Light can be measured. All natural things emit radio waves, and your brain "radiates" radio waves, mostly through your eyes. This is at the beginning of Genesis; everything is resonance, and there is sound and light.
This video breaks down how neurons generate and transmit living electricity to power human thoughts, sensations, and movements (0:47).
The Need for Bioelectricity
- The Human Brain Network: The human brain contains roughly 86 billion neurons (0:17). Each neuron exchanges signals with hundreds or thousands of others, creating a network with more possible connections than stars in a thousand Milky Way galaxies (0:24).
- The Distance Problem: While single-celled organisms rely on slow chemical diffusion to communicate, multicellular bodies need rapid long-distance signaling to react quickly to danger (3:00).
- Biological Telegraph: Humans contain roughly 60 kilometers of neurons stretched out like wires (4:03). Just as the transcontinental telegraph replaced horse-carried mail in 1861, neurons use electrical pulses to transmit messages across long distances almost instantaneously (2:22).
History and Experiments in Bioelectricity
- Luigi Galvani's Discovery: In the late 1700s, Italian scientist Luigi Galvani discovered that static electricity and lightning caused dissected frog legs to twitch (4:17). When touching the legs with two different metals also caused twitches, he proposed that bodies contain an internal "animal electricity" (5:50).
- Alessandro Volta's Battery: Fellow Italian scientist Alessandro Volta argued that the electricity actually came from the two different metals reacting with the fluids in the frog (6:22). This led him to invent the first battery, the voltaic pile, by stacking alternating layers of zinc, copper, and saltwater-soaked paper (6:36).
- Cockroach Leg Demonstration: Host Joe Hanson replicates these historical experiments using a homemade battery and a cockroach leg (8:23). Applying external voltage from the battery—or even the audio signal from a hip-hop track—stimulates the nerves and makes the leg twitch (9:32).
- Measuring Internal Signals: Using a neuron detector without any external battery, Hanson pushes on the cockroach leg to show that mechanical pressure generates internal electrical spikes (10:40). The nervous system encodes the strength of a stimulus by increasing the rate at which neurons fire (11:07).
How Neurons Work (The Action Potential)
- Neuron Anatomy: Almost all animals (except sponges) have neurons composed of a cell body, listening branches called dendrites, a long wire-like axon, and a gap at the end called a synapse (12:18).
- Resting Potential: Like a battery, a resting neuron separates electrical charges (13:33). A cellular pump pushes positively charged sodium ions out and brings positively charged potassium ions in (13:48). Combined with negatively charged proteins inside, the neuron maintains a resting internal voltage of about -70 millivolts (14:03).
- Firing a Signal: When dendrites receive a strong enough chemical signal from a neighboring neuron, the cell reaches a voltage threshold (15:19). Voltage-gated sodium channels suddenly open, allowing positive sodium ions to rush in and spike the internal charge in a millisecond (15:34).
- Resetting the Cell: Sodium doors then slam shut while potassium doors open, letting potassium rush out to drop the voltage back down (15:44). The sodium-potassium pump restores the original balance within five milliseconds (15:57).
- Chain Reaction: This electrical spike, called an action potential, triggers a chain reaction down the axon until it reaches the synapse, where it releases chemicals to stimulate the next neuron (13:26).
The Speed of Thought
- Slow vs. Fast Fibers: Stubbing a toe demonstrates that different nerve fibers carry signals at different speeds, which is why you feel the physical impact instantly but feel the pain a couple of seconds later (16:56).
- Uninsulated Nerves: In slower, uninsulated neurons, action potentials travel between 0.5 and 2 meters per second (about 4.5 miles per hour) (17:09).
- Myelin Insulation: Nerves can drastically increase speed by growing wider or wrapping their axons in a fatty insulation called myelin (17:23). Myelin forces the electrical signal to jump rapidly between gaps called Nodes of Ranvier, boosting signal speeds to 80 to 120 meters per second (roughly 270 miles per hour) (17:36).
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