Plasticity

What is neuroplasticity?

The brain’s ability to reorganize itself by forming new neural connections throughout life.

What is the most prominent form of neuroplasticity in adults?

Neurogenesis – the formation of new neurons.

Which brain regions are involved in adult neurogenesis?

Dentate Gyrus (Hippocampus)

What types of cells are involved in dentate gyrus neurogenesis?

Type 1 cells (radial astrocytes)

How many new neurons are generated daily per hippocampus in humans?

About 700 new neurons.

What is the annual turnover rate of hippocampal neurons?

Approximately 1.75%.

What are the key cell types in subventricular zone neurogenesis?

Ependymal cells

Where do new neurons migrate in rodents and humans?

Rodents: olfactory bulb; Humans: likely to the striatum.

How does exercise affect neuroplasticity?

Increases neurogenesis and BDNF production.

What does BDNF stand for and what is its function?

Brain-Derived Neurotrophic Factor; promotes neuron and synapse growth and resilience.

What are the effects of dietary restriction on the brain?

Increases BDNF

What dietary patterns are beneficial for brain plasticity?

Low-fat

Give an example of learning-induced plasticity in humans.

Learning to juggle increases grey matter in visual motion areas.

What are the two main types of stroke?

Ischemic (blocked vessels) and Hemorrhagic (ruptured vessels).

What causes excitotoxicity in stroke?

Overactivity of nutrient-deprived cells due to excess glutamate.

What happens during excitotoxicity?

ATP depletion

What causes cytotoxic edema?

Ion buildup draws water into cells

What are the types of cell death?

Necrosis (rupture) and apoptosis (programmed death).

What roles do thrombin and iron play in hemorrhagic stroke?

Thrombin increases NMDA sensitivity and inflammation; iron causes oxidative damage.

What are coup and contrecoup injuries?

Coup: damage at impact site; Contrecoup: damage opposite the impact site.

What are primary and secondary effects of TBI?

Primary: hematoma

What are symptoms of concussion?

Headache

What is the penumbra?

Region around necrotic tissue with viable but impaired neurons.

What molecular changes support recovery post-stroke?

Increased BDNF and NMDA activity

What is diaschisis?

Reduced activity or connectivity in areas distant from the injury.

Where does neurogenesis occur after injury?

Subventricular zone

What drug is FDA-approved for ischemic stroke?

tPA (Tissue Plasminogen Activator) within 3–4.5 hours post-stroke.

How does an enriched environment aid recovery?

Increases dendritic branching and motor function.

What is the goal of stem cell therapy?

To enhance brain repair via new cell growth.

What is the purpose of tDCS and rTMS?

tDCS stimulates lesioned areas; rTMS reduces inhibition from the opposite hemisphere.