Neuroscientists don't just record from the brain — they need to know what the animal is doing and experiencing at the same time. Behavior is the other half of the equation.

Two reasons to study behavior:
1. Behavior itself is interesting — studying it reveals decision-making strategies, memory quality, and how animals perceive the world
2. Relating behavior to neural activity — to understand the brain, you need to know what the animal is experiencing or doing while you record from it

Model organisms in neuroscience include mice, rats, flies, fish, monkeys, and humans. Each species brings different behavioral repertoires. The challenge: there are many levels of granularity:
• Coarse: did the monkey look left or right?
• Fine: what tiny nose twitch did the mouse make 200 ms before a decision?

🐭 Animals can't speak. So to study decision making, we need behavioral proxies — physical actions that report what the animal perceived or decided.

Two-Alternative Forced Choice (2AFC) in animals:
The same logic as in human psychophysics, adapted for animals that can't press buttons or speak:
• Mice: turn a wheel (left/right), lick one of two spouts, nose-poke into one of two ports
• Monkeys: look left or right (eye tracking), use a joystick

Example: the International Brain Laboratory showed mice a grating on the left or right side of a screen. Mice turned a wheel clockwise/counterclockwise to report which side they saw. Same experiment as human psychophysics — but the readout is the wheel.

The Niesol/Churchland 2019 study: mice performed a delayed 2AFC — they grab handles (initiating the trial), see the stimulus, wait 1 second, then lick a spout to report their decision. The 1-second delay separates perception from motor action, so neural recordings during the delay reflect the mouse's memory of what it saw — not the movement itself.

Sensors captured: handle grabs (trial start), lick spouts (choice), left/right decision, success/failure.