Objective To localize the language cortex associated with Chinese word processing by magnetic source imaging (MSI) Methods Eight right handed and one left handed healthy native Chinese subjects were examined by ...Objective To localize the language cortex associated with Chinese word processing by magnetic source imaging (MSI) Methods Eight right handed and one left handed healthy native Chinese subjects were examined by magnetoencephalography (MEG) and a 1 5T magnetic resonance imaging (MRI) unit All subjects were given pure tone stimuli 50 times, 150 pairs of Chinese words (meaning related or unrelated) auditory stimuli, and pure tone stimuli subsequently 50 times Evoked response fields time locked to the pure tone and Chinese words were recorded using a whole head neuromagnetometer in real time The acquired data were averaged by the acquisition computer according to the response to the pure tone, related pairs of words and unrelated pairs of words The data obtained by MEG were superimposed on MRI, using a GE Signa 1 5T system Results MEG, showed there were two obviously higher magnetic waves named M50 and M100, which were localized in the bilateral transverse temporal gyri in all subjects The responses to the pairs of Chinese words (meaning related or unrelated) were similar in the same hemisphere of the same subjects There was a higher peak during 300-600 ms in the right hemisphere of one left handed subject, but no peak in the left hemisphere, indicating that the language dominant hemisphere was localized in the right hemisphere Superimposing the MEG data on MRI, the language area was localized in the Wernicke's areas A 300-600 ms response peak was obsarved in each hemisphere (the amplitude of the 300-600 ms response peak in each hemisphere was almost the same) in two right handed subjects, showing that the language area was localized in the 2 hemispheres in the two subjects There was one peak in each hemisphere (300-600 ms response) in 6 subjects, but the amplitude of the wave in the left hemisphere in the 6 subjects was much higher than that in the right hemisphere By choosing randomly from the later component (300-600 ms response) several time points and superimposing them on MRI,展开更多
Aeromagnetic data over the Mamfe Basin have been processed. A regional magnetic gridded dataset was obtained from the Total Magnetic Intensity (TMI) data grid using a 3 × 3 convolution (Hanning) filter to remove ...Aeromagnetic data over the Mamfe Basin have been processed. A regional magnetic gridded dataset was obtained from the Total Magnetic Intensity (TMI) data grid using a 3 × 3 convolution (Hanning) filter to remove regional trends. Major similarities in magnetic field orientation and intensities were observed at identical locations on both the regional and TMI data grids. From the regional and TMI gridded datasets, the residual dataset was generated which represents the very shallow geological features of the basin. Processing this residual data grid using the Source Parameter Imaging (SPI) for magnetic depth suggests that the estimated depths to magnetic sources in the basin range from about 271 m to 3552 m. The highest depths are located in two main locations somewhere around the central portion of the study area which correspond to the area with positive magnetic susceptibilities, as well as the areas extending outwards across the eastern boundary of the study area. Shallow magnetic depths are prominent towards the NW portion of the basin and also correspond to areas of negative magnetic susceptibilities. The basin generally exhibits a variation in depth of magnetic sources with high, average and shallow depths. The presence of intrusive igneous rocks was also observed in this basin. This characteristic is a pointer to the existence of geologic resources of interest for exploration in the basin.展开更多
文摘Objective To localize the language cortex associated with Chinese word processing by magnetic source imaging (MSI) Methods Eight right handed and one left handed healthy native Chinese subjects were examined by magnetoencephalography (MEG) and a 1 5T magnetic resonance imaging (MRI) unit All subjects were given pure tone stimuli 50 times, 150 pairs of Chinese words (meaning related or unrelated) auditory stimuli, and pure tone stimuli subsequently 50 times Evoked response fields time locked to the pure tone and Chinese words were recorded using a whole head neuromagnetometer in real time The acquired data were averaged by the acquisition computer according to the response to the pure tone, related pairs of words and unrelated pairs of words The data obtained by MEG were superimposed on MRI, using a GE Signa 1 5T system Results MEG, showed there were two obviously higher magnetic waves named M50 and M100, which were localized in the bilateral transverse temporal gyri in all subjects The responses to the pairs of Chinese words (meaning related or unrelated) were similar in the same hemisphere of the same subjects There was a higher peak during 300-600 ms in the right hemisphere of one left handed subject, but no peak in the left hemisphere, indicating that the language dominant hemisphere was localized in the right hemisphere Superimposing the MEG data on MRI, the language area was localized in the Wernicke's areas A 300-600 ms response peak was obsarved in each hemisphere (the amplitude of the 300-600 ms response peak in each hemisphere was almost the same) in two right handed subjects, showing that the language area was localized in the 2 hemispheres in the two subjects There was one peak in each hemisphere (300-600 ms response) in 6 subjects, but the amplitude of the wave in the left hemisphere in the 6 subjects was much higher than that in the right hemisphere By choosing randomly from the later component (300-600 ms response) several time points and superimposing them on MRI,
文摘Aeromagnetic data over the Mamfe Basin have been processed. A regional magnetic gridded dataset was obtained from the Total Magnetic Intensity (TMI) data grid using a 3 × 3 convolution (Hanning) filter to remove regional trends. Major similarities in magnetic field orientation and intensities were observed at identical locations on both the regional and TMI data grids. From the regional and TMI gridded datasets, the residual dataset was generated which represents the very shallow geological features of the basin. Processing this residual data grid using the Source Parameter Imaging (SPI) for magnetic depth suggests that the estimated depths to magnetic sources in the basin range from about 271 m to 3552 m. The highest depths are located in two main locations somewhere around the central portion of the study area which correspond to the area with positive magnetic susceptibilities, as well as the areas extending outwards across the eastern boundary of the study area. Shallow magnetic depths are prominent towards the NW portion of the basin and also correspond to areas of negative magnetic susceptibilities. The basin generally exhibits a variation in depth of magnetic sources with high, average and shallow depths. The presence of intrusive igneous rocks was also observed in this basin. This characteristic is a pointer to the existence of geologic resources of interest for exploration in the basin.
