It used to be believed that you were born with all the neurons you were going to have. It wasn’t until the late 1960s that the birth of new brain cells, called neurogenesis, was observed in the hippocampus in the rat brain. Even then, scientists were skeptical that neurogenesis happened in humans. It wasn’t until the 1990s that neurogenesis was confirmed in the brains of humans, other primates, and several species. There are a number of behavioral, environmental, pharmacological and biochemical factors that affect this process, many of which you have the power to influence.
Neurogenesis is closely linked to the brain’s ability to physically alter synapses and neural pathways, known as neuroplasticity. Neuroplasticity occurs in response to the input your brain receives. Think of your neural pathways like roads on which information travels. The more you use certain information or repeat a behavior, thought, or emotion, the sturdier the correlating neural pathway becomes. Information you rarely access and behaviors and emotions seldom used cause a decrease in the neural pathways until connections may be completely lost in a process called synaptic pruning.
You’re shaping your brain all of the time with your life. In every moment, every single thing of which you are aware – sounds, sights, thoughts, feelings – and even that of which you are not aware – unconscious mental and physical processes – are based in and can be directly mapped to neural activity in your brain. What you do, experience, think, hope and imagine physically changes your brain structure and new neural pathways (synapses) are formed to store and retrieve the new information. (Read more: Masterpiece or Mess?)
The good news is that research indicates that new neurons are produced throughout adulthood. The bad news is that most of them don’t survive. More than half of the new cells die within just a few weeks of being born. It turns out that many of the neurons can be rescued from death by learning. Studies show that new neurons are kept alive by effortful learning, a process involving concentration in the present moment over an extended period of time and enriched environments.
If some kind of effortful learning happens when the cells are about a week old, the new cells become incorporated into brain circuits used for learning. The baby brain cells are then used to learn more efficiently in the future. This is a prime example of “use it or lose it.” In turn, some processes of learning and mental activity appear to depend on the presence of new brain cells.
Research shows that new neurons born in the adult brain support more plasticity because of their increased excitability. While having limited long-term restorative ability, the neurons still have therapeutic potential, for example in improving memory or rehabilitation from brain injury or stroke.
More neurogenesis is not better though in some cases of epilepsy.
Ways To Encourage Neurogenesis
Aerobic activity, such as running, interval training, cross fit, or yoga, is the single most effective way of boosting neurogenesis. Exercise is consistently proving to be the best thing you can do for your mind and body. Endorphins produced during physical activity act as potent antidotes to cortisol, the stress hormone. Exercise has been found to increase levels of brain derived neurotrophic factor (BDNF) and glial cell line-derived trophic factor (GDNF), which both support neurogenesis. During exercise, testosterone levels increase which has a beneficial effect on neurogenesis as well and also buffers the effects of psychological stress.
Studies show that even sex increases neurogenesis in the hippocampus, while also elevating your feel-good neurotransmitters.
Diet plays an important role in brain health and neurogenesis. While, on average, the brain represents only 2% of the body’s weight, it uses about 20% of the energy produced by the body. Your brain is 60% fat, and the right fats are absolutely essential to healthy brain function. Omega 3 fatty acids, in particular, docosahexaenoic acid (DHA) seem to be of particular importance to neurogenesis, and can be found in oily fish and some plants, like hemp.
You’ve probably heard that blueberries are good for your brain. Their blue coloring is due to anthocyanin dye, which research has linked to neurogenesis. Green tea has been confirmed to enhance neurogenesis in the brains of adult mice. Animal studies have found curcumin, to have neuroprotective properties and stimulate neurogenesis.
Surprisingly, caloric restriction has also been linked to improved memory function and increased neurogenesis in mice. In humans, caloric restriction works a little differently but has been shown to increase lifespan and have healthy long term effects. Research has shown caloric restriction to create a mild stress response in the body, increasing the production of BDNF and new neurons.
There’s ample scientific evidence to support the many benefits of meditation for your brain. It’s been found to increase gray matter density in a number of different brain regions, including the hippocampus. When practiced at night, meditation may also increase melatonin levels, which has a number of beneficial brain effects, including supporting neurogenesis. Yoga also benefits brain function and increased hippocampal volume has been observed in yoga practitioners.
Basically, decreasing stress, anxiety, and depression, which have been shown to limit neurogenesis, will help birth new brain cells.
4. Lifestyle Factors
- Sleep deprivation reduces hippocampal neurogenesis, but in the short term, the brain can recover from sleep deficit with a temporary surge in neurogenesis. Sleep plays a key role in cleaning the brain of toxins, and long term sleep deprivation is harmful to brain function and contributes to neurodegenerative diseases.
- Exposure to sunlight is known for increasing vitamin D production, but it also raises serotonin levels and BDNF in the brain.
- An enriched environment has also been found to have a positive effect on neurogenesis, upping survival rates and integration of new neurons into the hippocampus and social memory recall. For a rat, an enriched environment might consist of a running wheel, mazes, and socialization. For you, that might mean learning a new skill, traveling, getting together with friends regularly – anything that stimulates your brain and gets it out of the comfort zone.
5. Psychoactive Substances
- Antidepressants Science has observed reduced function and volume of the hippocampus in people suffering from depression and other stress-related disorders.
Antidepressant use has been shown to increase neurogenesis in the rat and human hippocampus, which may play a key in their success for some people.
- Psilocybin Magic mushrooms have been found to boost neurogenesis. Science isn’t really sure why. The effect may be because they reduce fear and stress. Psilocybin use has been shown to be effective in treating depression too.
- Cannabinoids Studies with a synthetic cannabinoid closely related to THC showed an increase in hippocampal neurogenesis in rats. Research has also found that cannabinoids encourage neuroplasticity and reduce depression.
- Other Ketamine, originally a mild anesthetic; ibogaine, found in the root of a tree in Africa; and a few other assorted substances have proven to up neurogenesis.
Neurogenesis is on the cutting edge of current research, with much remaining unknown about the process and the implications for its possible use in treating depression, anxiety, and neurodegenerative diseases.