acquired brain injury and damage to neuroplasticity (5)

neuroplasticity

the ability of the brain and other parts of the nervous system to change in response to experience

neurplasticity key points in change

developmental changes throughout lifespan, learning skills/knowledge, recovery from injury - reorganisation of connections

neuroplasticity (brain ‘change’)

the brain as a whole does not change shape. instead, change happens at the cellular level.

neuroplasticity (brain ‘change’) emphasized

cells can grow more dendrites and axonal branches, cells can phyiscally extend to create new connections, changes can happen at individual synapses

experience - expectant plasticity (definition)

refers to specied wide changes in the brain due to expected environmental experience during typical development

experience expectant plasticity (sensitve and critical periods)

as long as the right exposure occurs during sensitive or critical periods, expected connections and changes will occur.

myelination (an example of experience expectant plasticity) definition

the growth of white, fatty myelin around axons in the brain.

myelination, when does it start?

starts before birth, and continues through childhood and adolescence, into adulthood

myelination, when is the most intense period?

occurs just after birth, and during adolescence

synaptogensis

the rapid formation of new synapses between neurons in the brain

synaptogenesis (key points)

more dendrites, dendritic branches, and dendritic spines are formed in specific areas of the brain. large synaptogenesis period within the first 15 months after birth. occurs more rapidly in sensory and motor cortices (more slowly in association areas)

synaptic pruning

the process of eliminating synaptic connections

synaptic pruning (key points)

the way that the brain ‘fine tunes’ its connections, occurs first in sensory and motor cortices, later in association areas. it follows after synaptogenesis has occured.

periods of synaptogenesis and synaptic pruning (early childhood)

sees rapid synaptic growth in the frontal lobe, including the motor cortex and pre-frontal lobe.

periods of synaptogenesis and synaptic pruning (late childhood into adolescence)

more synapses form in the parietal and temporal lobes, for hearing, coordination, balance, recognition and language understanding

periods of synaptogenesis and synaptic pruning (late adolescence)

sees a rapid pruning of connections in the frontal lobe, particularly the pre- frontal cortex

experience dependent plasticity (definition)

the individually unique modification of already existing neural structure, and is dependent on exposure to the external environment.

experience dependent plasticity (is it time dependent?)

it is not time dependent, and actually involves no sensitive or critical periods…the more you use it, the more larger and more connected the brain cells will be

adaptive plasticity to brain injury

enables generation of new networks by sproutig new dendrites from healthy neurons, and extending axonal branches to make new connections with cells that were not being communicated with.

adaptive plasticity (sprouting)

dendrites grow and create new branches due to increased connection with other neurons.

adaptive plasticity (re-routing)

axonal branches grow to seek new connections with still healthy cells, to re-establish communication

adaptive plasticity (reassignment of function!)

occurs when an area of the brain that was responsible for one type of response to the environment can become responsible for a different responsibility

adaptive plasticity (reassignment of function!) example!

if one hand becomes paralysed or amputated, the brain area that controlled that hand could be stimulated and used for a different body part, ncluding the other hand.

adaptive plasticity (refers to…)

the ability of the neural pathways in the brain to cope with environmental change

neural plasticity ; sprouting

the neuron extends and grows new dendrite and axonal to form new (more) synapses

neural plasticity ; rerouting

a healthy neuron that has lost its connection will extend its axonal branches to seek new connections

changes at the synapse (learning a new skill or recovering from injury)

you are using neurons, meaning that the neuron is creating an action potential.

changes at the synapse (what happens at the synapse?)

neurotransmitters are released into the gap, if they bind to a receptor site on the next cell, they can successfully affect the next cell.

long term potentiation

long lasting strengthening of synaptic connections, results in more AMPA receptors on post synaptic neuron, results in more neurotransmitters being released

long term depression

long lasting weakening of synaptic connections, results in less AMPA receptors on post synaptic neuron, results in less neurontransmitters being released

brain injury definition

a brain injury is any type of damage or disorder that interferes with the functioning of the brain

acquired brain injury

refers to an alteration to the brain’s neural connections (how well the neurons can communicate) due to a change in the environment

traumatic brain injury

the result of external force that causes damage to the brain

biopsychosocial effects of acquired brain injuries (biological impairment)

will affect a person’s ability to directly sense the environment and the actions they can take

biopsychosocial effects of acquired brain injuries (psychological impairment)

affects memory, judgement, planning, mood, and attention

biopsychosocial effects of acquired brain injuries (social impairment)

affects a persons ability to maintain relationships and to work and live productively

APHASIA

the impairment of language.

APHASIA (broca’s aphasia)

impairment of speech production, a person is unable to produce fluent speech (written or spoken), must use effort to produce words, aware of aphasia, often frustrated

APHASIA (wernicke’s aphasia)

impairment of speech comprehension, unable to understand language in its written or spoken form, unaware that they have wernicke’s aphasia, speech remains fluent, but lacks meaning. may react literally to speech that is meant to be figurative ('ie its raining cats and dogs’)

stoke

a stroke occurs when blood supply to the brain is interrupted. cells that do not get blood supply die quickly, leading to brain damage.

stroke (ischaemic)

blood supply is stopped because there is a blockage in the blood vessel

stroke (heamorrhagic)

the lining of blood vessels become weak, and the vessel bursts causing bleeding in the brain

risk factors for stroke

old age, biological gender (males), genetics, smoking, blood pressure, poor diet, level of exercise

stroke symptoms

numbness or weakness in the face, arm or leg, especially on one side of the body, speech disturbance such as slurring, trouble walking dizziness, nausea, headache

stroke effects

any area that loses brain cells will lose its function, motor areas can lead to partial paralysis, sensory areas damaged can lead to a loss the ability to hear, see smell etc, memory areas affected could lead to a temporary or permanent loss of memory (amnesia)

epilepsy

a neurological disorder that involves recurrant, spntaneous seizures brought on by interference with typical brain activity

seizure

a surge of excessive electrical activity which activates too many neurons in the brain at the same time, leading to involuntary changes in movements, behaviour, awareness and mood.

what can seizures be triggered by?

environmental changes like flashing lights or stressful situations

chronic traumatic encephalopathy (CTE)

a progressive brain degeneration and fatal conditon brought about by repeated concussions

symptoms of CTE

loss of memory, mood swings, personality change, confusion

amnesia

a deficit in memory caused by brain damage, disease, or psychological trauma

retroactive (retrogade) amnesia

a loss of memory access to events that have occured, lost memories are likely to be closer in time to the incident that caused the amnesia

proactive (anterograde) amnesia

a loss of the ability to create new memories, leading to an inability to recall the recent past, while older, preserved memories remain intact.

dementia symptoms

memory loss, personality changes, behaviour changes, decline in cognive function such as reasoning

alzheimers disease (type of dementia)

most common type of dementia. explicit memories are affected first.