the consciousness-obliterating effects of general anesthetics may re-
sult from binding to microtubules. It is certainly the case that we are
far from understanding the behavioral effects of most drugs—from
general anesthetics to stimulants to psychedelics—based on what is
currently known about their membrane-receptor neurochemistry.
Figure 10.4. Internal cytoskeleton of an axon’s growth cone. The shaft of the
axon contains numerous microtubules (black lines), with some branching out
into the filopodia. The tips of the filopodia are filled with microfilaments (gray
lines), some of which are meshlike and some of which are larger bundles.