Every year, roughly 12 million people worldwide survive a stroke. Of those, only about 35% make a full recovery or live with only minor impairments, according to a 2020 review in Medicina. Nearly 100 million people globally live with the aftermath of a stroke, deficits in motor function, speech, cognition, or sensation that can persist for a lifetime.
But a wave of research over the past five years is fundamentally changing how scientists understand recovery. The brain, it turns out, is capable of far more neural growth and adaptation after stroke than previously appreciated. The question is why some brains achieve extraordinary recovery while others do not, and whether that capacity can be pharmacologically extended to everyone.
The plasticity toolkit
Three distinct mechanisms are now understood to underpin recovery after stroke, each offering a different therapeutic avenue.
The first is axonal sprouting, surviving neurons grow new branches and form new connections around damaged tissue. As Pankaj Sharma of Royal Holloway, University of London, describes it: “New freeways form and they go around the damaged area.”
The second is a more nuanced story. For decades, the dominant hypothesis was that uninjured brain areas “remap” themselves, taking over the functions of damaged regions. But a 2021 study by William Zeiger and Carlos Portera-Cailliau at UCLA (Nature Communications, DOI: 10.1038/s41467-021-24211-8) challenged this directly. Using two-photon calcium imaging in mice, they found no evidence of remapping. Instead, rehabilitation strengthened surviving neurons in the affected area, potentiating pre-existing circuits rather than recruiting new ones. The study suggests recovery is less about reassignment and more about amplifying what remains.
The third mechanism involves gamma oscillations, rhythmic electrical signals between 30 and 100 Hz that facilitate communication between brain cells. Parvalbumin (PV) interneurons generate these oscillations, and stroke damages their connections, reducing gamma activity. A 2025 study by Naohiko Okabe, S. Thomas Carmichael, and colleagues at UCLA (Nature Communications, DOI: 10.1038/s41467-025-57860-0) showed that rehabilitation works in part by repairing PV interneuron synapses and restoring gamma oscillations, and that a gamma-enhancing drug called DDL-920 can reproduce this effect in mice.
The genetics of recovery
Perhaps the most striking discovery involves the CCR5 gene. In 2019, Carmichael’s team at UCLA reported in Cell (DOI: 10.1016/j.cell.2019.01.044) that CCR5, a chemokine receptor involved in immune signaling, acts as a brake on neural recovery after stroke. A natural loss-of-function mutation called CCR5-Δ32, carried by roughly 10% of people of European descent and found at notably high frequencies in Ashkenazi Jewish populations, is associated with substantially better stroke outcomes.
This finding has direct therapeutic implications. Maraviroc, an FDA-approved CCR5 antagonist already used as an HIV drug, is now being studied for repurposing in stroke recovery at UCLA. If blocking CCR5 pharmacologically can mimic the natural advantage of the CCR5-Δ32 mutation, it would represent one of the first molecularly targeted stroke recovery treatments.
A pipeline of emerging therapies
The growing understanding of plasticity mechanisms has generated an unusually diverse treatment pipeline, with approaches ranging from anti-inflammatory drugs to psychedelics to brain-computer interfaces.
The University of Manchester is studying two inflammation-lowering drugs, including one used for rheumatoid arthritis, to reduce post-stroke brain inflammation, which in its acute phase causes additional damage beyond the initial infarction.
In the psychedelic space, two parallel tracks are advancing. At Johns Hopkins, a Phase 1 trial (NCT07053917) is beginning psilocybin-assisted therapy for chronic stroke, aiming to spur neuroplasticity in patients who have plateaued in conventional rehabilitation. Separately, Algernon NeuroScience and Semmelweis University in Budapest are running a Phase 2a randomized double-blind trial of DMT (N,N-dimethyltryptamine) at sub-psychedelic doses (40 patients), following a 2020 rat study (Experimental Neurology, DOI: 10.1016/j.expneurol.2020.113245) showing that DMT reduced infarct size and improved functional outcomes.
Stem cell approaches are also advancing. A 2025 study by Ruslan Rust and Christian Tackenberg at USC and the University of Zurich (Nature Communications, DOI: 10.1038/s41467-025-63725-3) showed that transplanted human neural stem cells in mice not only replaced lost neurons but also repaired the blood-brain barrier and reduced inflammation.
And on the hardware side, CorTec GmbH in Freiburg, Germany, received FDA Breakthrough Device designation in April 2026 for its fully implantable closed-loop brain-computer interface, the Brain Interchange. The first two patients have been implanted at the University of Washington, Seattle.
Why some recover and others don’t
Beyond treatments, researchers are building a more complete picture of what predicts recovery. A 2025 study of 2,172 patients by Celine Gillebert at KU Leuven and Nele Demeyere at Oxford (Imaging Neuroscience, DOI: 10.1162/IMAG.a.1050) found that pre-stroke brain health, total brain volume and white matter integrity, is a stronger predictor of cognitive outcome than the location or size of the stroke lesion itself. A separate 2025 study by Mellanie Springer and Deborah Levine at the University of Michigan (JAMA Network Open, DOI: 10.1001/jamanetworkopen.2025.2002) linked higher educational attainment to better post-stroke cognitive trajectories.
The convergence of these findings, genetic, structural, and pharmacological, suggests that stroke recovery is moving “into an era of molecular medicine,” as Carmichael has described it. The old view that recovery depends mostly on luck and intensive physiotherapy is giving way to a far more granular understanding: recovery can be predicted, augmented, and in some cases, pharmacologically induced.
Source: New Scientist, “How some people’s brains make an extraordinary recovery from stroke” by Jamie Ducharme, June 23, 2026.