Complex sentence: Tuberous electroreceptors show a V-shaped threshold tuning curve (similar to auditory system), which means they are tuned to a particular frequency; the frequency they are tuned to is usually closely matched to their own EOD frequency.
Split into simpler sentences: Tuberous electroreceptors show a V-shaped threshold tuning curve (similar to auditory system), which means that they are tuned to a particular frequency. This particular tuned-in frequency is usually closely matched to their own EOD frequency.