Saturday, July 18, 2009

What is Neuroplasticity?

Neuroplasticity refers to the brain's ability to re-organize itself by forming new neural connections in response to injury, dysfunction, new experiences or sensory stimulation.

Recent studies have showed that the brain ca "rewire" and restructure itself. The neurons located in the brain can build new or remodel old connections, can generate new paths through the cortex and assume new roles. According to this principle if part of the brain is damaged, it can be possible to train other areas to assume its roles and functions. This is often referred to as “rewireing the brain”. Neuroplasticity can result in one region of the brain colonizing another with effects on mental and physical function.

The realization that the brain is plastic and has the capacity to change its maps gives new hopes to individuals suffering from various brain related conditions. If the maps of the brain can change then there is reason to hope that people confronted with different kinds of issues, “including learning problems and psychological problems might be able to form new maps through activities that will allow the new neuronal connections by getting the healthy neurons to fire together and wire together” (Doidge 2007, 63)

Although once believed that as we aged, the brain became fixed, the new studies conducted in the most recent years has revealed that the brain never stops changing and adjusting. Neuroscientists now describe the brain as capable of change and produce new connections at any age.

References:1. Doidge, Norman. The Brain that Changes Itself. 2007. New York: Penguin Group , 2007. Print.

Wednesday, July 15, 2009

The "biology" of neuroplasticity

Let’s take a closer look at the "biology" of neuroplasticity to understand how these principles work.


The neuron


Neurons are the core components of the brain. A neuron has three parts – the dendrites, axon and cell body. The information flows along the neuron in one direction from the dendrites to the axon, via the cell body. Axons are often compared with wires, they carry electrical impulses at high speeds towards the dendrites or other neurones.


A neuron can receive excitatory signals and inhibitory signals. When it receives excitatory signals the neuron will fire off signals. When it receives inhibitory signals it becomes less likely to fire. The axons do not touch the other neurons, they are separated by a microscopic space called synapse. When the electrical signal arrives at the end of the axon it releases a neurotransmitter into synapses.

The neuron
A neurotransmitter is a chemical messenger that floats over the dendrite of the adjacent neuron, exciting it or inhibiting it. The alterations occur at the synapse level, strengthening or wakening the number of connections between the neurons. We call this process neurons “rewiring” or neurons “rewire” themselves.

"What Fire together Wire Together"

The neurons form strong connections to one another, when they are activated at the same moment. When an axon of a cell is near enough to excite cell of another neuron and repeatedly takes part in firing it, growth process or metabolic change takes place in one or both cells increasing the efficiency of one or both cells. This is often paraphrased as "Neurons that fire together wire together." It is commonly referred to as Hebb's Law ("http://en.wikipedia.org/wiki/Hebbian_theory")

Activity could produce changes in the structure of the brain

One of the first proofs that the brain can be modified through activity and stimulation came as a result of Mark Rosenzweig’s studies. In 1960, Mark Rosenzweig, a professor of psychology at the University of California at Berkeley, published findings showing that rats raised in enriched environments had heavier brains. His experiments showed that stimulation lead the brain to grow (Hirsh, Golinkoff, Eyer, 2003, 27). Therefore Rosenzweig was able to demonstrate that animals raised in enriched environments – surrounded by other animals, objects to explore, toys and running wells learn better than the identical animals that the animals that have not been exposed to these kind of stimuli.
Studies have shown that while completing an activity, the neurons in a center of a certain area of the brain that performs the activity are most committed to the task, while those on the border are less committed. Adjacent brain areas compete with each other to “recruit” these border neurons. Daily activities will determine who wins and will cause the map expansion of the brain area. The map expansion occurs at the boundaries between brain areas as a result of repeated activity. (Doidge 2007, 207). At the same time neuronal structure of the brain can be modified by experience and brain stimulation can lead to brain growth. The stimulating environment not only that is beneficial to development, but also will cause the brain to grow.

Marian Cleeves Diamond, a professor of anatomy and the first woman on the science faculty at Berkely in her book Enriching Heredity, speaks about the anatomy of the brain and how this can be changed by the environment. A stimulating environment will increases the cortical growth. Increases in cortical growth as a consequence of stimulating environmental can occur at every age, however the cerebral cortex is growing most rapidly in the first the first ten years, this being one of the reasons why it is very important to provide children with experiences through education and stimulating environments. Cognitively rich mental and physical activities will stimulate and exercise the brain. Learning a new skill such as dancing, play an instrument, learn a new language, through concentration, exercise will stimulate the neurons and preserve the brain’s balance system.

Plasticity is competitive

If we stop exercising certain mental skills the brain map allocated for that skill is turned over to the skills we practice instead. Plasticity is competitive. The more we practice an activity the more we make sure that its brain space is not lost to another. This has been demonstrated through sensory reassignment experiments that have demonstrated that when one sense is blocked, the cortex is deprived of receiving normal impulses and will start to receive impulses from other senses. At the same time, bad habits are difficult to unlearn. When we learn a bad habit, when we repeat the behaviour this takes claims more control of that map and prevents us from using that part of the brain for “good” habits. (Doidge 2007, 60)



References:
1. Wikipedia, "Hebbian theory." Wikipedia Encyclopedia. Web.6 Jul 2009.
2. Doidge, Norman. The Brain that Changes Itself. 2007. New York: Penguin Group , 2007. Print.
3. Kathy Hirsh-Pasek, Roberta Michnick Golinkoff, Diane E. Eyer. 2003 Einstein never used flash cards: How Our Children Really Learn. Rodale Books, 2003. Print
4. Diamond, Marian Cleeves. Enriching Heredity: Impact of the Environment on Brain Development. 1988.Free Press, 1988. Print
5. Diamond, Marian Cleeves. "The Brain. Use It or Lose It ." Mindshift Connection 1(1998): Print.

Tuesday, July 14, 2009

Neuroplasticity and FASD

At the present time there is no research that demonstrates the use of neuroplasticity principles to help individuals diagnosed with FASD.

However given the fact that neuroplasticity strategies have been applied successfully to individuals that suffered brain damage, stokes and even to those diagnosed with OCD, autism, and other FASD related disabilities, may let us speculate that these strategies would be effective if applied to individuals with FASD.

What is Fetal Alcohol Syndrome?

In the case of the prenatal exposure to alcohol, the developing brain cells and structures are underdeveloped or malformed. Due to exposure, they often create an array of primary cognitive and functional disabilities (including poor memory, attention deficits, impulsive behavior, and poor cause-effect reasoning) as well as secondary disabilities (for example, mental health problems, and drug addiction) (Streissguth, A. 1997)


Why do we think that Neuroplasticity can help FASD diagnosed individuals?

The neuroplasticity principles have been used successfully with individuals suffering from other brain related conditions. Strokes, or brain attacks, are a major cause of death and permanent disability. They occur when blood flow to a region of the brain is obstructed and may result in death of brain tissue. Yet neuroplasticity has been used successfully on some patients that suffered strokes. This shows that as long as there is adjacent living tissue, because the tissue is plastic, there might be how that it might take over.

Neuroplasticity has also been used to help individuals with various conditions, including learning disabled children improve their cognition and perception. (Doidge 2007, 47) According to Michael M. Merzenich, professor at the University of California and well known neuroscientist with numerous contributions to the field of neuroscience, “when learning occurs in a way consistent with the laws that governed brain plasticity the mental machinery of the brain can improve so that we learn and perceive with greater precision, speed and retention. (Doidge 2007, 47). The principle of “Compensatory masquerade”, which is a form of plasticity identified by the American researcher and scientist Jordan Grafman, also comes to support the idea that Neuroplasticity principles can be used with FASD individuals. According to this principle, the brain is assisted to find an alternative strategy for carrying out a task when the initial strategy cannot be followed due to impairment (the other three forms of plasticity identified by Grafman are Map expansion, sensory reassignment and mirror region takeover). This form of plasticity was used in the past, before neuroplasticity to help children with learning disabilities (by exploring alternative methods of learning such as switching people with reading problems to audio tape). According to this form of plasticity, there is more than one way for our brain to approach a task. Since the brain is able to find “alternative strategies” it very likely that this principle can be used to understand the brain of FASD patients in helping them to use other areas of the brain to take over lost functions. This can be another argument in favour of the neuroplasticity principles applied in the case of FASD individuals. According to the Encyclopaedia Britannica, one example is when a person attempts to navigate from one location to another. Most people, to a greater or lesser extent, have an intuitive sense of direction and distance that they employ for navigation. However, a person who suffers some form of brain trauma and impaired spatial sense will resort to another strategy for spatial navigation, such as memorizing landmarks. The only change that occurs in the brain is a reorganization of preexisting neuronal networks (http://www.britannica.com/EBchecked/topic/410552/neuroplasticity/276923/Compensatory-masquerade).



References:
1. Streissguth, A. Fetal Alcohol Syndrome: A Guide for Families and Communities. 1997. Baltimore: Brookes Publishing, 1997. Print
2. Doidge, Norman. The Brain that Changes Itself. 2007. New York: Penguin Group , 2007. Print.
3. Neuroplasticity, Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 05 July 2009 .