FoundationalConceptsNeuroscience

drugs that have an activating effect on acetylcholine circuitry may
increase the vividness of dreams. Nicotine is such a drug. People who
are using nicotine patches to help them quit smoking often report
increased vividness of dreaming. This is because the patch continues
to deliver nicotine to the body even during sleep, more than the per-
son would normally have at night if they were smoking, because they
would not be smoking during their sleep. (This assumes the patch is
being left on during sleep; some people choose to remove it, to reduce
the intensity of dreams.) Shamans in South America who use tobacco
as a divination tool may smoke before retiring for the night, to inten-
tionally increase the vividness of their dreams. Acetylcholinesterase
inhibitors decrease the chemical breakdown of acetylcholine after it is
released, thus prolonging its activity in the synaptic cleft. These drugs
are used in the treatment of dementia (see Chapter 19). A side effect is
increased vividness of dreams.
Dreams are ephemeral. We frequently awaken and have no memory
at all of dreaming. This is the case even though sleep studies have
demonstrated that everyone dreams every night. Or, we awaken and
are aware that we have been dreaming, but we cannot recall any spe-
cific content of the dreams. Or, we awaken and remember parts of a
dream or dreams but tend to forget things very quickly. Immediately
going over the dream story line in one’s own mind, writing it down, or
telling someone else will generally enhance recall. If memory resides
in activation of neural networks, all this is reasonable in that the net-
works activated during REM sleep may be novel ones, not necessarily
associated with previous learning and experience, and thus prone to
ready dissipation. Practice improves the recall of dreams.
Lucid dreaming occurs when one becomes aware of dreaming
while still asleep. That is, one is asleep in REM, eyes closed, motor
activity inhibited, and dreaming, and within the dream there is an