Probing top-down information in neocortical layer 1

Trends Neurosci. 2023 Jan;46(1):20-31. doi: 10.1016/j.tins.2022.11.001. Epub 2022 Nov 22.


Accurate perception of the environment is a constructive process that requires integration of external bottom-up sensory signals with internally generated top-down information. Decades of work have elucidated how sensory neocortex processes physical stimulus features. By contrast, examining how top-down information is encoded and integrated with bottom-up signals has been challenging using traditional neuroscience methods. Recent technological advances in functional imaging of brain-wide afferents in behaving mice have enabled the direct measurement of top-down information. Here, we review the emerging literature on encoding of these internally generated signals by different projection systems enriched in neocortical layer 1 during defined brain functions, including memory, attention, and predictive coding. Moreover, we identify gaps in current knowledge and highlight future directions for this rapidly advancing field.

Keywords: L1; attention; axonal imaging; memory; predictive coding; sensory neocortex.

Publication types

  • Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Attention
  • Mice
  • Neocortex*
  • Sensation