Questions on Simultaneous EEG and EMG Recording with Cyton

Dear team,
I am currently working on recording EEG and EMG signals simultaneously. However, during the experiment I noticed that EMG waveforms appear in the EEG channels. Since the connections were made following the steps provided on the OpenBCI website, I would like to better understand the internal channel connections and how signal processing is performed within OpenBCI.

My specific questions are listed below:
1. Role of BIAS: I understand that the BIAS pin is used for noise cancellation, but could you explain in detail how it works?
2. Ground (SRB): How does the SRB function within the EEG system?
3. BIAS and SRB Relationship: What is the relationship between BIAS and SRB in the signal processing of EEG, ECG, and EMG?
4. Channel Implementation: I have experimented with combinations using BIAS and SRB with the active channels of the Cyton board. Could you explain how the 8 channels are implemented in terms of signal acquisition?
5. EMG Electrode Placement:Why must EMG active electrodes be connected in the “up and down” method to represent the potential difference of the muscle?
5.1. Why can’t we use the same top-channel method as in EEG?
6. Simultaneous Recording:Is it possible to perform simultaneous EEG and EMG recordings without interference?
7. Cross talk: While recording the EEG the EMG cross talk was occurring and during the measurement of EMG the ECG cross talk was occurring, why? to understand this please explain the circuit connections.

Thank you
Best regards,
Raghul Jayaprakash R