CONDITIONING WITH COMPOUND STIMULI IN DROSOPHILA MELANOGASTER IN THE FLIGHT SIMULATOR
BJÖRN BREMBS* and
MARTIN HEISENBERG
Lehrstuhl für Genetik und
Neurobiologie, Biozentrum, Am Hubland, 97074
Würzburg, Germany
*
Present address: Department of Neurobiology and Anatomy, University of Texas,
Houston Medical School, 6431 Fannin, Houston, TX 77030, USA
Author for correspondence (e-mail:
heisenberg{at}biozentrum.uni-wuerzburg.de
)
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Fig. 1. The flight simulator. The fly is flying tethered in a cylindrical arena
homogeneously illuminated from behind. The fly's tendency to perform left or
right turns (yaw torque) during tethered flight is measured continuously and
fed into a computer. The computer controls background pattern position, heat
beam shutter closure and the colour of illumination according to the
conditioning rules. K indicates the motor control unit.
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Fig. 2. Results from the `Kamin control' experiment with patterns and colours as
elements of the compound. (A) Pooled compound training data for all flies used
in this experiment. The final 2 min test period (i.e. minutes 14-16) of each
subgroup is depicted in B—E (N=103). (B) Compound control
(N=25). (C) Colours alone. T-patterns were replaced by four vertical
bars (N=28). (D) Patterns alone. Colour filters were removed
(N=25). (E) Nonsense compound. The contingency between patterns and
colours was reversed such that positive scores would indicate a correct colour
choice and negative scores a correct pattern choice (N=25).
Statistical analyses are the results of a Wilcoxon matched-pairs test against
zero: ***significant at P<0.001;
**significant at P<0.01; NS, not significant.
Cross-hatched columns, training; open columns, test period; shaded areas,
compound stimulus; unshaded areas, single stimulus. Values are means ±
S.E.M.
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Fig. 3. Results of a representative blocking experiment. (A) Pooled
half-experiments with colours or patterns (with BG18 filter) during the first
training period (N=53). (B) Control group with patterns (white light)
during the first training period (N=27); the switch from white light
to monochromatic blue or green light erases the predictive value of the
patterns. (C) Control group with colours (replay) during the first training
period (N=26). Cross-hatched columns training; open columns, test
period; shaded areas, compound stimulus; unshaded areas, single stimulus.
Values are means ± S.E.M.
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Fig. 4. Results from the second-order conditioning control experiments. (A)
Experimental time course as in the blocking experiment depicted in
Fig. 3 (N=20). (B)
Time course as in A, but with the duration of the unreinforced presentation of
the compound stimulus reduced from 10 to 4 min prior to testing
(N=22). Cross-hatched columns, training; open columns, test period;
hatched columns, second-order training (no heat); shaded areas, compound
stimulus; unshaded areas, single stimulus. Values are means ±
S.E.M.
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Fig. 5. Results from the sensory preconditioning experiments. In the
preconditioning phase, the compound stimulus is presented without
reinforcement. Results from corresponding half-experiments have been pooled.
(A) 10 min of preconditioning (N=56). (B) 16 min of preconditioning
(N=56). In the final test, the alternative stimulus to that used in
the training period is used. Cross-hatched columns, training; open columns,
test period; shaded areas, compound stimulus; unshaded areas, single stimulus.
Values are means ± S.E.M.
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© The Company of Biologists Ltd 2001
