A Visual Circuit Related to the Nucleus Reuniens for the Spatial-Memory-Promoting Effects of Light Treatment

Neuron. 2021 Jan 20;109(2):347-362.e7. doi: 10.1016/j.neuron.2020.10.023. Epub 2020 Nov 9.


Light exerts profound effects on cognitive functions across species, including humans. However, the neuronal mechanisms underlying the effects of light on cognitive functions are poorly understood. In this study, we show that long-term exposure to bright-light treatment promotes spatial memory through a di-synaptic visual circuit related to the nucleus reuniens (Re). Specifically, a subset of SMI-32-expressing ON-type retinal ganglion cells (RGCs) innervate CaMKIIα neurons in the thalamic ventral lateral geniculate nucleus and intergeniculate leaflet (vLGN/IGL), which in turn activate CaMKIIα neurons in the Re. Specific activation of vLGN/IGL-projecting RGCs, activation of Re-projecting vLGN/IGL neurons, or activation of postsynaptic Re neurons is sufficient to promote spatial memory. Furthermore, we demonstrate that the spatial-memory-promoting effects of light treatment are dependent on the activation of vLGN/IGL-projecting RGCs, Re-projecting vLGN/IGL neurons, and Re neurons. Our results reveal a dedicated subcortical visual circuit that mediates the spatial-memory-promoting effects of light treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Lighting / methods*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Midline Thalamic Nuclei / chemistry
  • Midline Thalamic Nuclei / metabolism*
  • Nerve Net / chemistry
  • Nerve Net / metabolism*
  • Organ Culture Techniques
  • Photoperiod*
  • Spatial Memory / physiology*
  • Visual Pathways / chemistry
  • Visual Pathways / metabolism*