Abstract Details

Title Lesions to Dorsal Stream Modulate Responses to Language Repetition in Speech-motor Cortex

Topic Aging, Dementia, and Behavioral Neurology

Presentation(s) S18 - Behavioral Neurology and Neuropsychiatry (4:30 PM-4:42 PM)

Poster/Presentation
Number 006

Background According to the dual stream model of language, the ventral stream is involved with mapping sound to meaning. The dorsal stream is specialized for mapping sound onto articulatory-based representations (ie phonological processing). Literature in behavioral neuropsychology, aphasia, and neurosurgical stimulation provide evidence that phonological working memory and language repetition is supported by the dorsal stream. However, connectivity-level evidence for this claim is lacking.

Objective The goal of this project is to elucidate the areas of the brain involved in phonological working memory using Voxel-Based Lesion Activity Mapping (VLAM).

Design/Methods We investigated the regions of the brain involved in phonological working using a technique called Voxel-based Lesion Activity Mapping (VLAM). In VLAM, the presence or absence of a lesion at each voxel of the brain is related to variability in neural activity in a reference region. 55 participants with brain tumor performed sentence and word repetition tasks. By examining the lesion sites which lead to reduced activity in speech-motor cortex, during repetition tasks, we were able to draw conclusions about the regions of the brain involved in phonological working memory.

Results Voxels associated with statistically significant decreases in BOLD activity in speech-motor cortex during sentence repetition are strongly concentrated in supramarginal gyrus, angular gyrus, and posterior STG/STS. A similar but smaller cluster of significant voxels was observed in the VLAM analysis for word repetition. Lastly, we found that the supra-sylvian component of the dorsal stream is modulated by task complexity whereas the infra-sylvian component of the dorsal stream is not modulated by task complexity.

Conclusions This is the first investigation demonstrating modulation of activity in speech-motor cortex during repetition task as a function of damage to upstream language network sites. This VLAM study provides sensitive and specific evidence that lesions to structures in the dorsal stream modulate responses to repetition in speech-motor cortex.

Authors/Disclosures
William Burns PRESENTER	Mr. Burns has nothing to disclose.
Frank Garcea	No disclosure on file