The concept of synapses is key to understanding the functions of the human brain. The brain consists primarily of a network of neurons, which are cells that receive and transmit electrochemical signals by means of specialized junctions called synapses. Synaptic activity is regulated through two primary mechanisms: short-term potentiation (the increase in signal amplitude over time) and long-term potentiation (a persistent increase in signal amplitude). These mechanisms allow for memory formation, as well as learning.
The increase in frequency is accomplished by the action potential, which travels along axons between presynaptic and postsynaptic neurons. The action potential is initiated when voltage-gated sodium channels open briefly to allow positively charged ions (Na+) into the cell, depolarizing it. This change of polarity causes voltage-gated calcium channels to open as well, allowing more positive charges into the cell.
The strength of the signal is governed by neurotransmitters, which are molecules released at the synapse to transmit information across it. The main classes of neurotransmitter in our species are glutamate, GABA, acetylcholine and dopamine.
Glutamate is the most abundant, and has been shown to be critical in memory formation. Short-term potentiation occurs when glutamate binds with AMPA receptors on the postsynaptic neuron's dendrites. The binding causes calcium ion channels to open briefly, which leads to an influx of calcium ions into the cell that allows for increased synaptic activity.
GABA, which is the most abundant inhibitory neurotransmitter in our species, plays a major role in long-term potentiation. The influx of calcium ions caused by glutamate binding to AMPA receptors leads to activation of protein kinase C (PKC), which phosphorylates certain synapse proteins and increases their affinity for GABA.
Acetylcholine is the primary neurotransmitter in the brain, and has been shown to play an important role in memory formation. Acetylcholine binds to both pre- and postsynaptic receptors, but it is primarily responsible for long-term potentiation.
The majority of humans are considered to be intelligent, and yet the majority of human activity is completely unimportant. This is because intelligence does not correlate with wisdom or knowledge. Intelligence appears to exist only for two reasons:
1) For the purpose of solving specific problems in a cognitive manner.
2) To create novel thoughts, i.e., increase synapse in neurotransmitters.
Humans do not solve problems in a cognitive manner. Human intelligence is only useful for very specific purposes, such as driving cars or fixing computers. Humans are also incapable of logical thought processes, and their social activity consists mainly of gossiping about one another.
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