mastrd at ctrvax.Vanderbilt.edu (Russell Mast) writes:
jerwin at antioch.edu wrote:
> I recently read in the New York Times (Wednesday, 27 Oct 1993, page b7)
> that the FDA has approved the preliminary tests of Ibogaine on
> drug abusers.
I, too, read about the funding of serious research into ibogaine treatment,
I think in a little Chicago-based leftist news mag called "In These Times",
though perhaps it was elsewhere.
> This drug is supposed to break down an addiction by stimulating
> cells in the cerebellum with the aid of the inferior olive. This
> subject has brough up two questions in my mind.
> How exactly is the cerebellum related to memory (spec. drug addiction)?
As for the relation of ibogaine to cerebellum, or any other specific brain
structures, I cannot comment. As for the relation between "memory" and
drug addiction, I guess I don't understand what you mean. My understanding
is that the brain structures most involved in addiction and related
behaviors are telencephalic limbic nucleii, like the septal nuclei.
Current evidence indicates pretty strongly that two brain structures,
the ventral tegmental area and the nucleus accumbens, are heavily
involved in addiction, with the neurotransmitter dopamine playing a
crucial role. Thus, stimulation of the dopaminergic pathway from the
VTA to the NA is highly rewarding, and several addictive drugs,
including cocaine, amphetamine, heroin, and nicotine, lead either to
increased dopamine release or increased dopamine efficacy in the NA.
The discovery of this connection is one of the major achievements of
neuroscience over the past few years, and has been very under-
publicized. ("Discovery" may be the wrong word, since the first hints
came from the work of Jim Olds, way back in the 50's, but recent work
has greatly clarified the picture.)
There is a good deal of evidence for a function of the cerebellum in
learning, but probably not the kind of learning involved in addiction.
The cerebellum is more likely to be involved in things like learning
how to ride a bicycle, or play the piano, or hit a baseball -- things
requiring precise motor coordination. So if ibogaine does have an
effect on addiction, it is unlikely to be via the cerebellum. But it
would not be very surprising if it turned out to affect other regions
of the brain: most neurochemicals have pretty widespread effects.