U1 AOS 2 - TEST 2 - BRAIN PLASTICITY Flashcards
(28 cards)
Neuroplasticity
How the neural connections within a brain and the brain itself, changes, in structure and function, over an individual’s life span.
Developmental plasticity
Refers to changes in the brain taking place during periods of growth and development. Involves:
- synaptogenesis
- long term potentiation
- long term depression
Synaptogenesis
Refers to synapse creation and the creation of new neural pathways, which takes place throughout childhood most prominently, as children are regularly involved in new experiences.
It can also include:
- the growth of the axon or dendrites of the pre-synaptic neuron for new connections to be made
This is quickest in motor and sensory areas, to respond to an influx of environmental information.
Long term potentiation
This takes place when a synapse is repeatedly stimulated, with neurotransmitters sent repeatedly across the synaptic gap, resulting in the neural connection strengthening in efficiency.
- axon terminals release more neurotransmitters
- branches of dendrities increase, and there are more dendritic receptor sites on the post synaptic neuron
Eventually, neurotransmitters are released almost simultaneously.
Long term depression
This is where repeatedly low levels of activity result in a weakening of sypnaptic connections.
Over time, these connections may be removed completely, through synaptic pruning.
Development of neuroplasticity
- Sensory areas
- Visual cortex is formed by age 10
- Bursts of activity in early adolescence - 1/2 connections are removed
- Association areas are still forming well beyond 20 years old
- Approximately stable at 30 years old
Types of experience plasticity
Experience - independent:
- takes place regardless of experience
- unfolds through a series of genetic events
- eg. genetics govern neural development in the prenatal stage
Experience-expectant_
- development is triggered due to specific cues occuring at specific times
- eg. eyes opening for the first time resulting in development of the visual cortex
Experience-dependent
- Unique brain changes taking place due to personal experiences
- Eg. playing the violin due to taking music lessons and practising at home
Adaptive Neuroplasticity
Adaptive plasticity is how the brain reorganises neural connections to respond to damage in specific regions of the brain.
This is entirely dependent on the injury and the individual exhibiting it, and in some cases, brain trauma may result in permenant loss of function.
Maximising and maintaining brain function - 1st way
Mental Stimulation - - Involves activity which regularly stimulates synapses, avoiding synaptic pruning.
- Stronger connections are built, resulting in higher levels of functioning
- Eg. doing crossword ouzzles
Maintain and maximise function - 2nd way
Physical activity -
- Involves regular movement of the body, which can result in increased heart flow, and subsequently, increased transportation of oxygen to the brain cells
- Aerobic exercise is considered most benefitial
- Range of benefits including increased density of dendrites, and increased functioning of chemicals aiding in maintenance and growth of neurons
Maintain and maximise function - 3rd way
Diet -
- Involves a healthy balance of different food groups - regulating the intake, frequency and type of food
- Specifically, the natural compound polyphenols can enhance synaptic transmission, increase the formation and survival of neurons in specific areas of the brain, and minimise chronic inflammation
Adaptive - Rerouting
- Rerouting - nearby, healthy neurons create alternative neural pathways. They need to be activated repeatedly to be long-term potentiated.
An action may become more effortful and less efficient.
I.e, driving on back roads instead of freeway (a viable option, but slower and different)
Sprouting
Sprouting - existing, adjacent, neurons create new axon terminals and dendrities for the formation of new pathways
I.e, creating a new road entirely
Aquired Brain Injury - Define
The result of damage to the brain, taking place after birth, at any other point within an individual’s life. Symptoms can range from mild (use of aid or equipment to complete specific activities is needed), to profound (cannot function independently).
ABI - Biological impacts
Biological - Internal, physiological impacts - regions of brain, neuroplasticity, neurons - i.e impaired sensory functions, muscle weakness, seizures, etc.
ABI - Psychological Impacts
Psychological - Impacts on mental state, cognitions and coordination of response - i.e emotional instability, memory loss, slowed thinking, etc.
ABI - Social impacts
Social - Impacts on the way that an individual functions as a member of society, interacting with others - ie. difficulty following social rules and conventions, aggressive verbal behaviour, poor ability to manage conflict.
ABI - Causes
- Physical trauma - Brought on by an external force - i.e sport injuries, domestic violence, etc.
- Disease and infection
- Oxygen deprivation - either during birth or other times
- Poisoning + Alcohol/Drug Abuse
4 Major types of ABI’s
Traumatic - Involves sudden physical impact to the brain, from an external force - if the head is hit hard enough, the cerebrospinal fluid is not sufficient of a cushion enough to protect the membranes of the brain
Aphasia - An acquired language disorder, resulting from damage to language processing centres
Concussion - Mild traumatic brain injury, with temporary effects. Involves the brain bouncing around the skull.
Stroke - Interruption to the brain’s blood supply or involving bleeding vessels in the brain. It is serious as brain tissue will die without sufficient blood supply, resulting in neurological deficits or even death.
Different types of Aphasia
Wernicke’s Aphasia - trouble comprehending speech, where an individual can string the words together to form the patterns of conversation, but the words are not meaningful
Broca’s Aphasia -can understand speech, but cannot produce it, leading to little connection between meaningful words
Neurological disorder - define
Diseases that affect the brain, spinal cord or other neurons in the body. They are either the result of an aquired brain injury, or a congenital condition (during development in utero).
Chronic Traumatic Enceclopathy
CTE is a neurodegenerative disease (neurons cease function over time), which results from repeated impacts to the head. It is common in sport players and domestic violence survivors.
CTE - Sport Players
- CTE was identified first by Dr Harrison Martland, in 1928 as ‘Punch Drunk Syndrome,’ where boxers experienced long-lasting effects from their matches, and were more likely to develop a neurodegenerative disease in the future
- Most prominent in football (tackled by other players, hit by ball, etc.)
Physiological basis - CTE
- It involves progressive and widespread damage to the brain
- It also involves the build-up of the protein tau in neurons (exists to keep neurons stable), which can disrupt the processes keeping neurons healthy, eventually resulting in loss of neurons, atrophy/loss of brain tissue, and loss of brain volume.
