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Abnormalities of P300 cortical current density in unmedicated depressed patients revealed by LORETA analysis of event‐related potentials
Author(s) -
KAWASAKI TOSHIHIKO,
TANAKA SHIN,
WANG JIJUN,
HOKAMA HIROTO,
HIRAMATSU KENICHI
Publication year - 2004
Publication title -
psychiatry and clinical neurosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.609
H-Index - 74
eISSN - 1440-1819
pISSN - 1323-1316
DOI - 10.1111/j.1440-1819.2004.01195.x
Subject(s) - n100 , psychology , event related potential , audiology , lateralization of brain function , oddball paradigm , neuroscience , electroencephalography , right hemisphere , electrophysiology , medicine
The purpose of the present study was to investigate the neural substrates underlying event‐related potential (ERP) abnormalities, with respect to the generators of the ERP components in depressed patients. Using an oddball paradigm, ERP from auditory stimuli were recorded from 22 unmedicated patients with current depressive episodes and compared with those from 22 age‐ and gender‐matched normal controls. Cortical current densities of the N100 and P300 components were analyzed using low‐resolution electromagnetic tomography (LORETA). Group differences in cortical current density were mapped on a 3‐D cortex model. The results revealed that N100 cortical current densities did not differ between the two groups, while P300 cortical current densities were significantly lower in depressed patients over the bilateral temporal lobes, the left frontal region, and the right temporal–parietal area. Furthermore, the cortical area in which the group difference in P300 current density had been identified was remarkably larger over the right than the left hemisphere, thus supporting the hypothesis of right hemisphere dysfunction in depression.