How the Brain Works The Facts Visually Explained by DK (z-lib.org)

THE BRAIN OF THE FUTURE

The Unexplored Brain 186 187

TH

AL

AM

US

BR

A

IN

S

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M

The brain’s relay station

It is already well known that the

thalamus acts as a relay station

for all incoming sensory

information (except smell), but

more is now being discovered

about how it preprocesses this

information in a complex and

selective manner before it travels

to sensory zones in the cortex.

The thalamus is also central for

the regulation of arousal, and,

with its links to the hippocampus,

it plays an important role in

memory. Deep brain stimulation

(see p.185) of the thalamus has

been used to treat conditions

including tremors.

Located in the hypothalamus, the

tiny suprachiasmatic nucleus (SCN)

sets the body’s circadian rhythm—

our 24-hour sleep-wake cycle.

This biological clock drives vital

homeostatic functions, including

body temperature, feeding, and

hormone levels. The SCN also

coordinates the activities of many

organs. Microscopic electrodes or

lasers could one day adjust these

cycles and patterns.

THE SCN

SCN

Heart

Liver

Stomach

Ovary

HAVE ALL THE

BRAIN’S PARTS

BEEN DISCOVERED?

Not yet. In 2018, improved

microscopes uncovered a small

region at the brain–spinal cord

junction, which was named

the endorestiform

nucleus.

Intralaminar nuclei, involved

in consciousness, alertness,

and feelings of pain

Nuclei of anterior lobe, concerned

with learning and memory

Ventral anterior

nucleus, involved in

voluntary movement

Internal medullary lamina,

a layer of white matter

Medial dorsal nucleus,

involved in memory

Lateral geniculate

nucleus involved

in vision

Medial geniculate

nucleus involved

in hearing

Lateral nuclei

(pulvinar), crucial

for visual

cognition

Thalamic nuclei

Investigations into lesser-known nuclei are revealing

lots of surprises. For example, the pulvinar nucleus

helps the vision centers map out and measure

a scene and how we reach

out to objects there.

DESPITE ITS BODY-WIDE

EFFECTS, THE SCN

CONTAINS ONLY 20,000

NEURONS AND IS

SMALLER THAN

THIS LETTER O

US_186-187_Unexplored_brain.indd 187 20/09/2019 12:38