Most fundamental cognitive processes rely on brain networks that include both cortical
and subcortical structures. Studying such networks using functional magnetic resonance
imaging (fMRI) requires a data acquisition protocol that provides blood-oxygenation-level
dependent (BOLD) sensitivity across the entire brain. However, when using standard
single echo, echo planar imaging protocols, researchers face a tradeoff between BOLD-sensitivity
in cortex and in subcortical areas. Multi echo protocols avoid this tradeoff and can
be used to optimize BOLDsensitivity across the entire brain, at the cost of an increased
repetition time. Here, we empirically compare the BOLD-sensitivity of a single echo
protocol to a multi echo protocol. Both protocols were designed to meet the specific
requirements for studying small, iron rich subcortical structures (including a relatively
high spatial resolution and short echo times), while retaining coverage and BOLD-sensitivity
in cortical areas. The results indicate that both sequences lead to similar BOLD-sensitivity
across the brain at 7 T.
