Summary: A new study reveals how hibernation dynamically reshapes neural architecture to help brains adapt to extreme metabolic shifts. The study investigated how the visual processing centers of squirrels handle the physiological strain of deep sleep and periodic arousal.
While previous research established structural changes in the brain’s touch-processing regions, this study mapped the visual cortex, discovering that specific neuron populations undergo rapid structural alterations during deep hibernation that completely reverse within 1.5 hours of waking up. This remarkable, high-speed cellular adaptability offers promising insights for treating human brain injuries and accelerating stroke recovery.
Key Facts
- Targeted Visual Mapping: The study investigated a visual brain region to see if the dramatic neural rewiring previously observed in touch-processing brain areas during hibernation occurred universally across other sensory systems.
- Selective Neural Sensitivity: Researchers tracked two distinct neuron populations within the visual cortex during deep hibernation and periodic arousal stages. Only one population exhibited structural alterations, while the other remained entirely unchanged.
- Ultra-Fast Reversibility: The structural changes observed during deep hibernation are highly transient, completely reversing and returning to normal within just 1.5 hours after the animals arouse from deep sleep.
- Zero Long-Term Deficits: Structural assessments conducted six months post-hibernation revealed absolutely no lingering differences in neuron structure between hibernating and non-hibernating squirrels.
- Clinical Promise for Stroke: Safely unlocking and leveraging this natural, rapid mechanism of neuroplasticity could help human adult brains become highly adaptable, drastically improving recovery outcomes after a stroke or neural impairment.
Source: SfN
Understanding how hibernation affects neurons sheds light on how neurons adapt to changing states and can inform treatment strategies for conditions in which neurons are damaged or impaired.
In a new Journal of Neuroscience paper, researchers led by Hendrikje Nienborg, from the National Eye Institute, used squirrels to assess how hibernation alters neuron structure in a brain area that responds to visual information from the eyes.
Why focus on this visual brain area? According to Nienborg, research shows strong neuron structure changes from hibernation in a part of the brain that processes touch, and these findings led to assumptions that neuron changes were happening in the visual brain as well.
The researchers assessed how two types of neurons in the visual brain area were affected during different stages of hibernation: deep sleep and an arousal stage that periodically occurs.
One of the neuron populations had altered structure during deep hibernation compared to nonhibernating squirrels, while the other neuron population was unchanged. These effects reversed within 1.5 h after the animals aroused from deep hibernation.
The researchers further assessed changes six months after hibernation and discovered there were no neuron structure differences between hibernating and nonhibernating squirrels.
Nienborg looks forward to taking this work further by exploring how neuron function changes during and after hibernation: “We know these structural changes have implications for neural communication, learning, and recovery after conditions like stroke.
“To see that there is a mechanism in the brains of these hibernating animals that [is so quick to change] is exciting because if we can figure out how to leverage this mechanism, we can potentially help human adult brains be more [adaptable] too, especially during recovery after stroke.
“We know a lot about how brain areas support visual processing, so exploring functional changes in the visual brains of squirrels is a very likely next step.”
Key Questions Answered:
A: Hibernation demands extreme energy conservation, dropping body functions to a fraction of normal baseline levels. By structurally altering specific neuron populations, the brain can safely power down its high-energy communication lines without causing permanent damage. It’s a beautifully coordinated defense mechanism that preserves the brain’s baseline architecture while completely cutting down on metabolic costs.
A: This is the most exciting takeaway for neuroscientists. While human brains take months or years to slowly rewire after an injury, hibernating animals possess a biological trigger that lets them flip a switch. Within 1.5 hours of waking up, the altered neurons rapidly snap back into place, restoring normal communication and learning pathways almost instantly.
A: A stroke starves human brain cells of oxygen, causing rapid neural damage and impairing critical functions. If scientists can isolate and replicate the biochemical triggers that allow squirrels to rapidly morph, protect, and restore their neurons without long-term damage, they could potentially activate those same adaptive pathways in human stroke survivors to dramatically accelerate healing and brain plasticity.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this visual neuroscience research news
Author: SfN Media
Source: SfN
Contact: SfN Media – SfN
Image: The image is credited to Neuroscience News
Original Research: Open access.
“First-trimester nonsteroidal anti-inflammatory drugs exposure and risk of major congenital malformations: A retrospective register-based cohort study” by Allison Fultz, Carlos A. Mejias-Aponte, Christina Jacob, Laura Castillo, Francisco M. Nadal-Nicolas, Gao Yue, Wei Li and Hendrikje Nienborg. Journal of Neuroscience
DOI:10.1523/JNEUROSCI.0077-26.2026
Abstract
Hibernating animals can show neuroplasticity throughout the hibernation season. In ground squirrels, decreased dendritic arborization in the hippocampus, somatosensory cortex, and thalamus during deep hibernation (“torpor”) suggests that this neuroplasticity is a brain-wide phenomenon.
However, the degree to which neuroplasticity occurs in the visual system is not clear. While transient retinal changes have been reported during torpor, neuroplasticity beyond the retina remains unknown.
Here, we characterized hibernation-related neuroplasticity in the primary visual cortex (V1), the first cortical area to receive visual information, in the thirteen-lined ground squirrel (Ictidomys tridecemlineatus).
We compared neuronal morphology in Golgi-stained samples from male and female hibernating or non-hibernating squirrels. For the hibernating squirrels, brain tissue was sampled during two different epochs: torpor and inter-torpor arousal. Dendritic arborization decreased during torpor in V1 layer 2/3 pyramidal neurons, manifesting as decreases in dendritic length, number, and complexity.
These changes fully reversed during inter-torpor arousal, indicating that on average dendritic arbors grew by 0.75 mm (65%) over ∼1.5 hours. No morphological differences between hibernating and non-hibernating squirrels were apparent when compared 6 months after the hibernation season.
We also found no neuroplastic changes in V1 layer 4 spiny stellate neurons, unlike in this cell type the somatosensory cortex. Together, this revealed, for the first time, hibernation-related neuroplasticity in V1 in support of a brain-wide mechanism but with area-specific differences.
The speed and magnitude of this naturally occurring neuroplasticity could make ground squirrel V1 a powerful translational model system for conditions requiring neuroplasticity, such as recovery from stroke.
