Sample entropy can be used to assess BOLD signal complexity and predictability in resting-state and task fMRI. Task-relevant brain regions tend to display significantly lower entropy than less relevant regions. This trend appears most distinctly in tasks that involve cortical structures, such as a motor task involving the motor cortex, as opposed to tasks that involve subcortical nuclei, such as an emotion task involving the amygdala. Additionally, there is a strong negative correlation between BOLD signal amplitude and entropy that appears only in task-based fMRI, indicating that BOLD signal, as recruited by a task, becomes more predictable as amplitude increases.
How to access this content:
For one year after publication, abstracts and videos are only open to registrants of this annual meeting. Registrants should use their existing login information. Non-registrant access can be purchased via the ISMRM E-Library.
After one year, current ISMRM & ISMRT members get free access to both the abstracts and videos. Non-members and non-registrants must purchase access via the ISMRM E-Library.
After two years, the meeting proceedings (abstracts) are opened to the public and require no login information. Videos remain behind password for access by members, registrants and E-Library customers.
Keywords