2b. Neuroplasticity Flashcards
Neuroplasticity
The ability of the brain to alter its own structure following changes within the body or in the external environment
What part of the neurons are grey and white matter?
Grey matter: Cell bodies
White matter: Myelin sheaths and axon
Synaptic plasticity
The ability of a single neuron to form new synaptic connections and break up the old ones
When is a connection formed between two nearby neurons?
When the two neurons are frequently fired in response to multiple action potentials
Cortical remapping
Phenomenon when brain area X assumed the function of brain area Y possibly due to injuries or other causes
Who performed the juggling experiment?
Draganski et al. (2004)
Draganski: Aim
Study to find out whether human brain can really change in response to environmental demands
Draganski: How were groups allocated?
Used a self-selected sample and random sampling design where volunteers were randomly allocated to two conditions.
Draganski: Process
- MRI performed before
- Juggler group spent 3 months learning juggling and second MRI was taken
- They than spent next 3 months not juggling and third MRI was taken
- Control groups just went about daily lives for 6 months and MRIs were taken at same intervals
Draganski: What characteristics did participants require?
No prior experience to juggling
Draganski: Results of first MRI
Comparisons of first brain scans were similar
Draganski: Results of second MRI
Second scan showed more grey matter in juggling group than control group in the mid temporal area (both hemispheres).
Draganski: Results of third MRI
Showed decrease in grey matter in juggling group but still greater than the control group
Draganski: What is mid-temporal area associated with?
Coordination of movement
Draganski: Analysis
- Brain changes are more pronounced in those who trained better
- Certain areas of brain grow in response to learning
- Failure to practice meant they shrink back significantly though not to initial state
Who performed the London taxi driver experiment?
Maguire et al
Maguire: Aim
To see relationship between number of years of experience with taxi driving and anatomy of one’s brain
Maguire: Participants
- 16 right handed male licensed drivers. Average years of experience around 14 years
- Control: 50 right handed male drives between 30-60 years of age who didn’t drive a taxi
Maguire: Results
- Increased grey matter in posterior hippocampus for taxi drivers but decreased in anterior
- Increased grey matter in anterior hippocampus for control
- No difference in overall volume just redistribution of volume
Maguire: Process
- Took scans from a a database
- Data was measured using voxel-based morphology and pixel counting
- VBM was used to measure density of grey matter
- Pixel counting calculated area of hippocampus using pixels in images
Maguire: Quasi or lab?
Quasi as they didn’t randomly assign people, differences already existed. Study was correlational
Maguire: Alternative explanation for results
Taxi drivers have redistribution but what if those born with larger grey matter in posterior hippocampus tend to choose professions based in navigations?
Maguire: How did he falsify alternative explanation?
Examined correlation between hippocampal volume and time spent as a taxi driver
Maguire: Result of correlational test
- Positive correlation between posterior hippocampus and time spent as a taxi driver
- Negative with anterior for taxi drivers
- Showed result of neuroplasticity
Maguire: Accepted conclusion
P. hippocampus is involved with previously learned spatial information while a. hippocampus deals with learning new spatial information
Neural networks
When a neuron is stimulated, an action potential travels down the axon. Neural networks are created when a neuron or set of neurons are repeatedly stimulated
Long term potentiation
Neurons start to sprout more dendrites to adapt. This means increases in number of synapses available for certain behavior
Synaptic pruning
Process by which extra neurons and synaptic connections are eliminated in order to increase the efficiency of neuronal transmissions. Results from reduced potentiation
