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SMR Enhancement
Target Band: 12.0 - 15.0 Hz
Primary Hub: Sensorimotor Cortex (C3, C4, Cz)
Modality: Amplitude Training (Operant Conditioning)
Clinical Rationale
The Sensorimotor Rhythm (SMR) is an idle rhythm of the motor cortex, presenting as a spindle-like activity primarily over the central strip (C3, Cz, C4). First identified by Dr. M.B. Sterman in cats, reinforcing this frequency reduces motor excitability and raises the seizure threshold.
In clinical practice, SMR training is the gold standard for reducing impulsivity, hyperactivity, and physical tension while maintaining cortical alertness—often described as a state of "relaxed focus."
Standard Parameters
| Parameter | Value | Notes |
|---|---|---|
| Reward Band | 12.0 - 15.0 Hz | May need adjustment (11-14 Hz or 13-16 Hz) based on individual peak alpha. |
| Inhibit 1 (Low) | 4.0 - 7.0 Hz (Theta) | Target < 20% time over threshold. Prevents drifting into drowsiness. |
| Inhibit 2 (High) | 22.0 - 30.0 Hz (High Beta) | Target < 10% time over threshold. Crucial for filtering muscle artifact (EMG). |
| Active Electrode | C4 (Right Hemisphere) | Right hemisphere is preferred for initial SMR training to avoid over-arousal. |
| Reference | A2 (Right Ear/Mastoid) | Ipsilateral or linked ears setup. |
Common Mistakes
- Ignoring EMG Artifact: Jaw clenching will falsely elevate frequencies in the 15+ Hz range, which can leak into the SMR band. Strict high-beta inhibits are mandatory.
- Over-rewarding: Setting the SMR reward threshold too low (resulting in >80% reward time) fails to challenge the brain, rendering the operant conditioning ineffective. Aim for 60-65% reward time.
- Wrong Hemisphere: Training SMR on the left hemisphere (C3) in highly anxious individuals can occasionally trigger over-arousal or agitation. Default to C4 unless guided by QEEG.