Attention-like processes underlying optomotor performance in aDrosophila choice maze

Abstract

ABSTRACT:The authors present a novel paradigm for studying visual responses in Drosophila. An eight-level choice maze was found to reliably segregate fly populations according to their responses to moving stripes displayed on a computer screen. Visual responsiveness was robust in wild-type flies, and performance depended on salience effects such as stimulus color and speed. Analysis of individual fly choices in the maze revealed that stereotypy, or choice persistence, contributed significantly to a strain's performance. On the basis of these observations, the authors bred wild-type flies for divergent visual phenotypes by selecting individual flies displaying extreme stereotypy. Selected flies alternated less often in the sequential choice maze than unselected flies, showing that stereotypy could evolve across generations. The authors found that selection for increased stereotypy impaired flies' responsiveness to competing stimuli in tests for attention-like behavior in the maze. Visual selective attention was further investigated by electrophysiology, and it was found that increased stereotypy also impaired responsiveness to competing stimuli at the level of brain activity. Combined results present a comprehensive approach to studying visual responses in Drosophila, and show that behavioral performance involves attention-like processes that are variable among individuals and thus sensitive to artificial selection.

Attention-Like Deficit and Hyperactivity in aDrosophilaMemory Mutant

“…The maze, described previously (van Swinderen and Flores, 2007), consists of 3-mm-wide paths grooved into a 28 ϫ 19 ϫ 1 cm acrylic slab placed groove-face down on a glass plate to form a closed horizontal choice platform. The platform was positioned 3 cm above an up-ended 19-inch flat-screen computer monitor (Mitsubishi Diamondpro 930), on which was displayed a green/ black grating of 1 cm spatial resolution, moving at 3 Hz (or other frequencies, as specified).…”

“…All statistics were t tests of experimental means, unless otherwise specified. Visual stimuli presented to flies running the maze were exactly as described previously (van Swinderen and Flores, 2007): 1 cm green/black gratings moving at 3 Hz (or other frequencies, as specified). For distraction experiments, we followed two distinct paradigms.…”

“…As a case in point, recent work has shown that the learning mutants dunce 1 and rutabaga 2080 appear to be less distracted by competing visual stimuli compared with wild-type flies, in both behavioral and electrophysiological paradigms (van Swinderen, 2007). Using a recently developed optomotor maze (van Swinderen and Flores, 2007), in which walking flies make successive turn choices in response to visual underlying moving gratings, dunce and rutabaga mutants were also found to display significantly greater optomotor responses in the maze than did wild-type flies, leading to the hypothesis that higher optomotor scores predict defective suppression mechanisms characteristic of attention (van Swinderen, 2007). Interestingly, the Drosophila radish 1 mutation did not show a significant optomotor response in the maze under the same conditions that produced strong responses in dunce 1 and rutabaga 2080 .…”

The Attention Span of a Fly

“…1 These included electrophysiological measures of brain responses to competing visual stimuli as well as a behavioral paradigm of flies walking through a choice maze while responding to visual stimuli. 2 In the brain recording preparation, local field potential (LFP) activity in the 20-30 Hz range was found to be transiently associated with novel images and suppressed for competing, non-novel images. The selective brain response to novel images lasted on average 9-12 seconds in wild-type flies, or about 3-4 exposures (cycles) of the two image choices rotating around the flies at 0.33 Hz.…”

Big ideas for small brains: what can psychiatry learn from worms, flies, bees and fish?

“…Suppression mechanisms are involved in both sleep and attention, perhaps for homoeostatic purposes during sleep, 64 and as a crucial counterpart to stimulus selection. 65 Taken together these findings suggest that suppression mechanisms are important for the fly brain, but more broadly might be central to how any brain works. 66 Thus, by tapping into this fundamental brain function (the ability to shut-out the world in an adaptive, experience-dependant manner), we may be getting somewhat closer to measuring the actual brain processes that are compromised across diverse spectra of cognitive dysfunction, while still working with the same efficient genetic model that gave us our first molecular insights into behavior.…”