Two examples of learning curves using HR recordings.

<p>Lines are smoothed (0.5 s and 1.0 s sliding window in A and B, respectively). Line plot of HR is expressed as percentage change above average pre-stimulus values representing the “learning curve” for first three training sessions in two bats. Each bat acquired a robust and relatively stable response on the third day that was rapidly re-established on day 7 in the first bat (A).