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Poster B38, Thursday, August 16, 3:05 – 4:50 pm, Room 2000AB

Oscillatory dynamics during lexico-semantic retrieval: Evidence for neuroplasticity of language in patients with left-hemisphere temporal tumors

Shuang Geng1, Lucia Amoruso1, Polina Timofeeva1, Santiago Gil Robles2, Íñigo Pomposo2, Nicola Molinaro1,3, Manuel Carreiras1,3;1BCBL,Basque Center on Cognition, Brain and Language, San Sebastian, Spain, 2Neurosurgery Cruces University Hospital. BioCruces, Bilbao, Spain, 3Ikerbasque, Basque Foundation for Science, Bilbao Spain

M/EEG studies investigating the oscillatory dynamics subserving language production suggest that word retrieval might be functionally related to power changes in low-frequency bands (theta and alpha). However, little is known about how oscillatory activity within this frequency range is modulated in patients with tumors in the temporal lobe, a brain region typically associated to semantic processing. We recorded magnetoencephalographic (MEG) signals from 5 patients with tumors in their left temporal lobe while they performed a picture-naming task before and 3 months after surgery. The basic idea behind this task is that the picture represents the concept to be expressed and thus, naming the picture, requires access to lexical memory. We performed time–frequency analysis to examine how power varied during word retrieval before and after surgery. In line with previous studies, we found modulations in the theta-alpha frequency range during lexico-semantic retrieval. More specifically, we found left-lateralized post vs. pre significant differences in these frequency bands in the time window were previous effects on lexical access have been reported (from ~200ms after picture onset up to ~500ms). Overall, these results suggest that theta-alpha frequencies are involved in lexical-semantic retrieval and that the presence of tumors in temporal areas induce plastic functional changes in the neural oscillatory dynamics associated to word retrieval.

Topic Area: Language Disorders