DevelopmentIntegrative Physiology and BehaviorJournalSensory Systems

Spatial Information in a Non-retinotopic Visual Cortex

Reptilian cortex shows excellent visual processing despite poor retinal mapping.

Turtle dorsal cortex (dCx), a three-layered corticalarea of the reptilian telencephalon, receives inputsfrom the retina via the thalamic lateral geniculate nu-cleus and constitutes the first cortical stage of visualprocessing. The receptive fields of dCx neuronsusually occupy the entire contralateral visual field.Electrophysiological recordings in awake and anes-thetized animals reveal that dCx is sensitive to thespatial structure of natural images, that dCx recep-tive fields are not entirely uniform across space,and that adaptation to repeated stimulation is posi-tion specific. Hence, spatial information can be fou ndboth at the single-neuron and population scales.Anatomical data are consistent with the absence ofa clear retinotopic map ping of thalamocortical pro-jections. The mapping and representation of visualspace in this three-layered cortex thus differ fromthose found in mammalian primary visual cortex.Our results support the notion that dCx performs aglobal, rather than local, analysis of the visual scene.

Fournier, J., Müller, C.M., Schneider, I., Laurent, G. (2018). Spatial Information in a Non-retinotopic Visual Cortex. Neuron 97:164-180.