Hum – Leonard Susskind
Yes, there is a video titled “What Happens to YOUR BRAIN When You Hum for 60 Seconds? Leonard Susskind explains” from the channel The Susskind Physics. In this presentation, Susskind provides a detailed scientific explanation of the physiological and neurological mechanisms triggered by humming.
The Mechanism of Humming
According to the video, humming for 60 seconds initiates a “negotiation” between several systems in the brain [00:00]. The key components involved include:
- Nitric Oxide Spike: Humming creates oscillating airflow in the nasal cavity, which increases nasal nitric oxide production by approximately 15-fold compared to normal breathing [10:46]. This molecule acts as a vasodilator and a neuromodulator in the brain [11:06].
- Vagus Nerve Stimulation: The act of humming activates the laryngeal muscles, which are controlled by the vagus nerve. This rhythmic activation sends signals to the brain stem, specifically the nucleus tractus solitarius, helping to regulate autonomic function [09:04].
- Autonomic Balance: Because humming can only occur during exhalation, it naturally extends the exhale phase. This shifts the body’s balance toward the parasympathetic nervous system (rest and digest), slowing the heart rate and increasing heart rate variability [16:53].
- Acoustic Dual-Input: Unlike external sounds, humming reaches the auditory system through both air conduction and bone conduction. This dual input requires the brain to integrate two versions of the same sound, engaging the motor and auditory cortices simultaneously [05:40].
Neurological Effects
Susskind explains that after about 30 to 60 seconds of sustained humming, the brain’s oscillatory dynamics begin to shift [29:24]:
- Alpha Wave Increase: There is an increase in alpha power in the auditory and parietal regions, which is associated with a relaxed but wakeful state [30:16].
- Predictive Coding: Because the sound is self-generated, the “prediction error” in the auditory cortex is low. This allows the cortex to relax its vigilance, leading to the subjective feeling of calm and a reduction in the urgency of the external world [25:33].
You can watch the full explanation here:
PDF Transcript: When You Hum for 60 Second
It takes only 60 seconds – Det tar bara 60 sekunder