Why Cerebral Blood Flow?

CBF is required for cognition!

• Neurons are high maintenance!
  • Brain consumes as much as 30% of all metabolic resources
• Does not store any energy.
• Tight control is necessary to feed the brain.
  • The neurovascular unit

How it's studied

• To understand how neuronal activity is associated with NVC we have to measure both actual activity and vascular changes.
• Can't do that in humans!

The Neurovascular Unit

• Refers to the the neurons, astrocytes, pericytes, smooth muscle cells, and endothelial cells that control blood flow through a specific vascular bed.

Neurovascular Coupling

A more detailed view...

What makes CBF potentially unreliable?

Consider the pathway

• Deep nuclei.
• Vasoactives can be released by different pathways.
  • E.g. NA, ACh, NPY

Consider Brain State

• Alert versus impaired
• Cholinergic Activation?
• Disease vs. Healthy
  • Alzheimers Disease
  • VCID (vascular cognitive impairment and dementia)
  • Stroke

So how reliable is it?

Have all fMRI studies been invalidated?

fMRI is quite reliable

• Bullet One
• Bullet Two
• Bullet Three

Reliability

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Proin urna odio, aliquam vulputate faucibus id, elementum lobortis felis. Mauris urna dolor, placerat ac sagittis quis.

Validity

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Proin urna odio, aliquam vulputate faucibus id, elementum lobortis felis. Mauris urna dolor, placerat ac sagittis quis.

The real questions lie in how to interpret the data