TITLE:
Localizing the Language Network with fMRI and Functional Connectivity: Implications for Pre-Surgical Planning
AUTHORS:
Victoria Lyn Ives-Deliperi, James Thomas Butler
KEYWORDS:
Brain Mapping, fMRI, Functional Connectivity, Language, Pre-Surgical Planning
JOURNAL NAME:
Open Journal of Modern Neurosurgery,
Vol.8 No.2,
April
11,
2018
ABSTRACT:
Object: Functional
MRI is frequently applied to lateralize language
in pre-surgical planning, with potential to localize
functionally important cortex too. Here we present BOLD signal activation
maps and related functional connectivity, in response to three commonly administered
fMRI language tasks. Methods: Datasets from 55 pre-surgical fMRI studies
were analyzed. Verbal response naming, covert word generation and passive listening
tasks were administered in all studies. Single-subject analyses, group analyses
and region-of-interest analyses were conducted, and a multi-subject functional connectivity
analysis was performed. Results: Single-subject analyses revealed that clinically important language regions were activated
in all but three patients using the panel of tasks. Group analyses revealed significant bilateral BOLD signal increases in anterior
and posterior language regions in response
to verbal response naming and bilateral signal increase in posterior language regions
only in response to passive listening. Covert word generation activated anterior language regions bilaterally and posterior language cortex in the dominant hemisphere. Functional connectivity analyses confirmed that activated regions were significantly correlated in all tasks. Conclusion:
The findings of single-subject and group analyses add to the evidence supporting
the use of a panel of fMRI tasks to map the language network for pre-surgical planning. Our findings
support the additional use of functional connectivity analysis in routine language
mapping to add to the localization value to fMRI. In addition,
the results of our investigation demonstrate these
three commonly applied tasks reliably activate unique aspects of the language network,
which advocates closer individual inspection, guided by the
surgical intervention planned.