Title: Identifying and mapping human neocortical laminar ensemble dynamics during arousal, task engagement and visual perception
Abstract
The layered architecture of the neocortex forms the fundamental basis for complex neural computations. However, identifying these layer-specific subcircuits and deciphering their functional contributions in the human brain remains challenging. Recent advances in high-resolution neural recording technologies now permit investigation of human cortical layers and their circuit composition with unprecedented detail. Using Neuropixels probes (N=17 participants) and “thumbtack” laminar electrodes (N=7 patients) in human frontal and temporal cortex with positioning and relationships to cortical layers verified through precise imaging techniques and histology, we identified robust patterns of neurophysiological activity, including local field potential co-modulation and spectral features, that consistently segment the cortical column into its distinct layers. We found that neurons within these physiologically defined layers possess distinct electrophysiological profiles (waveforms, firing patterns, spatiotemporal dynamics), reflecting diverse underlying cell types. These cell-types form layer-specific ensembles exhibiting characteristic oscillatory coupling patterns both within and across laminae. Furthermore, these layer- and cell-type-specific subcircuits demonstrate distinct engagement profiles during baseline activity, across fluctuations in arousal state, and during task performance, including visual perception. This work provides a validated framework for mapping laminar circuits in vivo and reveals the functional composition and architecture of layer-specific cellular dynamics in the human neocortex at unprecedented detail, which multiplexes in service of distinct cognitive functions and brain states.