Pairing broadband noise with cortical stimulation induces extensive suppression of ascending sensory activity

Abstract

Objective The corticofugal system can alter coding along the ascending sensory pathway. Within the auditory system, electrical stimulation of the auditory cortex (AC) paired with a pure tone can cause egocentric shifts in the tuning of auditory neurons, making them more sensitive to the pure tone frequency. Since tinnitus has been linked with hyperactivity across auditory neurons, we sought to develop a new neuromodulation approach that could suppress a wide range of neurons rather than enhance specific frequency-tuned neurons. Approach We performed experiments in the guinea pig to assess the effects of cortical stimulation paired with broadband noise (PN-Stim) on ascending auditory activity within the central nucleus of the inferior colliculus (CNIC), a widely studied region for AC stimulation paradigms. Main results All eight stimulated AC regions induced extensive suppression of activity across the CNIC that was not possible with noise stimulation alone. This suppression built up over time and remained after the PN-Stim paradigm. Significance We propose that the corticofugal system is designed to decrease the brain’s input gain to irrelevant stimuli and PN-Stim is able to artificially amplify this effect to suppress neural firing across the auditory system. The PN-Stim concept may have potential for treating tinnitus and other neurological disorders.

Ultrasound Produces Extensive Brain Activation via a Cochlear Pathway

“…Array placement within the ICC was confirmed by observing frequency response maps that increased in best frequency with increasing depth. The A1 probe was placed such that electrical stimulation of A1 resulted in descending activation of the ICC, based on previous studies (Markovitz et al, 2015b). For SC1 placements, the location of SC1 was confirmed by observing the induced SC1 activity responding to electrical stimulation (biphasic, cathodic-leading pulse, 205 ms/phase, level of 2.82 mA) of different body regions (e.g., foot, shoulder) as is expected for the somatotopic map of SC1 (Rapisarda et al, 1990).…”

“…In SC1 mapping experiments, site locations in SC1 were identified by imaging the exposed cortical surface with the inserted array shanks using a microscope mounted camera (OPMI 1 FR pro, Carl Zeiss Meditec, Dublin, CA). Locations across animals were then normalized based on their relative distances from the middle suture line, bregma, and the lateral suture line, as successfully performed in previous studies from our lab (Markovitz et al, 2013(Markovitz et al, , 2015b.…”

An Investigation of Feasibility and Safety of Bi-Modal Stimulation for the Treatment of Tinnitus: An Open-Label Pilot Study

“…Bi‐modal stimulation is emerging as a compelling approach to tinnitus treatment . De Ridder et al paired tones with VNS in 10 tinnitus patients who were previously unresponsive to other treatments.…”

Ultrasound Produces Extensive Brain Activation via a Cochlear Pathway

“…Electrode Site Reconstructions: In SC1 mapping experiments, site locations in SC1 were identified by imaging the exposed cortical surface with the inserted array shanks using a microscope mounted camera (OPMI 1 FR pro, Zeiss, Dublin, CA). Locations across animals were then normalized based on their relative distances from the middle suture line, bregma, and the lateral suture line, as successfully performed in previous studies from our lab (Markovitz et al, 2013(Markovitz et al, , 2015b.…”