fMRI BOLD: Overview

capillary

bed

venules

arterioles

basal state

capillary

bed

venules

arterioles

stimulated state

- normal flow

- basal level [Hbr]

- basal CBV

- field gradients around

vessels resulting from Hbr

- normal signal

- increased flow

- decreased [Hbr]

- increased CBV

- lower field gradients around

vessels due to lower [Hbr]

- increased signal

= HbO2

= Hbr

Previous slide

Next slide

Back to first slide

View graphic version