By activating a particular part of the brain that releases the neurotransmitter acetylcholine, scientists at Cal Irvine were able to change the amount of detail contained in memories. The researchers stimulated the nucleus basalis in rats (using either weak or strong stimulation) while the rats were given tones of different frequency to listen to. The ones whose nucleus basalis received strong stimulation (and thus were exposed to more acetylcholine) showed evidence of remembering specific frequencies, which the rats who received only weak stimulation did not. Acetylcholine is known to be important in learning and memory, but this is the first time anyone’s been able to stimulate a specific brain area to increase the quality of a memory. Here’s the press release.