brain health · Feb 18, 2025

Neurogenesis: How the Body Regenerates Brain Cells Naturally

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By Liad Stearns, MS

Neurogenesis is the process of generating new neurons — your brain’s communication cells that are responsible for transmitting information throughout the brain and body via electrical and chemical signaling. This process is essential for key brain functions, including adaption (the brain’s ability to change and reorganize in response to new experiences, learning, or environmental changes), rewiring, and forming new neural connections, which regulate learning, memory, cognitive flexibility, and mood regulation.

For years, scientists believed neurogenesis only occurs during childhood when the brain is rapidly developing. However, recent research has shown that the brain continues to produce new neurons into adulthood, maintaining its ability to change, build new connections, and repair.

While neurogenesis naturally declines with age, lifestyle factors like exercise, diet, sleep, and mental stimulation can all influence the brain’s ability to regenerate and stay resilient. Our growing understanding of neurogenesis highlights opportunities to keep your brain sharp, recover from injury, and improve symptoms of neurodegenerative diseases.

The Evolution of Neurogenesis Research

For a long time, scientists thought of the adult brain as “fixed” and incapable of generating new neurons. However, this was challenged in the 1960s when Joseph Altman provided evidence of neurogenesis in adult rodents. His research suggested that new neurons were being produced in the hippocampus, a brain region integral to memory and learning [1]. However, at the time, the idea that adult brains could create new neurons was considered largely improbable, and scientists ignored Altman’s findings.

In the 1980s, Michael Kaplan expanded upon Altman’s findings. He confirmed neurogenesis in the neocortex of adult mammals (the neocortex is involved in cognition, perception, and motor skills), while Fernando Nottebohm provided strong evidence of new neurons forming in songbirds [2, 3]. Over time, more studies were conducted in animal models, mostly rodents, and the results supported the idea that neurogenesis continued beyond early development.

However, the most significant breakthrough came in the 1990s when Fred Gage and Peter Eriksson used the “gold standard” adult hippocampal neurogenesis method to provide the first direct evidence of neurogenesis in adult humans [4].

Despite these advances, there’s still an ongoing debate about neurogenesis in adult humans. Some studies argue that neurogenesis declines to negligible levels in adulthood, while others provide evidence of continuous neuron formation throughout life [5, 6, 7].

Direct confirmation of neurogenesis has been observed in rodents, birds, and primates, and mounting evidence suggests this to be true in humans as well. Deepening our understanding of how neurogenesis functions in humans could lead to new insights in treating neurodegenerative diseases, mental health disorders, and brain injuries.

How Neurogenesis Works in the Brain

Neurogenesis is an essential process underlying various brain functions, including learning and recovery. For example, newly formed neurons in the hippocampus are involved in specific forms of learning and memory, and their loss is associated with cognitive impairments [8]. Additionally, a natural and temporary increase in neurogenesis is seen following traumatic brain injury (TBI), which may contribute to cognitive recovery [9].

Where does neurogenesis occur?

According to our current knowledge, neurogenesis primarily occurs in two brain regions:

Hippocampus: The hippocampus, a seahorse-shaped structure in your brain, is the most well-established site for adult neurogenesis [10]. It’s the primary region for your brain’s learning, memory, and mood regulation functions. Research suggests that new neurons you develop in the hippocampus as an adult not only survive, but also undergo a process called synaptogenesis (the formation of new synaptic connections that allow neurons to communicate) and integrate functionally into pre-existing neural circuits [11]. This dynamic integration highlights the brain’s remarkable capacity for adaptation, allowing the brain to modify its responses based on new experiences and information.
Subventricular Zone: The subventricular zone, located in the walls of the lateral ventricles (two fluid-filled cavities in your brain), generates neurons that migrate to the olfactory bulb, the part of your brain that processes smells. Similarly to the hippocampus, new neurons in the subventricular zone can integrate functionally into neural circuits involved in olfactory processing [12].

Neurogenesis has also been observed in other regions, including the amygdala (responsible for emotional regulation) and striatum (involved in motor control) [13]. However, it occurs at significantly lower levels, so its functional significance is questioned.

Neurogenesis and brain injuries

Traumatic brain injuries (TBIs), strokes, and concussions can cause lasting impairments in brain function, especially in highly vulnerable parts of the brain like the hippocampus. If you have a head injury, your brain will spontaneously activate regenerative repair mechanisms, increasing neurogenesis and triggering a temporary surge in neural stem cells. These stem cells proliferate and develop into new neurons, which migrate to affected areas in an attempt to replace lost or dysfunctional cells.

While this regenerative process highlights the brain’s capacity for self-repair, neurogenesis on its own is often insufficient for complete recovery [14, 15]. Because TBI and other brain injuries are recognized as important risk factors for neurodegenerative diseases, scientists are exploring pharmacological interventions and lifestyle changes to improve recovery outcomes and enhance the survival and integration of new neurons.

Can neurogenesis slow cognitive decline?

Emerging research indicates a growing connection between neurogenesis and cognitive decline, which has become evident in neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Impaired neurogenesis has been linked to cognitive and motor decline, while enhancing neurogenesis may provide a therapeutic approach to slowing cognitive decline and alleviating related symptoms.

The relationship between adult hippocampal neurogenesis and cognitive impairment in Alzheimer’s disease is well-established, with reduced neurogenesis in the hippocampus correlated with cognitive decline and the progression of the disease [16]. Hippocampal shrinkage in Alzheimer’s is associated with a decrease in neurogenesis, indicating that the reduction in new neuron growth may contribute to both the structural atrophy of the hippocampus and the worsening of cognitive symptoms [17]. Similarly, Parkinson’s disease is characterized by the loss of dopaminergic neurons (brain cells that produce and release dopamine, a chemical involved in movement, motivation, and pleasure), where dysregulated neurogenesis in the substantia nigra has also been observed [18].

While the exact mechanisms and extent of the impact of neurogenesis in neurodegenerative diseases are unclear, studies suggest that targeting these pathways could offer potential strategies to slow disease progression and improve cognition. Some approaches for boosting neurogenesis include pharmacological treatments, stem cell therapies, and lifestyle changes like physical exercise, which has been found to stimulate neurogenesis and enhance cognitive function [19].

5 Factors That Affect Neurogenesis

Research suggests that various lifestyle factors can impact neurogenesis, which can be easily adopted into your routine. Here’s a breakdown of key factors that are involved:

1. Exercise

Aerobic activities like running, cycling, and swimming have been shown to significantly promote neurogenesis by increasing brain-derived neurotrophic factor (BDNF), which supports neuronal growth and survival [20].
Regular physical activity improves cognitive functions, such as memory and learning. These benefits may extend to neurodegenerative conditions, potentially slowing the progression of diseases like Alzheimer’s and Parkinson’s [21].

2. Diet

Omega-3 fatty acids (found in fish and flaxseeds) support neuron formation [22].
Polyphenols (found in berries, dark chocolate, and green tea) have neuroprotective properties [22].
High-fat and high-sugar diets may promote systemic inflammation and oxidative stress, which reduce BDNF, a key protein that supports neuron growth and survival [22].
Essential nutrients such as alpha lipoic acid (ALA), taurine, vitamin B3, and berberine have anti-inflammatory and antioxidant properties that protect neurons and support brain energy metabolism. Tonum’s product Nouro packs these all into one supplement, which has been shown to reduce hippocampal shrinkage [23, 24].
Intermittent fasting and caloric restriction have been associated with increased neurogenesis, likely due to their effects on metabolic pathways and cellular stress responses [22].

3. Environmental factors

Cognitive Stimulation: Engaging in mentally stimulating activities, like learning new skills, reading, or playing musical instruments, enhances neurogenesis and cognitive reserve [25].
Social Interaction: Maintaining strong social connections and regular social activities promotes neurogenesis [26].

4. Stress and sleep

Chronic stress inhibits neurogenesis, especially in the hippocampus, which is vital for memory and learning [27].
Lowering cortisol levels through stress management techniques such as mindfulness, meditation, yoga, and deep breathing supports the survival and growth of new neurons [28].
Sleep deprivation suppresses neurogenesis in the hippocampus, leading to cognitive impairments and mood disorders [29]. Sleep loss has separately been shown to increase stress hormones called glucocorticoids, which inhibit hippocampal neurogenesis [30].
Prioritize 7–9 hours of quality sleep per night and practice stress management techniques such as mindfulness, meditation, or deep breathing exercises to protect your brain.

5. Aging

Neurogenesis declines with age, with a 30% reduction in immature neurons between middle age and 90 years [31].

Takeaways

Caring for your cognitive health doesn’t have to be overwhelming—small, intentional changes can make a big difference. Science shows that neurogenesis continues throughout life, meaning it’s never too late to support your brain. Here’s what you can do today:

Move your body: Aim for at least 150 minutes of moderate aerobic activity per week, such as brisk walking, cycling, or swimming, to support brain function and neurogenesis.
Eat brain-friendly foods: Incorporate brain-boosting foods like fatty fish, leafy greens, berries, nuts, and olive oil into your diet while minimizing processed foods and excess sugar.
Prioritize sleep and stress management: Prioritize 7–9 hours of quality sleep per night and practice stress management techniques such as mindfulness, meditation, or deep breathing exercises to protect your brain.
Stay socially and mentally active: Stay mentally and socially active by playing an instrument, reading, engaging in any art form of your liking, or spending time with friends and family.
Supplement smartly: Take research-supported supplements like Nouro, which was developed in collaboration with Duke University to reduce hippocampal shrinkage, activate neural growth, and promote cognitive health.

References

Liad Stearns, MS is a freelance health and science writer based in San Francisco, CA. She holds a master’s degree in neuroscience from Tulane University and has experience in product development within the glucose monitoring space, as well as working as a health coach in a functional medicine practice.