Mark Geyer, PhD
Interviewd Summer 1999
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Archived Profiles
Dr. Mark Geyer has been a member
of the faculty in the School of Medicine at U.C. San Diego since 1973, where
he is currently Professor of Psychiatry and Adjunct Professor of Neurosciences.
He is also the Field Editor for Preclinical Psychopharmacology, for the journal
Psychopharmacology and is co-director of the Neurosciences Unit of the Dept.
of Veterans Affairs, MIRECC. Born and raised in Portland, Oregon, he received
his Bachelor of Arts degree from the University of Oregon Honors College and
his doctorate in Psychology from U.C.S.D. As the author of over 200 journal
articles, Dr. Geyer's research in information processing with both clinical
populations (patients with schizophrenia) and animal models has brought him
international recognition in the field of psychobiology.
How does the MIRECC utilize animal models to advance research on psychotic
disorders?
Patients with certain psychotic disorders are found to have abnormalities in
information processing. These abnormalities can be studied in similar ways in
different species. For example, measures of the startle response in both rodents
and humans can inform us of sensory gating deficits. Such measures are used
in the MIRECC to study the course of illness and the response to specific treatments
in patients with schizophrenia. In parallel studies in rodents, my colleagues
and I first produce similar deficits in sensory gating by various means and
then seek to identify new drugs by testing the ability of certain compounds
to normalize the deficits. For example, rats reared in social isolation early
in development exhibit the same loss of sensory gating that we have found in
patients with schizophrenia.
I have recently reported that the novel potential antipsychotic M100907,
which blocks the receptors at which hallucinogenic drugs act, normalizes the
deficits in startle gating in isolation-reared rats. Similarly, I have used
this animal model to test the effectiveness of another novel drug that is
in clinical trials for the treatment of schizophrenia, LU-111995. This drug
blocks the D4 dopamine receptors (mentioned in the accompanying article) as
well as the so-called hallucinogen receptors. I believe that such measures
might be able to help us identify which antipsychotic drugs will best treat
particular patients. In the clinical studies in the MIRECC, these same measures
are being used to predict and assess the responses of individual patients
to different antipsychotic treatments.
Are there any new breakthroughs in technology that will influence this
work?
One of the most exciting new areas comes from the application of molecular biology
to psychiatric neuroscience. For example, we are now studying genetically engineered
mice in which specific genes for specific receptors, such as the D4 dopamine
receptor, have been deleted.
What has been the biggest obstacle in finding drugs that are specific
in treating schizophrenic patients without harmful side effects?
It has often been suggested that schizophrenia represents a group of disorders
having a variety of different causes despite some similarities in the clinical
syndromes. If this is true, then different drugs might prove to be specifically
beneficial in different patients. It has been relatively easy to find drugs
that are specific for a receptor, but hard to find drugs that are specific to
a disorder.
It is hoped that the scientific study of such questions in clinical populations,
using the same quantifiable measures and the same new and selective drugs
being studied in rodents, could lead to more specific treatments for schizophrenia
that would minimize the unwanted side effects produced by the less selective
drugs currently being used.
How do you view your role in the MIRECC?
I provide a reductionist, scientific view to a group of researchers that are
primarily clinically trained. My perspective is somewhat different from that
of the clinicians, in that I tend to think more about the contributions of brain
systems to specific behavioral phenomena rather than focus on the complex syndromes
that have been defined via clinical descriptions. I do not begin with the premise
that the term schizophrenia refers to a single disease that is biologically
meaningful, but rather a collection of disorders having a variety of different
causes.
What event/events first sparked your interest in Psychology in general
and biological psychology in particular and what keeps you here?
Originally, I was a pre-med biology student in college, until I read a book
called the Organization of Behavior by Donald Hebb. I became fascinated by the
idea of understanding the brain mechanisms responsible for complex behavior.
So I decided to go to graduate school in Psychology even though I had not taken
a single course in Psychology. I used to study things one cell at a time, using
electrodes in sea-slugs or microscopes to measure chemicals in single cells.
I've gradually moved to more complex behavioral studies in both rodents and
humans, but still apply the principles of basic science. I've stayed in this
area of work because it continues to be one of the great frontiers of biology
- how does the brain work?
How do you spend your time outside of work?
Other than frequent walks on the beach, I work most of the time when I'm not
travelling. My wife and I are both scientists and travel a great deal - that's
probably our major form of recreation - traveling.
