Selective Activation of Neuronal Targets With Sinusoidal Electric Stimulation

Abstract

Electric stimulation of the CNS is being evaluated as a treatment modality for a variety of neurological, psychiatric, and sensory disorders. Despite considerable success in some applications, existing stimulation techniques offer little control over which cell types or neuronal substructures are activated by stimulation. The ability to more precisely control neuronal activation would likely improve the clinical outcomes associated with these applications. Here, we show that specific frequencies of sinusoidal stimulation can be used to preferentially activate certain retinal cell types: photoreceptors are activated at 5 Hz, bipolar cells at 25 Hz, and ganglion cells at 100 Hz. In addition, low-frequency stimulation (≤25 Hz) did not activate passing axons but still elicited robust synaptically mediated responses in ganglion cells; therefore, elicited neural activity is confined to within a focal region around the stimulating electrode. Our results suggest that sinusoidal stimulation provides significantly improved control over elicited neural activity relative to conventional pulsatile stimulation.

Are long stimulus pulse durations the answer to improving spatial resolution in retinal prostheses?

“…In a comparison between 20 Hz sinusoidal and square-wave stimulation, square-wave thresholds were 22.8±35.5% higher, lending further credence to reports that sine wave stimulation preferentially elicits responses in RGCs whilst avoiding axonal activation (12,13). A subsequent human psychophysical comparison suggested that percepts to sinusoidal stimulation were round and confined, in contrast to the elongated arcs perceived with squarewave stimulation.…”

Random Noise Stimulation Improves Neuroplasticity in Perceptual Learning

“…This point should be clarified in future studies with the application of more specific frequency ranges (e.g., 40 -60 Hz vs 80 -100 Hz). In this respect, studies have shown that different classes of neurons are activated at different frequencies (Freeman et al, 2010). Because different cortical areas contain different neuronal types, a specific band of frequencies might lead to the response of a subpopulation of neurons.…”

Flexible Polyimide Microelectrodes Array for Transcorneal Electrical Stimulation

“…Only a few authors suggest stimulation by sinusoidal and conventional waveforms [9]- [11]. Reported TES does not use biological waveforms or typical membrane potential to stimulate.…”