Topography of a Visuomotor Transformation

• Published in: Neuron (Cambridge, Mass.) Mass.), 2018-12, Vol.100 (6), p.1429-1445.e4
• Main Authors: Helmbrecht, Thomas O., dal Maschio, Marco, Donovan, Joseph C., Koutsouli, Styliani, Baier, Herwig
• Format: Article
• Language: English
• Subjects: Animals; Animals, Genetically Modified; Axon guidance; Brain Mapping; Calcium - metabolism; Channelrhodopsins - genetics; Channelrhodopsins - metabolism; Cluster analysis; Cues; Danio rerio; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Hindbrain; Larva; Localization; Luminescent Proteins - genetics; Luminescent Proteins - metabolism; Motor Activity - physiology; motor map; Neuroimaging; Neurons; Neurons - physiology; optic tectum; Optogenetics; Photic Stimulation; reticular formation; Retina; Sensorimotor integration; Sensorimotor system; Software; space code; Superior Colliculi - cytology; superior colliculus; Swimming; tectal projectome; Tectum; Topography; Transcription Factors - genetics; Transcription Factors - metabolism; Visual Pathways - cytology; Visual Pathways - physiology; Visual Perception - physiology; visuomotor transformation; Zebrafish; Zebrafish Proteins - genetics; Zebrafish Proteins - metabolism
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/j.neuron.2018.10.021

The brain converts perceptual information into appropriate patterns of muscle activity depending on the categorization and localization of sensory cues. Sensorimotor information might either be encoded by distributed networks or by “labeled lines” connecting sensory channels to dedicated behavioral pathways. Here we investigate, in the context of natural behavior, how the tectum of larval zebrafish can inform downstream premotor areas. Optogenetic mapping revealed a tectal motor map underlying locomotor maneuvers for escape and approach. Single-cell reconstructions and high-resolution functional imaging showed that two spatially segregated and uncrossed descending axon tracts selectively transmit approach and escape signals to the hindbrain. Moreover, the approach pathway conveys information about retinotopic target coordinates to specific premotor ensembles via spatially ordered axonal projections. This topographic organization supports a tectum-generated space code sufficient to steer orienting movements. We conclude that specific labeled lines guide object-directed behavior in the larval zebrafish brain. [Display omitted] •The tectal motor map in zebrafish larvae is topographically organized•A cellular resolution anatomical atlas of tectal projection neurons is generated•Segregated tectal output pathways convey looming/dimming and prey-likeinformation•Retinotopically organized tectal projections relay prey location to the hindbrain Helmbrecht et al. identify neural pathways connecting the tectum to target areas. Combining optogenetics, imaging, and single-cell reconstructions, they assign behavioral functions to distinct classes of projection neurons conveying information about valence and location of visual objects to premotor circuits.