Plasticity Flashcards
(38 cards)
What is neural plasticity?
The brains ability to structurally and functionally adapt to recognise neural circuits
What is habituation?
a process that causes an organism to become less responsive to repeated exposure to a stimulus as it recognises that it is not dangerous
What is sensitisation?
a process that allows an animal to generalise an overside response elicited by a noxious stimulus to a variety of other, non-noxious stimulus
What is reactivation?
wiping out the response to ignore the stimulus
What causes sensitisation?
changes in synaptic efficacy at the sensory-motor synapse
Where does the response occur during habituation?
in the motor-neuron disease
What does sensitisation do?
re-establishes that activity in the motor neuron to pre-habituated levels
How long does sensitisation last?
about an hour
Activation of what enhances release of transmitters from the sensory neuron onto the motor neurons?
serotonergic modulatory interneurons
What does the increase in release of transmitters from the sensory neuron to the motor neuron do?
increases the activity in the motor neuro synapse and causing the motor neurons to contract
What are the two major ascending pathways that carry sensory information to the brain?
-dorsal column-medial lemniscus pathway
-spinothalamic pathway
What does the dorsal column-medial lemniscus pathway localise sensations from?
-fine touch
-vibration
-two-point discrimination
-proprioception form the skin and joints
What does the spinothalamic pathway localise sensations from?
-crude touch
-pain
-temperature
Where do the pathways carrying sensory information to the brain synapse?
in the ventricle thalamic nucleus
Where do the pathways carrying sensory information to the brain project to?
the primary sensory cortex
Where is S1?
on the post-central gyrus
How is somatosensory mapping done?
recording of the brain while stimulating the periphery
What parts of the body have larger representations in the brain?
most sensitive parts - hands and feet
Are the representations plastic?
Representations can be re-mapped
e.g.. amputations of finger, these representations formerly will now represent other parts of the body such as the other digits
What happens to the representations if the body part is used frequently?
increase in size
How does 2DG mapping work?
2DG is taken up by the glucose transported
if labelled with a radioactive isotope, it can be imaged
What plasticity occurs in individuals that are congenitally blind?
cortical areas usually used for visual processing are activated during other tasks such as hearing and reading
To what extent does plasticity occur in blind individuals?
Dependent on how long the individual has been blind for
In blind individuals, following plasticity, what do the visual areas that are now not being used contribute to?
-braille reading and tactile discrimination
-auditory localisation and discrimination
-verbal memory and language
