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Glossary[edit | edit source]

EC
Eyes Closed
EO
Eyes Open
Synchrony training
According to Scholarpedia, synchrony means "adjustment of rhythms of self-sustained periodic oscillators due to their weak interaction". I guess that's easier to understand if you look at the clocks they use as examples for this. Basically, the cells in the brain are like those clocks in that they have their own rhythms, which can sometimes match up with the rhythm of other cells. When they do, they are in synchrony, which means that they fire at very similar (or same) frequencies. If you have a lot of cells synchronized at the same frequency, then the signal at that frequency will become stronger (increase in amplitude), and that's what we can measure with TAG Sync. What's special about TAG Sync, when compared to most other protocols, is that using TAG Sync you combine the signal from two electrodes (Fz and Pz, usually) and train this signal; when it gets strong it means that cells under both electrodes are synchronized at the same frequency, so it is measuring long-range connections between cells in the brain. That makes it possible to train these long-range connections, which according, to a lot of new neuroscience literature, is a very good thing to do.
Coherence training
Coherence is similar to Synchrony, but not the same. According to Scholarpedia, "The coherence of a signal pair is also a correlation coefficient (squared); it measures the phase consistency between pairs of signals in each frequency band." I think a correlation coefficient basically means you have run some statistics on two signals to look at their correlation; this is not what you do with synchrony since synchrony does not need you to run statistics because it will just increase the amplitude of a signal directly. Phase consistency I guess means how often two signals are in rhythm with each other or not, so it is similar to synchrony in that way but it is more of an indirect measurement, since it is statistical it will measure averages over time.
Phase training
Phase-training, I guess is any training that focuses more on timing of signals. TAG Sync is built on the principle of Phase-Amplitude Coupling, which means for example the phase (timing) of theta waves in the brain will control the amplitude of higher frequency signals like gamma. Theta and gamma are phase-amplitude coupled signals. That means you can use theta to change gamma. This applies for many (perhaps all brainwaves): the phase of lower frequency signals will control the amplitude of higher frequency signals in general, I think. This is a part of Cross-Frequency Coupling which is another principle TAG Sync makes use of.