So, there’s this substance in the brain that works on neurons very much like Scotts Miracle-Gro, the water soluble nitrogen-phosphorous-potassium plant additive that has been around for decades. Just like plant Miracle-Gro does, Brain Derived Neurotrophic Factor (BDNF) essentially turns impoverished neurons in the brain into enriched super-neurons with massive amounts of dendritic and axonal branches and roots capable of making a significantly increased number of connections in your brain and my brain. Those two different neuron possibilities, hand-drawn by the father of neuroscience himself (Santiago Ramon y Cajal), look like this:
The more brain neurons we have and the more branches they have, the more connections they can make. The more connections our brain cells can make, the more energy and information they can process. The more energy and information our brain cells can process, the more energy and information we are able to engage the people, places and things in our life with. And just as with plants, enriched tends to be much healthier than impoverished.
But BDNF not only nourishes “root” growth and connectivity (synaptogenesis), it also plays a critical role in my brain and your brain growing new brain cells (neurogenesis). Quite predictably, BDNF plays an important role the Homer1A protein’s role in forming and retaining long-term memories, in other words, in learning.
Myokine, My Sweet Myokine!
But here’s a cool added benefit of BDNF – it works as a myokine! Great, you say. What’s a myokine? Well, the root “myo” refers to me. But more specifically, my muscles. So, a myocardial infarction turns out to be muscle cells in my heart dying from oxygen deprivation (Necrosis – a stinky way for cells to die, literally. Apoptosis is the anti-inflammatory preferred programmed cell death of choice). Myokines, on the other hand, are kind to the muscle cells in my heart (and everywhere else). They are small proteins that promote regeneration and repair. That would be BDNF!
Oh, and one more benefit from BDNF: it counteracts depression. The folks over at Neurotic Physiology are good enough to explain how that happens:
I’m sure you all knew that the hippocampus is associated with learning and memory, but it is ALSO associated with depression. Or, more specifically, with antidepressants. We used to think that antidepressants worked because they increased the neurotransmitter serotonin in the brain. …Traditional antidepressants like Prozac produce peak serotonin levels in the brain within about 6-8 hours. But the antidepressant effects take longer. WAY longer, up to several weeks. So if the increases in serotonin themselves weren’t causing the antidepressant effects, what was?
Well, it turns out that, if you treat an animal with a drug like Prozac for a few weeks, long enough to get a clinical effect in humans, you also get neurogenesis in the hippocampus, along with increases in BDNF. So the idea is that, somehow, antidepressants increase BDNF, which helps to increase neurogenesis, and this produces antidepressant effects.
There are other studies to support this. For example, (acute or chronic) stress and increases in the stress hormone corticosterone will cause decreases in BDNF, and decreases in neurogenesis, and stress itself is associated with the development of major depressive disorder. Not only that, but people with depression actually show lower levels of BDNF in their blood than people without.
Movin’ On Up
So, how can we increase our brain’s and body’s production of Human Miracle-Gro? Well first, here’s one way – regular exercise. Yep. That old bugaboo you’ve not only heard over and over again here in this blog, but all over the internet from the likes of Daniel Wolpert, Mike Evans and even old-timers like Jack LaLanne. But how do we actually know that exercise is good for producing BDNF? Why from studying mice, of course. Here’s what Wikipedia has to say about it:
The mechanism for this is due to BDNF activating the signal transduction cascades, MAP kinase and CAMKII, which regulate the expression of the transcription factor, CREB, and protein synapsin I. The mitochondria and the uncoupling protein, UCP2, which is mainly present in the brain’s mitochondria, have been thought to interact with this signal transduction cascade during physical activity. CREB and synapsin I both play a role in enhancing plasticity by changing the structure of the neuron and strengthening its signaling capability, therefore affecting long term potentiation. CREB specifically aids in spatial learning and regulating gene expression, while synapsin I modulates the release of neurotransmitters and affects the actin cytoskeleton of the cell which enhances the signaling capability of the neuron by changing its shape and density.
Aren’t you glad that I don’t write like this?
Stockpiling the Gro-Hormone
So, how else might we increase our supply of Human Miracle-Gro? Some people (and I happen to be one of them) think that how BDNF increases energy and information processing in the brain and regenerates and repairs muscle cells in my body frequently shows up through an energetic experience that human beings have given a descriptive name to. We call it “love.”
Now, I could write pages and pages about this energy and my direct and indirect experience of it. Instead though, I’m going to offer up a BDNF-increasing quote that I’ve prefaced my Right Listening book with. It’s from pastoral counseling professor David Augsburger who observed: “Being listened to is so close to being loved that most people can’t tell the difference.” What David doesn’t offer guidance on is how to skillfully love someone when you have a situation-specific, impoverished neural network, and they say something that makes reactive, vindictive Retaliation Energy rush through your nervous system.
Which is one reason that Right Listening is … a practice.