Using electrical stimulation for sensory restoration and modulation of attention

Our sensory perceptions play a fundamental role in guiding behavior, relying on a series of intricate processes. These include decoding the physical properties of stimuli—such as light intensity and sound pressure—into meaningful features for object recognition. This transformation involves both bottom-up processing (driven by signals from peripheral sensors to central neural circuits) and top-down modulation (in which attention and prior knowledge shape perceptual interpretation). For those suffering from sensory loss, electrical stimulation through auditory and visual prosthetics can be used to restore sensory abilities. In addition, sub-perceptual electrical microstimulation can be used to modulate top-down behavioral and attentional processes. This thesis explores both applications of electrical stimulation, with the vision that future prosthetic technologies could potentially integrate sense restoration with concurrent engagement of attentional neural mechanisms to further improve sensory perception. Our work in the sensory restoration field centers on addressing the challenges faced by currently available auditory prosthetics. For users of the cochlear implant, for example, perception of music and speech recognition in noisy environments remain challenging. Motivated to overcome these limitations, we focus our efforts on development of an auditory nerve implant that bypasses the cochlea entirely and stimulates auditory nerve fibers directly. Intraneural stimulation offers many advantages over traditional cochlear implant stimulation but introduces new challenges such as the complex spatial organization of frequency regions within the auditory nerve. Our work utilizes electrophysiological studies to explore the variance of this tonotopic organization and demonstrates methods to reduce current spread and provide precise frequency targeting during stimulation. We also present studies in a large animal model (rhesus macaque) to test the feasibility and efficacy of an auditory nerve implant prototype currently being developed for human use. To further explore top-down attentional and behavioral processes, we investigate how microstimulation of the visual cortex can enhance perception of visual stimuli. Our work shows the ability of subtle, low amplitude microstimulation to significantly improve detection of a visual stimulus during a challenging behavioral task. The implications of these findings are that microstimulation could be used to improve visual perception of relevant stimuli in situations involving high noise or significant distractors. Combining this form of microstimulation with sensory restoration technologies could lead to improved performance in future prosthetic devices.

Author dc:creator

• Sondh, Inderbir

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/11299/277398

OAI identifier oai:identifier

oai:conservancy.umn.edu:11299/277398