19mm-hmm that saw the brain is hardwired
2:21since birth and it has huge cultural and
2:24clinical implications you talk about the
2:26neurons that fire together wire together
2:28so I learn how to do something and I
2:30start to create this neural pathway then
2:34all these different elements start to
2:36line up and it becomes this pattern and
2:40this is the way that we learn by
2:42understanding that neural plasticity is
2:45available does it give us hope and
2:47encouragement that we can change the way
2:49that we that we've been doing things
2:51especially if it's something that has
2:54not been only producing positive results
2:56emphatically yes you know one way to
2:59think about plasticity is you know when
3:03neurons fire in a repeated pattern and
3:07and they learn something they fire
3:08faster stronger signals so you your
3:11brain gets better at doing whatever you
3:13choose to do mm-hmm
3:15so if you choose well it's going to get
3:18better at that it's sort of like snow on
3:19a hill in winter yeah if you want to do
3:21something for the first time and it's a
3:23virgin Hill you can ski down that
3:25pliable snow take and take many
3:28different paths mm-hmm
3:30if you go down that hill and you had a
3:32good run being human you might want to
3:34do that running
3:36and again and again and then what will
3:37happen is you'll get better at doing
3:40that run you'll get tracks in the snow
3:42you keep it up you can get ruts in the
3:44snow to the point that those neurons
3:47that are doing that activity are are so
3:50fast so good at it that it's hard to do
3:52it a different way mm-hmm so plasticity
3:55also contributes to habits bad and good
3:58and so yes you can sculpt your brain by
4:02the choices you make so then how do you
4:05unwind that if this has been you know
4:07there's a stimulus and the response that
4:09your brain has recognized this happens
4:12this is the way that you've taught me
4:13that you want me to respond how do you
4:15then start to change that well you have
4:18to you have to block it in some way and
4:20you know one of the ways that this came
4:22to light and in a story that teaches
4:25many lessons has to do with the work of
4:28Edward Tabb who actually worked with
4:29stroke patients
4:30yeah early on he made some really
4:33important discoveries so if you if you
4:36know someone who's had a stroke they're
4:38often told that they should have
4:39physiotherapy for about six weeks mm-hmm
4:42and that's what our insurance companies
4:44will offer often cover and that's
4:45because about a hundred years ago it was
4:48discovered that after a stroke you know
4:50there might be a clot in the brain or
4:51bleeding but there has to be a lot of
4:53chemical work in the brain to to deal
4:55with that and even if the stroke is very
4:58local in a certain part of the brain
5:00there's kind of a global non-functioning
5:03immediately after the stroke in this
5:05period of crisis and what we now know is
5:09that if you try to use your arm let's
5:11say there was a stroke here and it
5:13blocked the use of this arm if you try
5:15to use that arm and over and over and it
5:20doesn't work you will learn it doesn't
5:21work and this circuit for that arm will
5:25actually enter a state of dormancy and
5:27it basically turns that circuit down
5:29it's already damaged but it kind of
5:31turns the whole circuit off completely
5:33mm-hmm what you'll probably try to do is
5:35use your good hand and because you're
5:39not using this hand the plastic brain is
5:41they use it or lose it brain so whatever
5:43potential that existed in this circuit
5:45now starts to atrophy or fade away
5:48and if you're using this hand which is
5:50this part of the brain this will get
5:52stronger so whatever word tab did is he
5:55realized that this is actually a problem
5:57relying on just the good hand because
5:59you're further weakening the damaged
6:03hand as you know so he would put this
6:05hand in a cast or a sling and he would
6:09then force the person to train retrain
6:12the use of this arm almost like they
6:14were a child learning to use child's
6:15toys up mm-hm and he actually found that
6:18he could get function back by doing that
6:20so this is really important you've got
6:22to block the habit and sometimes you use
6:26something almost artificial to block it
6:27well and that's because it's not
6:29actually not the hand that's damaged
6:31part of the brain that that sends the
6:34signals to the hand to be used right and
6:37this learned non use I over the years as
6:39I as I've been in this game for a while
6:42I realized that learn non use exists not
6:44just in strokes but it exists in
6:45multiple sclerosis and Parkinson's and
6:48in in lots of human can brain conditions
6:51neurological and even psychiatric that
6:53it's a core sort of protection of the
6:55brain when something's not working to
6:57say okay let's use our resources where
7:00they they'll be of benefit to me mm-hmm
7:03and to turn those circuits off and just
7:05knowing that means you if a person can't
7:08do something you don't if they can't do
7:10something now you don't assume there's
7:12no function there it may just be turned
7:14off and that that was one of the most
7:16important insights for me yeah that
7:20allowed me to realize that a lot of
7:22people who look like they're incurable
7:24might actually be helped so you know
7:27when I was a medical student and if
7:29let's say someone couldn't had a stroke
7:31and they lost 90% of function the
7:35assumption was you know you'd go to some
7:37kind of x-ray or brain scan and you
7:39would see a lesion you just say oh yes
7:41that's responsible for it ninety percent
7:43of the cells governing the use of this
7:44hand must be dead but it turns out
7:48that's often not the case what what you
7:50very frequently have is what I call the
7:52noisy brain and so some cells die that's
7:56true and there's nothing you can do
7:58about that you know some cells are sick
8:00they're metabolically compromised
8:02they're in an area adjacent to the six
8:04cells so what you often have is the
8:06following the cells that were adjacent
8:10to the dead cells that were that we're
8:12getting signals from of it some of them
8:14are suddenly bereft of signals and I
8:17think they go dormant others that are
8:19near the sick cells near the dead cells
8:22are still sick and they're firing but
8:24they're not firing at normal rates they
8:26may be firing too slow we know this from
8:28brain injury we know this from lots of
8:30different studies or firing irregularly
8:33think of a heart that has an arrhythmia
8:34mm-hmm so they're sending junk data now
8:37to healthy cells mm-hmm and the healthy
8:39cells are not getting good input but if
8:42you think about it it may be only a
8:44small percentage of the cells that are
8:47damaged in a person who's lost 90% of
8:49function so if we can resynchronize
8:51those healthy cells which we can start
8:54with we can resync ratan resynchronize
8:56the sick cells and there are many ways
8:58to do that sometimes functional medicine
8:59can help you do that we can find ways of
9:02getting the nutrients and are the oxygen
9:05to those cells hyperbaric oxygen was is
9:08one way but there are many many
9:09different ways to do it and we can also
9:11set up a neurofeedback setup where we
9:15actually train the brain to refire at
9:17different rates and there's many ways of
9:19doing that mm-hmm
9:20we can get function back much more
9:23quickly than we might imagine once we
9:26quiet the noise in the brain let's say
9:27somebody lost the use of their middle
9:30finger it was amputated and if you take
9:32a look at the brain map of the index
9:34finger and the ring finger and so on and
9:36you can see that they will then start to
9:38move in and take over that space that
9:40was previously occupied by the brain map
9:42and in essence they're squeezing it out
9:44because it's not being used yes like
9:46there are people who are born with
9:47webbed fingers mm-hmm and when now that
9:50we can map them in different ways but if
9:53you do a brain map of a person with a
9:55webbed hand there's just one map for the
9:58whole through all four fingers because
10:00they're always used at the same time and
10:02so neurons that fire together wire
10:04together so there's just actually one
10:06map and there's a procedure for people
10:08who are born with this these kind of web
10:10fingers that separates the fingers so
10:12that they can use them in two
10:13mm-hmm and six weeks later if you remap
10:16their brains they'll have discrete air
10:18areas in their brain maps for each of
10:20those fingers you know you talk about
10:22that person who's had the stroke and
10:24there has actually been some physical
10:26damage in their brain in that in those
10:29initial weeks when they're recovering
10:30from that it's going to be difficult for
10:32them to be sending out a signal to the
10:34to the damaged motor neurons within
10:39within weeks we start if there's
10:42absolutely no input we start to see
10:44changes there was an experiment done by
10:46a colleague of mine aveiro Pasquale yoni
10:49was a remarkable man and at one point he
10:54took people this was an experiment I
10:58think he did as I recall in Spain and he
11:00he gave them masks that gave them
11:02absolute blind blindness they couldn't
11:05see anything and within I think it was
11:09like 24 to 48 hours the occipital lobe
11:13which is where the visual cortex is so
11:16that's the part of the brain that really
11:18processes vision because it had no input
11:21whatsoever was now processing sound and
11:23touch and not only was it where your
11:25occipital lobe changed its function yes
11:28it changed its function completely and
11:31you know we've kind of sensed this I
11:33mean you know there have been you know
11:35literary stories of blind people like I
11:38don't know like Homer and Milton and
11:40remarkable memories sometimes in these
11:42poets and and
11:44so there is a kind of reassignment
11:49giving that can happen very very quickly
11:51for a life sustaining activity and we
11:54know that people who are blind I have a
11:57friend who was blind and now she listens
12:01to audiobooks mm-hmm well she could
12:05listen to audiobooks before she was
12:06blind but she can listen to them so fast
12:09I can't make out a single word and she
12:12went through you know all the great
12:13Russian authors and the great French
12:15authors and the great English authors
12:16and you wouldn't be able to make out a
12:18word she turns that machine up so fast
12:20because we thing to it and fast forward
12:22yeah fast fast fast forward I mean you
12:25can't even make out the words
12:27but she has all of this you know this
12:29huge part of her brain now you know this
12:31this huge server that is devoted to plus
12:36her original auditory cortex which has
12:38been recommitted to this new task in
12:41your book the brains way of healing you
12:43start to say now here's how we can start
12:45to use that ability to start to deal
12:47with chronic pain do you you know as we
12:51start to use this as a way of dealing
12:53with chronic pain because we've got a
12:55problem in North America we deal with
12:57chronic pain an awful lot with
12:59prescription drugs
13:00yeah and opioids that's all about
13:02plasticity in fact if I could just say
13:04so I mean the reason people get addicted
13:06to opioids is the following when these
13:10drugs were developed first of first of
13:11all we had sort of short-term morphine
13:14like drugs yeah and then the drug
13:18company said well look these people are
13:20in terrible pain let's say people with
13:21terminal cancer and so on and so forth
13:24maybe we can make a long-acting drug and
13:27in those days the model was very much a
13:30machine like model again it was like a
13:32lock and key model in general what
13:34happens is there's a cell and it's got a
13:36receptor site and if you can get a
13:39morphine like substance onto the cell
13:42you can turn off paint mm-hmm but the
13:45idea was it was like the chemical was
13:48like the key that fit into the lock
13:49which was this scepter on the cell and
13:51if it was a machine the idea would be
13:54just bombard bombard it with enough
13:57morphine like substance and the pain
13:59will go away
14:00that's a pre neuro plastic model of the
14:02brain but what really happens is the
14:05brain adapts to everything so the brain
14:07is saying boy oh boy there's a lot of
14:10morphine like substance around here I
14:12better not be overly sensitive to it and
14:14it basically kind of down regulates and
14:16gets less sensitive at that point you
14:20notice that your opioids aren't working
14:22as well as they were before and so you
14:24up the dose mm-hmm and you crave it more
14:27and so that's how you get into an
14:29addictive cycle
14:29it's the neuro plastic brain adapting to
14:31this exhaustion is external substance I
14:34also I'm fascinated by the concept of
14:37exercise and how important it is in our
14:40overall
14:41being but particularly in our cognitive
14:43well-being and you devote a chapter to
14:45that why why is exercise so
14:48fundamentally important to all of us
14:50well I mean for starters why do we
14:54develop brains one of the reasons we
14:56need brains is because we live in a
14:58changing world and we are very mobile
15:02creatures and so we walk into change we
15:05walk from our explored environment that
15:07we we know into an unexplored
15:10environment and so we have to we're
15:12gonna have to learn and you know one of
15:15the things they discovered this was just
15:17with you know experiments with rats and
15:19mice is if you put them on running
15:20wheels this was some of the early
15:22neuroplasticity experiments their brains
15:24get a bigger volume and they actually
15:26grow new cells and then hit the campai
15:28which is the part of the brain that
15:30deals with short-term memory and this
15:35was proposed by rusty gage who was one
15:37of the co discoverers of the neuronal
15:39stem cell that this is what he called
15:43anticipatory proliferation so let's say
15:45you have something like a rat or a mouse
15:47and there's a new predator in the
15:49environment or there's no food left
15:51mm-hmm and they have to leave let's say
15:55it's a predator they they have to go
15:56pretty far they're leaving their
15:58explored territory and they're going to
16:01an unexplored territory so it's as
16:03though when we start going on really
16:06long walks
16:07we're using our limbs a lot it's clear
16:10we're going to have to be doing a lot of
16:12learning mm-hmm and so we we create
16:15these new cells they proliferate in our
16:17brains and our in our hippocampus so
16:20that we'll be able to do that short-term
16:21learning so that's at least one of the
16:24reasons why I think there's an
16:25association between movement and and
16:30learning but it could even be deeper I
16:33mean to some extent the effects of
16:35exercise you know it's not just that you
16:37get new blue new cells in your
16:39hippocampus you many many things happen
16:43and there are there grain growth of
16:45brain growth factors there's brain
16:48derived neurotrophic factor which
16:49consolidates connections between cells
16:51there's something called glial derived
16:53Nurik
16:54traffic factor which is for the the
16:57infrastructure and perhaps even more
16:59than that in the brain these glial cells
17:01also communicate but they also do give
17:07all the support systems for the neurons
17:09in the brain so this is triggered by
17:10exercise too I mean plenty of studies
17:13now show that exercise if you exercise
17:18it it's and do a few other things you
17:21lower your risk for Alzheimer's this is
17:23a big deal this is a big deal it's a
17:26really big deal it's like there's so
17:28much to cover here and one of the things
17:30that I think must be challenging for you
17:33is that you can't come and say there's a
17:35one-size-fits-all here because every
17:37single brain is different in every life
17:39experience is different the way that you
17:40think the way that you've interacted
17:42with the world and so on affects how
17:44you're going to respond to to the change
17:46and what put you in that particular
17:49position but it appears to me that this
17:53is a tool that anybody can use to
17:57address challenges that they're having
17:58with their own life in so many different
18:01ways emotionally psychologically you
18:06know physically of course and then
18:07dealing with a wide variety of motor
18:12challenges and an even ability to think
18:16it must be very exciting for you that
18:19you're constantly discovering new ways
18:21to apply this yeah and like that
18:26confused horseman riding off in all
18:27directions sometimes let's say there's
18:30somebody watching the show going ok I
18:31you know how do I start to apply this to
18:34my life where does somebody get started
18:35from your perspective well just start
18:39with thought I think that you know
18:43there's one of the one of these sort of
18:45sad legacies of the this machine model
18:48of the brain has been Minh
18:53simplistic genetic determinism so that
18:56people thought that you know I I you
18:59know I I'm a I've come out of the box
19:03like a computer and I've got certain
19:04specs and that's all that there is to
19:06to it mm-hmm and that's a really
19:09problematic idea and you know there are
19:11psychologists who've talked about a
19:13growth mindset and a non growth mindset
19:16and that model produces a non growth
19:19mindset and you know even things like IQ
19:22can be raised I've now seen this a
19:26number of times so there there's just so
19:28many developments that a person can do
19:30and so you've just got to just discard
19:32that machine model you're running on a
19:34machine it's it's it's still a popular
19:37model among many neuroscientists they
19:39like to think I mean at the very
19:41beginning of modern science you know
19:43Descartes described the the physical
19:46brain as a hydraulic machine and he
19:49thought that there were the nerves were
19:50like vessels and currents moved up and
19:52down them and he was a very smart person
19:54he was trying to deal with something
19:55complicated and these hydraulic machines
20:00when he wrote were impressive at the
20:01time and from that we got a notion of
20:04currents and of course the currents
20:06aren't fluid or gas they're not they're
20:09not the kind of stuff he thought they
20:10were but there are currents then when
20:12electrical machines came along we
20:14started to talk about brains as having
20:17circuits and there's something to that
20:19we talked about that still but brain
20:21circuits are not just electrical their
20:23electrochemical that's not quite right
20:25and now that computers are everywhere
20:26people in in artificial intelligence
20:30frequently talk about thought as though
20:32it's software and the and the computer
20:35is though it's hardware and that's not
20:37right because you know the software
20:40rewrites and changes the hardware and
20:42that's that's pretty significant mm-hmm
20:44so it doesn't change it infinitely you
20:47know this isn't about magic this is
20:48about science and you know the kinds of
20:51improvements I write about in multiple
20:53sclerosis traumatic brain injury
20:54learning disorders stroke psychological
20:57problems autism mm-hmm
21:00they're not magic I'm trying to explain
21:02how they're possible they might feel
21:04like magic if you've if you're stuck in
21:07that machine model mm-hmm but that's
21:09what has to be modified or discarded
21:12it's just really it has to be understood
21:14as a simile sometimes the brain is a
21:17machine like but not as a metaphor it is
21:19not a machine right and one of the other
21:22things that I note is yes you can think
21:24it you can make changes internally but
21:27at times you need external input as well
21:30yes be able to change the way in which
21:32your brain is interacting with the world
21:35and so it's we're gonna we've still got
21:39a long way to go we're still early days
21:40but there continued to be so many new
21:43discoveries in the way in which we can
21:45apply in neuroplasticity to our own
21:47well-being it could it challenges
21:49conventional wisdom and I applaud you
21:51and thank you for bringing it to our
21:53attention this is fascinating we're way
21:56over time already but I want to thank
21:58you for coming in and doing this thank
22:00you
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