Fig. 2.

LTFE in the EOD frequency. a, Response of a female fish to a 1 mV/cm stimulus, 3 Hz below its EOD frequency. Initially, a 2-min-long stimulus was presented. The resulting JAR (*) is enlarged in the inset. The EOD frequency relaxes back to baseline after stimulus offset. Another stimulus was presented 0.5 later for 0.5 hr. The JAR is maintained throughout the entire stimulus period and reaches a stable frequency (691.7 Hz; 5.1 Hz elevation; top dashed line) after 9 min. Furthermore, the EOD frequency right after stimulus offset decays rapidly to a stable but still elevated level (2.8 Hz elevation;arrow), from which it gradually returns back to baseline (bottom dashed line) over 1.2 hr. The frequency and duration of the stimulus presentations are indicated by the bold line underneath the EOD frequency. b, Response of a male fish to a 100 mV/cm stimulus, 3 Hz below the EOD frequency. Again, an initial 2-min-long presentation (*) does not result in LTFE (inset), whereas a 3-hr-long stimulation (onset 0.5 hr later) results in LTFE. The initial frequency elevation is 8.5 Hz (arrow), and the duration until decline to baseline (bottom dashed line) is ∼9 hr. Note that JAR and LTFE magnitude are larger and that LTFE also lasts longer than ina.