How Does a Child's Brain Develop? | Susan Y. Bookheimer PhD | UCLAMDChat

00:28:09
https://www.youtube.com/watch?v=vpXrgJ5aj_4

Resumo

TLDRIn this UCLA Health webinar, Dr. Susan Bookheimer, a professor of psychiatry, focuses on child brain development, emphasizing how connections in the brain—termed the human connectome—are formed and their significance to brain function. She explains critical development phases at age two and during adolescence, including the pruning of neurons and the importance of myelination. The talk also highlights environmental influences on brain development, such as exposure to substances, and discusses ongoing research at UCLA exploring these themes in various age groups, particularly focusing on the adolescent brain and conditions like autism.

Conclusões

  • 🧠 Brain connections are vital for cognitive functions.
  • 👶 Early brain development involves excess neurons, with pruning later on.
  • 🔄 Use it or lose it: active connections are maintained.
  • 💡 Adolescence is marked by significant brain changes and emotional sensitivity.
  • ⚡ Myelination speeds up neural communication and is crucial for development.
  • 📉 The gray matter thins while white matter grows as a person matures.
  • 🌍 Environmental factors can severely impact brain development.
  • 🔍 Autism affects brain connection trajectories from an early age.
  • 📊 Research is ongoing to understand individual differences in brain connectivity.
  • 🤝 Functional connectivity is key for effective communication across brain regions.

Linha do tempo

  • 00:00:00 - 00:05:00

    Dr. Susan Bookheimer discusses the development of a child's brain in a UCLA health webinar, focusing on brain connections known as the human connectome. She explains the significance of connections over brain size, how brain development involves loss and pruning of neurons, and how experiences shape this process. Key developmental stages include periods around age two and adolescence, emphasizing the importance of 'use it or lose it' in maintaining essential connections.

  • 00:05:00 - 00:10:00

    The explanation continues with an overview of brain growth patterns from infancy through adolescence, highlighting dendritic branching, myelination, and the pruning of neurons. A detailed comparison of MRI scans between children and adults shows differences in gray and white matter, illustrating the brain's transition from plasticity to efficiency in connection retention.

  • 00:10:00 - 00:15:00

    The talk elaborates on myelination's role in speeding up neural communication. Dr. Bookheimer illustrates this process with brain scans from infants to young adults, demonstrating how increased myelin enhances the performance of brain connections. The growth of white matter, indicating improved communication pathways, contrasts with the reduction of gray matter as the brain matures.

  • 00:15:00 - 00:20:00

    Functional connectivity is discussed, emphasizing the need for different brain regions to communicate for complex tasks. Dr. Bookheimer explains the significance of various brain networks, like the language network and the default mode network while highlighting differences in the brain's modular development between children and adults, particularly in linguistic processing.

  • 00:20:00 - 00:28:09

    As the webinar concludes, the impact of environmental factors on brain development is addressed, especially in adolescence. Dr. Bookheimer reaffirming that while substantial knowledge exists, significant questions regarding brain connectivity influences remain, particularly regarding modern challenges like technology and substance exposure. She mentions ongoing research projects aimed at further understanding these connections.

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Vídeo de perguntas e respostas

  • How do children get into an MRI scanner?

    We use special tools like practice scanners, magnet-compatible video projectors, and audio systems to create a virtual reality experience, helping children feel comfortable.

  • Can we see learning disabilities in brain scans?

    While there are subtle differences in the brains of individuals with learning disabilities, these cannot be identified at the individual level but may be observable when comparing larger groups.

  • What makes the brain of a child with autism different?

    The brains of children with autism develop on a different trajectory, forming different kinds of connections, often showing a higher number of local connections but fewer long-range connections.

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Rolagem automática:
  • 00:00:00
    hello welcome to today's UCLA health
  • 00:00:03
    webinar my name is dr. Susan book heimer
  • 00:00:05
    I am a professor of psychiatry and bio
  • 00:00:07
    behavioral sciences here at UCLA and I
  • 00:00:09
    do research in brain imaging today's
  • 00:00:12
    topic is going to be how does a child's
  • 00:00:14
    brain develop during this talk you can
  • 00:00:18
    ask questions on Twitter at UCLA MD chat
  • 00:00:22
    or go ahead and just ask a question on
  • 00:00:24
    Facebook we'll save them for the end
  • 00:00:26
    today what I'm going to be focusing on
  • 00:00:29
    are first how brain development is
  • 00:00:32
    designed to form connections which
  • 00:00:34
    together we call the human connectome
  • 00:00:36
    I'll also talk about how these
  • 00:00:39
    connections relate to brain function and
  • 00:00:41
    I'll talk about the adolescent brain the
  • 00:00:44
    teen brain and why that teen brain is so
  • 00:00:47
    let's say difficult I'll also talk about
  • 00:00:50
    a few things that can go wrong in brain
  • 00:00:52
    development because of these abnormal
  • 00:00:54
    connecting connections that can develop
  • 00:00:56
    and then I'll mention some studies that
  • 00:00:58
    were going on at UCLA now that you could
  • 00:01:01
    consider participating in one of the
  • 00:01:04
    first things that we need to know about
  • 00:01:05
    brain development is that it's really
  • 00:01:07
    not about size the brain in fact does
  • 00:01:10
    get bigger but that's not really what's
  • 00:01:12
    important what's important is what's
  • 00:01:13
    happening inside brain development is
  • 00:01:16
    all about forming connections we are
  • 00:01:19
    actually born with a lot more brain
  • 00:01:20
    cells than we're going to use and in two
  • 00:01:23
    critical periods of development at about
  • 00:01:26
    age two and then again at adolescence we
  • 00:01:28
    actually lose a lot of neurons during
  • 00:01:31
    this period of time however our brains
  • 00:01:33
    are forming connections the good ones
  • 00:01:35
    the ones that we are using are going to
  • 00:01:37
    be maintained and the rest are going to
  • 00:01:39
    be pruned away just like we would cut
  • 00:01:41
    off an old branch that is no longer
  • 00:01:43
    useful so we use the phrase use it or
  • 00:01:46
    lose it when we think about brain
  • 00:01:47
    development in this way there's a very
  • 00:01:50
    important relationship between our
  • 00:01:52
    environments and our brains what our
  • 00:01:55
    brains are exposed to what we do what we
  • 00:01:57
    see and experience will all help
  • 00:02:00
    determine which of those connections are
  • 00:02:01
    going to stay and which ones are going
  • 00:02:03
    to be cut away this is a picture of the
  • 00:02:07
    fetal brain growth from the age of 25
  • 00:02:10
    days all the way up to birth
  • 00:02:12
    and you can see that the brain starts
  • 00:02:14
    very very primitive and very quickly
  • 00:02:16
    develops into having the general brain
  • 00:02:18
    shape but the main thing that changes is
  • 00:02:21
    the folds in the brain the folds in the
  • 00:02:24
    brain which give rise to this
  • 00:02:26
    characteristic brain pattern are there
  • 00:02:28
    because they increase the surface area
  • 00:02:31
    by having folds we can get more neurons
  • 00:02:33
    into that tissue and the more neurons we
  • 00:02:36
    have the more we are able to use that
  • 00:02:38
    information to do complex tasks that
  • 00:02:40
    humans do so humans have the most folded
  • 00:02:42
    brains that there are there are three
  • 00:02:45
    major changes that take place during
  • 00:02:47
    brain development the first one is that
  • 00:02:50
    what we call the proliferation of
  • 00:02:51
    dendritic branches just as a tree grows
  • 00:02:54
    with a long central stalk which we would
  • 00:02:57
    call in the brain and axon it also
  • 00:02:59
    develops all of these branches and brain
  • 00:03:02
    cells sprout these branches which
  • 00:03:04
    connect to other brain cells so that's
  • 00:03:08
    one thing that occurs another one is
  • 00:03:09
    this process called myelination which
  • 00:03:11
    I'll show some pictures of in just a bit
  • 00:03:13
    but this is a covering of the axons
  • 00:03:15
    these are the major branches that I was
  • 00:03:17
    talking about and these this myelin is
  • 00:03:23
    made of a very fatty substance that
  • 00:03:24
    actually comes from certain kind of
  • 00:03:26
    neuron and it's like an insulation
  • 00:03:28
    material that allows information to
  • 00:03:30
    process and to be sent very quickly from
  • 00:03:33
    one brain cell to the next
  • 00:03:34
    and finally there's that process of
  • 00:03:36
    pruning dying off of brain cells and
  • 00:03:39
    brain connections that looks that look
  • 00:03:41
    is that they're no longer needed here's
  • 00:03:44
    a picture of what it looks like across
  • 00:03:46
    development in the newborn brain we have
  • 00:03:49
    a fair number of neurons here but as you
  • 00:03:51
    can see they're very simple they've got
  • 00:03:53
    a single long axon that's not really
  • 00:03:55
    connected to anything and only a few
  • 00:03:57
    little branches and the cells themselves
  • 00:03:58
    are quite small during development these
  • 00:04:02
    branches really start growing quite a
  • 00:04:04
    bit although the actual number of
  • 00:04:05
    neurons is not changing by nine months
  • 00:04:08
    you can start to see many of these
  • 00:04:10
    connections forming and becoming more
  • 00:04:13
    complex but look at the age of two years
  • 00:04:15
    look how incredibly dense all those
  • 00:04:18
    connections are they're the same number
  • 00:04:20
    of neurons here but that's connected
  • 00:04:23
    everything is practically connected to
  • 00:04:24
    everything else
  • 00:04:26
    however if you contrast that with a
  • 00:04:28
    young adult brain you can see that a lot
  • 00:04:30
    of those connections have started to
  • 00:04:32
    prune away and the cells themselves are
  • 00:04:35
    larger and the connections between cells
  • 00:04:38
    are thicker they've become stronger with
  • 00:04:41
    age but they're fewer of them this is
  • 00:04:43
    the general process what we talk about a
  • 00:04:46
    transition between brain plasticity that
  • 00:04:50
    is the potential for the brain to do a
  • 00:04:51
    lot of different things and brain
  • 00:04:53
    efficiency that is just keeping those
  • 00:04:56
    connections that we need so that we can
  • 00:04:59
    use our brain energy as efficiently as
  • 00:05:01
    possible this is an MRI scan of a seven
  • 00:05:06
    year old and a thirty year old to
  • 00:05:08
    demonstrate one of these processes and
  • 00:05:10
    that is the thinning of the gray matter
  • 00:05:12
    the pruning or the breaking away and
  • 00:05:15
    dying off of neurons in the young brain
  • 00:05:19
    the seven year old brain you can see
  • 00:05:21
    that there's a lot of this thick grey
  • 00:05:23
    matter around here and you compare that
  • 00:05:26
    to the same area in the adult brain
  • 00:05:28
    where it looks much thinner so the
  • 00:05:31
    between the ages of seven and thirty we
  • 00:05:34
    are still losing a lot of neurons this
  • 00:05:38
    graph actually shows the statistical
  • 00:05:40
    change over time from the age of five
  • 00:05:42
    through the age of 20 the brighter
  • 00:05:45
    colors mean thicker cortex the darker
  • 00:05:48
    colors mean thinner cortex and so the
  • 00:05:50
    brain thins although different areas of
  • 00:05:53
    the brain thin at different rates over
  • 00:05:56
    this period of time and in fact the
  • 00:05:59
    frontal lobes are the last areas of the
  • 00:06:01
    brain to thin
  • 00:06:02
    they don't even complete their
  • 00:06:04
    maturation until at least the mid to
  • 00:06:07
    late 20s now I'm going to talk a little
  • 00:06:13
    bit about myelination these are brain
  • 00:06:16
    scans from the age of one week through
  • 00:06:19
    the age of ten years and of course you
  • 00:06:21
    can see that the brain has gotten a lot
  • 00:06:22
    bigger but one of the other changes that
  • 00:06:24
    you can see pretty clearly here is that
  • 00:06:26
    this brain looks very dark as does this
  • 00:06:29
    one whereas these brains look much
  • 00:06:31
    lighter well the reason why that's
  • 00:06:33
    happening is because we have no myelin
  • 00:06:36
    none of that fatty substance in the
  • 00:06:39
    infant brain it slowly starts to develop
  • 00:06:41
    and then accelerates incredibly rapidly
  • 00:06:43
    so it's the myelin that makes this white
  • 00:06:47
    matter these connection tissues look
  • 00:06:50
    very very white and I'll explain a
  • 00:06:51
    little bit more about myelin and how
  • 00:06:53
    that works this is a picture of a brain
  • 00:06:55
    cell called a neuron and this is the
  • 00:06:58
    axon that long central branch that will
  • 00:07:01
    lead this brain cell to another brain
  • 00:07:03
    cell in order to make connections at
  • 00:07:06
    birth there is no insulation around any
  • 00:07:09
    of these connections but what happens is
  • 00:07:11
    a certain kind of brain cell comes in
  • 00:07:14
    and forms a little sheath and wraps
  • 00:07:16
    itself around that axon and a number of
  • 00:07:20
    these different neurons wrap themselves
  • 00:07:21
    around the axon it's like the kind of
  • 00:07:24
    insulation that you would see on an
  • 00:07:25
    electrical wire we don't actually see
  • 00:07:27
    the wires we just see the plastic
  • 00:07:29
    surroundings that insulates the wire it
  • 00:07:32
    allows that electricity to move safely
  • 00:07:34
    within that wire but here in this case
  • 00:07:37
    of myelin it also allows something
  • 00:07:39
    special to happen since the brain
  • 00:07:42
    communicates with electrical signals
  • 00:07:44
    this fatty substance allows those
  • 00:07:47
    signals to skip over from these
  • 00:07:50
    different nodes all the way down it
  • 00:07:52
    allows sort of a speed Dimond pathway of
  • 00:07:55
    connection and so the more myelin there
  • 00:07:58
    is the faster these connections can form
  • 00:08:00
    and therefore the better the
  • 00:08:02
    communication can be between two
  • 00:08:04
    different brain regions in this MRI scan
  • 00:08:08
    that we see here we are seeing the
  • 00:08:10
    infant brain from the first hundred days
  • 00:08:13
    of life up into 300 days of life so this
  • 00:08:16
    is early in the first year of life this
  • 00:08:19
    is the MRI scan and this area down below
  • 00:08:23
    just shows that white matter the part of
  • 00:08:26
    the white matter where the myelin is
  • 00:08:29
    that fatty substance that helps form
  • 00:08:32
    those connections at birth almost
  • 00:08:34
    nothing is myelinated in fact there
  • 00:08:36
    really only two areas of the brain that
  • 00:08:38
    have this myelin that allow for this
  • 00:08:40
    rapid connection one is the visual
  • 00:08:43
    cortex so eyes through the central part
  • 00:08:45
    of the brain into the visual system and
  • 00:08:47
    the other is the mouth motor cortex and
  • 00:08:50
    you can guess why an infant doesn't have
  • 00:08:52
    to do
  • 00:08:52
    very much except find what it wants to
  • 00:08:55
    suck and have the motor system to suck
  • 00:08:58
    it that's all an infant wants to do but
  • 00:09:00
    as the infant starts to develop more and
  • 00:09:03
    more systems come online this myelin
  • 00:09:06
    starts to get formed and it allows that
  • 00:09:07
    child to develop faster and better
  • 00:09:11
    cognitive skills so the more that brain
  • 00:09:14
    is in use the more that this white
  • 00:09:16
    matter starts to develop and we see that
  • 00:09:18
    within one year of life we go from
  • 00:09:20
    almost no myelin in to a well myelinated
  • 00:09:22
    brain this is another picture of this
  • 00:09:26
    comparing again that same seven year old
  • 00:09:29
    with a 30 year old and I've just
  • 00:09:31
    outlined here the white matter of the
  • 00:09:34
    brain and you can see this is the white
  • 00:09:36
    matter this is where the neurons are and
  • 00:09:37
    these are where the connections are and
  • 00:09:39
    you can see how much that white matter
  • 00:09:41
    has grown over that period of time so
  • 00:09:44
    where the gray matter has shrunk the
  • 00:09:47
    white matter the connections have grown
  • 00:09:50
    so it's all about forming connections
  • 00:09:53
    here's another picture of connections
  • 00:09:56
    that you might have heard about this
  • 00:09:57
    connection is called the corpus callosum
  • 00:09:59
    it's a connection of those fibers as
  • 00:10:02
    connecting fibers between neurons that
  • 00:10:04
    connects the left side of the brain to
  • 00:10:06
    the right side of the brain and this is
  • 00:10:08
    a picture of the brain cut right down
  • 00:10:10
    the middle so this would be the nose
  • 00:10:12
    this is the back of the brain the top of
  • 00:10:14
    the brain and this is right down the
  • 00:10:16
    center here you can see in the
  • 00:10:18
    seven-year-old here is the corpus
  • 00:10:19
    callosum here in white and you can see
  • 00:10:22
    how thin it is right here and and in the
  • 00:10:24
    back whereas at the 30 year-old level
  • 00:10:27
    it's very nice and thick so over time
  • 00:10:31
    our two hemispheres have learned how to
  • 00:10:33
    talk to one another and to do it very
  • 00:10:35
    very quickly and efficiently so why do
  • 00:10:39
    we have all of this connection well
  • 00:10:42
    different parts of the brain have
  • 00:10:44
    different roles each part of the brain
  • 00:10:46
    does something different but it doesn't
  • 00:10:48
    do it all by itself to work every part
  • 00:10:50
    of the brain has to talk to other parts
  • 00:10:52
    of the brain it sends electrical signals
  • 00:10:54
    throughout the brain through those white
  • 00:10:57
    matter tracts to form these connections
  • 00:10:59
    so that different areas can talk to each
  • 00:11:02
    other and work together to perform
  • 00:11:05
    complex tasks
  • 00:11:06
    like talking as I am doing with you
  • 00:11:08
    today and this is all about connectivity
  • 00:11:12
    or what we would call functional
  • 00:11:14
    connectivity that is not just the
  • 00:11:16
    structure of those pathways but what
  • 00:11:18
    those pathways are doing and the
  • 00:11:20
    cognitive skills that can emerge because
  • 00:11:22
    the brain is using those pathways to
  • 00:11:25
    talk to other areas of the brain here's
  • 00:11:30
    a picture just of the white matter all
  • 00:11:32
    by itself this is from a technique
  • 00:11:34
    called diffusion tensor imaging and the
  • 00:11:37
    different colors represent what
  • 00:11:39
    direction the pathways are going in now
  • 00:11:42
    I don't want to focus on the colors
  • 00:11:45
    themselves because today we don't care
  • 00:11:47
    so much about the direction but rather
  • 00:11:49
    about the difference between the infant
  • 00:11:51
    brain and the adult brain and here in
  • 00:11:54
    the infant brain even at birth we can
  • 00:11:56
    see that there are important connections
  • 00:11:58
    in the brain
  • 00:11:59
    major fiber pathways this one for
  • 00:12:01
    example going from the motor system down
  • 00:12:04
    through the spinal cord and the corpus
  • 00:12:07
    close and connecting the two hemispheres
  • 00:12:09
    of the brain but notice on the outside
  • 00:12:11
    there is just very little happening
  • 00:12:13
    there those fine connections have not
  • 00:12:15
    been formed compare that to the adult
  • 00:12:17
    brain and see how elaborate and deep all
  • 00:12:20
    these connections are so development is
  • 00:12:23
    really all about forming connections and
  • 00:12:25
    forming them the right way together
  • 00:12:29
    these connections form distinct
  • 00:12:32
    functional networks there are many
  • 00:12:34
    different kinds of networks in the brain
  • 00:12:36
    functional networks in the brain I'm
  • 00:12:38
    just listing a few of them here for
  • 00:12:39
    illustration for example the visual
  • 00:12:42
    network collection of brain regions
  • 00:12:44
    which together allow us to see the world
  • 00:12:47
    and to make sense of what we see figure
  • 00:12:50
    out where things are when we see them
  • 00:12:52
    the auditory network does the same thing
  • 00:12:55
    but with what we hear sensory network
  • 00:12:58
    where our bodies are and how we feel our
  • 00:13:01
    bodies so these are brain regions that
  • 00:13:03
    are connected together left hemisphere
  • 00:13:05
    with right hemisphere and several areas
  • 00:13:07
    across the brain that work together to
  • 00:13:10
    perform the complex tasks of vision
  • 00:13:12
    hearing sensation moving but we also
  • 00:13:16
    have some more complicated networks with
  • 00:13:18
    more elaborate functions
  • 00:13:20
    the language network for example so as I
  • 00:13:22
    talked to you today I have many regions
  • 00:13:25
    of the brain that are involved in
  • 00:13:27
    language they're spread all throughout
  • 00:13:29
    my brain although mostly for me in the
  • 00:13:31
    left hemisphere of my brain and they all
  • 00:13:33
    have to work together in a network there
  • 00:13:36
    are atention networks there's several
  • 00:13:37
    different intention networks and there's
  • 00:13:40
    a southern network called the salience
  • 00:13:41
    network this is a network of brain
  • 00:13:43
    regions that find out what's important
  • 00:13:46
    in the environment and distinguish what
  • 00:13:48
    is important from things that are less
  • 00:13:50
    important so that it can focus on that
  • 00:13:52
    which is most meaningful and significant
  • 00:13:55
    the default mode network is a completely
  • 00:13:58
    different thing we often call this the
  • 00:14:00
    task negative Network this is what you
  • 00:14:02
    do when you're not thinking this is what
  • 00:14:04
    we do when we're at rest essentially we
  • 00:14:07
    turn off our brain we let it just wander
  • 00:14:10
    and it's very important for us to do
  • 00:14:11
    this it gives our brain arrest it allows
  • 00:14:13
    our memories to be consolidated without
  • 00:14:15
    being bothered by the things that we are
  • 00:14:17
    seeing and hearing and it's probably
  • 00:14:19
    very active while we're sleeping and we
  • 00:14:21
    need all of these networks as well as
  • 00:14:23
    many more we can measure these
  • 00:14:27
    functional brain networks with
  • 00:14:29
    techniques including functional MRI so
  • 00:14:32
    functional MRI is a MRI technique it
  • 00:14:35
    requires no radiation
  • 00:14:37
    it requires no injections it's perfectly
  • 00:14:39
    safe and it measures blood flow in the
  • 00:14:42
    brain we can measure it during task
  • 00:14:44
    performance so if I were in a brain
  • 00:14:46
    scanner right now and I were doing a
  • 00:14:49
    language task more blood would flow to
  • 00:14:51
    my language areas of my brain and we'd
  • 00:14:53
    be able to see that in MRI we can also
  • 00:14:56
    look at correlated activity across the
  • 00:14:59
    brain while we're just at rest sitting
  • 00:15:01
    in a scanner because different areas of
  • 00:15:03
    our brain which normally communicate
  • 00:15:05
    which are normally well connected will
  • 00:15:07
    change their blood flow spontaneously at
  • 00:15:10
    about the same time so these are great
  • 00:15:15
    techniques for learning about brain
  • 00:15:17
    function during development because
  • 00:15:19
    they're completely safe for children so
  • 00:15:21
    fMRI shows the basic outlines of brain
  • 00:15:24
    networks at birth and to show you an
  • 00:15:26
    example of this I'm going to show you
  • 00:15:28
    the brain of an eight week old infant
  • 00:15:30
    that we did an MRI scan on and by
  • 00:15:33
    looking at this infant just a truss
  • 00:15:36
    actually sleeping while in the scanner
  • 00:15:38
    we are able to look at the correlated
  • 00:15:40
    activity across the brain to identify
  • 00:15:43
    key networks this is the sensory motor
  • 00:15:46
    Network so this is the motor area of the
  • 00:15:48
    brain where we control our movement this
  • 00:15:50
    is the auditory Network this is where we
  • 00:15:52
    hear the visual network where we see and
  • 00:15:55
    even at birth we have the more complex
  • 00:15:58
    salience Network the network that tells
  • 00:16:01
    babies what is important to them and
  • 00:16:04
    it's really quite remarkable that we are
  • 00:16:05
    born with the basics of these networks
  • 00:16:08
    already connected up in our brains
  • 00:16:12
    networks develop however from these very
  • 00:16:15
    primitive networks over time usually
  • 00:16:17
    with experience so there's a basic
  • 00:16:19
    structure that we're born with but these
  • 00:16:22
    structures are shaped by our experiences
  • 00:16:25
    they are shaped into distinct modules so
  • 00:16:29
    for example this is a picture of the
  • 00:16:31
    language module the group of language
  • 00:16:33
    areas which have to connect together and
  • 00:16:35
    work together to perform language and
  • 00:16:37
    these modules are highly distinct and
  • 00:16:40
    within the modules they're highly
  • 00:16:42
    integrated so they talk within a module
  • 00:16:44
    to each other but they're separate from
  • 00:16:46
    other modules I'll explain what that
  • 00:16:47
    means
  • 00:16:48
    functional activity through development
  • 00:16:51
    changes so that the brain becomes more
  • 00:16:54
    modular and it becomes more efficient so
  • 00:16:58
    in these functional MRI scans of
  • 00:16:59
    language in the young children we see
  • 00:17:03
    that there is a great deal of diffuse
  • 00:17:04
    activity across the brain it's in both
  • 00:17:07
    the left hemisphere and in the right
  • 00:17:09
    hemisphere
  • 00:17:10
    and it's pretty big when we compare the
  • 00:17:13
    same language tasks to young adults we
  • 00:17:16
    see the same brain regions but look it's
  • 00:17:18
    now mostly centered in the left side of
  • 00:17:21
    the brain in the MRI world left is right
  • 00:17:24
    and right is left so this is the left
  • 00:17:26
    side of the brain we see it's more
  • 00:17:27
    specialized and we also see that less
  • 00:17:30
    tissue is dedicated to it because what
  • 00:17:32
    has happened is these modules have
  • 00:17:34
    become specialized and used solely for
  • 00:17:37
    language without any of this extra stuff
  • 00:17:39
    this extra stuff would have been stuff
  • 00:17:41
    that will have been pruned away by the
  • 00:17:43
    time we get to adulthood and that is
  • 00:17:45
    really the process of brain matter
  • 00:17:47
    that helps to support these functional
  • 00:17:49
    networks now we can look at functional
  • 00:17:52
    networks in a variety of different ways
  • 00:17:54
    but one is by looking at graphs so this
  • 00:17:57
    is a graph of a brain network where
  • 00:17:59
    we've laid out all the different brain
  • 00:18:01
    regions in a network and in the adult we
  • 00:18:04
    see that this network all talks to each
  • 00:18:06
    other but in the children they don't
  • 00:18:09
    really talk so closely so the
  • 00:18:11
    connections have all not been as well
  • 00:18:13
    developed here as in here we can look at
  • 00:18:16
    this in another way when we look at the
  • 00:18:18
    relationship between two different
  • 00:18:19
    networks in this case we're talking
  • 00:18:21
    about the tasks positive or attention
  • 00:18:23
    network and the tasks negative or our
  • 00:18:26
    resting or default mode Network and what
  • 00:18:28
    you can see in this typically developing
  • 00:18:30
    child is that the networks themselves
  • 00:18:33
    form discrete very distinct modules that
  • 00:18:37
    all talk to each other but are separate
  • 00:18:39
    from the other modules so these are
  • 00:18:41
    completely separate except for one point
  • 00:18:43
    which allows switching between the two
  • 00:18:46
    well contrast with the network
  • 00:18:49
    organization of a child with an autism
  • 00:18:52
    spectrum disorder where the same modules
  • 00:18:54
    exist but they're not as well integrated
  • 00:18:57
    within and there's too much crosstalk
  • 00:18:59
    between so this makes it so that each
  • 00:19:03
    module has interference from another
  • 00:19:06
    module and it makes it more difficult to
  • 00:19:08
    process information very clearly there
  • 00:19:11
    are other things that we could learn
  • 00:19:12
    about developmental disabilities
  • 00:19:14
    developmental disorders using this kind
  • 00:19:17
    of brain connectivity technique here for
  • 00:19:20
    example is a study of children who are
  • 00:19:23
    typically developing and children with
  • 00:19:25
    autism when they're exposed to rewards
  • 00:19:28
    and in this case the reward would be
  • 00:19:30
    simply seeing a smiling face
  • 00:19:33
    most of us respond very nicely to a
  • 00:19:35
    smiling face and we have a reward center
  • 00:19:37
    in the brain that does that with this
  • 00:19:39
    kind of brain scanning we can see that
  • 00:19:41
    the reward network while fully intact in
  • 00:19:43
    a typically developing kid is not
  • 00:19:45
    working as well and the children with
  • 00:19:48
    autism and this is the difference
  • 00:19:49
    between groups suggesting to us that
  • 00:19:51
    there is a problem in the reward network
  • 00:19:54
    of the brain of children with autism
  • 00:19:57
    environmental exposures can also have
  • 00:20:00
    the very major of
  • 00:20:01
    on brain development this is prenatal
  • 00:20:03
    exposure to alcohol at the top here we
  • 00:20:06
    have a typically developing child in the
  • 00:20:08
    nine month range and you can see the
  • 00:20:11
    corpus callosum here and here and you
  • 00:20:13
    can see the white matter and the gray
  • 00:20:15
    matter this Chuck this is a MRI scan of
  • 00:20:19
    a child who is
  • 00:20:20
    sapote was severely exposed to alcohol
  • 00:20:24
    prenatally and I think the first thing
  • 00:20:27
    that you can see right off the bat is
  • 00:20:28
    that there is no corpus callosum at all
  • 00:20:31
    so the big major connecting fibers that
  • 00:20:34
    connect the right and left sides of the
  • 00:20:35
    brain is simply missing and when we look
  • 00:20:38
    inside the brain we see a similar
  • 00:20:39
    pattern a lack of connectivity some
  • 00:20:42
    abnormalities in several different parts
  • 00:20:44
    of the brain so environmental exposures
  • 00:20:46
    can have a profound effect upon brain
  • 00:20:48
    development and I mentioned before that
  • 00:20:51
    adolescence is a time of great rapid
  • 00:20:55
    brain change with this influx of
  • 00:20:57
    hormones the brain becomes very
  • 00:20:59
    sensitive to new experiences
  • 00:21:02
    it becomes very reward sensitive and it
  • 00:21:05
    becomes driven towards novelty and also
  • 00:21:08
    in particular to social experiences this
  • 00:21:11
    makes a lot of sense because when kids
  • 00:21:13
    grow up and become adolescents they need
  • 00:21:15
    to find a way to launch and they can't
  • 00:21:17
    do that unless they become interested in
  • 00:21:19
    new things and in new people of course
  • 00:21:23
    their emotion networks also become very
  • 00:21:26
    active and yet there's a problem because
  • 00:21:29
    the area of the brain that helps to
  • 00:21:31
    regulate and control these emotional
  • 00:21:34
    experiences and these impulses does not
  • 00:21:36
    come online until at least the 20s and
  • 00:21:39
    sometimes quite late in the 20s so we
  • 00:21:41
    have this situation where there's a lot
  • 00:21:43
    of impulsive impulsivity and a lot of
  • 00:21:47
    emotional arousal without the ability to
  • 00:21:50
    regulate that arousal that's why teens
  • 00:21:52
    are the way they are and that's why it's
  • 00:21:55
    so difficult for teens because they get
  • 00:21:58
    exposed to novel experiences which can
  • 00:22:01
    have negative consequences and they
  • 00:22:03
    don't have quite the regulation that is
  • 00:22:06
    built into the brain to calm that down
  • 00:22:08
    and to control it there is so much more
  • 00:22:11
    that we do not know about brain
  • 00:22:13
    development in fact
  • 00:22:14
    we're really just starting to scratch
  • 00:22:16
    the surface how did these connection
  • 00:22:18
    xions how does the human connectome
  • 00:22:20
    develop over time and in particular how
  • 00:22:22
    do individual differences in connections
  • 00:22:26
    relate to behavior to cognitive
  • 00:22:28
    strengths to cognitive weaknesses how do
  • 00:22:32
    our individual experiences affect the
  • 00:22:34
    development of this connectome and what
  • 00:22:37
    are the effects of things that we are
  • 00:22:38
    exposed to and particularly our kids
  • 00:22:40
    today are exposed to like video games
  • 00:22:41
    and social media and things like that
  • 00:22:43
    how does that affect brain development
  • 00:22:45
    what are the effects of environmental
  • 00:22:47
    exposures toxins also things that people
  • 00:22:53
    will will take drugs things like that
  • 00:22:55
    what are the effects of these on our
  • 00:22:57
    brain connections there's so much that
  • 00:22:59
    we still don't know and these are
  • 00:23:00
    questions that we at UCLA are trying to
  • 00:23:02
    answer with research there are a few
  • 00:23:05
    research projects we're doing right now
  • 00:23:06
    and one is the human connectome
  • 00:23:10
    development project where we are
  • 00:23:12
    bringing children in from the ages of 5
  • 00:23:14
    through 21 and scanning their brains to
  • 00:23:17
    look at the functional connections and
  • 00:23:19
    the structural connections and also
  • 00:23:21
    doing a series of tests on cognition how
  • 00:23:25
    they solve problems and what kinds of
  • 00:23:27
    things they've been exposed to and also
  • 00:23:29
    their emotional experiences to try to
  • 00:23:30
    understand this brain development the
  • 00:23:33
    adolescent brain and cognitive
  • 00:23:35
    development study or ABCD is a study of
  • 00:23:38
    10,000 children across the country 1,000
  • 00:23:41
    in Los Angeles County alone
  • 00:23:43
    they are recruited from select schools
  • 00:23:46
    in Los Angeles County at the ages of
  • 00:23:48
    nine and ten and followed for ten years
  • 00:23:50
    to see what is happening exactly in
  • 00:23:53
    adolescence during that very critical
  • 00:23:55
    adolescent period we're also studying
  • 00:23:58
    the human connectome in older folks
  • 00:24:00
    between 35 and a hundred to find out
  • 00:24:03
    what makes a brain age well and
  • 00:24:06
    gracefully what makes people healthy
  • 00:24:07
    throughout their life and what are some
  • 00:24:09
    of the changes that can affect that
  • 00:24:10
    brain development over time so you if
  • 00:24:13
    you're interested you can reach us at HC
  • 00:24:16
    P at UCLA edu or this this is our
  • 00:24:19
    website or ABC study to see if your
  • 00:24:22
    child is in one of our ABCD schools or
  • 00:24:26
    hcp at UCLA edu
  • 00:24:28
    if you are older and are interested in
  • 00:24:30
    thinking about getting a picture of your
  • 00:24:32
    own brain and everyone gets a picture of
  • 00:24:34
    their brain so I would like to thank you
  • 00:24:37
    so much for paying attention and you can
  • 00:24:40
    ask questions now on twitter using the
  • 00:24:43
    hashtag UCLA UCLA md chat or just go
  • 00:24:46
    ahead and contact us with Facebook and I
  • 00:24:49
    believe that we already have a few
  • 00:24:50
    questions so I will answer a few for
  • 00:24:54
    starters okay one question how do you
  • 00:24:59
    get children to go into an MRI scanner
  • 00:25:01
    well we have special tools in our MRI
  • 00:25:05
    scanner to make it easier for children
  • 00:25:07
    first we have a practice scanner but
  • 00:25:09
    inside the scanner we have special
  • 00:25:10
    magnet compatible video projectors video
  • 00:25:14
    goggles and audio systems so that the
  • 00:25:18
    child essentially experiences something
  • 00:25:20
    that looks like a virtual reality
  • 00:25:21
    experience and we were able to show the
  • 00:25:24
    movies play games while they're in the
  • 00:25:26
    scanner so they don't get much of the
  • 00:25:28
    feeling of being cooped up in a hole and
  • 00:25:31
    we also train them in advance so we've
  • 00:25:33
    been very fortunate and able to get most
  • 00:25:35
    of our children safely and comfortably
  • 00:25:39
    into the scanner without anxiety another
  • 00:25:44
    question can we see learning
  • 00:25:48
    disabilities when we see a brain scan so
  • 00:25:51
    that's a very good question because the
  • 00:25:53
    brains of individuals with different
  • 00:25:56
    learning problems such as dyslexia or
  • 00:25:58
    auditory processing difficulties do have
  • 00:26:01
    some subtle differences but
  • 00:26:03
    unfortunately they are very very subtle
  • 00:26:05
    so we cannot look at a scan and say that
  • 00:26:08
    is a child that has or will have a
  • 00:26:10
    learning disability the brains look very
  • 00:26:12
    much the same there is no brain damage
  • 00:26:14
    that causes learning disabilities on the
  • 00:26:18
    other hand if we look at many many
  • 00:26:19
    children together who have learning
  • 00:26:21
    disabilities and compared their brains
  • 00:26:23
    with typically developing children then
  • 00:26:26
    sometimes we do see some subtle
  • 00:26:27
    differences differences in the reading
  • 00:26:30
    areas of the brain differences in the
  • 00:26:32
    way that different areas of the language
  • 00:26:34
    system are connected together so we
  • 00:26:36
    can't see them but not at the individual
  • 00:26:38
    level
  • 00:26:41
    okay what makes the brain of a child
  • 00:26:43
    with autism different that's a very good
  • 00:26:46
    question there are a number of
  • 00:26:49
    differences that we see in the brains of
  • 00:26:52
    children with autism and we're doing
  • 00:26:53
    many studies right now on on children
  • 00:26:57
    with autism young adults with autism and
  • 00:26:59
    even infants who are at high risk for
  • 00:27:01
    developing autism we believe that autism
  • 00:27:04
    is a problem of the development of these
  • 00:27:06
    connections that are set on a wrong
  • 00:27:09
    trajectory very very early in life we
  • 00:27:13
    are getting better at identifying what
  • 00:27:15
    some of these problems are and trying to
  • 00:27:17
    intervene early so that these children
  • 00:27:19
    will have the best outcomes but in
  • 00:27:21
    general just as in the learning
  • 00:27:23
    disabilities when we look at a brain of
  • 00:27:25
    a child with autism we don't see
  • 00:27:27
    anything wrong there is not damage to
  • 00:27:30
    the brain it's merely developing in a
  • 00:27:32
    different trajectory forming different
  • 00:27:34
    kinds of connections that the brains of
  • 00:27:38
    children with autism will sometimes form
  • 00:27:39
    a lot of local connections but the long
  • 00:27:42
    range connections may not be as intact
  • 00:27:44
    so this is something that we're
  • 00:27:45
    beginning to learn more and more about
  • 00:27:47
    and hope to be able to have more answers
  • 00:27:49
    for you as the years go by and if we
  • 00:27:54
    have no more questions
  • 00:27:55
    then I would like to thank you so much
  • 00:27:57
    for your attention and have a great day
  • 00:28:00
    thank you
  • 00:28:04
    [Music]
  • 00:28:07
    you
Etiquetas
  • brain development
  • human connectome
  • adolescent brain
  • myelination
  • pruning
  • environmental influences
  • autism
  • learning disabilities
  • functional MRI
  • UCLA research