Posts Tagged ‘bdnf’

The Phrenology of Fear

Thursday, January 28th, 2010
Mortified Mouse

Mortified Mouse

Scientists at Emory University, extending the work of others scientists who have identified the amygdala (an almond-shaped brain region) as key to our fear response, have shown that the prelimbic cortex plays a role, too.

Kerry Ressler, MD, PhD, and his team found that without a critical growth factor in the prelimbic cortex mice become less prone to remember a previously frightening experience. This finding could benefit the diagnosis and treatment for anxiety disorders such as post-traumatic stress disorder and phobias.

BDNF (brain-derived neurotrophic factor) has been called Miracle-Gro for brain cells. The protein protects cells from stress and stimulates them to forge new connections. Previous studies had shown that blocking BDNF’s action in the amygdala made it more difficult for fear memories to take hold.

“The prelimbic cortex is part of the medial prefrontal cortex, which appears to be important for emotional regulation in rodents as well as humans,” Ressler says. “Evidence is building that these regions may be dysregulated or even over-active in fear and anxiety disorders in humans.”

“This work is important for extending our understanding of how BDNF is important for neuronal plasticity, learning and memory,” Ressler says. “Together with our previous work, these data suggest that preventing neural plasticity in very precise, but critical brain regions, can have vastly different effects on emotional memory.

“It is becoming increasingly clear that these prefrontal cortex regions are functionally associated with regions of the brain known for a long time to be involved in emotion, such as the amygdala and hippocampus,” he adds. “Understanding the molecular and cellular mechanisms of these connections in rodent models will provide scientists a better understanding of how these similar areas are functioning in humans.”

See the report in Science Codex

Doidge – Part 3 – The Science of Brain Training

Friday, November 21st, 2008
Norman Doidge: The Brain That Changes Itself

Norman Doidge: The Brain That Changes Itself

(This post is adapted from an entry on our sister blog at mindevolvesoftware.com)

In Chapter three of his book, Doidge focuses on the remarkable career and contributions to the understanding of brain science of Michael Merzenich , a scientist driven by the desire to solve real world problems (like understanding autism) and not content to leave the solutions to others. With Merzenich, a practical solution is part of the scientific challenge.

This section of the book is a must-read for anyone interested in the science behind brain plasticity, brain training, learning and learning dysfunctions, autism, and brain aging. But I will highlight some of the particularly luminous thoughts:

Merzenich: The brain is “like a living creature with an appetite” what we feed it to some extent determines how it thrives. When we engage our brains it matters what we do with them.

Shifting brain maps: By microscopic mapping of the surface of the brain, Merzenich showed that the areas of the brain controlling and responding to things like touch shifted over time depending upon what the brain needed to do with them. (Use two fingers together all the time, the brain maps for those two fingers become merged.)

Competitive plasticity: The brain is constantly assessing how important it is to allocate space to certain skills and functions. The more we demand of a certain skill (like playing the piano) the more space and brain power it gets. The less we use a certain function or skill, the more it loses its brain real estate to other functions.

The role of close attention in plastic change: Merzenich found that repetition alone isn’t enough for plastic change. When monkeys in his research performed tasks repeatedly their brain maps changed, but only if they paid close attention to the task did the changes hold long term. (This is a underpinning tenet to the Brain Fitness Pro training exercise and crops up on the training blog all the time.)

Why children learn so easily… and why adults don’t. Brain-derived neurotrophic factor or BDNF plays a critical role in triggering the brain’s ability to absorb and learn. In children during the critical period of learning the child’s body releases a lot of BDNF, keeping the brain constantly stimulated to absorb new information. Children’s brains are engaged and absorbent throughout this period. But at the end of the critical period, the body releases a whole lot more BDNF, a trigger that effectively shuts down the critical period and puts an end to this process.

It may seem odd that we’re designed to stop learning effortlessly past a certain point, but it would be difficult to function as an adult if we were constantly distracted and unable to determine priorities and accumulate the wisdom of trial and error.

Restimulating plasticity in adults: As Doidge puts it, “We rarely engage in tasks in which we must focus our attention as closely as we did when we were younger.” Merzenich found that the brain’s ability to grow new nerve cells, forge plastic change, and learn new skills wasn’t completely shut off in adults, but required certain conditions to be opened up again. The first condition is highly focused attention. The second is reward or satisfaction, which can come from novelty, pleasure, or a sense of achievement. (Again, these are foundations of the Brain Fitness Pro design.)

In Merzenich’s own words: “Everything that you can see happen in a young brain can happen in an older brain.”

This phase of Merzenich’s career lead him to help found Posit Science, a company that publishes brain training software to help children with learning disabilities and to provide brain training for older people who are losing or don’t want to lose memory function or mental sharpness as they age.

(As I’ve written elsewhere, Posit Science seems to have great products, but they’re unfortunately very expensive, and prohibitively expensive in many situations that could really help people. A full program for an adult costs over $600. That’s why I believe that Brain Fitness Pro should remain affordable, in order to bring these kinds of benefits to those who need them but just don’t have hundreds of dollars to spend.)

Related posts:

Building a Better Brain — in the second case study Doidge focuses on Barbara Arrowsmith Young’s discovery that learning disabilities can be mitigated by training the weaker areas of the brain to be stronger.

Part 2 – Rewiring balance — Doidge explores the incredible contributions of Michael Merzenich (the founder of Posit Science).