Images from the Marin research group
A second project in the Marin lab involves the regulation of numbers of specific types of neurons by hormonal signals, linking environmental conditions including nutrition to plasticity of neuronal composition. We focus on a particular structure in the fruit fly brain, the mushroom body, which is used in olfactory learning and memory and is composed of thousands of cells belonging to just a few main subtypes. We have found that levels of an important insect hormone known as juvenile hormone (mimicked by many synthetic insecticides) appears to control the number of one mushroom body neuron subtype during development. After adding an analogue of this hormone to the animals' diet or ablating the gland that generates the hormone, we can compare the numbers of total neurons as well as those of neurons belonging to a particular subtype. (A) The protein Dachshund (green) is a nuclear marker for all mushroom body neurons. (B) The protein Ecdysone Receptor B1 (magenta) is a nuclear marker for the earliest born subtype of mushroom body neurons. These images are single optical slices at comparable positions from two different samples belonging to the same genotype, sex, and treatment group.