The paper, hastily and badly summarised
The authors describe and extensively document how a Raspberry Pi can be used to, for example, study how fruit flies react to light. Why is this interesting? It provides ways to build a system that can react to the subject’s changes in behaviour using a very accessible platform: the humble Pi.
Not only can existing reactions to light or chemicals be studied using setups like these. By inserting genes that are sensitive to, for instance, light (optogenetics) in front of a gene of interest, you can control that gene’s expression using light!
Slightly bigger picture
Well, I just love it when researchers create a tool that is simply easier to use, build, and of course afford. Seeing a small thing powered by a familiar, tiny circuit board sitting on a table might make a cool new field all that more accessible, in general.