ABSTRACT
Objective:To observe the activation of cerebral regions during swallowing by magnetoencephalography (MEG), and discuss the temporal and spatial characteristics of neural circuit.Methods:Ten healthy subjects were selected, and the magnetic signals of their brains were recorded using 148 channel full head type MEG system in the magnetic shielding room.Data were analyzed using CURRY8 analysis software and the localization algorithm was based on minimum modulus low resolution electromagnetic imaging method (LORETA). Every 300 ms data were set as an independent analysis stage and made the highest position of the cerebral cortex F-distribution values (F-distributed) as the activation area.The activation areas were analyzed during swallowing through time and space location.Results:Paracentral lobule, anterior central gyrus, medulla oblata, posterior central gyrus, inferior frontal gyrus, parietal lobules, angular gyrus, corpus callosum, middle frontal gyrus, cingulate gyrus, orbital gyrus, thalamus, bottom of third ventricle, corona radiata, precuneus, frontal insula, cerebellopontine angle, superior frontal gyrus and basal ganglia area were activated during swallowing, in which the top eight brain regions were paracentral lobule, anterior central gyrus, corpus callosum, posterior central gyrus, superior parietal lobule, middle frontal gyrus, cingulate gyrus, and basal ganglia.When the 10 subjects performed the deglutition, MEG signals of 8 subjects were mainly activated by the left cerebral hemisphere at 0-300 ms, the bilateral cerebral hemisphere or intermediate region at 301-600 ms, and the right cerebral hemisphere at 601-900 ms.MEG signal of 1 subject was activated by the right cerebral hemisphere at 0-300 ms, and the left cerebral hemisphere at 301-600 ms and 601-900 ms.MEG signal of 1 subject was mainly activated by the right cerebral hemisphere at 0-300 ms and 601-900 ms, and in the intermediate region at 301-600 ms.Conclusion:During swallowing the MEG signals appeared left laterality in the early stage and right laterality in the later stage, and showed a close correlation with time.There may be a swallowing neural circuit composed by the central region, corpus callosum, superior parietal lobule, middle frontal gyrus, cingulate gyrus and basal ganglia, in which the central region is the core.
ABSTRACT
@#Objective To investigate the value of synthetic aperture magnetometry (SAM) in localizing motor cortex and epileptogenic focus for brain lesions near the central sulcus and to clear its advantage in the localization. Methods 12 patients (6 patients with epilepsy) were enrolled in this study. Before the operation, the patients were all taken Karnofsky Performance Status Score (KPS), examined with MEG by SAM technique in the localization of motor cortex and epileptogenic focus to determine their position relationship, and guide the scheme of surgery programme. During the operation, the location of hand-motor functional area were identified with evoked potential monitoring awaking test, and epileptogenic focus with electrocorticogram (ECoG) monitoring. The accuracy of location was assessed with the hand movement and KPS score, and the epileptic attack were evaluated with Engel curative effect grading. They were followed up for 2 years. Results The motor cortex of all the patients were located near the precentral gyrus with SAM and the localization of epileptogenic focus in 6 patients by SAM was consistent with that by ECoG. All the operations were based on and guided by the SAM. After the operations, the motor function and KPS score of 8 patients improved. No extra functional lesions happened in all patients. Epilepsy was well controlled in 5 cases. Conclusion SAM can correctly localize the motor cortex and epileptogenic focus. Meanwhile position relationship between the intracranial lesions and motor functional areas and epileptic focus can be clear. It is a valuable method for surgical planning and epilepsy controlling and will decrease the occurrence of neurological deficits after operation.