IS THE BRAIN ONE BIG COMPUTER?

IS THE BRAIN ONE BIG COMPUTER?

The brain functions as an incredibly sophisticated electrical and chemical machine, using a seamless two-step process to transmit and process information via its fundamental unit, the neuron (nerve cell).¹

The communication within the brain relies on the following cycle:

---

⚡ 1. The Electrical Signal (Action Potential)²

Information travels rapidly within a single neuron as an electrical signal called an action potential (or nerve impulse).³

• Basis: The neuron maintains an electrical charge difference, or resting membrane potential, across its cell membrane, established by an unequal distribution of positively and negatively charged ions (primarily Sodium (⁴$Na^+$), Potassium (⁵$K^+$), and Chloride (⁶$Cl^-$)) inside versus outside the cell.⁷

• Firing: When a neuron receives enough stimulation from its neighbors to reach a specific voltage threshold, voltage-gated ion channels rapidly open.⁸

  • This causes a sudden, massive influx of positive ions (⁹$Na^+$) into the cell, which momentarily reverses the electrical charge from negative to positive—this is the action potential.¹⁰

• Propagation: This electrical spike then travels quickly and in an all-or-nothing fashion down the length of the neuron's transmitting fiber, the axon, until it reaches the end terminal.¹¹

---

🧪 2. The Chemical Signal (Neurotransmitters)¹²

Once the electrical signal reaches the end of the axon, it must cross a tiny gap, the synapse, to communicate with the next neuron.¹³ This is where the signal converts from electrical to chemical.¹⁴

• Conversion and Release: When the action potential arrives at the axon terminal, it triggers the release of specialized chemical messengers called neurotransmitters into the synaptic cleft (the gap).¹⁵

• Crossing the Synapse: The neurotransmitters quickly diffuse across this gap and bind to receptors on the receiving neuron's dendrites.¹⁶ This binding is specific, like a key fitting a specific lock.¹⁷

• Effect: The action of the neurotransmitter on the receptor determines the next step for the receiving neuron:¹⁸

  • Excitatory Neurotransmitters (e.g., Glutamate) push the receiving neuron's voltage toward its firing threshold, making it more likely to generate its own action potential.¹⁹

  • Inhibitory Neurotransmitters (e.g., GABA) push the voltage away from the firing threshold, making it less likely to fire.²⁰

By constantly integrating thousands of these excitatory and inhibitory chemical inputs, the receiving neuron determines whether to generate its own electrical signal, thereby perpetuating the communication throughout the brain's vast neural circuits.²¹

Key Chemical Messengers

Neurotransmitter	Primary Role(s)
Glutamate	Major Excitatory neurotransmitter; learning and memory.
GABA (Gamma-Aminobutyric Acid)	Major Inhibitory neurotransmitter; calming, anxiety regulation.
Dopamine	Reward, motivation, motor control.
Serotonin	Mood, sleep, appetite.
Acetylcholine	Muscle contraction (PNS), attention, memory (CNS).

Diagram of Brain

Is the brain like a big phone system or is it one big computer with ON or OFF states ? Neither of the above is correct.

Let's look at the brain as an orchestra. In an orchestra, you have different musical sections. There is a percussion section, a string section, a woodwind section, and so on. Each has its own job to do and must work closely with the other sections. When playing music, each section waits for the conductor. The conductor raises a baton and all the members of the orchestra begin playing at the same time playing on the same note. If the drum section hasn't been practicing, they don't play as well as the rest of the orchestra. The overall sound of the music seems "off" or plays poorly at certain times. This is a better model of how the brain works. We used to think of the brain as a big computer, but it's really like millions of little computers all working together. Diagram of Brain

IS THE BRAIN ONE BIG COMPUTER? VIDEO