Fly escape mechanisms help us understand basic brain functions
How human brains function is still not well understood. Part of the problem is the extreme complexity of our brain. Flies have a brain that is far less complex than the human brain, but at the same time is still capable of directing actions that ensure fly survival. So, while human brains and those of other mammals remain almost impossible to study, we can study the fly brain in great detail to get pointers on what to look for in the human brain.
Thanks to many years of research in the field, in the fruit fly we can switch single neurons in the brain either on or off. In a recent study (Gao et al., 2019) from Gwyneth Card’s laboratory at Janelia research campus, VA, USA, Gao and colleagues elucidated the brain mechanisms that allow flies to escape predators. Their question was: how does a fly decide what to do when there is a predator approaching?
The authors created a model for approaching predators by making a dome containing a black object that would increasingly come closer to the fly, thus simulating a predator getting closer to the fly. Depending on the approach speed the flies behaved differently. In the case of a slowly incoming object, a fly would first spread its wing and then fly away. In the case of fast incoming object, the fly does not spread its wings, but instead just does a “barrel roll”. It has been shown that in the case of a quickly approaching predator, this escape mode allows the flies to not be caught compared to when it first spreads its wings. The authors then measured the activity of the brain while varying the speed at which the black object was coming closer. They discovered that depending on the incoming speed of the object, the fly brain reacts differently. In the case of slow speed, the fly would use only one visual projection neuron (a neuron is a cell that compose the brain carrying electrical stimuli). In the case of fast-approach, 2 neurons would be firing an electric signal, resulting in a stronger impulse, which then activates a different neuron compared to a single neuron firing, thus allowing the fly to quickly react with its barrel roll motion.
This publication is one in a series of studies helping us understand how the brain operates at a basic level and will be provide the foundation for further studies trying to decipher functions of the human brain.
Citation: Gao, R. et al. (2019) ‘Cortical column and whole-brain imaging with molecular contrast and nanoscale resolution’, Science, 363(6424), p. eaau8302. doi: 10.1126/science.aau8302.
Thanks to many years of research in the field, in the fruit fly we can switch single neurons in the brain either on or off. In a recent study (Gao et al., 2019) from Gwyneth Card’s laboratory at Janelia research campus, VA, USA, Gao and colleagues elucidated the brain mechanisms that allow flies to escape predators. Their question was: how does a fly decide what to do when there is a predator approaching?
The authors created a model for approaching predators by making a dome containing a black object that would increasingly come closer to the fly, thus simulating a predator getting closer to the fly. Depending on the approach speed the flies behaved differently. In the case of a slowly incoming object, a fly would first spread its wing and then fly away. In the case of fast incoming object, the fly does not spread its wings, but instead just does a “barrel roll”. It has been shown that in the case of a quickly approaching predator, this escape mode allows the flies to not be caught compared to when it first spreads its wings. The authors then measured the activity of the brain while varying the speed at which the black object was coming closer. They discovered that depending on the incoming speed of the object, the fly brain reacts differently. In the case of slow speed, the fly would use only one visual projection neuron (a neuron is a cell that compose the brain carrying electrical stimuli). In the case of fast-approach, 2 neurons would be firing an electric signal, resulting in a stronger impulse, which then activates a different neuron compared to a single neuron firing, thus allowing the fly to quickly react with its barrel roll motion.
This publication is one in a series of studies helping us understand how the brain operates at a basic level and will be provide the foundation for further studies trying to decipher functions of the human brain.
Citation: Gao, R. et al. (2019) ‘Cortical column and whole-brain imaging with molecular contrast and nanoscale resolution’, Science, 363(6424), p. eaau8302. doi: 10.1126/science.aau8302.