Whereas
flies use many sensory modalities, most of the behaviors we casually
observe are dominated by visual control. For this reason, presenting
controlled visual environment to tethered flies continues to be a powerful
experimental paradigm. Most experiments have been done in simple arenas,
either patterns attached to a rotating drum, or in recent years, using
cylinders covered with LEDs. Conventional display technologies (LCDs,
CRTs, etc.) can not be used as stimuli for insect experiments, because
their refresh rates are typically several times slower than the flicker
fusion rate of insect visual systems. LEDs are used because they can
be rapidly refreshed, which is necessary to maintain the illusion of
motion. We have designed modular panels of 64 LEDs each, which can be
snapped together to ‘tile’ an experimental environment with
controllable displays. The panels are individually addressed and communicated
with via a rapid serial interface. The panels have been designed to
be extremely bright (with the added flexibility of individual pixel
programmable brightness control), allowing experimentation over a broad
range of behaviorally relevant stimuli conditions. The panels are controlled
via a microprocessor controller which, for most experiments, will not
require a computer in the loop, significantly reducing the infrastructure
necessary for experiments. This technology allows an experimenter to
build a visual arena with a customized geometry in a matter of hours.
Figure
3. A group of LED panels displaying a pattern (the number 5). These
panels will be used to tile an arena for use in fly behavioral assays.
Figure
4. The electronics and connections for each LED panel. Each panel
has an on-board microprocessor for maintaining high refresh rates and
brightness control.
