EEG microstates

These tend to last anywhere from milliseconds to seconds and are hypothesized to be the most basic instantiations of human neurological tasks, and are thus nicknamed "the atoms of thought".

[2] In their 1999 paper in the European Archives of Psychiatry and Clinical Neuroscience,[1] Koenig and Lehmann had been analyzing the EEGs of those with schizophrenia, in order to investigate the potential basic cognitive roots of the disorder.

When Koenig and Lehman ran their experiment in 1999 they constructed these sequences by starting from a subject's eyes-closed resting state EEG.

This process is repeated several times using different randomly selected prototype maps from among the collected data to use for statistical comparison and variance determination.

[8] It is the current hypothesis that EEG Microstates represent the basic steps of cognition and neural information processing in the brain, but there is still much research that needs to be done to cement this theory.

Koenig, Lehmann et al. 2002 [17] This study investigated EEG Microstate variance across normal humans of varying ages.

[17] As for the cause of this, they hypothesized that it was due to the growth and restructure of neural pathways, Van De Ville, Britz, and Michel, 2010 [3] In a study conducted by researchers in Geneva, the temporal dynamics and possible fractal properties of EEG microstates were analyzed in normal human subjects.

Since microstates are a global topography, but occur on such small time scales and change so rapidly, Van De Ville, Britz, and Michel hypothesized that these "atoms of thoughts" are fractal-like in the temporal dimension.

This hypothesis was initially illuminated by the strong correlation between the rapid time scale and transience of EEG microstates and the much slower signals of a resting state fMRI.

[21] Similar abnormalities were reported in a study with adolescents with 22q11.2 deletion syndrome, a population that has a 30% risk of developing psychosis.

[9] This suggests temporal lobe malfunction, which has been reported in fMRI studies of those with PD; they spent an average of 9.26 milliseconds longer in this microstate than did control subjects.