Avian brain

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Avian brain: a quick guide

What the brain does
The bird brain is its control center. It processes what birds see and hear, helps them learn, remember, and make decisions, and coordinates movement for activities like flying and singing.

Main parts
- Forebrain (telencephalon): the brain’s thinking area, including the pallium and the underlying subpallium.
- Brainstem and cerebellum: control basic functions and sharp, coordinated movement.

Structure and function
- Pallium: the main part of the forebrain, made up of the hyperpallium (top part) and other pallial areas. It handles perception, learning, and thinking.
- Wulst and sensory cortex: the dorsal part (Wulst) helps with higher processing of senses; pallial circuits connect in both horizontal and vertical directions.
- Nidopallium caudolaterale (NCL): a key center for goal-directed actions. It’s strongly influenced by dopamine and links rewards, rules, memory, and decision-making. Birds with higher cognitive abilities tend to have a larger NCL.
- Subpallium: includes the striatum and pallidum, which connect different parts of the forebrain and help control movement and behavior.
- Song learning: Area X in songbirds is important for learning songs; it works with other basal ganglia-like structures to shape vocal learning.
- Visual and social processing: birds have strong visual and auditory processing; social behavior relies on brain organization in these areas.
- Sensory cortex-like regions: the pallium has layered areas that process sensory information and support perception and learning.

Brainstem and cerebellum details
- Cerebellum: a highly folded, important structure for balance, movement, and precise control. Different birds show different folding patterns depending on their lifestyles.
- Other brain areas: the thalamus and midbrain connect senses to action, while the hindbrain links the brain to the spinal cord.

Lateralization
Bird brains have two hemispheres that specialize in different tasks. The left side often helps separate important signals from distractions, while the right side is more easily distracted and linked to fear and quick responses. Some birds also show left-hemisphere dominance in learning tasks.

Evolution and brain size
- Birds evolved from dinosaurs and show a big brain relative to body size in many species.
- The unique bird brain has the Wulst (hyperpallium), which is thought to be analogous to the mammalian neocortex and supports higher thinking.
- Parrots and corvids (like crows and ravens) have especially large brains for their body size and show remarkable problem-solving and learning.
- Over millions of years, bird brains expanded and reorganized, with several shifts in brain size relative to body size after the age of dinosaurs.

Energy use
Birds have many neurons packed into their brains and use a lot of energy, but their neurons may demand less glucose than mammal neurons. This, plus their high body temperature, helps support dense, efficient neural networks.

In short
Birds may not have a mammal-like cortex, but their brains are highly capable. Specialized pallial circuits, a dopamine-influenced NCL, a robust cerebellum, and strong sensory and social processing allow birds to fly, vocalize, learn, and think in sophisticated ways.