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What patterns do you see?. Brain Evolution. Brain Evolution. Forebrain enlarges in many groups, especially amniotes Why ? Motor control/ regulation of sensory input Enlarged even more so in mammals – why ? Absolute brain size increases in many groups, as does relative brain size.
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Brain Evolution • Forebrain enlarges in many groups, especially amniotes • Why? Motor control/ regulation of sensory input • Enlarged even more so in mammals – why? • Absolute brain size increases in many groups, as does relative brain size
Brain Allometry Line of isometry
Beyond Size • See variation across vertebrates in prominence of regions Based on what each part does Obvious across major vertebrate groups… Fig. 16.33
Beyond Size • See variation across species within major groups in prominence of regions … and obvious… Relates to lifestyle and …
Telencephalon Hippocampus Neocortex Processes sensory information Olfactory cortex; dorsal ventricular ridge in reptiles, birds Controls movement, part of limbic system Fig. 16.42
Telencephalon Evolution Lateral pallium Dorsal pallium Notice how different regions enlarge in different groups Fig. 16.43
Bird Brains • Lateral pallium hypertrophies • Most of bird cerebrum is DVR • Dorsal DVR • Bird “neocortex” • Visual, somatosensory, motor cortex Crow making a tool: http://www.youtube.com/watch?v=TtmLVP0HvDg Crow meta-tool use: http://www.youtube.com/watch?v=4RpOGYYKdaQ
Mammal Brains • Dorsal pallium = neopallium = isocortex • Outer layer of cerebral hemispheres • Higher-order functions described earlier • Variation in folding of neocortex • Gyrencephalic= Folded often complexly • Lissencephalic= smooth
Neocortex Variation Can see big and small, smooth and folded within groups Why have folding? Placental mammals Gyrencephalic Marsupials Monotremes Lissencephalic
All sensory, but olfactory Motor response! Touch, pain!