Neuroplasticity

where/when does neuroplasticity occur?

• many levels - molecular, cellular, systems, behavior

• Occurs during development, in response to the environment, in support of learning, in response to disease, or In relation to therapy

what is Neuroplasticity is driven by?

 The genetic code
 Injury
 Experience

where does neuroplasticity happen in the body?

 Occurs in the soma, in the axon, in the dendrite, and/or at the synapse
 Can be morphological and/or physiological
 Occurs throughout the lifespan

Neurogenesis

new cell development from neural stem cells

Angiogenesis

blood vessel proliferation ( stimulated by endothelial cells releasing growth factors

Neurovascular coupling

spatial and temporal association between blood flow to and activation of
neurons (functional MRI)

what is plasticity dependent on?

return of perfusion to an area (better perfusion associated with greater synaptogenesis and dendritic spine density)

Use It or Lose It

Failure to drive specific brain functions can lead to functional degradation

Use it and Improve It

Training that drives a specific brain function can lead to an enhancement of that function

Specificity

The nature of the training experience dictates the nature of the plasticity

Repetition Matters

 Induction of plasticity requires sufficient repetition
 Examples: 2500 hand movement repetitions over 5 days in healthy adults
 9600 retrievals over 4 weeks in injured animals

Intensity Matters

Induction of plasticity requires sufficient training intensity

Salience Matters

 The training experience must be sufficiently salient to induce plasticity
 The ventral tegmental area of the brainstem is rich with dopaminergic neurons that project to many areas of the brain including the limbic system and the hippocampus
 The circuitry is thought to play a large role in motivation, attention, learning, memory, reward, and addiction
 Research had demonstrated that stimulation of this circuitry via drugs, electrical stim, and activity can produce lasting plastic changes and significantly alter behavior

age matters

Training-induced plasticity occurs more readily in younger brains

Transference

Plasticity in response to one training experience can enhance the acquisition of similar behaviors

Interference

Plasticity within a given neural circuitry can impede the induction of new, or expression of existing, plasticity within the same circuitry

BDNF

• member of neurotrophin family

• neuroprotection, neurogenesis

• key mediator of motor learning and recovery

what does BDNF do

 Facilitates long-term potentiation ( a long lasting increase in the strength of connection between 2 neurons that are repeatedly activated together) and
by promoting dendritic growth and remodeling
 Animal work – blocking BDNF impairs ML
 Aerobic exercise increases BDNF in multiple CNS areas including the hippocampus, cerebellum, cerebral cortex, SC
 Levels increase for 10-60 min post exercise in humans

Mood

 Reduction in hippocampal size is often seen in major depression:
 Mild stress can enhance learning and memory
 Prolonged stress can cause retraction/atrophy of neuronal processes and neuronal loss

Progesterone after CNS injury can

 Reduce apoptosis
 Decrease inflammation
 Enhance myelination
 Improve recovery of motor function

Caloric Restriction can

 Increase neurogenesis
 Mitigate injury related decreases in synaptic plasticity
 Curcumin can enhance cell survival
 Flavanols (ginseng, gingko biloba) can promote angiogensis, enhance synaptic plasticity
 Antioxidants provide neural protection