What is explainable variance?
Any neural signal can be divided in to two distinct components: the deterministic part that is predictable from the stimulus, and the stochastic part that cannot be predicted from the stimulus alone. (The stochastic part reflects the true noise level, sampling limitations and other uncontrolled factors.) Because the stochastic part of the response cannot be predicted from the stimulus alone, it will never be possible to predict 100% of the total variance in responses. The explainable variance is the part of the variance that does not reflect noise, and is therefore potentially explainable.
