Fourth Annual Grant Winners 2003-2004
Richard Speiler, Ph.D., Oceanographic Center
Robin Sherman, Ph.D., Farquhar College of Arts and Sciences
Dean Richard Dodge – Oceanographic Center
Dean Norma Goonen – Farquhar College of Arts and Sciences
Title: A New Model for the Study of the
Vertebrate Cerebellum: The Yellow Stingray, Urobatis Jamaicensis
The function of the cerebellum in vertebrates,
including humans, is poorly understood; in part, because
of the conflicting data obtained from the common vertebrate
models, mice and rats. Fishes, in general, have several
advantages as vertebrate models for basic brain function
and a number of neurological and endocrine functions relevant
to human health have been originally worked out in fish
models. Fishes are phylogenetically closer than mammals
to the basic vertebrate blueprint and thus allow behavioral
and neurological studies of fundamental brain systems without
the interaction of more recently evolved functions. Further,
the absence of a highly developed telencephalon allows
ready access to many structures without cerebral interference.
However, a disadvantage of working with most fishes is
the relatively small size of the brain that often hinders
or precludes the use of many standard neurological techniques.
In contrast, a group of chondrichthians, the stingrays,
has a brain size rivaling mammalian rodent models. Of particular
interest to our research, stingrays, like mammals, have
a large, complex, three-lobed cerebellum. However, in the
yellow stingray these lobes are completely separated. Through
substantial trial and error, we have worked out the surgical
procedures and have found the lobes can be individually
manipulated to examine behavioral correlates of specific
lobes. Yellow stingrays are abundant in many areas, they
are hardy, and tolerate anesthesia and the surgical procedures
well. The potential for these animals as vertebrate models
of cerebellar-controlled behavior is clear. At this point,
we have only been able to examine gross motor behaviors.
For example, ablation of the center lobe causes a fixed-pattern
hyperactivity. To continue, we require a method of measuring
and quantifying coordinated fixed-pattern activity, i.e.
feeding and swimming, as well as training-associated memory.
To accomplish this we are requesting funding for a high-speed
digital video camera and a swimming chamber.