Sample response

One effect of one neurotransmitter on a behavior is the effect of acetylcholine on memory as seen in a study by Antonova et al (2011).  Acetylcholine seems to play a role in the encoding of spatial memories.  This has been shown in research by Kesner in rats and Antonova wanted to show the effect in humans using a similar spatial task.

The sample was made up of only males.  It was a double blind study and the participants were either injected with scopolamine – a drug that blocks acetylcholine receptor sites – or a placebo.  They were then asked to play a virtual reality game in which they had to remember how to get to a certain place in the game.   Once they found where the “pole” was that they were looking for, they would be “put” at a new starting point and asked to find the pole again.  They were in an fMRI while carrying out the task so that brain activity could be observed.

The researchers found that when the participants were injected with scopolamine, they took longer to find the “pole” than did the group that received the placebo.  In addition, the fMRI showed more activity in the hippocampus in the placebo group than in the scopolamine group.   The hippocampus is where STM is transferred to long-term memory; it is also where there are many acetylcholine receptor sites in the brain.   This study seems to show that acetylcholine plays a key role in the encoding of spatial memory.