Mammal and Primate Brains Flashcards
what are common characteristics of early mammals
shrew-like insectivores, small, larger laterally placed eyes, dichromatic colour vision, nocturnal
important adaptations in early mammals
olfaction adaptations, hearing adaptations (ear drums, long coiled cochlea, hair cells that amplify vibrations)
what are the types of cortices in the mammalian brain
allocortex → made up of archicortex ( hippocampus, 3 layers) and Paleocortex (piriform cortex 3-5 layers)
Neocortex (6 layers)
what were the innovation of the Neocortex in the mammalian brain
lamination of the six layers, Sensory inputs from the thalamus target neurons in layer 4 of the cortex (projects to layers 5 and 2, 3)
what is thought to be the origin of the neo cortex
the dorsal cortex found in reptiles, mammals closest relatives
name the similarities between the dorsal and neo cortex
Neuron structure, layer makeup, inputs from dorsal thalamus, Projects to extra telencephalic targets
what are the differences between the dorsal and neo cortex
three layers in dorsal 6 in neo, dorsal has no contralateral projections or projections to spinal cord or auditory input from thalamus
what is the functional advantage of the neocortex
Efficient structure that can grow in size without impairing functionality
what are the innovations of placental mammal brains
corpus callosum, motor and premotor cortices, Betz cell (primates) / gigantopyramidal neurons (largest projection neurons)
what are the Primate clades
hominoids (greater and lesser apes), hominids (includes great apea and humans), hominins (humans and extinct ancestors after split with chimps)
what facial adaptation evolved with primates
forward facing eyes and depth perception
important brain changes from early primates compared to tree shrews
larger visual areas, expanded posterior parietal regions, VENTRAL PREMOTOR CORTEX (greater dexterity), granular prefrontal cortex (sensory inputs/outputs) LATERAL PREFRONTAL CORTEX (decision making, integration with other regions)
