Brain Evolution

cerebral cortex

cerebral cortex

outer lay of the cerebral hemispheres

neocortex

centrally involved with all aspects of cognition and behavior (sensation, motor control, cognition, planning)

frontal lobe (LS)

executive functions, motor

parietal lobe (LS)

sensorimotor functions

temporal lobe (LS)

memory, audition

occipital lobe (LS)

vision

Frontal lobe (MS)

social cognition, emotion control

parietal lobe (MS)

autobiographical memory

temporal lobe (MS)

memory, expertise

occipital lobe (MS)

vision

insula

internal representation of the body, feelings of pain, disgust, empathy

sensory cortex

receive sensory input

motor cortex

send motor output

association cortex

integrative functions, planning, language, tool use, complex cognition

association cortex

expanded greatly in primates

gyrus

having a highly convoluted brain allows for more neocortical surface area in a smaller volume!

neocortex

a 6-layered structure that covers the surface of the cerebrum

layer IV

primary input, more sensory info comes in here

layer V

primary output, most commands go out from this layer

Social Theories

decision making, relationships, attract mates, expanded neocortex

Foraging Theories

some foods require more learning to acquire

ecological theories

more cognitively demanding food leads to bigger brain and slower life history

extractive theories

convergent evolution, larger brains, slow life history, problem solving, learning, planning

relative brain size

E = kP^α

encephalization

the enlargement of the brain relative to its expected size

encephalization quotient

EQ = observed brain size / predicted brain size

endocasts

show basic gyrus/sulcus features, comprehensive brains, how we know what extinct hominid brains look like

The Front-Orbital Sulcus

brain size isn't everything, can have a restricted brain even with a smaller brain size

energetic constraints

brains are expensive and need a lot of energy to function

50% increase in energy

energetic constraints for a mother when lactating

expensive tissue hypothesis

humans reduced their GI tract to reallocate resources to the brain with better diets