Please note the introduction of a new forum on PF, Mind & Brain Sciences. For the sake of consistency and focus, we would like for all biological topics pertaining primarily to the mind, brain, and behavior to be posted in the new Mind & Brain Sciences forum rather than in the Biology forum. Relevant topics range from synaptic transmission and neuronal signaling to gross neuroanatomy, from perception to cognition and consciousness, from neural development in individual organisms to the evolution of brain structures and functions within and across species, and so on. Essentially, please discuss all things mind and brain in the new forum. Existing threads in the Biology forum pertaining primarily to the mind/brain, and whatever new threads are posted here that are primarily about the mind/brain, will be moved to the Mind & Brain Sciences forum accordingly.