In French, “cultiver son jardin intérieur” means to tend to your internal garden—to take care of your mind. The garden metaphor is particularly apt: taking care of your mind involves cultivating your curiosity (the seeds), growing your knowledge (the trees), and producing new thoughts (the fruits).
Due to the random nature in the expression of these genes, researchers are currently unable to precisely control the labeling process, which makes it very hard to identify specific neurons. They get a good idea of what the circuit looks like, but not exactly which class of cells each neuron belongs to.