Secrets of Brain Function: Energy Efficiency, Neuroplasticity and the Consciousness Bottleneck

Introduction: The Dilemmas Science Addresses

From high school days, many of us have heard: “Humans use only 5–10% of their brains.” This claim—even among the educated—raises questions:

• Are there “locked” brain regions we don’t use?
• Why does the brain, capable of billions of operations per second, consume 20% of the body’s energy while processing just 100–200 conscious bits of information per second?
• How to justify this evolutionary “flaw”—a supercomputer without an adequate power supply?

Scientific answers debunk myths and reveal nature’s genius optimization.

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Debunking the “10% Myth”: Why the Brain Is Always 100% Active

Fact: Techniques like functional MRI (fMRI) show all brain regions are active daily, just not simultaneously. The energy paradox (2% body mass ↔ 20% energy) is explained by:

• Adenosine triphosphate (ATP)—the energy-storage molecule—is consumed massively: A single neural signal can burn 1 million ATP molecules to:
  • Maintain electrochemical gradients (Na⁺/K⁺ pumps),
  • Synthesize neurotransmitters.
• Energy-saving mechanisms:
  • Reduced synchronized activity: Mass neuron firing would trigger epileptic seizures and massive energy waste.
  • Sparse coding: Few neurons activate for specific stimuli (e.g., recognizing a familiar face).
  • Default mode network (DMN): Even at rest, the brain uses 60–80% energy to sustain “standby” networks (planning, introspection).

Key insight: The brain isn’t “underused”—it’s perpetually active but selective.

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Why the Gap Between Neural and Conscious Processing?

Data: Unconscious processes handle billions of bits per second, while conscious awareness (working memory) holds just 7±2 items (Miller’s Law). Evolution explains this:

1. Survival filters:
   • The thalamus and reticular formation only admit critical signals (sudden movement, loud noises).
   • This prevents cortical overload.
2. Energy efficiency:
   • Conscious processing requires synchronization across cortical regions (via gamma waves, ~40 Hz), an energy-intensive process.
3. Global Workspace Theory (Stanislas Dehaene):
   • Information becomes conscious only when it ignites a brain-wide neural network—demanding time and energy.

Example: While cycling, your cortex is free for conversation—automated skills “live” in subconscious structures (basal ganglia, cerebellum).

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What Is the “Unused” Capacity For? Neuroplasticity and Reserves

So-called “inactive” zones actually serve as:

• Neuroplasticity reserves:
  • Learning a language or instrument activates previously “silent” areas (e.g., London taxi drivers’ enlarged hippocampi).
  • After brain damage (e.g., stroke), these zones compensate for lost functions.
• Energy reserves:
  • During intense cognition (chess, math), local blood flow can surge by 50%.
• Subconscious intelligence:
  • Creativity and intuition emerge when unconscious networks integrate data (University of Vienna, 2023).

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Conclusion: Perfect Balance, Not an Evolutionary Flaw

The brain isn’t “energetically irrational”—it’s masterfully optimized:

• 🔋 Energy efficiency > mass activation,
• 🛡️ Consciousness limitation prevents overload,
• 🌱 Excess capacity enables adaptation.
  As Nikola Tesla noted: “Nature is infinitely more perfect in its simplicity than man in his complexity.”