Journal of Neuroscience, Vol 10, 351-360, Copyright © 1990 by Society for Neuroscience
Neural circuits mediating visual flight control in flies. II. Separation of two control systems by microsurgical brain lesions
K Hausen and C Wehrhahn
Max-Planck-Institut fur biologische Kybemetik, Tbingen, Federal Republic of Germany.
The role of 2 sets of interneurons in the optic lobes of blowflies in
visual course control was studied by means of brain lesions. The first set
comprises the cells HS and H2, which respond to global horizontal motion.
The second set are the FD-cells, which respond selectively to local
horizontal motion. All these cells are output neurons of the third optic
ganglion of flies and are thought to be coupled via descending neurons to
the flight motor system. In 2 series of experiments specific cells of these
2 sets were inactivated by microsurgical brain lesions L1 and L2
respectively. The effects of the lesions on visual course control were
tested by measuring the yaw torque responses of the animals in restrained
flight before and after the operation. The flies were stimulated in these
tests with monocular and binocular motion of periodic gratings moving in
either the horizontal or the vertical direction. Lesion L1 in the right
side of the brain inactivates the right HS-cells and the left H2- and
FD-cells. This leads to a complete block of the response to binocular
clockwise horizontal motion and a reduction of the response to monocular
motion from front to back on the right side of the animal. Application of
L1 also leads to a pronounced response to binocular motion from front to
back not observed in normal animals. The response to monocular vertical
motion is unaffected. Lesion L2 reduces all responses to monocular and
binocular horizontal motion present in normal animals. The behavioral
effects of the lesions are highly specific and consistent with predictions
based on the well-known anatomical and physiological properties of the
neural circuitry investigated. The results demonstrate directly that the
HS-, H2-, and FD-cells control motion- induced steering maneuvers in
flight.
Previous Article | Next Article
