Japanese people living in the United States are more similar
to those of Americans than to their relatives back home.^14
Sane in the Membrane
Whether you’re going over a presentation, doing your
taxes, or deciding what to watch on Netflix, your thoughts
are the end result of countless chemical (and electrical)
reactions that occur across the quadrillion connections that
neurons make with one another in your brain. And the
success of these processes may come down to one vital,
unsung hero of our cognitive function: the cell membrane.
Aside from forming protective barriers, membranes also
provide the “ears” of neurons by cradling receptors for
various neurotransmitters within. Neurotransmitters are
chemical messengers, and there are dozens of them in the
brain (you may have heard of the A-listers serotonin and
dopamine, neurotransmitters associated with positive mood
and reward). Much of the time, receptors for these
messengers will sit under the membrane’s surface, lying in
wait for the right signal before bobbing up to the surface
like buoys on the water.
A properly functioning neuron must have the ability to
increase or decrease its sensitivity to outside signals, and it
does this by increasing and decreasing the number of buoys
allowed to the surface. For this to occur, the cell membrane
must possess the property of fluidity. This is true of most
cells in the body, but it is especially important for neurons.
If the nerve cell membrane is too rigid, receptor availability