Noninvasive Deep Brain Stimulation via Temporally Interfering Electric Fields

"The timing of the spikes or the first spikes of bursts, relative to the peak of the TI envelope, was −2.8 ± 4.8 ms, i.e., when the envelope amplitude was >97% of its peak amplitude, which was not different from the timing of spikes evoked by 10 Hz stimulation relative to the 10 Hz sinusoid peak (−1.3 ± 2.2 ms; pairwise t test, p = 0.47)."

TI Stimulation: Concept and Validation of Neural Firing Recruitment, p. 1031

Precise spike timing relative to a 10 Hz envelope demonstrates temporal coordination/entrainment in vivo, analogous to timing-based binding and scheduling seen in AI attention mechanisms .

Figures

Figure 1 (p. 1029) : Introduces the TI mechanism and validates neural activation, supporting envelope-synchronized spiking as a temporal coordination signature in the brain .

"We found that by changing the current ratio between the electrode pairs, while keeping the current sum fixed, the peak envelope modulation became increasingly close to the electrode pair with the lower current, with the peak moving 20% of the radius away from the center in the 1:2.5 case and 35% of the radius away from the center in the 1:4 case. This suggests the possibility of ‘live steering’ of activity from one deep site to another within the brain, without having to physically move the electrodes themselves."

RESULTS, p. 1032

Controllable steering of effective stimulation demonstrates selective routing/gating of neural impact, conceptually paralleling attention routing and gating modules in AI systems .

Figures

Figure 5 (p. 1039) : Behavioral responses shift with current ratio changes, indicating functional routing of causal influence to different motor subregions .

"We demonstrate the ability of TI stimulation to mediate activation of hippocampal neurons without recruiting overlying cortical neurons and steerably probe motor cortex functionality without physically moving electrodes by altering the current magnitudes delivered to a fixed set of electrodes."

RESULTS, p. 1030

Demonstrates causal control over access to and activation of deep versus superficial circuits, a key capability for probing and modulating putative consciousness-related networks in vivo .

"We found that TI stimulation at amplitudes sufficient to recruit deep brain structures, such as the hippocampus, did not alter the neuronal and synaptic integrity of the underlying tissue 24 hr after stimulation, at least as reflected by the stains we used."

DISCUSSION, p. 1038

Reports safety at effective amplitudes, supporting the feasibility of repeated causal interventions to test consciousness-relevant hypotheses without overt tissue damage .

Figures

Figure 5 (p. 1039) : Shows that changing stimulation parameters causally evokes specific motor outputs, evidencing controllable causal manipulation of brain function .