Precise sound characteristics drive plasticity in the primary auditory cortex with VNS-sound pairing.

Introduction: Repeatedly pairing a tone with vagus nerve stimulation (VNS) alters frequency tuning across the auditory pathway. Pairing VNS with speech sounds selectively enhances the primary auditory cortex response to the paired sounds. It is not yet known how altering the speech sounds paired with VNS alters responses.

Vagus nerve stimulation paired with tones restores auditory processing in a rat model of Rett syndrome.

Background: Rett syndrome is a rare neurological disorder associated with a mutation in the X-linked gene MECP2. This disorder mainly affects females, who typically have seemingly normal early development followed by a regression of acquired skills. The rodent Mecp2 model exhibits many of the classic neural abnormalities and behavioral deficits observed in individuals with Rett syndrome.

Pairing vagus nerve stimulation with tones drives plasticity across the auditory pathway.

Previous studies have demonstrated that pairing vagus nerve stimulation (VNS) with sounds can enhance the primary auditory cortex (A1) response to the paired sound. The neural response to sounds following VNS-sound pairing in other subcortical and cortical auditory fields has not been documented. We predicted that VNS-tone pairing would increase neural responses to the paired tone frequency across the auditory pathway.

Vagus Nerve Stimulation Rate and Duration Determine whether Sensory Pairing Produces Neural Plasticity.

Repeatedly pairing a brief train of vagus nerve stimulation (VNS) with an auditory stimulus drives reorganization of primary auditory cortex (A1), and the magnitude of this VNS-dependent plasticity is dependent on the stimulation parameters, including intensity and pulse rate. However, there is currently little data to guide the selection of VNS train durations, an easily adjusted parameter that could influence the effect of VNS-based therapies. Here, we tested the effect of varying the duration of the VNS train on the extent of VNS-dependent cortical plasticity.

Varying Stimulation Parameters to Improve Cortical Plasticity Generated by VNS-tone Pairing.

Pairing vagus nerve stimulation (VNS) with movements or sounds can direct robust plasticity in motor or auditory cortex, respectively. The degree of map plasticity is influenced by the intensity and pulse width of VNS, number of VNS-event pairings, and the interval between each pairing. It is likely that these parameters interact, influencing optimal implementation of VNS pairing protocols.

Shank3-deficient rats exhibit degraded cortical responses to sound.

Unlabelled: Individuals with SHANK3 mutations have severely impaired receptive and expressive language abilities. While brain responses are known to be abnormal in these individuals, the auditory cortex response to sound has remained largely understudied. In this study, we document the auditory cortex response to speech and non-speech sounds in the novel Shank3-deficient rat model.

Degraded neural and behavioral processing of speech sounds in a rat model of Rett syndrome.

Individuals with Rett syndrome have greatly impaired speech and language abilities. Auditory brainstem responses to sounds are normal, but cortical responses are highly abnormal. In this study, we used the novel rat Mecp2 knockout model of Rett syndrome to document the neural and behavioral processing of speech sounds.

Speech training alters consonant and vowel responses in multiple auditory cortex fields.

Speech sounds evoke unique neural activity patterns in primary auditory cortex (A1). Extensive speech sound discrimination training alters A1 responses. While the neighboring auditory cortical fields each contain information about speech sound identity, each field processes speech sounds differently.