Week Ten - Neuroplasticity Flashcards
What is Neuroplasticity?
The ability of the NS to respond to stimuli by organising its structure, function and connections
- eg after brain injury
- eg disease
What is Hebbs Rule?
Neurons that wire together, fire together
Eric Kandel & the Sea Slug
First evidence of how memory formation results from molecular changes
Bliss & Lomo (1973) LTP
Formed the basis of molecular neuroplasticity that obeys Hebbian principles. Found LTP in mammalian hippocampal slices
What is LTP?
The persistent strengthening of synapses based on recent patterns of activity. Long-lasting increases in the signalling between two neurons.
Exercise and Depression relationship with Neurogenesis?
Exercise increase neurogenesis
Depression decreases neurogenesis
What is adaptive plasticity?
When associated with a gain in function
What is maladaptive plasticity?
Negative consequences such as a loss of function or increased injury.
Can occur in conjunction with adaptive changes.
Spinal Cord Injury and Brain Plasticity?
Training induced changes in brain plasticity can occur in the absence of any behavioural change. This suggests that the connection between the limb and brain isn’t working/severed. Potential treatment option would be stem cells.
Epilepsy occurring years after cerebral trauma indicates?
Progressive plastic changes in the brain leading to alterations in signalling and disinhibition in non-related areas, leading to seizures.
How can we see maladaptive plasticity?
Show that it is related to a change in function/behaviour
- greatest plasticity = greatest movement problem.
Treatment during Acute phase
Treatment in the acute phase may be beneficial when done at the site of injury
Treatment during Chronic phase?
Chronic pain may occur, central changes in the joint and have maladaptive change to the CNS
How to reverse abnormal changes to CNS?
Treat the injury (bottom up) - however its weak
Target the brain (top down) - addresses the pain sensitisation
Maladaptive plasticity is seen to occur in response to treatment of what type of disorders?
Neuropsychiatric. Following from antipsychotic drugs eg tardive dyskinesia
Addiction and Maladaptive Plasticity?
Maladaptive plasticity can occur in the subcortical reward circuit. Prefrontal regulation of limbic circuits are significantly reduced eg loss of modulation. This leads to drug seeking being under the control of brain regions with little control imposed by neo-cortex. Very resistant to reversal
What is Neurodegeneration?
A progressive decline in behaviour and neural function often through a pathogenic process and maladaptive cycle.
Compensatory mechanisms may fail and become pathogenic. eg AD
What happens when cochlear implanted are fitted to congenitally deaf children? Study
In the absence of normal stimulation, there is a sensitive period of about 3.5 years during which the auditory system remains maximally plasticity. Remains in some but not all children until age 7. After 7, plasticity is greatly reduced.
Helps decide when to place a cochlear implant.
What is Metaplasticity?
The modification of plasticity induction by the previous activity of the same postsynaptic neuronal network
A lasting after-effect of an initial bout of neural activity which changes the state of the participating neurons such that the ability to induce synaptic plasticity in those neurons at a later time is altered.
Chronic Pain and addressing approaches?
Chronic pain causes changes to the structure of the brain as well as causing reductions in cognitive ability
- Target the injury
- this only addresses the nociceptive signals from the peripheral receptors
- very weak relationship between the extent of musculoskeletal damage and the extent of pain - Target pain centrally
- address the pain sensitisation
