GABA- and serotonin-expressing neurons take part in inhibitory as well as excitatory input pathways to the circadian clock of the Madeira cockroach Rhyparobia maderae.

In the Madeira cockroach, pigment-dispersing factor-immunoreactive (PDF-ir) neurons innervating the circadian clock, the accessory medulla (AME) in the brain's optic lobes, control circadian behaviour. Circadian activity rhythms are entrained to daily light-dark cycles only by compound eye photoreceptors terminating in the lamina and medulla. Still, it is unknown which neurons connect the photoreceptors to the clock to allow for light entrainment.