Dendritic calcium signals in rhesus macaque motor cortex drive an optical brain-computer interface

Area of Science:

• Neuroscience
• Biomedical Engineering
• Optical Imaging

Background:

• Calcium imaging is vital for in vivo neural population recording.
• Current methods struggle to access deep cortical layers in macaques due to light scattering.
• Understanding motor cortex function is key for advanced brain-computer interfaces (BCIs).

Purpose of the Study:

• To develop an advanced imaging system for chronic, deep-layer neuronal recording in awake, behaving macaques.
• To explore the potential of imaging dendritic calcium signals for motor control studies.
• To create and test an optical BCI (oBCI) using these signals.

Main Methods:

• Developed a chronic, motion-stabilized two-photon imaging system for macaques.
• Imaged apical dendrites to gain access to deep and superficial cortical neurons in motor cortex.
• Combined two-photon imaging with CLARITY for volumetric analysis.
• Developed an oBCI driven by recorded dendritic signals.

Main Results:

• Achieved optical access to large populations of neurons across cortical layers via dendritic imaging.
• Observed neuronal dendritic signals tuned to specific arm movement directions.
• Successfully decoded movement direction online using the oBCI.
• Verified that imaged dendrites originated from deep layer neurons, including Betz cells.

Conclusions:

• The developed system enables deep cortical neuron imaging in macaques during motor tasks.
• Apical dendritic imaging provides a viable strategy for accessing diverse neuronal populations.
• This approach facilitates the study of motor control and the development of novel BCIs.