This confocal section of a Drosophila brain shows cortex and astrocyte-like glia (green) and neuropil (immunolabeled against glutamate synthetase, red). Inhibiting expression of Appl (the Drosophila homolog of the gene encoding amyloid precursor protein) in cortex and astrocyte-like glia influences sleep-wake regulation and glutamate recycling genes such as glutamate synthetase. For more information, see the article Farca Luna et al. (pages 4289–4300).