Neuropixels reveal structure-function relationships in monkey V1 in vivo.

Area of Science:

• Neuroscience
• Visual Neuroscience
• Computational Neuroscience

Background:

• The functional processing of visual information by diverse neuronal populations in the primate primary visual cortex (V1) is not fully understood.
• The relationship between neuronal structure and in vivo function in V1 remains a critical knowledge gap.

Purpose of the Study:

• To investigate the relationship between structural properties and in vivo functional responses of neuronal populations in macaque V1.
• To delineate distinct neuronal cell classes based on electrophysiological properties and analyze their laminar organization, functional selectivity, and network interactions.

Main Methods:

• High-density Neuropixels electrodes were used to record large neuronal populations across V1 layers in macaques.
• A non-linear dimensionality reduction approach on waveform shape was employed to classify neurons into nine putative cell classes (4 narrow-spiking, 4 broad-spiking, 1 tri-phasic).
• Analyses included laminar organization, spike amplitude, spatial features, functional properties (e.g., direction and orientation selectivity), and network connectivity via cross-correlation.

Main Results:

• Nine distinct cell classes were identified, including narrow-spiking (NS), broad-spiking (BS), and tri-phasic (TP) neurons.
• NS neurons were concentrated in layer 4 and more numerous than parvalbumin-positive neurons.
• A specific NS cell class in layer 4B exhibited strong direction selectivity and bursting activity, potentially corresponding to neurons projecting to the MT area.
• Distinct functional interactions were observed between different cell classes through cross-correlation analysis.

Conclusions:

• High-resolution electrophysiology successfully revealed novel relationships between neuronal structure and in vivo function in primate V1.
• The findings provide in vivo evidence for fundamental aspects of the V1 microcircuit predicted by anatomical studies.
• This research can inform the development of biologically realistic microcircuit models of the primate V1 and potentially other cortical areas.