The Leaky Integrator Model

1. The Leaky Integrator Model for lever-pressing mice Dan and Jinsook

2. The Experiment • Mouse wants happy center stimulations • Two levers • Different probabilistic rewards • Fatigue makes switching strategy important • Reward probabilities change in middle of trial (which lever has higher reward switches)

3. Why is this interesting • We want to understand how strategic decision making goes down in the brain • The leaky integrator model worked well with monkeys making saccades • Here rats do what they want when they want, so it’s more complicated and realistic; How does the model hold up?

4. The Leaky Integrator Model • Internal expectation function • Add to function when press -> reward, subtract when press -> no reward • Event memory degrades exponentially • Resets whenever mouse switches • We choose memory half-life of 1 sec, initial expectation = 1, reward = +1, noreward = -1

5. Mice are bad at calculus • Switch much more often when expectation function is low, but often don’t switch when it’s low

6. Better than matching? • Next step is to see if it improves modeling accuracy over matching