Lacunal is a genre with no audio component whatsoever — it exists exclusively as structured neural-feed data transmitted directly into the listener's BCI, where it occupies the brain's auditory processing centers with precisely engineered absence. Rather than sound, Lacunal composes with gaps: deliberate silences in cognition, momentary suppressions of ambient neural noise, the sensation of a sound that almost happened. Listeners describe the experience as hearing something just below the threshold of perception, a music made entirely of implication. The genre emerged around 2201 in the mid-Circuit research clinics, where neurologists studying tinnitus suppression accidentally discovered that controlled absence-states could produce profound aesthetic experiences in BCI-equipped subjects. Early Lacunal pieces lasted under three minutes; the genre's current form spans immersive hour-long compositions.