Flies have a lower seizure threshold on exposure to high frequency electrical stimuli (HFS) compared to wild type. Seizures induced by a single HFS stimulus of 40V can be completely suppressed by 10mM valproate.

Undisturbed sda^unspecified flies do not show defects in specific behaviours; they eat, walk, jump, fly, groom, court and mate normally and show normal positive-phototaxis and negative-geotaxis behaviours. The overall level of activity also appears normal. Homozygotes are bang sensitive; after mechanical shock they show a behavioural phenotype with several distinguishable phases. Firstly, they show an initial behavioural seizure characterised by leg shaking, abdominal muscle contractions, wing flapping and proboscis extension, this phase usually lasts several seconds. Secondly, they show complete paralysis for approximately 20 seconds. Thirdly, they show "recovery seizure", characterised by massive uncoordinated motor activity somewhat similar to the initial seizure. Finally, they right themselves and resume normal behaviour. The time for 50% recovery in sda^unspecified flies is about 37 seconds. Immediately after recovery, sda^unspecified flies cannot be reparalysed. This "refractory period" is about 7 minutes in sda^unspecified flies. sda^unspecified is weakly semidominant; heterozygous flies mostly show normal behaviour, although 1-2% are bang sensitive. This semidominant behaviour is more apparent in young flies, with as many as 45% of 1-2 day old flies showing some bang sensitive paralytic behaviour. Under conditions of mild to moderate stimulation, the giant fibre-dorsal longitudinal muscle (GF-DLM) responses of sda^unspecified flies are normal. High frequency stimulus of the giant fibre results in seizures in the giant fibre pathway. The seizure thresholds of sda^unspecified flies (6.2 +/- 0.8 and 6.8 +/- 1.0V for males and females respectively) is considerably lower than that of wild-type flies (30.1 +/- 3.8 and 44.5 +/- 4.4V for males and females respectively). After the seizure, there is a period of "synaptic failure" where stimulation of the giant fibre fails to evoke DLM potentials.