Activation of primate frontal eye fields with a CMUT phased array system

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Imaging

Background:

• Invasive neural stimulation and recording methods pose risks and limitations.
• Non-invasive brain stimulation techniques, such as Transcranial Focused Ultrasound (TFUS), are being developed to overcome these challenges.
• Existing TFUS applications require refinement for improved efficacy and precision.

Purpose of the Study:

• To develop and evaluate a novel non-invasive neural stimulation approach using custom capacitive micromachined ultrasonic transducers (CMUTs).
• To investigate the effects of TFUS on neural activity and behavior in a non-human primate model.
• To demonstrate the feasibility of targeted neural stimulation in the Frontal Eye Fields (FEF).

Main Methods:

• Utilized a custom-built CMUT array for delivering ultrasonic waves through the skull.
• Targeted the Frontal Eye Fields (FEF) using co-registered MRI and CT scans.
• Administered Transcranial Focused Ultrasound (TFUS) to a non-human primate performing a discrimination behavioral task.

Main Results:

• Observed immediate changes in local field potential (LFP) signals during TFUS, with increased voltage upon cue presentation.
• Detected increased alpha band activity during stimulation, with specific rebound points along the electrode shank.
• Demonstrated the ability to "steer" stimulation to different targets and observed a directional bias in saccades.

Conclusions:

• Presented a new method for non-invasive neural stimulation during behavioral tasks.
• Highlighted the potential for steering stimulation patterns and targeting with transducer arrays.
• Emphasized the improved prospects for clinical and research applications of non-invasive neural stimulation.