Page 65 - MEGIN Book Of Abstracts - 2023

ized in the (peri)tumor region only, or decreases with Oscillatory and structural signatures of language
distance from the tumor. Materials and Methods: plasticity in brain tumor patients: A longitudinal
Weighted global and local brain network clustering study (2021)
was determined in 71 glioma patients and 53 controls
by using magnetoencephalography. Tumor cluster- Amoruso, Lucia; Geng, Shuang; Molinaro, Nicola;
ing was determined by averaging local clustering of Timofeeva, Polina; Gisbert-Muñoz, Sandra; Gil-Robles,
regions overlapping with the tumor, and vice versa for Santiago; Pomposo, Iñigo; Quiñones, Ileana; Carreiras,
non-tumor regions. Euclidean distance was determined Manuel
from the tumor centroid to the centroids of other
regions. Results: Patients showed higher global cluster- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain;
ing compared with controls. Clustering of tumor and University of the Basque Country, UPV/EHU, Bilbao, Spain;
non-tumor regions did not differ, and local clustering BioCruces Research Institute, Bilbao, Spain; Basque Center on
was not associated with distance from the tumor. Post Cognition, Brain and Language (BCBL), San Sebastian, Spain
hoc analyses revealed that in the patient group, tumors
were located more often in regions with higher cluster- ABSTRACT Recent evidence suggests that damage to
ing in controls, but it seemed that tumors of patients the language network triggers its functional reorga-
with high global clustering were located more often in nization. Yet, the spectro-temporal fingerprints of this
regions with lower clustering in controls. Conclusions: plastic rearrangement and its relation to anatomical
Glioma patients show non-local network disturbances. changes is less well understood. Here, we combined
Tumors of patients with high global clustering may magnetoencephalographic recordings with a proxy
have a preferred localization, namely regions with measure of white matter to investigate oscillatory
lower clustering in controls, suggesting that tumor activity supporting language plasticity and its relation
localization relates to the extent of network disruption. to structural reshaping. First, cortical dynamics were
Impact statement This work uses the innovative frame- acquired in a group of healthy controls during object
work of network neuroscience to investigate functional and action naming. Results showed segregated beta
connectivity patterns associated with brain tumors. (13-28 Hz) power decreases in left ventral and dorsal
Glioma (primary brain tumor) patients experience pathways, in a time-window associated to lexico-
cognitive deficits and epileptic seizures, which have semantic processing (~250-500 ms). Six patients with
been related to brain network alterations. This study left tumors invading either ventral or dorsal regions
shows that glioma patients have a spatially widespread performed the same naming task before and 3 months
increase in global network clustering, which cannot after surgery for tumor resection. When longitudinally
be attributed to local effects of the tumor. Moreover, comparing patients' responses we found beta com-
tumors occur more often in brain regions with higher pensation mimicking the category-based segregation
network clustering in controls. This study emphasizes showed by controls, with ventral and dorsal damage
the global character of network alterations in glioma leading to selective compensation for object and action
patients and suggests that preferred tumor locations naming, respectively. At the structural level, all patients
are characterized by particular network profiles. showed preoperative changes in white matter tracts
possibly linked to plasticity triggered by tumor growth.
Keywords: functional connectivity, glioma, magnetoen- Furthermore, in some patients, structural changes were
cephalography, neuro-oncology, resting-state also evident after surgery and showed associations
with longitudinal changes in beta power lateralization
Brain connectivity (2021), Vol. 11, No. 10 (33947274) (4 toward the contralesional hemisphere. Overall, our
citations) findings support the existence of anatomo-functional
dependencies in language reorganization and high-
light the potential role of oscillatory markers in tracking
longitudinal plasticity in brain tumor patients. By doing

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