title: The neural organization of semantic memory: Electrophysiological activity suggests feature-based segregation.
abstract: Despite decades of research, it remains controversial whether semantic knowledge is anatomically segregated in the human brain. To address this question, we recorded event-related potentials (ERPs) while participants viewed pictures of animals and tools. Within the 200-600-ms epoch after stimulus presentation, animals (relative to tools) elicited an increased anterior negativity that, based on previous ERP studies, we interpret as associated with semantic processing of visual object attributes. In contrast, tools (relative to animals) evoked an enhanced posterior left-lateralized negativity that, according to prior research, might reflect accessing knowledge of characteristic motion and/or more general functional properties of objects. These results support the hypothesis of the neuroanatomical knowledge organization at the level of object features: the observed neurophysiological activity was modulated by the features that were most salient for object recognition. The high temporal resolution of ERPs allowed us to demonstrate that differences in processing animals and tools occurred specifically within the time-window encompassing semantic analysis.
authors.affiliation: Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA. tatiana@nmr.mgh.harvard.edu
authors.forename: Tatiana
authors.initials: T
authors.lastname: Sitnikova
authors.forename: W Caroline
authors.initials: WC
authors.lastname: West
authors.forename: Gina R
authors.initials: GR
authors.lastname: Kuperberg
authors.forename: Phillip J
authors.initials: PJ
authors.lastname: Holcomb
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D003265:Contingent Negative Variation / Q000502:physiology; D004193:Discrimination Learning / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D006801:Humans; D009415:Nerve Net / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D012660:Semantics; D014705:Verbal Behavior / Q000502:physiology; D014706:Verbal Learning / Q000502:physiology*; D014825:Vocabulary