1. Neuroplasticity

2. What is Neuroplasticity?
The brains ability to change throughout the course of life.
Change occurs through the making and breaking of synaptic connections between neurons
Reasons for change:
Genetic: normal pre-programmed development of the brain
Environmental: injury, brain damage or simply learning new skills
Neuroplasticity can be observed on different scales:
Smallest scale: at the level of a single neuron, it takes the form of synaptic plasticity (the ability of the neuron to form new synaptic connections and break up old ones)
Synaptic plasticity depends on the activity of neurons
“neurons that fire together, wire together”
“neurons that fire out of sync, fail to link”
Largest scale: it takes the form of cortical remapping (phenomenon when brain area X assumes the functions of brain area Y, for example, due to injury)

3. Remapping of Sensory Cortex
One of the early studies of neuroplasticity on the level of cortical remapping was done by Merzenich et al (1984)
Researchers studied the cortical representation of the hand in eight adult owl monkeys.

4. Methods: Merzenich et al (1984)
sensory inputs from all of the fingers were mapped in the cortex. To do this, electrodes were inserted in the cortical area known to be responsible for sensation from the hand, then researchers stimulated various areas on all the fingers one by one and noted which electrode was responding to stimulation. Monkeys were anesthetized before this procedure.
The third digit (middle finger) oon the monkey’s hand was amputated.
Sixty-two days later, a remapping was done to see how the cortical area responsible for sensitivity from the hand changed after amputation. +

5. Results: Merzenich et al (1984)
Results showed that there were five distinct area in the brain, each responsible for one finger
It was found that the adjacent areas (those responsible for sensitivity from digits 2 and 4) spread and occupied parts of the now unused area.
The areas responsible for digits 2 and 4 became larger while the areas responsible for digits 1 and 5 stayed the same.
It was concluded that cortical remapping of sensory inputs from the hand occurs within 62 days in owl monkeys.

6. Neuroplasticity as a Mechanism of Learning
Neuroplasticity is not confined to making up for damage. It occurs on a regular basis in our daily lives.
Neuroplasticity is thought to be the brain mechanism of learning (when you learn, your brain gradually reshapes itself)

7. Draganski et al (2004)
Aim:
to find out whether the human brain can really change structure in response to environmental demands.
Methods:
Researchers used a random sampling design and a self-selected sample – they randomly allocated a sample of volunteers into one of two groups: jugglers and non-jugglers.
They made sure that both groups had no experience of juggling before the start of the experiment
The first brain scan was performed at this point,.
Participants in the juggler group subsequently spent three months learning a classic juggling routine with three balls.
The second brain scan was performed after
Then the participants spent another three months where they were instructed not to practice juggling.
Finally, the third brain scan was performed after this non-practice period.
The control group just lived their daily lives and had their brains scanned three times on the same schedule as the jugglers

8. Results of Draganski et al (2004)
Comparisons of brain scans in the two groups prior to the start of the experiment showed no differences in brain structure
At the second scan, however, the juggler group had significantly more grey matter in some areas of the cortex, most notably the mid-temporal area in both hemispheres.
These areas were known to be implicate din coordination of movement
At the time of the third scan these differences decreased, but the amount of grey matter in these areas in jugglers was still greater than at the time of the first scan.
In other words, as you learn a simple juggling routine, certain areas of your brain grown. When you don’t practice, they shrink back significantly but perhaps no to the initial state.

9. Practical Applications
All the evidence discussed so far challenges the idea that the brain is “fixed” and that certain psychological functions are hard-wired in certain parts of the brain.
At least to some extent, the brain is a plastic structure that can adapt itself to the demands of the environment.
This raises questions like: can we use brain plasticity for practical purposes? Potential applications are countless.
For example: can we rewire the visual cortex of blind people so that they can “see” using some other senses?
Human echolocation: some blind people can acquire the ability to see around them with echoes: they produce clicking sounds with their mouths and analyze echoes as the sounds bounce off the objects in front of them.
Studies have demonstrated that this auditory information in such people is processed in the visual rather that auditory cortex areas.