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