QUESTION:
What role do crickets play in the experiments, or what specific experiment
will be done on them?

ANSWER from Eberhard R. Horn on April 21, 1998:
Basically, my interest is not directed to the biology of crickets. I use
them as an experimental model system, which means that the gravity
sensory system of the crickets offer better possibilites to answer
specific basic questions about the neurobiology of the nervous system.
1. The crickets have a well organized gravity sense organ in which the
numbers of sensory units can be counted without injuring the animal.
2. Their nervous system possesses the property of neuronal plasticity,
i.e., it can adapt to modifications of the sensory input to the gravity
sense organ and by this neuroplastic property it can adapt to a
(probably genetically) given value.
3. The crickets have an individual specific nerve cells which respond to
stimulation of the gravity sense organ by a lateral body roll. This kind
of stimulation is clearly related to gravity. If one founds a gravity
sensitive nerve cell in different animals one knows that it is always
the neurone with the same property. In contrast to the cricket,
vertebrates have hundreds of such nerve cells which differ in their
response characteristics so that it is nearly impossible to identify a
specific individual nerve cell.
4. The crickets perform a behavioural response by which the efficiency
of the neuronal network can be measured in which the information is
transmitted.

These advantages lead you to the specific studies which we have planned
to perform with the crickets after landing of the shuttle Columbia at
the beginning of May.
We will study
1. the structure of their gravity sense organ,
2. the structure of the specific gravity sensitive neurons and, as a
control, that of gravity insensitive neurons, by means of
neurophysiological recordings and subsequent application of specific
staining techniques,
3. the efficiency of the neuronal network by using the behavioral
approach. The behavior we are investigating is the so-called
compensatory head movement, which  is a counterroll of the head during a
passive lateral roll of the animal.