Oscillations in the central brain of Drosophila are phase locked to attended visual features

Significance There is increasing evidence that even the smallest animal brains provide a capacity for selective attention and subjective awareness, but it is unknown if similar mechanisms might be employed as in higher animals. Recent work in insects highlights a brain structure, the central complex (CX), which could support selective attention processes. Recording from the CX of behaving flies making decisions in a virtual reality environment, we show that visual selection is achieved by phase-controlled endogenous 20- to 30-Hz oscillations that lock onto temporal features of attended visual objects. This suggests an oscillation-driven binding mechanism in the insect brain that employs a similar beta frequency range as has been observed for feature binding in humans. Object-based attention describes the brain’s capacity to prioritize one set of stimuli while ignoring others. Human research suggests that the binding of diverse stimuli into one attended percept requires phase-locked oscillatory activity in the brain. Even insects display oscillatory brain activity during visual attention tasks, but it is unclear if neural oscillations in insects are selectively correlated to different features of attended objects. We addressed this question by recording local field potentials in the Drosophila central complex, a brain structure involved in visual navigation and decision making. We found that attention selectively increased the neural gain of visual features associated with attended objects and that attention could be redirected to unattended objects by activation of a reward circuit. Attention was associated with increased beta (20- to 30-Hz) oscillations that selectively locked onto temporal features of the attended visual objects. Our results suggest a conserved function for the beta frequency range in regulating selective attention to salient visual features.