Source localization of sensory gating: a combined EEG and fMRI study in healthy volunteers

TY - JOUR

T1 - Source localization of sensory gating: a combined EEG and fMRI study in healthy volunteers

AU - Bak, Nikolaj

AU - Glenthøj, Birte Yding

AU - Rostrup, Egill

AU - Larsson, Henrik B

AU - Oranje, Bob

N1 - Copyright © 2010 Elsevier Inc. All rights reserved.

PY - 2011/2/14

Y1 - 2011/2/14

N2 - Reduced sensory gating appears to be among the core features in schizophrenia. The sources of sensory gating however are largely unknown. The aim of the current study was to identify these sources, with concurrent EEG and fMRI methodology. Twenty healthy male volunteers were tested with identical P50 suppression paradigms in two separate sessions: an EEG setting, and an EEG concurrent with fMRI setting. The stimuli in the P50 paradigm consisted of weak electrical stimulation of the left median nerve. The stimuli were presented in pairs with either 500 ms or 1000 ms interstimulus intervals (ISI). No difference was found between the EEG setting and the concurrent EEG and fMRI setting. P50 suppression was, in both settings, found only in the 500 ms trials, not in the 1000 ms trials. EEG-dipole modeling resulted in 4 sources located in the medial frontal gyrus, the insula, the hippocampus, and primary somatosensory cortex. These sources corresponded to significant fMRI clusters located in the medial frontal gyrus, the insula, the claustrum, and the hippocampus. Activity in the hippocampus and the claustrum was higher in the trials with suppression, suggesting that these brain areas are involved in the inhibitory processes of P50 suppression. The opposite was found for activity in the medial frontal gyrus and the insula, suggesting that these brain areas are involved in the generation of the P50 amplitude. To our knowledge, this is the first study demonstrating that P50 suppression can be reliably assessed inside an MRI scanner.

AB - Reduced sensory gating appears to be among the core features in schizophrenia. The sources of sensory gating however are largely unknown. The aim of the current study was to identify these sources, with concurrent EEG and fMRI methodology. Twenty healthy male volunteers were tested with identical P50 suppression paradigms in two separate sessions: an EEG setting, and an EEG concurrent with fMRI setting. The stimuli in the P50 paradigm consisted of weak electrical stimulation of the left median nerve. The stimuli were presented in pairs with either 500 ms or 1000 ms interstimulus intervals (ISI). No difference was found between the EEG setting and the concurrent EEG and fMRI setting. P50 suppression was, in both settings, found only in the 500 ms trials, not in the 1000 ms trials. EEG-dipole modeling resulted in 4 sources located in the medial frontal gyrus, the insula, the hippocampus, and primary somatosensory cortex. These sources corresponded to significant fMRI clusters located in the medial frontal gyrus, the insula, the claustrum, and the hippocampus. Activity in the hippocampus and the claustrum was higher in the trials with suppression, suggesting that these brain areas are involved in the inhibitory processes of P50 suppression. The opposite was found for activity in the medial frontal gyrus and the insula, suggesting that these brain areas are involved in the generation of the P50 amplitude. To our knowledge, this is the first study demonstrating that P50 suppression can be reliably assessed inside an MRI scanner.

U2 - 10.1016/j.neuroimage.2010.11.039

DO - 10.1016/j.neuroimage.2010.11.039

M3 - Journal article

C2 - 21109008

SN - 1053-8119

VL - 54

SP - 2711

EP - 2718

JO - NeuroImage

JF - NeuroImage

IS - 4

ER -