44
THE PHYSICAL BRAIN
Babies and Young Children 45Children’s brains
After birth, babies’ brains are like sponges; they are incredible
at taking in information from the world around them and trying
to make sense of it. During the first few years, the brain grows
and develops rapidly, with brain volume doubling in the first
year of life. Synapses grow and form new connections quickly
and easily, a process called neuroplasticity.AT THE PEAK OF BRAIN
DEVELOPMENT, ABOUT
250,000 NEURONS
FORM EVERY MINUTE
NEWBORN 9 MONTHS 2 YEARS
WHY IS OUR
BRAIN WRINKLY?As human intelligence
evolved, our cortex expanded.
But bigger heads would mean
that babies could not fit
through the birth canal.
A folded cortex packs
more tissue into a
smaller volume.
The cerebrum enlarges, and the eyes
and ears mature, moving into
position. Some parts of the
fetus’s body may respond
to touch.
(^11) WEEKS
The brain stem is mostly
mature and controls reflexes
such as blinking. Sleep and
wake cycles begin, and
the fetus responds to
loud noises.
5 M
ON
TH
S
Gyri
formCerebellumFrontal lobeInsula is found
deep inside
lateral sulcusSulci
formIn the last couple of months of gestation, the
cerebral cortex grows and develops rapidly,
and characteristic grooves appear.
Babies are born with as many
neurons as adults, but most
are not yet mature.9 M
ON
TH
S^ /
BI
RT
H
CerebellumContours
of cortexCerebrumPrefrontal
cortexBrain stemSensory and motor areas of the brain are well
connected and developed, but large areas,
such as the prefrontal cortex, are still
immature. Changes in the hippocampus
and amygdala allow long-term
memories to be retained.Reticular
formation
HippocampusAmygdala
Parietal
cortexPrefrontal
cortex3 Y
EA
RS
Building
connections
Peak plasticity for
each region of the
brain is different.
Sensory areas build
synapses rapidly four
to eight months after
birth, but prefrontal
areas do not reach
peak plasticity until
an infant is around
15 months old.US_044-045_Babies_and_Young_Children.indd 45 20/09/2019 12:32