  Action potentials are the basic unit of information in the nervous system and
their reliable detection and decoding holds the key to understanding how the
brain generates complex thought and behavior. Transducing these signals into
microwave field oscillations can enable wireless sensors that report on brain
activity through magnetic induction. In the present work we demonstrate that
action potentials from crayfish lateral giant neuron can trigger microwave
oscillations in spin-torque nano-oscillators. These nanoscale devices take as
input small currents and convert them to microwave current oscillations that
can wirelessly broadcast neuronal activity, opening up the possibility for
compact neuro-sensors. We show that action potentials activate microwave
oscillations in spin-torque nano-oscillators with an amplitude that follows the
action potential signal, demonstrating that the device has both the sensitivity
and temporal resolution to respond to action potentials from a single neuron.
The activation of magnetic oscillations by action potentials, together with the
small footprint and the high frequency tunability, makes these devices
promising candidates for high resolution sensing of bioelectric signals from
neural tissues. These device attributes may be useful for design of
high-throughput bi-directional brain-machine interfaces.
