The complexity of the brain makes it one of the the hardest tissues in which to map gap junctions to specific cell types. Focusing on a single structure within the brain and then extrapolating from these observations is one way to reduce brain complexity sufficiently to obtain a rough idea of innexin distribution amongst cell types. The mushroom bodies (MBs) are a component of the olfactory processing and associative learning circuit (Heisenberg, 2003, Connolly et al, 1996) and there are a number of reasons to focus attention on these structures:
- Ease of identification. Their elaborate and prominent axonal morphology renders them easy to identify by GAL4 directed reporter expression (Yang et al, 1995.) and antibody staining (Kurusu et al, 2002.).
- Relating defects to development/function. Their development and function has been studied in detail (Heisenberg, 2003, Crittenden et al. 1998, Ito et al. 1997).
- MB structures consist of both neurons (as shown above) and glia (More brain morphology - mushroom body glia) - the two main cell types found in the nervous system. Notably, developmental studies reveal a dynamic interaction between MB neurons and associated glial cells (Awasaki and Ito, 2004, Watts et al. 2004).