Adult neurogenesis and hippocampal plasticity
Neurogenesis in the adult brain
Key takeaway for patientsThe adult brain keeps a capacity for renewal. Activity, sleep and the control of stress and inflammation are the conditions that favor it.
For much of the twentieth century the adult brain was thought to make no new neurons. It is now established in animals, and supported by evidence in humans that is still debated, that neural stem cells in the hippocampus, a region central to memory and mood, go on producing neurons in adult life.
New cells must survive and connect to be of use. Growth factors such as BDNF, physical activity and learning favor their survival; chronic stress and inflammation work against it.
Key steps in adult neurogenesis
- Neural stem cell activation
- Stem cells in the dentate gyrus of the hippocampus begin to divide.
- Proliferation and differentiation
- Daughter cells commit to becoming neurons.
- Survival and maturation
- Growth factors such as BDNF decide which new cells survive.
- Integration
- Surviving neurons wire into existing memory circuits.
Factors that suppress neurogenesis
Experimental studies point to several factors that lower the production or survival of new neurons:
- Chronic stress and raised cortisol
- Suppress the proliferation of new cells.
- Neuroinflammation
- Reduces the survival of new neurons.
- Sleep deprivation
- Lowers hippocampal neurogenesis in experimental studies.
- Aging and inactivity
- The rate declines with age and with a sedentary life.
Clinical management and physician guidance
There is no clinical test of neurogenesis; assessment looks at the factors known to influence brain health.
- Cognitive and metabolic assessment
- History, mood and memory, with metabolic, thyroid and inflammatory markers where indicated.
- Physician-guided lifestyle
- Aerobic activity, sleep and the management of stress.
- Monitoring and follow-up
- Symptoms and markers are reviewed over time, and the plan is adjusted to them.
Research focus in neurogenesis
| Core focus area | Biological target | Clinical relevance |
|---|---|---|
| Stem cell niche | Dentate gyrus of the hippocampus | Where new neurons arise |
| Growth factors | BDNF and its TrkB receptor | Survival of new neurons |
| Exercise | Aerobic activity and cerebral blood flow | Activity-related increases in neurogenesis |
| Stress biology | Glucocorticoid receptors | Suppression of neurogenesis by chronic stress |
Frequently asked questions
- Does the adult brain really make new neurons?
- It is well established in animals. In humans the evidence points the same way, though how much continues into old age is still debated.
- What supports it?
- In studies, aerobic exercise, learning and good sleep are linked with more new neurons.
- Can it be measured in a clinic?
- No. Physicians assess memory, mood and the health factors linked with it.
Academic references and literature
- Eriksson PS et al. (1998). Neurogenesis in the adult human hippocampus. Nat Med, 4(11), 1313-7. PMID 9809557.
- van Praag H, Kempermann G, Gage FH (1999). Running increases cell proliferation and neurogenesis in the adult mouse dentate gyrus. Nat Neurosci, 2(3), 266-70. PMID 10195220.
- Boldrini M et al. (2018). Human Hippocampal Neurogenesis Persists throughout Aging. Cell Stem Cell, 22(4), 589-599.e5. PMID 29625071.
This guide belongs to the Cognitive program