Figure 8. Common response function allows even weakly-responsive neurons to contribute.

For identified dopamine neurons in the variable-expectation experiment, response to unexpected rewards versus 90% expected rewards (re-plotted from Fig. 4d). Black line, linear regression, which assumes that each neuron’s response is divided by the same value. The slope of this line corresponds to 1-β (see text). Orange line, hypothetical scenario in which each neuron’s response is subtracted by the same value, rather than divided. Dotted line, identity (y = x).