Visualizing retinotopic half-wave rectified input to the motion detection circuitry of Drosophila.
In the visual system of Drosophila, photoreceptors R1-R6 relay achromatic brightness information to five parallel pathways. Two of them, the lamina monopolar cells L1 and L2, represent the major input lines to the motion detection circuitry. We devised a new method for optical recording of visually evoked changes in intracellular Ca2+ in neurons using targeted expression of a genetically encoded Ca2+ indicator. Ca2+ in single terminals of L2 neurons in the medulla carried no information about the direction of motion. However, we found that brightness decrements (light-OFF) induced a strong increase in intracellular Ca2+ but brightness increments (light-ON) induced only small changes, suggesting that half-wave rectification of the input signal occurs. Thus, L2 predominantly transmits brightness decrements to downstream circuits that then compute the direction of image motion.
Reiff
Dierk F
DF
Max Planck Institute of Neurobiology, Martinsried, Germany. reiff@neuro.mpg.de
Plett
Johannes
J
Mank
Marco
M
Griesbeck
Oliver
O
Borst
Alexander
A
D000818:Animals; D002118:Calcium / Q000378:metabolism; D004330:Drosophila; D005074:Evoked Potentials, Visual / Q000502:physiology; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000166:cytology / Q000502:physiology*; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology*
D002118:Calcium