Attentional switching in humans and flies: rivalry in large and miniature brains Steven Mark Miller, Trung Thanh Ngo, and Bruno van Swinderen explore the phenomenon of perceptual rivalry, where attention alternates between competing percepts, in both humans and flies. Recent studies in fruit flies, Drosophila melanogaster, suggest that the origins of attentional rivalry may be ancient. Individual variation in the rate of attentional rivalry exists in both humans and flies, with genetic influences in humans. Slower rivalry rates are associated with bipolar disorder (BD), a heritable psychiatric condition. Fly rivalry may serve as a powerful model to study genetic and molecular influences on rivalry rate and potentially shed light on human cognitive and behavioral dysfunction. Perceptual rivalry, including binocular rivalry (BR) and ambiguous figure rivalry (AFR), is characterized by involuntary alternations in perception due to conflicting or ambiguous sensory input. BR occurs when stimuli are presented separately to each eye, while AFR involves ambiguous figures like the Necker cube. These phenomena have been studied for over a century, with recent advances in psychophysical and neuroscientific methods leading to a better understanding of their underlying mechanisms. Research has shown that BR rate is slower in individuals with BD, suggesting a potential biological marker for the disorder. This finding has led to renewed interest in individual differences in rivalry rates, with studies indicating that BR rate is highly reliable within and between individuals. Genetic studies have also shown that BR rate is heritable, with substantial genetic contributions to individual variation. These findings suggest that BR rate could be used as an endophenotype for BD, aiding in diagnosis and understanding the disorder's genetic basis. In addition to clinical applications, BR rate can be explored as an endophenotype for heritable conditions, representing an intermediate phenotype that marks an underlying at-risk genotype. Studies have shown that BR rate is influenced by various factors, including stimulus salience, and is affected by neurotransmitters such as serotonin and noradrenaline. These findings suggest potential targets for candidate gene studies and further research into the molecular mechanisms underlying individual variation in rivalry rate. The study of perceptual rivalry in flies has revealed that they exhibit similar attentional switching behaviors to humans, with evidence of alternating unilateral LFP activity during visual rivalry. This suggests that flies may use similar mechanisms to resolve perceptual conflicts, potentially involving interhemispheric switching of activity states. These findings highlight the potential of using Drosophila as a model organism to study the genetic and molecular basis of individual variation in switch rate, as well as other applications relevant to clinical psychiatry.Attentional switching in humans and flies: rivalry in large and miniature brains Steven Mark Miller, Trung Thanh Ngo, and Bruno van Swinderen explore the phenomenon of perceptual rivalry, where attention alternates between competing percepts, in both humans and flies. Recent studies in fruit flies, Drosophila melanogaster, suggest that the origins of attentional rivalry may be ancient. Individual variation in the rate of attentional rivalry exists in both humans and flies, with genetic influences in humans. Slower rivalry rates are associated with bipolar disorder (BD), a heritable psychiatric condition. Fly rivalry may serve as a powerful model to study genetic and molecular influences on rivalry rate and potentially shed light on human cognitive and behavioral dysfunction. Perceptual rivalry, including binocular rivalry (BR) and ambiguous figure rivalry (AFR), is characterized by involuntary alternations in perception due to conflicting or ambiguous sensory input. BR occurs when stimuli are presented separately to each eye, while AFR involves ambiguous figures like the Necker cube. These phenomena have been studied for over a century, with recent advances in psychophysical and neuroscientific methods leading to a better understanding of their underlying mechanisms. Research has shown that BR rate is slower in individuals with BD, suggesting a potential biological marker for the disorder. This finding has led to renewed interest in individual differences in rivalry rates, with studies indicating that BR rate is highly reliable within and between individuals. Genetic studies have also shown that BR rate is heritable, with substantial genetic contributions to individual variation. These findings suggest that BR rate could be used as an endophenotype for BD, aiding in diagnosis and understanding the disorder's genetic basis. In addition to clinical applications, BR rate can be explored as an endophenotype for heritable conditions, representing an intermediate phenotype that marks an underlying at-risk genotype. Studies have shown that BR rate is influenced by various factors, including stimulus salience, and is affected by neurotransmitters such as serotonin and noradrenaline. These findings suggest potential targets for candidate gene studies and further research into the molecular mechanisms underlying individual variation in rivalry rate. The study of perceptual rivalry in flies has revealed that they exhibit similar attentional switching behaviors to humans, with evidence of alternating unilateral LFP activity during visual rivalry. This suggests that flies may use similar mechanisms to resolve perceptual conflicts, potentially involving interhemispheric switching of activity states. These findings highlight the potential of using Drosophila as a model organism to study the genetic and molecular basis of individual variation in switch rate, as well as other applications relevant to clinical psychiatry.