Method for sampling cerebral insular cortex activity
Disclosed herein is a technique for observing the insular cortex activity by using electroencephalograms. A method for sampling cerebral insular cortex activity includes: recording electroencephalograms (EEGs) provided by a plurality of EEG electrodes; creating a three-dimensional model in the form of a mesh in which a subject's brain is decomposed into a plurality of sites according to the subject's brain structure and positioning the plurality of EEG electrodes by reference to an image representing the subject's brain and head structure; creating a forward model by modeling a correlation between the activities of the respective brain sites of the three-dimensional model and an electroencephalogram distribution of the positioned EEG electrodes; and associating, by reference to information about a region of interest measured by functional magnetic resonance imaging (fMRI) and the forward model, data about the electroencephalograms recorded with the cerebral activity of the region of interest.
1. A method for sampling cerebral insular cortex activity, the method comprising:
recording electroencephalograms (EEGs) provided by a plurality of EEG electrodes;
creating a three-dimensional model in the form of a mesh in which a subject's brain is decomposed into a plurality of sites according to the subject's brain structure and positioning the plurality of EEG electrodes by reference to an image representing the subject's brain and head structure;
creating a forward model by modeling a correlation between the activities of the respective brain sites of the three-dimensional model and an electroencephalogram distribution of the positioned EEG electrodes;
estimating, by reference to information about a region of interest measured by functional magnetic resonance imaging (fMRI) and the forward model, signal sources of the EEGs associated with the cerebral activity of the region of interest, the region of interest measured by fMRI being an insular cortex that starts cerebral activity when the subject is expecting a presentation of a pleasant image or an unpleasant image but without actual presentation of the pleasant image or the unpleasant image;
performing a time-frequency analysis on signals of the signal sources of the EEGs to obtain a spectrum signal, the spectrum signal being based on a first signal measured over a pleasant image expectation period and a second signal measured over an unpleasant image expectation period; and
representing the cerebral activity of the region of interest as numerical data based on the spectrum signal in an α band, wherein the numerical data includes a time-frequency difference between the first signal of the pleasant image expectation period and the second signal of the unpleasant image expectation period.
2. The method of claim 1 , wherein
recording the electroencephalograms includes decomposing the recorded electroencephalograms provided by the plurality of EEG electrodes into a plurality of independent components, removing unnecessary ones of the independent components, and back-projecting the rest of the independent components, other than the unnecessary ones, on an EEG electrode basis to generate electroencephalogram information about the EEG electrodes.
3. The method of claim 1 , wherein
the forward model is created by modeling a correlation between the activities of respective brain sites of the three-dimensional model in the form of a mesh and appearance of electroencephalograms to the respective EEG electrodes.
4. The method of claim 2 , wherein
the region of interest measured by fMRI is an insular cortex starting cerebral activity when a pleasant image is expected and when an unpleasant image is expected.
5. The method of claim 2 , wherein
the forward model is created by modeling a correlation between the activities of respective brain sites of the three-dimensional model in the form of a mesh and appearance of electroencephalograms to the respective EEG electrodes.
6. The method of claim 1 , wherein
the forward model is created by modeling a correlation between the activities of respective brain sites of the three-dimensional model in the form of a mesh and appearance of electroencephalograms to the respective EEG electrodes.
7. The method of claim 4 , wherein
the forward model is created by modeling a correlation between the activities of respective brain sites of the three-dimensional model in the form of a mesh and appearance of electroencephalograms to the respective EEG electrodes.