Table 1.

Summary of potential mechanisms associated with ultrasound neuromodulation.

Mechanisms	Description
Membrane deformation causing capacitance changes	Capacitance changes have been observed during artificial membrane deflection [19] and deformation of in vitro membranes [20,21] and modeled in simulations [26]. Capacitance can be altered by membrane volume changes or be associated with a flexoelectric effect (a property of the membrane that causes a spontaneous electric polarization when submitted to a mechanical strain gradient [18]).
Soliton model	Changes in membrane conformation could arise from interfering with a thermodynamic process involved in electromechanical pulse traveling during AP [25].
Intramembrane cavitation model	Ultrasound-induced intramembrane cavitation within the bilayer membrane induces a current through membrane capacitance changes [22].
Mechanosensitive ion channels modulation	A number of mechanosensitive ion channels has seen in vitro to be sensitive to ultrasound waves (TREK-1, TREK-2, TRAAK [11]; voltage-gated Na+ and Ca+ [10]; Piezo1 [12,13]; and Piezo2 [31]).
Modulation of TRPA1 channels in astrocytes	Ultrasound opens TRPA1 channels in astrocytes, inducing glutamate- releasing Best1 as a mediator of glia-neuron interaction [14].
Thermal modulation	Heating reversibly alters the membrane capacitance, resulting in depolarization [27,28]. FUS can increase temperature at specific regimes. Neuronal membrane conductance and synaptic potentials are altered by temperature changes [30].

AP, action potential; FUS, focused ultrasound; TRPA, transient receptor potential ankyrin.