Remotely induced electrical modulation of deep brain circuits in non-human primates

Area of Science:

• Neuroscience
• Biophysics
• Medical Engineering

Background:

• Noninvasive neuromodulation techniques are crucial for treating deep brain disorders.
• Focused electric fields can be generated noninvasively using combined magnetic and focused ultrasonic fields.
• Understanding parameters that effectively modulate neural activity is essential for this novel technique.

Purpose of the Study:

• To investigate the parameters that modulate neural activity using combined magnetic and focused ultrasonic fields.
• To determine the effect of pulse repetition frequency on evoked neural responses in deep brain circuits.
• To assess the potential of this noninvasive method for targeted neuromodulation.

Main Methods:

• Applied combined magnetic and focused ultrasonic fields to deep brain visual circuits in non-human primates.
• Quantified electroencephalographic gamma activity evoked in the visual cortex.
• Tested various pulse repetition frequencies (5 Hz, 10 kHz, 50 kHz) of ultrasonic stimulation.

Main Results:

• A strong magnetic field inhibited evoked gamma responses, replicating previous findings.
• This inhibition was frequency-dependent, observed only at 5 Hz, not at higher frequencies.
• Neuromodulatory effects were transient, with no observed safety issues.

Conclusions:

• The combined magnetic and focused ultrasonic field method can transiently inhibit deep brain neural activity in primates.
• Low pulse repetition frequencies (e.g., 5 Hz) of ultrasound are most effective for achieving this inhibition.
• This noninvasive technique holds promise for targeted treatments of neurological and mental disorders.