Abstract
The looming stimulus-evoked flight response is an experimental paradigm for studying innate defensive behaviors. However, how the visual looming stimulus is transmitted from the retina to the brain remains poorly understood. Here, we report that superior colliculus (SC)-projecting RGCs transmit the looming signal from the retina to the brain to mediate the looming-evoked flight behavior by releasing GABA. In the mouse retina, GABAergic RGCs are capable of projecting to many brain areas, including the SC. Superior colliculus (SC)-projecting GABAergic RGCs (spgRGCs) are mono-synaptically connected to the parvalbumin-positive SC neurons known to be required for the looming-evoked flight response. Optogenetic activation of spgRGCs triggers GABA-mediated inhibition in SC neurons. The ablation or silence of spgRGCs compromises looming-evoked flight response but not image-forming functions. Therefore, this study shows that spgRGCs control the looming-evoked flight response by regulating SC neurons via GABA, providing novel insight into the regulation of innate defensive behaviors.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Grant support: This work was supported by grants from the National Key R&D Program of China (2017YFE0103400 to Y.S.), the National Nature Science Foundation of China (81470628 Y. S. 81800872 to Q.D.).
Section on Figure 6 updated to clarify chemogenetic inhibition of spgRGCs suppresses looming-evoked response.; Figure 2-6 revised; Supplemental files updated.
https://datadryad.org/stash/share/YS9pm9qamxaOdXrf1F9YSOVJzIopL1c9Lg2e7Q6E46c