Open AccessTiming and connectivity in the human somatosensory cortex from single trial mass electrical activity
Author(s) -
Ioannides Andreas A.,
Kostopoulos George K.,
Laskaris Nikolaos A.,
Liu Lichan,
Shibata Tadahiko,
Schellens Marc,
Poghosyan Vahe,
Khurshudyan Ara
Publication year - 2002
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.10023
Subject(s) - somatosensory system , magnetoencephalography , neuroscience , habituation , psychology , set (abstract data type) , homogeneous , brain activity and meditation , brain mapping , cortex (anatomy) , connectome , insula , electroencephalography , computer science , functional connectivity , physics , thermodynamics , programming language
Abstract Parallel‐distributed processing is ubiquitous in the brain but often ignored by experimental designs and methods of analysis, which presuppose sequential and stereotypical brain activations. We introduce here a methodology that can effectively deal with sequential and distributed activity. Regional brain activations elicited by electrical median nerve stimulation are identified in tomographic estimates extracted from single trial magnetoencephalographic signals. Habituation is identified in both primary somatosensory cortex (SI) and secondary somatosensory cortex (SII), often interrupted by resurgence of strong activations. Pattern analysis is used to identify single trials with homogeneous regional brain activations. Common activity patterns with well‐defined connectivity are identified within each homogeneous group of single trials across the subjects studied. On the contralateral side one encounters distinct sets of single trials following identical stimuli. We observe in one set of trials sequential activation from SI to SII and insula with onset of SII at 60 msec, whereas in the other set simultaneous early co‐activations of the same two areas. Hum. Brain Mapping 15:231–246, 2002. © 2002 Wiley‐Liss, Inc.