Article

In functional magnetic resonance imaging studies, picture naming
engages widely distributed brain regions in the parietal, frontal, and temporal
cortices. However, it remains unknown whether those activated areas, along with
white matter pathways between them, are actually crucial for naming. OBJECTIVE: We aimed to identify nodes and pathways implicated in naming in healthy older
adults and test the impact of lesions to the connectome on naming ability.
METHODS: We first identified 24 cortical nodes activated by a naming task and
reconstructed anatomical connections between these nodes using probabilistic
tractography in healthy adults. We then used structural scans and fractional
anisotropy (FA) maps in 45 patients with left hemisphere stroke to assess the
relationships of node and pathway integrity to naming, phonology, and nonverbal
semantic ability. RESULTS: We found that mean FA values in 13 left hemisphere
white matter tracts within the dorsal and ventral streams and 1 interhemispheric
tract significantly related to naming scores after controlling for lesion size
and demographic factors. In contrast, lesion loads in the cortical nodes were not
related to naming performance after controlling for the same variables. Among the
identified tracts, the integrity of 4 left hemisphere ventral stream tracts
related to nonverbal semantic processing and 1 left hemisphere dorsal stream
tract related to phonological processing. CONCLUSIONS:
Our findings reveal white
matter structures vital for naming and its subprocesses.
These findings
demonstrate the value of multimodal methods that integrate functional imaging,
structural connectivity, and lesion data to understand relationships between
brain networks and behavior.

Langue : ANGLAIS