Ch
i
a mp
ee nz
(
00 m 6,2
i l lon )
(300 mill io Cat
Afr
0.5 1
Homo habilis
3 t whale ( ,000 millio o l i P n) F
hale (1,500 mil w li in
Homo erectus
Australopithecines Human/Chimpanzee common ancestor
400
on
600
800
1,000
1,200
1,400
1,600
Mean cranial volume (cm3)
g (160 milli Do o
)
Rat (21 million)
Homo heidelbergensis
200
n)
Mouse (4 million)
n)
8
n)
ica
ne lep
a
nt
00 0 , 1 (1
l io mil
i l l io
n)
h
Number of neurons in the cerebral cortex ...
0m
Neanderthals/ Denisovans
2
23,0 0
Modern humans
Gorilla
Chimpanzee
4
Human (
First appearance (millions years ago)
0.25
0
Brain evolution: size and complexity
The Human Connectome Project is an international research project that aims to build a ‘network map’ of the human brain’s connectivity, focusing principally on the brain’s ‘wiring’ – the white, myelin-rich tracts – using functional magnetic resonance imaging. The hope is that this will shed light on the anatomical and functional connectivity within the human brain and produce a body of data that will aid research into brain disorders. To the right is a representation of brain connectivity obtained using magnetic resonance imaging. Colours of the outermost ring map to regional areas of the cortex. The innermost rings represent average regional volume; surface area; thickness; curvature; and degree of specific connectedness, respectively. The development of strong Artificial Intelligence may also depend on mirroring the living connections of the human brain in the computers of the future.
Total length of myelinated fibres in central nervous system of a typical 20-year-old human male female
176,000 km 149,000 km
Distance to the moon from Earth
406,000 km