Open AccessLow‐resolution electrical tomography of the brain during psychometrically matched verbal and spatial cognitive tasks
Author(s) -
Koles Zoltan J.,
FlorHenry Pierre,
Lind John C.
Publication year - 2001
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 - 10.1002/1097-0193(200103)12:3<144::aid-hbm1011>3.0.co;2-3
Subject(s) - electroencephalography , psychology , cognition , audiology , set (abstract data type) , artifact (error) , elementary cognitive task , alpha (finance) , pattern recognition (psychology) , neuroscience , cognitive psychology , developmental psychology , computer science , psychometrics , medicine , construct validity , programming language
EEGs were recorded from 75 normal, young, female subjects during psychometrically matched verbal (WF) and spatial (DL) cognitive tasks to elicit the differences in the electrical source distribution inside the brain. Recordings were obtained using 43 EEG and 3 guard electrodes then visually edited and spatially filtered to remove extracerebral artifacts. Twenty 1‐sec artifact‐free epochs were obtained and analyzed from 42 and 60 subjects during WF and DL respectively. Of these subjects, 20 were placed in a training set and the remainder into a test set. The baseline for the comparison of the two tasks was established by factoring the average cross‐spectral matrices of the training‐set EEGs, computed in the theta, alpha, and beta frequency bands into spatial patterns common to the two tasks. Only those spatial patterns that contributed to the correct classification of subjects in the test set were included in the source analysis. The source‐current density distributions were obtained using the LORETA‐KEY© algorithm. The results show that the source‐current density distribution is related to the putative functional activity in the brain in all three frequency bands. The electrical effects of the tasks are both most highly localized and lateralized in the theta band. The effects in the alpha and beta bands are much more generalized and are strongly lateralized only during one and the other of the tasks respectively. The conclusion is that WF is mainly a left central and bilateral frontal cerebral process while DL is mainly a right central and bilateral posterior cerebral process. Hum. Brain Mapping 12:144–156, 2001. © 2001 Wiley‐Liss, Inc.