for centuries doctors and scientists
have tried to unlock the mysteries of
the human brain
how is it organized
emotions are centered in the lower part
of the brain which areas control
different mental functions
and how is it all wired together to
generate our subjective psychological
experience
for the past 100 years neuroscientists
have approached the brain like map
makers charting its features and
activities within well-defined
boundaries
the prefrontal cortex is celebrated as
the seed of rationality the motor cortex
plans and coordinates movement
the somatosensory cortex and parietal
lobes control our perception of the
physical world
the temporal lobes process memories
language and emotion
the occipital lobe processes and
integrates visual information and the
cerebellum helps execute our body's
motor commands
scientists have looked at the brain
through the lens of our beliefs about
what it means to be human so when we're
looking at parts of the brain trying to
figure out what they do scientists are
usually using beliefs about what makes a
human mind and some of those ideas you
can trace all the way back to plato
but researchers are finding problems
with this picture
recent studies of traditional categories
of cognitive brain functions like memory
show surprising amounts of activity that
overlap different parts of the brain
so much that the simple map in its
strict categories lose their meaning
the way that we've been conceptualizing
the mind doesn't map very well at all
to the the functions of different
systems in the brain these kinds of
distinctions are very subjective and
it's probably better to try to look at
the brain and figure out what its
organizational properties are without
appealing to these culturally laden
categories which aren't respected by the
brain
russell poldrak is doing just that at
his lab at stanford university he's
taking a computational approach to
understanding the organizing features of
our mind if you have people perform you
know a bunch of different psychological
tasks that vary in the psychological
functions that we think they engage
let's collect a bunch of data on a bunch
of different tasks and ask the data what
kind of structure there is
poldrack's lab used machine learning to
try to isolate neural activity related
to memory recall
but rather than simply mapping into
memory centers the data correlated with
more general constructs of activity ones
for which we don't yet have names
what that has shown us in some cases is
that things that we might have thought
were measuring the same thing really
don't seem to be measuring the same
thing at all
i think we need to fundamentally rethink
how we conceptualize the functions of
the brain within neuroscience there's a
i think a broad agreement that you know
the brain is a computational machine and
we need to understand sort of you know
what the computations are that it's
doing and that we should be able to
ultimately understand psychological
function in terms of those computations
part of the challenge here is we don't
really even have a good language for
describing those computations other than
math so it raises essentially a question
of you know whether we're going to end
up with models of the brain that are
really good at predicting
you know activity of the brain but that
we can't sort of give human
understandable explanations to
deep in the jungles of southeast asia
lives the world's strangest flower
this is the reflecia arnold eye it's
affectionately known as the corpse
flower because it smells like rotting
meat to attract pollinating flies
it's the largest flower in the world
with the size and weight of a small
child
but the weirdness doesn't end there
reflecia is not just a flower
it's a parasite
they require part of all of their
nutrients and water from another plant
as a result we often find alien genetic
materials in the genome of a parasitic
plant and many times it's from the host
one of the hypothesis is that parasitic
plant they steal from the host as a
weapon to make them a better parasite
lyming thai is the latest of a long line
of biologists to attempt to sequence
rafflesia's notoriously unwieldy genome
biologists struggled because the
reflections genome features highly
repetitive elements called transposons
known as jumping genes for their ability
to cut and paste themselves at repeating
intervals
most organisms silence these elements
but reflecia is not most organisms these
highly repeated elements it's causing a
lot of problem for scientists
who trying to assemble genomes it's
basically like putting a jigsaw puzzle
but every piece is identical
this year with the help of a
bioinformatics team tai successfully
created a draft genome for a species of
reflecia her findings were even more
shocking than biologists had expected
all plants they more or less
have a similar set of genes in rough
lesia what we found is that it has lost
nearly half of the conserved plant genes
which is really a record-breaking
finding
also found that ninety percent of
reflections genome consists of repeating
dna like transposons
that's highly unusual
no one knows why but the answer may
transform our understanding of parasite
genomics with the advances of these
genome sequencing technology we can
explore
all weird branches of the tree of life
and then understand how rules can be
bent by all sorts of really creative
strategies
life is really diverse and nature often
surprises
in the early 20th century sleep became a
popular topic for researchers the weapon
of choice was the newly invented
electroencephalograph
or eeg a machine measuring electrical
activity in the brain
this approach produced many insights but
it also set up a bias in the studies
that sleep is a neurological phenomenon
and its purpose is located in the brain
everybody has thought that sleep is of
the brain by the brain for the brain
this is a famous quote by alan hobson
who's a brilliant sleep scientist that
made some huge huge contributions to the
field
but it really overlooks the the fact
that in fact we're not brains we're not
walking brains we're organisms we're
integrated everything we do is
integrated with everything else
the first cracks in this brain-centric
view started to show when the swiss
scientist irene tobler noticed that
cockroaches sleep
since then we've learned that simpler
creatures with less and less brain also
sleep
and recently a new discovery has changed
the narrative entirely
this is a hydra
it's one of the simplest forms of animal
life
instead of a brain hydras have nerve
nets the most basic nervous systems in
nature
this year a group of japanese scientists
demonstrated that hydro sleep
living proof that sleep evolved before
brains
but if sleep didn't evolve in and for
the brain what is it for
more and more scientists are looking in
peripheral tissues and asking how the
body can impact the brain and how the
brain can impact the body specifically
with respect to sleep regulation in my
lab the current hypothesis is
that there are some situations that the
brain can't fix itself but that sleep
can lower the activation energy to have
this these circuits begin to find that
solution so the idea then is that when
you're asleep you're using less energy
but the energy that you are using you're
using in a different way
that you're supporting functions that
you would not be able to otherwise
support if you were awake
the research on hydras is the latest in
a growing body of evidence that sleep
first evolved to help regulate
metabolism and enhance repair and only
later took on brain related functions i
really do believe that sleeping
metabolism are intertwined so that's
going to be the future
[Music]
um