Looking at the brain stem
Scientists at Princeton have been able to make unusually detailed fMRI images of the brain stem. The brain stem is tiny and deeply buried, which has made it hard to image in the past. It’s a small but crucial area between the brain and the spinal cord; it controls the brain activity necessary for basic cardiovascular functions, digestion, and alertness. It’s also the source from which various neurotransmitters travel to the rest of the brain. Researchers have been largely limited to studying these neurotransmitters at some point downstream of their origin, but the new images show activity in the brain stem itself associated with changing levels of dopamine. Dehydrated subjects were put in a situation where they were sometimes given something to drink and sometimes not, so their brain stems could be monitored as they either received the reward or were denied it (dopamine is associated with the reward-seeking circuitry of the brain). Given the central role that the brain stem plays, and the difficulty of imaging it before, this is an exciting development. The press release I linked to above has a couple of images, which mostly give you an idea how deeply buried this thing is.
