Neural Modulation of the Primary Auditory Cortex by Intracortical Microstimulation with a Bio-Inspired Electronic System

Abstract

Nowadays, the majority of the progress in the development of implantable neuroprostheses has been achieved by improving the knowledge of brain functions so as to restore sensorial impairments. Intracortical microstimulation (ICMS) is a widely used technique to investigate site-specific cortical responses to electrical stimuli. Herein, we investigated the neural modulation induced in the primary auditory cortex (A1) by an acousto-electric transduction of ultrasonic signals using a bio-inspired intracortical microstimulator. The developed electronic system emulates the transduction of ultrasound signals in the cochlea, providing bio-inspired electrical stimuli. Firstly, we identified the receptive fields in the primary auditory cortex devoted to encoding ultrasonic waves at different frequencies, mapping each area with neurophysiological patterns. Subsequently, the activity elicited by bio-inspired ICMS in the previously identified areas, bypassing the sense organ, was investigated. The observed evoked response by microstimulation resulted as highly specific to the stimuli, and the spatiotemporal dynamics of neural oscillatory activity in the alpha, beta, and gamma waves were related to the stimuli preferred by the neurons at the stimulated site. The alpha waves modulated cortical excitability only during the activation of the specific tonotopic neuronal populations, inhibiting neural responses in unrelated areas. Greater neuronal activity in the posterior area of A1 was observed in the beta band, whereas a gamma rhythm was induced in the anterior A1. The results evidence that the proposed bio-inspired acousto-electric ICMS triggers high-frequency oscillations, encoding information about the stimulation sites and involving a large-scale integration in the brain.

Rat Locomotion Detection Based on Brain Functional Directed Connectivity from Implanted Electroencephalography Signals

“…Some studies have suggested the use of high gamma signals to decode highly fractionated movements [ 57 ], further controlling prosthetic limbs with large degrees of freedom [ 58 , 59 ]. Another study suggested that the intracortical microstimulation based on implanted neuroprosthesis induced the gamma band oscillations in the primary auditory cortex in a similar way as a natural sensory information communication process [ 60 ]. All those results showed that the analysis of gamma band signal might be a potential method for improving the accuracy of neuroprosthetic control.…”

An iEEG Recording and Adjustable Shunt-Current Conduction Platform for Epilepsy Treatment

“…The clinical application of pacemakers, neural stimulation, artificial retinae, and vagus nerve stimulation has driven smart implantable electronic devices towards precision therapy [15]. Intracortical microstimulation (ICMS) based on an implanted neuroprosthesis can trigger gamma oscillations in the primary auditory cortex in a similar way to the natural communication process [16]. Neurostimulation has been employed in epilepsy treatment over the past decade.…”

Intracranial Monitoring to Verify Novel Transcranial Electric Stimulation in an Epileptic Swine Model

“…With modern technologies, forced electric fields can be used to stimulate the brain, probe neural patterns, and treat brain diseases [1]. Regarding neuroprostheses translation, intracortical microstimulation via the acoustoelectric transduction of ultrasonic signals was used to investigate brain plasticity in a rat model [2]. Clinically, neuromodulation such as deep brain stimulation (DBS) therapy for drug-resistant epilepsy has shown therapeutic effectiveness [3,4].…”