Summary: New research from NYU Langone shows that stimulating the vagus nerve boosts perceptual learning in mice, enabling them to distinguish finer sensory differences over time. This stimulation engages brain systems involved in attention, memory, and plasticity, and may have implications for improving sensory-based skills in humans, including adaptation to cochlear implants.
Researchers trained mice to discriminate musical tones and found that animals receiving vagus nerve stimulation (VNS) during training continued to improve beyond the performance ceiling reached by unstimulated mice. Stimulated mice made roughly 10% fewer errors on standard tests and about half as many errors on the most difficult discriminations. Brain imaging and targeted manipulations revealed that VNS activates the central cholinergic system and enhances plasticity in the auditory cortex, suggesting a mechanism by which this approach sharpens perception and consolidates learning.
The research highlights the potential of VNS as a tool to accelerate perceptual learning and sensory adaptation. While the findings are promising, the authors emphasize the need for careful translation to humans because the vagus nerve is more complex in people than in mice.
Key Facts
- Vagus nerve stimulation enhanced auditory perceptual learning in mice, improving their ability to detect subtle tone differences.
- VNS increased neuroplasticity in the auditory cortex and recruited the central cholinergic system, a network linked with attention and memory.
- Findings point toward potential clinical uses, such as speeding adaptation to cochlear implants and improving sensory rehabilitation.
Source: NYU Langone
Overview
Perceptual learning—the process of refining sensory skills through experience—helps animals and humans sharpen abilities like distinguishing pitches, recognizing subtle visual features, or interpreting complex sounds. The vagus nerve, a major conduit of signals between the brain and organs such as the heart and gut, is increasingly targeted with mild electrical pulses to modify brain activity and treat conditions ranging from epilepsy to depression. This study examines whether activating the vagus nerve during training can push perceptual learning past its typical limits.
In the study, 38 mice were trained on an auditory discrimination task. All animals improved with practice, but those receiving VNS during training continued to refine their performance after the unstimulated group had plateaued. On average, stimulated mice showed meaningful reductions in error rates, particularly on the most challenging trials that required distinguishing very similar tones.
To uncover how VNS produced these benefits, the team measured brain activity and manipulated specific circuits. VNS increased activity in the cholinergic basal forebrain, a system that supports attention and memory. When the researchers suppressed this cholinergic region during stimulation, the enhanced learning effect disappeared, indicating that cholinergic recruitment is critical for VNS-driven gains. Two-photon imaging also revealed changes in auditory cortical responses consistent with increased neuroplasticity—cellular adaptations that help newly learned skills persist after training ends.
Although earlier animal studies of VNS produced mixed results, this investigation demonstrates a clear benefit for perceptual learning when stimulation is paired with training. The authors note that the learning enhancement emerged gradually; initial distraction from the unfamiliar electrical pulses may delay observable improvements until animals acclimate to the sensation.
Beyond basic science, these results suggest practical applications. Perceptual learning plays a central role in adjusting to cochlear implants and other sensory prostheses. Because implant recipients often require months to adapt—and some continue to experience communication difficulties—pairing device use with targeted VNS could accelerate adaptation and improve daily functioning, such as understanding speech in noisy environments or hearing approaching vehicles.
Vagus nerve stimulators used in clinical settings are compact and vary in invasiveness: some devices are implanted in outpatient procedures, while others are noninvasive units applied externally to the neck. The researchers plan follow-up studies to test VNS in rodents with cochlear implants and to explore translation steps needed for human trials. They caution that human applications require additional testing, since human vagus anatomy and function differ from those of mice.
Funding: This study was supported by National Institutes of Health grant DC012557, with additional funding from the U.S. Department of Defense and the National Science Foundation.
Contributors from NYU Langone include Kathleen Martin, BS; Robert Froemke, PhD; Eleni Papadoyannis, MA; Jennifer Schiavo, PhD; Saba Shokat Fadaei, MS; Habon Issa, BS; Soomin Song, PhD; and Sofia Orrey Valencia, BS. Collaborators included researchers at the Friedrich Miescher Institute for Biomedical Research, Baylor College of Medicine, and the University of Oregon.
About this research
Author: Shira Polan
Source: NYU Langone
Contact: Shira Polan – NYU Langone
Image credit: Neuroscience News
Original Research: Closed access. “Vagus nerve stimulation recruits the central cholinergic system to enhance perceptual learning” by Kathleen Martin et al., published in Nature Neuroscience.
Abstract
Vagus nerve stimulation recruits the central cholinergic system to enhance perceptual learning
Perception can be refined by experience, up to certain limits. It is unclear whether perceptual limits are absolute or could be partially overcome via enhanced neuromodulation and/or plasticity. Recent studies suggest that peripheral nerve stimulation, specifically vagus nerve stimulation (VNS), can alter neural activity and augment experience-dependent plasticity, although little is known about central mechanisms recruited by VNS. Here we developed an auditory discrimination task for mice implanted with a VNS electrode. VNS applied during behavior gradually improved discrimination abilities beyond the level achieved by training alone. Two-photon imaging revealed VNS-induced changes to auditory cortical responses and activated cortically projecting cholinergic axons. Anatomical and optogenetic experiments indicated that VNS can enhance task performance through activation of the central cholinergic system. These results highlight the importance of cholinergic modulation for the efficacy of VNS and may contribute to further refinement of VNS methodology for clinical conditions.