Volume 16, Number 18,
Issue of September 15, 1996
pp. 5844-5853
Copyright ©1996 Society for Neuroscience
Correspondence of Escape-Turning Behavior with Activity of
Descending Mechanosensory Interneurons in the Cockroach,
Periplaneta americana
Received Feb. 21, 1996; revised June 21, 1996; accepted June 25, 1996.
Shuping Ye and
Christopher M. Comer
Neuroscience Group, Department of Biological Sciences, University
of Illinois at Chicago, Chicago, Illinois 60607
Two bilaterally paired mechanosensory neurons that respond to
antennal touch stimulation recently have been described in the
cockroach Periplaneta americana. Here chronic recordings
were used to describe the activity of these interneurons in relation to
behavior. Parallel intra/extracellular recording experiments showed
that both pairs of previously identified descending mechanosensory
interneurons (DMIs) were activated after touch stimulation of the
antennae and before initiation of escape. On a trial-by-trial basis,
the bilateral pattern of their activity was correlated with sensory
input and behavior: when one antenna was touched, the contralateral DMI
axons displayed impulses earlier and in greater numbers than their
ipsilateral homologs; turns were made toward the side with greater DMI
activity, i.e., away from the touched antenna. One parameter of DMI
activity (the bilateral difference in number of DMI impulses) was
correlated with the angular amplitude of turning. In the absence of
touch stimulation, unilateral electrical stimulation of a cervical
connective via the chronic electrodes produced turning movements
similar to natural escape turning and of appropriate directionality.
These results support the hypothesis that neural activity in DMIs is
involved in the control of antennal touch-evoked escape, and they
provide a basis for a model of DMI specification of the direction of
escape turning.
Key words:
antennae;
chronic recording;
cockroach;
escape
behavior;
sensory coding;
touch