How our brains shape our destiny
have you ever wondered
what helped to shape the person you are
today for the decisions that you make
the habits that you hold how you like to
spend your time
with who and where even your deeply held
beliefs
your ideology and your identity what
helped
to create those many of us might like to
believe that we are masters of our own
destiny
but increasingly neuroscience is
challenging that idea
we can now peer into the brain and see
how vast swords
of our complex behavior are biologically
ingrained
and for me what all this touches on and
dances around
are some key questions about what it
means to be human
it’s about fate it’s about free will and
it’s about
our brains and to kick-start our
exploration
of these great topics i’d like you to
listen to this
complete gobble the goop right okay now
take a listen to this the camel was kept
in a cage at the zoo
poor camel okay now we’re going to
revert to the original file
and suddenly your brain makes sense of
it
it’s because the two files have a
similar cadence or frequency
and your brain is overlaying the sense
sentence
onto the incoming gobbledygook
this helps us to understand how our
brains operate as prediction machines
we use our past experiences our wisdom
our knowledge as a foundation or a lens
a prism by which to view incoming
information
and that creates our current sense of
reality our perception of the world
and it’s that which then helps us to
decide
how to act in the future and how our
life
stories are created
now this concept
helped me to understand my life
trajectory
i used to work as a nursing assistant in
a psychiatric hospital
i was working with children that had
been detained and sectioned under the
mental health act
i fondly remember how they used to play
basketball
in the courtyards they used to
enthusiastically bang on the bongo drums
in music sessions or they’d be quietly
reading harry potter in a corner but my
overriding memory of the place is a
feeling of deep claustrophobia
and frustration for the children
their constant battle with
medication-induced lethargy
the experience created in me a deep
desire to find out more about the brain
and behavior in an effort to try and
discover new treatments that might help
these children and others
and so i joined a growing army of
neuroscientists and i did a phd in
neuropsychiatry and became a fellow
in order to understand more about the
brain
now the brain is generally now agreed
to be our organ of destiny it’s this
majestic organ that only weighs about
1.5 kilograms so that’s just
two percent of your total body mass and
yet it magically
conjures up all of your thoughts your
emotions
and instructs you to interact with the
world in the way that you do
and it does this via 86 billion
nerve cells eight to six billion that’s
a high number it’s about 14
and a half times the number of people on
this planet in terms of nerve cells
in your brain and even more incredible
is that each one of these nerve cells
connects
to up to 10 000 other nerve cells in
order to create the most
intricate electric circuit board
imaginable
with around 100 trillion connections in
it now why am i calling it a circuit
board
because each one of those nerve cells
uses
the power of electricity pumping sodium
and potassium ions in and out of the
membrane
across the whole circuit of your brain
in order to dictate your emotions your
behaviors
and allow you to process information and
there’s a lovely
albeit slightly mean experiment that
helps demonstrate the power of
electricity in our nervous system
so this is an electric shock panel and
if we apply it to a nerve cell not in my
brain
but into my body there’s a collection of
nerve cells called the ulnar nerve tract
which runs from shoulder to wrist
to control movement in my hand it’s
usually under the control of the motor
cortex here
what we’re going to do is apply a small
electric shock to the ulnar nerve
through the skin switching it on
and off and on
and off and this is happening
quite quickly so the electricity the
signal is being conveyed about speeds of
120 miles an hour and it’s now causing
some pain and distraction for me
um now around 100 or so years ago
a new field of cartography started
mapping not the oceans or the land or
the skies
but mapping the nerve cells in our
bodies and the muscles that they
innovate
skip forwards to today and we’re now
starting to map
these connections within our mind this
neural circuitry of our brain
and what that information is telling us
is that we can now start to use this map
and employ it on people that have been
suffering for many years from symptoms
of depression
or obsessive compulsive disorder or
heroin addiction
these patients opt to undergo brain
surgery and have a minuscule version of
this electric shock panel
embedded deep in discrete regions and
circuits within the brain
to apply an electric current which will
instantaneously switch
off their symptoms offering real relief
to people that have been suffering for
years
but was there anything about these
people’s brains that predisposed them
to suffer in this way we’re actually
also living in a genomics revolution so
we can now sequence
really quickly the 3.2 billion base
pairs that makes up
our individual blueprints for life our
dna code
and what this sequencing information is
telling us is that there’s
huge numbers of our complex behaviors
that are also biologically ingrained
so not just our predisposition to mental
ill health
but also complex traits like our
intelligence or how long we might live
there’s a high genetic biological
element to this
it might be hundreds or thousands of
genes working in tandem
and the majority of these genes are
involved in dictating
how that neural circuitry is laid down
in the first place
in exciting new technological
developments
we can now even peer into the brain
as it’s being built and what scientists
are finding
is that in the human brain 20 weeks
before the birth of a baby you can see
these anatomical signatures these
changes
in the brain that correlate with the
genes that predispose
to symptoms as complex as autism or
attention deficit hyperactivity disorder
adhd
or even symptoms that might not emerge
for decades down the line
major depressive disorder bipolar or
even schizophrenia
you may have heard of the phrase
you’re wired that way well it’s not just
a metaphor
and there’s another new exciting
area of research called epigenetics
that’s helping us to understand
exactly how utterly intertwined nature
and nurture can be
and there’s a lovely example that helps
us to appreciate this
so mice usually love the sweet smell of
cherries
a waft of it reaches their nose and it
sends an electric signal
from the nose to the nucleus accumbens
the region that’s involved in pleasure
motivating the mice to scurry around in
order to hunt out this sweet treat
now researchers wafted in the smell of
cherry and then
shortly afterwards applied a mild
electric shock
and very quickly the mice associated
these memories and learnt to freeze in
anticipation of a shock whenever they
smelt cherries
after this the researchers let the mice
be they had a wonderful happy life
they settled down had children those
pups left home
and they went on to have nice lives and
have children of their own
so now we’re talking about the
grandchildren
of the original mice and it seems as
though this traumatic memory had
cascaded across the generations
via biology there was a change in the
grandfather’s sperm
not in the code itself but in the shape
of its dna and this shape change
altered the way that enzymes could
access different genes
within that sperm and that affected the
way that the neural circuitry of the
pups
and the grand pups brain circuit was put
together
and this sent the electric circuit from
the nose
re-routing it to the amygdala a
different brain region that’s involved
in the fear response
and so the pups learnt through this
mechanism
to be highly sensitive to the smell of
cherries
okay but how does this relate to us
humans
well prisoners of war from the u.s civil
war
when they return home and have children
their sons
have an 11 percent higher mortality rate
by the age of 42
compared to descendants of other
veterans
and in a very fascinating but very small
study those people that survived the
holocaust
their descendants carry an epigenetic
mark
of the memory there’s a change in the
way that the gene
for cortisol a hormone that’s involved
in the stress
response is expressed
okay so our fate our destiny
can be written into our dna entwined in
the way that it’s structured and
expressed
and we can carry memories across
generations
but thankfully not all of our fate
is written in stone in its entirety
there is still potential for change
and this occurs by this wonderful
mechanism called plasticity
as you learn something new a new
connection forms between one nerve cell
and another
as that learned thing becomes a memory
it becomes the default
route within your brain by which to
process information and it becomes a
stable connection
and what you can see in this movie here
are proteins being
shuttled across a nerve cell to help
with that laying down of
new memories within the mind
and that new passageway of thinking
can then become a habit in your behavior
but it’s not as simple as that sometimes
it can be very
difficult to allow people to change
their minds
and to think in a new way to learn from
their environment afresh
and this is a neat illusion that helps
demonstrate that point
so when we get to the back end of this
hollow mask the shadow information is
telling us that the eyes
and the nose are pointing backwards but
we’re used to seeing faces in our
environment
and so we ignore those shadow cues and
just see
another face pointing out
in this way we can start to understand
how our brains
make assumptions based on our past
experiences
and sometimes those assumptions can be
so
inbuilt into our identity that in order
for us to see the world afresh it would
require
widespread demolition and rebuilding
work
and it can be sometimes just too costly
for me there’s something quite beautiful
about
viewing all of our behaviors
as this simple output this mechanistic
processing of all the information that’s
coming in from the outside world
being overlaid by our cartography our
unique
dna code that sculpted our brain
to give rise mechanistically to our
behaviors
and our views and also there’s some
promising research coming out of
neuroscience
in the fields of resilience and finding
out how we can cultivate
a more flourishing brain and this gives
me hope
for some of the children that i was
talking about
earlier on also as a first-time
parent i find this neuroscience
knowledge
empowering rather than
constantly worrying about how i can hone
my son’s developing brain
i find it reassuring to think that
actually what’s done is done his brain
is his
and rather than worry in this age of
parental anxiety
actually i should just sit down and play
with him
but biological determinism rightly makes
people nervous
there’s been some aborig acts genocide
and eugenics
but perhaps neuroscience knowledge
should be used instead
by each of us to start to appreciate
how evolution has provided us with this
organ that allows us to display this
vast
breadth of behaviors for each one of us
on this planet to have a very unique and
individual
cartography of the mind which gives rise
to very different behaviors and very
different views
and actually maybe we should appreciate
this neurodiversity
because it’s only when we start to pull
all of that individual different ways of
thinking
that we can truly harness the collective
cognitive capacity that we as a species
are capable of
you