How to Increase Intelligence and Enhance Learning (BDNF)

Brain-derived neurotrophic factor — or BDNF for short — is one of the most important compounds that your brain uses to promote the growth and development of neurons [R, R].

BDNF is a “neurotrophic factor” — a family of compounds that also includes nerve growth factor (NGF), neurotrophin, and others — and which play many key roles that support your brain’s ability to grow and learn [R, R, R, R].

For example, your brain uses BDNF to stimulate the production of new neurons (through the process known as neurogenesis) [R].

BDNF also helps existing neurons grow new connections to other brain cells, which gives it a key role in synaptic plasticity. By extension, BDNF is critical for your ability to learn and store new information and memories [R, R, R, R].

BDNF also helps brain cells recover from damage, as well as helps neurons to maintain their myelin sheaths — the fatty coating over neurons that enables them to transmit and receive electrical signals as efficiently as possible [R, R, R].

All together, the many important roles that BDNF plays throughout your brain also makes it one of the most important factors that can affect your cognitive ability! In this post, we’ll be looking at the BDNF gene, the main gene that is responsible for determining how much of this important compound your brain produces.

BDNF is one of the main compounds your brain uses to promote the growth and development of neurons. By stimulating key processes such as neurogenesis, synaptic plasticity, and more, the total amount of BDNF your brain produces can have a significant effect on your overall cognitive ability.

One of the most important factors that determines your overall levels of BDNF is the (aptly-named) BDNF gene, the main gene responsible for creating BDNF in your brain and throughout the rest of your body.

This gene has been extensively studied, as the variants that different people carry for this gene can have a very significant influence on how much BDNF they produce — and therefore how much of it is available in the brain to help promote neurogenesis and synaptic plasticity.

Because the functions of BDNF are so important for overall brain function, genotypes for SNPs in the BDNF gene have been associated with many aspects of cognitive function, including overall cognitive ability [R, R], fluid intelligence [R], learning and memory [R, R, R, R], cognitive flexibility (executive function) [R], and even total brain size [R, R]!

The genetic variations you carry in the main BDNF gene determines how much BDNF you produce, which in turn affects many different aspects of your cognitive function.

One of the most important and highly-studied SNPs for determining your total overall levels of BDNF is rs6265, also known as the “Val66Met” polymorphism [R, R]. You can see your genotype for this critical SNP in the table below:

The two possible alleles for this SNP are the major ‘C’ allele (also widely referred to as the valine, or “val”, allele), and the minor ‘T’ allele (also known as the methionine, or “met”, allele) [R, R].

When it comes to cognitive function, it’s better to carry the homozygous major ‘CC’ (“val/val”) genotype, which about 64% of the general population has.

For example, a targeted gene study gave 437 people a large number of cognitive tests, while also recording their genotype for this BDNF SNP. They found that people who carried two copies of the ‘C’/“val” allele showed significantly enhanced verbal memory and visuospatial processing ability compared to people who carried copies of the ‘T’/“met” allele [R].

Similarly, another targeted study in 114 healthy people found that carriers of two ‘C’/“val” alleles had significantly higher levels of fluid intelligence (“performance IQ”) relative to people with one or more copies of the ‘T’/“met” allele [R].

Because this SNP is so widely studied by scientists, there are literally dozens of other studies that have shown similar results! Instead of going through them all individually, we’ll summarize them in the list below.

The beneficial ‘C’ (“val”) allele of rs6265 has also been associated with:

• Better working memory (on the n-back task) [R]
• Enhanced learning and memory [R, R, R, R]
• Increased executive function and greater cognitive flexibility [R, R]
• Larger overall brain volume [R], as well as higher amounts of grey matter in several key cognition- and memory-related brain areas (such as the prefrontal cortex and hippocampus) [R, R]
• Increased activation in the hippocampus while storing and recalling memories (leading to 25% enhanced memory performance compared to “met” allele carriers) [R, R, R]
• Better reading comprehension and verbal memory, as well as more efficient brain activation (in children) [R]
• Greater resilience against the negative effects of stress and anxiety [R, R, R]

All in all, a very large body of evidence indicates that it’s better to carry the ‘C’ allele for this important BDNF SNP!

Having more copies of the good ‘C’ (“val”) allele for rs6265 is associated with a large number of cognitive and other benefits — whereas people who carry the bad ‘T’ (“met”) allele are at a relative disadvantage.

In general, the benefits of the good ‘C’ (“val”) allele stem from relatively increased overall levels of BDNF in the brain, whereas the bad ‘T’ (“met”) alleles are worse because they decrease the amount of BDNF a person produces [R, R, R, R].

However, the genotype you carry for this SNP also changes the way that neurons store and use BDNF. Normally, BDNF needs to kept close to neural synapses (the place where two neurons “connect” to each other) in order to help trigger plasticity-related changes. However, the ‘T’/“met” allele causes neurons to store BDNF farther away from synapses, in the main “body” of the cell (the “soma”) [R, R, R, R]. This makes it more difficult for BDNF to be activated by neural activity, which further contributes to the cognitive effects of the different rs6265 genotypes [R, R, R].

Lower levels of active BDNF ultimately makes your brain less able to grow and adapt to new information, which is most likely where this SNP’s major cognitive effects come from. For example, deleting the BDNF gene in mice causes greatly reduced synaptic plasticity [R], which in turn produces significant impairments in their ability to learn [R].

Given everything we know about the many different ways this gene can influence peoples’ cognitive ability, it’s likely that similar mechanisms are at play in humans as well.

Compared to carriers of the ‘T’ allele, people with the beneficial ‘CC’ genotype for rs6265 have a copy of the BDNF gene that produces more active BDNF.