The last two papers I read were “An active, microfabricated, scalp electrode array for EEG recording” and “A dry electrode for EEG recording” by Babak A. Taheri, Robert T. Knight and Rosemary L. Smith.
In them, it was discussed the use of active dry or wet electrodes for EEG recordings. The main discussion aimed to prove the usability of dry electrodes against the problems that wet electrodes face on long EEG recordings such as limited size, electrolyte paste, skin preparation and sensitivity to noise. The new dry electrode was tested on human subjects in 4 modalities of EEG activity:
- Spontaneous EEG;
- Sensory event-related potentials;
- Brain-stem potentials;
- Cognitive event-related potentials;
The performance of the dry electrode compared favourably with that of the standard wet electrode in all tests, with the advantage of no skin preparation, no electrolyte gel, and higher signal-to-noise ratio.
However, there are still disadvantages like: bulky size due to additional electronics and limitations of power sources; noise due to limitations of the electronics available; motion artefacts due to poor skin-to-electrode contact; and higher cost. In the present day, technology may have solved these disadvantages but only future readings will tell [me].
These two papers, together with the previous ones, start to give me some understanding of how to read data from brain. However, my question remains: how can we write back? And what would be the consequences?