title: Connectivity constraints on cortical reorganization of neural circuits involved in object naming.
abstract: The brain's plasticity in response to sensory deprivation and other perturbations is well established. While the functional properties of the reorganized areas are under vigorous investigation, the factors that constrain cortical reorganization remain poorly understood. One factor constraining such reorganization may be long-distance subcortical connectivity between relevant cortical regions-reorganization attempts to preserve the functionality of subcortical connections. Here we provide human neurophysiological evidence for the role of the subcortical connections in shaping cortical reorganization of the networks involved in object naming following perturbation of normal function. We used direct electrical stimulation (DES) during surgical removal of gliomas to identify the sites that are involved in naming different categories of objects. The sites that were selectively inhibited in naming either living or non-living objects were displaced relative to those observed with other subject populations, possibly reflecting cortical reorganization due to slowly evolving brain damage. Subcortical DES applied to the white matter underlying these regions also led to category-specific naming deficits. The existence of these subcortical fiber pathways was confirmed using diffusion tensor tractography. These results constitute the first neurophysiological evidence for the critical role of subcortical pathways as part of the neural circuits that are involved in object naming; they also highlight the importance of subcortical connectivity in shaping cortical reorganization following perturbations of normal function.
authors.affiliation: Dipartimento di Psicologia, Università di Milano Bicocca, Piazza dell'Ateneo Nuovo 1, Edificio U6, 20126 Milano, Italy. costanza.papagno@unimib.it
authors.forename: Costanza
authors.initials: C
authors.lastname: Papagno
authors.forename: Marcello
authors.initials: M
authors.lastname: Gallucci
authors.forename: Alessandra
authors.initials: A
authors.lastname: Casarotti
authors.forename: Antonella
authors.initials: A
authors.lastname: Castellano
authors.forename: Andrea
authors.initials: A
authors.lastname: Falini
authors.forename: Enrica
authors.initials: E
authors.lastname: Fava
authors.forename: Carlo
authors.initials: C
authors.lastname: Giussani
authors.forename: Giorgio
authors.initials: G
authors.lastname: Carrabba
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Bello
authors.forename: Alfonso
authors.initials: A
authors.lastname: Caramazza
mesh_terms: D001931:Brain Mapping / Q000379:methods; D001932:Brain Neoplasms / Q000601:surgery; D002540:Cerebral Cortex / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D056324:Diffusion Tensor Imaging; D004558:Electric Stimulation; D005260:Female; D005556:Form Perception / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D005910:Glioma / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008297:Male; D057567:Memory, Long-Term / Q000502:physiology; D008570:Memory, Short-Term / Q000502:physiology; D009275:Names; D009415:Nerve Net / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology*; D009483:Neuropsychological Tests; D019635:Neurosurgical Procedures; D011184:Postoperative Period; D011578:Psycholinguistics; D021641:Recognition, Psychology / Q000502:physiology; D012640:Seizures / Q000209:etiology / Q000503:physiopathology