eggroll¹ mutant flies do not show any elevation in response to across a range of spatiotemporal frequencies of contrast-reversing sine-wave gratings as compared to responses from control flies.

Hemizygous male and homozygous female adults become sluggish in behaviour a few days after eclosion and then begin to die (most flies are dead within 2 weeks of eclosion). One day old adults have essentially normal brain morphology, but by 4 or 5 days after eclosion there is widespread degeneration in the brain, including in the cortex, lamina, medulla and central brain. By 12 days after eclosion there is also retinal degeneration. Neuronal and glial cells contain cytoplasmic inclusions not normally seen in wild-type flies. Multilamellar structures develop in the neuropil as the flies age. Inclusion bodies are also detectable in the brains of third instar larvae and pupae.