Researchers at Tohoku University have demonstrated in mice that vagus nerve stimulation (VNS) delivered after motor training can enhance long-term learning, with effects linked to rhythmic changes in cerebral blood vessel activity rather than direct neurotransmitter modulation alone. The findings are published in iScience.
The vagus nerve serves as a primary communication route between the body’s internal organs and the brain. VNS is an established clinical intervention for several neurological conditions, but its potential role in supporting memory consolidation and motor learning has been less well characterised. In this study, researchers developed a small cuff electrode affixed to the left cervical vagus nerve of mice and examined the effects of post-training stimulation on a cerebellum-dependent eye-movement task, the horizontal optokinetic response (HOKR), in which animals learn to track moving visual patterns more accurately over successive sessions.
VNS was administered after each training session rather than during it. Stimulation did not improve performance within individual training sessions, but mice receiving VNS demonstrated stronger long-term learning on subsequent days compared with controls, suggesting that the stimulation acts on post-training consolidation processes.
To investigate the underlying mechanism, the team used fibre photometry to measure blood-volume dynamics near the cerebellar flocculus, a region involved in HOKR learning. A single VNS train produced a biphasic vascular response: an initial decrease in local blood volume followed by a delayed increase. Repeated stimulation induced rhythmic blood-volume oscillations, and mice exhibiting larger oscillations tended to show greater learning gains by day five.
The authors propose that VNS may enhance learning by modulating the brain’s metabolic environment through rhythmic vascular activity, creating conditions more conducive to lasting synaptic change. Future work will focus on optimising stimulation protocols and clarifying the mechanisms by which the brain-body axis contributes to long-term plasticity.
Source: Chen J et al. Vagal nerve stimulation induces vascular oscillations and enhances long-term learning. iScience (2026). DOI: 10.1016/j.isci.2026.117413
