Meet: Danny Riley, Ph.D.
The Effects of Microgravity on Neuromuscular Development
What I do on Neurolab:
Our experiment on Neurolab is on developing rats, neonatal rats, which
are born very immature. They go through maturation of the nerve and muscle
system, called the neuromuscular system, in the first three weeks of their
life. That's equivalent to a human from 2 months in utero through the
first year of life, so it's a very compressed time period of development
for the rat. During this period, when the nerve-muscle system is developing,
we believe that gravity stimulation, the weight-bearing/the loading on
the leg muscles, is important for full development. Without gravity the
nerve and muscles may not complete development or they may develop in
an abnormal direction. There are some muscles which are very involved
with lifting the body up against gravity. These are called the weight-bearing
muscles or anti-gravity muscles. We think that this set of muscles and
their nerve fibers and the motor neurons that supply these muscles are
going to be dependent on the weight-bearing, as opposed to other muscles
in the leg which do not perform weight-bearing. These are non-weight-bearing
or non-anti-gravity muscles which should develop without the stimulus
So when animals go into space, we're going to study the nerve and muscles
of these two types of muscles. We expect that the lack of gravity will
affect the weight-bearing muscle development, either slow it down or it
will be incomplete or possibly go off in an abnormal direction. We think
these findings will be relevant to human development. In utero, the developing
human is exercising its legs by pushing against the wall of the uterus.
We believe that this activity serves a purpose, in that it puts a load
on the weight-bearing muscles and stimulates the genes of the nervous
system and the muscles to be fully expressed. The normal development of
the nerve-muscle system is the product of genes and environment; in this
case gravity is the environmental factor. (For
more information about Dr. Riley's research, click here)
My Career Journey
I started at the University of Wisconsin. That's where I went through
undergraduate and graduate training and earned a Ph.D. in anatomy. I'm
very interested in biological structure, trying to figure out the function
that comes from structure. After I got my Ph.D., I went to the National
Institutes of Health for post-doctoral training to investigate various
aspects of nerve generation. Nerves are very important for muscle, which
is the area that I studied during my Ph.D. research. From there I went
to the University of California, San Francisco, as a faculty member for
8 years and then moved to Medical College of Wisconsin, where I am presently
a professor of Cellular Biology & Anatomy.
Likes/Dislikes about career
[The best part about my job is] seeing things for the first time that
no one else has really seen before. Doing an experiment, getting results,
cutting a section of some muscle tissue and when you get "TO" the microscope
and actually see a change and recognizing what made this kind of alteration.
Actually what's even more exciting is to make a prediction and then be
surprised because the change is opposite to what you predicted. It says,
hey I don't know everything, there's more to learn. That's why I'm in
the field I am in, because I'm always learning. I never want to stop learning.
I always have a curiosity about how things work. So that's what I get
- that's the kind of reward I get.
The least favorite part I think is having to constantly lobby for money
for research and the resources to do things in the space program. I think
it's essential that we have a space program. Technologies that spin off
are going to help us in the long run. Moneys are tight and space research
is expensive, but it's a unique tool. So you spend a lot of time trying
to convince the government to spend money on these various areas. In part
it's good because it allows you to think about why are you doing what
your doing, but after a while, if you have to keep explaining it too often,
you spend too much time doing that and not enough time working on the
actual project and thinking about the science and what your trying to
study. So that becomes frustrating. I used to say, "There aren't enough
hours in the day" and now there's not enough weeks in the day. There's
just too much to do.
The challenge of finding out things and also helping - having some spin-offs
from basic research that may improve the quality of life is what motivates
me. The basic goal with the space program is understanding muscle biology
so that humans can be in space and not have any kind of permanent muscle
defect, that affects their performance or health. Then that information
hopefully spins off into helping with a disease - a muscle disease on
Earth. We never know when or from where the next surprise or exciting
answer is going to come. Insights often happen 6:00 pm on Friday when
only the janitor is there - everyone else went home. You run out in the
hall to tell the janitor, "look at the slide - this is a fantastic result!"
That's what keeps things going.
I think that this endeavor is something that, for those of us who are
in it, are in it for advancing basic biomedical knowledge, which is the
foundation for medicine, which relates to improving the quality of human
life. So we see it as a practical point-of-view, making a contribution
to understanding and knowledge of neuroscience biomedical issues.
Spare time is for going back to what actually got me interested in science
in the first place. Fortunately, my wife and I like to go fishing because
we like to eat fish. So, we make it a point to have one day on the weekend
that we spend some time together and that's one of the activities that
we like to do. I grew up doing that in Northern Wisconsin. Instead of
just cleaning a fish, I used to dissect it and study the muscles, the
nerves and the heart. It would take me hours to do that. I've always been
fascinated by all kinds and forms of life.
In the past, I have been involved with space missions studies on my
own, but for this experiment I am fortunate to have a terrific collaborator,
my wife. She's the expert on the nerve side and I'm the expert on the
muscle side. This is a unique opportunity for us to use our two fields
of expertise to come together. This is really the first time we've worked
together. We've always helped out each other as far as a sounding board
on some of our experiments, but no this is the first time she has been
directly involved. We recognize the great complexity of the problem and
the value of a team approach. The Neurolab Mammalian Development Team
of 7 investigations is a very well integrated effort.
The team approach has been a positive experience because you can't be
an expert in every area. We can see that various aspects are being covered
by other individuals. So, ultimately, when we do the mission and interpret
it, we will rely on what's happening and the information of our collaborators
or peers. And I think that way, the interpretation of our own experiment
will be much better, because it's not just us doing it in isolation. It
will make more sense. We should be able to get further along in our research.