Biomedical Engineering Reference
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Figure 13.3
Representation of the common spectral cortical activation within the analyzed experi-
mental population using the average cortical model provided by McGill University as a common
source space.
a particular frequency band during the execution of two tasks by a population. The
yellow indicates the cortical areas where significant differences were found in the
power spectra activity of all of the subjects, the red indicates the areas where differ-
ences were noted in all but one of the subjects, and so forth. The gray indicates areas
in which the spectral activity is not common to all the subjects. All of the cortical
spectral activities presented in color are statistically significant at 5% Bonferroni
corrected for multiple comparisons.
13.6
Conclusions
The capabilities of the high-resolution EEG mapping techniques have reached levels
where they are able to follow the dynamics of brain processes with a high temporal
resolution and an appreciable spatial resolution, on the order of 1 or 2 square centi-
meters. Appropriate mathematical procedures are now able to return us information
about the cortical sources active during the execution of a series of experimental
tasks by a single subject or a group of subjects. Such procedures are quite similar to
those employed for the past decade by scientists using the fMRI as a brain imaging
device. In this chapter we briefly presented a body of techniques able to return useful
information about the cortical areas where statistically significant brain activity
occurs in the spectral domain during the execution of two tasks. Such techniques are
relatively easy to implement and could constitute a valid support for the EEG data
analysis
of
complex
experiments
involving
several
subjects
and
different
experimental paradigms.
References
[1]
Nunez, P.,
Electric Fields of the Brain,
New York: Oxford University Press, 1981.
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