Dissociable laminar profiles of concurrent bottom-up and top-down modulation in the human visual cortex

Elife. 2019 May 7;8:e44422. doi: 10.7554/eLife.44422.

Abstract

Recent developments in human neuroimaging make it possible to non-invasively measure neural activity from different cortical layers. This can potentially reveal not only which brain areas are engaged by a task, but also how. Specifically, bottom-up and top-down responses are associated with distinct laminar profiles. Here, we measured lamina-resolved fMRI responses during a visual task designed to induce concurrent bottom-up and top-down modulations via orthogonal manipulations of stimulus contrast and feature-based attention. BOLD responses were modulated by both stimulus contrast (bottom-up) and by engaging feature-based attention (top-down). Crucially, these effects operated at different cortical depths: Bottom-up modulations were strongest in the middle cortical layer and weaker in deep and superficial layers, while top-down modulations were strongest in the superficial layers. As such, we demonstrate that laminar activity profiles can discriminate between concurrent top-down and bottom-up processing, and are diagnostic of how a brain region is activated.

Keywords: attention; fMRI; human; laminar; layer; neuroscience; visual cortex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Attention
  • Female
  • Healthy Volunteers
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Visual Cortex / physiology*
  • Visual Perception*
  • Young Adult