Chapter 4: Brains Arrive

• Introduction
• In early animals, the nervous system is mostly about processing senses and controlling movement.
• As brains increase in size, disproportionate amount of the new space go to internal processing.
• First Brains
• Point to point, sensory systems.
• The striatum is an organizer for signals
• Motor outputs
• The different motor regions are very different from each other.
• The olfactory part of the brain is different from the other sensory systems
• Associative instead of point to point.
• Brain Expansion
• The size of the brain relative to the size of the animal is constant in fish and reptiles.
• But not for mammals or birds
• Protomammals develop better hearing and olfaction
• Birds develop better vision
• Brain size in both jumps 300%
• Note that a larger brain can be a disadvantage
• Higher metabolic cost
• The protomammals were evolving "wildly" because of intense competition with the dinosaurs.