BCIs, or Brain-Computer Interfaces, also known as BMIs, or Brain-Machine Interfaces, are devices that process brain activity to control external devices, allowing users to interact with them using their thoughts. They fall into two main paradigms: invasive, which involves neurological implants, and non-invasive, which involves an electrode headset placed near the scalp. These types of technology are used in the medical field and for user interaction with machines.
😪 Delta (0.5–4 Hz) - Deep sleep
🧘 Theta (4–8 Hz) - Drowsiness, meditation
😌 Alpha (8–12 Hz) - Calm focus
🤔 Gamma (30–100 Hz) - High-level cognition
EEG (Electroencephalogram) Explained
- EEG (electroencephalogram) measures electricity in the brain and records it
- electrodes analyze the difference in charge between two areas of different charge, known as a dipole
- Excitatory Postsynaptic Potential (EPSP), positive inside, negative outside, distant extracellular space becomes relatively more positive
- Inhibatory Postsynaptic Potential, vice versa to EPSP
- cerebral cortex contains billions of pyramid shape neurons parallel to each other but perpendicular to scalp
- combined creates a larger dipole that is detectable
- years of training to accurately read EEG signals
1.) Why might tests like noisy signals like EEG still be useful in serious tech like brain-computer interfaces? --- Despite having a low signal-to-noise ratio (SNR), noisy signals in EEGs are still useful as they provide real-time, non-invasive access to brain activity patterns that can be decoded using advanced signal processing and machine learning techniques to control external devices or interpret cognitive states.