How is the human brain unique Flashcards
when do we see the two burst in brain size in human evolution
the first happens around 2 MYA with rise of the genus Homo (body and brain evolved together), the second burst happens with the evolution of homo sapiens (brain increases without body increase)
what behavioural correlates cause brain size change in australopithecines
: tool making and sociality
what behavioural correlates cause brain size change in homo erectus
: tool making, fire control, nutritious diet, reduction of teeth size, the support of growth of metabolically expensive tissue
what behavioural correlates cause brain size change in neanderthals
more sophisticated tools, hunting, body decoration, burial of dead, language
what is the theory of how the lateral prefrontal cortex evolved in primates (unique to primates)
addition of a granular layer to frontal cortex became the prefrontal cortex overtime
which region grew the most in human evolution
the neocortex, occupies 80 % of brain
what is different about size of temporal lobe in humans
Overall volume, surface area and white matter volume significantly large than predicted for and ape with a human sized brain
what is the Signal that may indicate departure of humans from other species
the volume of prefrontal white matter → humans have expanded proportion of white matter in frontal cortex compared to other primates
what is the differences of the frontal pole in humans to other apes
it is disproportionately large, when looking at spatial organisation of the frontal pole, grey stain ratio in layer II was lower in humans compared to apes → means there is increased space for neuronal connections, greater number of dendritic spines to foster greater connection
what are neuropil
space between cell bodies, acts as a proxy for neural connections
what is different about cortical connections in humans
we have direct connections, with larger brain size = more extensive connection, direct connection between motor cortex and jaw, face, tongue and larynx → possible cause for evolution of language
why did the brain stop growing
cost outweigh benefits, birth canal too small to support bigger head
