Brain waves

Brain waves 

Brain cells communicate both sensory and motor impulses with the help of electrical current in all states of life i.e. resting, sleeping & activity, through neural network

Difference from common electricity: Brain waves are ionic currents rather than flowing currents, are measured in voltage (micro voltage) rather than ampere.

Human brain - a most efficient machine: Brain consumes only 12 to 20 watts power, less than our dim household bulb while performing complex cognitive tasks.

Ultra low voltage operation: As compared to microprocessors of today, operating at 0.8 to 1.2 volts, the human brain operates far below this threshold as:

At Cellular level, a resting neuron's potential difference across the membrane is -70 mv (-0.07 V), which is 20 times weaker than a 1.5 V AA battery;

At Scalp level, when millions of neurons fires together, in this sync activity the brain waves voltage fluctuate from 10 to 100 micro volt, which is 150,000 times weaker than our household battery.

Biological voltage efficiency: This is made possible because of unique work design of the brain as specific to:

1. Ion movement: instead of electrons, shifting physically charged ions of Na, K, Ca across neural membrane;

2. Spike based: event based neuron firing activity for a milliseconds,

3. Massive parallelism: unlike a centralized microprocessor of computer of gigahertz speed, all 86 billion neurons (most of them resides in brain's cerebellum and cerebral "pre frontal cortex"), working simultaneously at lower localized frequencies ranging from 1 to 100 hertz.

Measuring Brain Waves: 

Brain waves are measured in frequency (Hertz) and voltage, not ampere, because EEG records tiny fluctuations in micro volts (μV) from ionic current, not the flowing current.
[Here Frequency is Hz or waves per second and Voltage is size/height of the waves.]

Inverse relationship: There is generally an inverse relationship in frequency and voltage, i.e. slower waves having high voltage and faster waves having lower voltage.
1. Slow waves: Lower frequencies & higher amplitude. When brain is resting, healing or unplugged from active tasks.
2. Fast waves: High frequencies & shorter wavelengths. When brain is actively working, processing information or focused. 

Types of brain waves in human:

1. Delta / 0.5-4 Hz / slowest speed / deep sleep / highest voltage, 100-200 μV

2. Theta / 4-8 Hz / slow speed / light sleep, day dreaming, intuition, deep meditation / medium high voltage, 20-100 μV

3. Alpha / 8-12 Hz / moderate speed / calm quiet awake / medium voltage, / 20-100-200 μV

4. Beta / 12-30 Hz / fast speed / active, alert / low voltage, 5-10 mv μV

   a. Low Beta / 12-15 Hz / fast but idle

   b. Beta / 15-22 Hz / high engagement

   c. Hi Beta / 22-30 Hz anxiety, stress, excitement

5. Gamma / 30-100 Hz / fastest speed / peak concentration, insight, simultaneous processing of information from different brain areas / very low voltage, under 5 μV

Frequency and Mental states:

Slow waves 

• Low frequency / High voltage.
• During deep sleep (Delta waves).
• The brain is not actively processing complex information.
• Billions of neuron can fire in a slow, unified, rhythmic pattern.
• Because they fire together, the voltage is high.

Fast waves:

• High frequency / Low voltage.
• While awake & mentally active (Beta & Gamma waves).
• Different parts of the brain process different information simultaneously.
• Neurons fire rapidly & independently to handle these distinct tasks.
• This higher frequency desynchronization causes the electrical signals to cancel out resulting in low voltage.

Sum up:

1. Slow speed allow neurons to match in step (creating high voltage). High voltage, high synchrony.
2. Fast speed force neurons to work independently (creating low voltage). Low voltage de synchrony.