How neurons mediate perception

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A rush of cold wind sends chills up your spine, the sudden touch of hot pavement against the balls of your feet makes you dance, and the sharp edges of a serrated knife cutting the tip of your finger causes you to holler in pain. Although many of us have experienced these sensations, few of us understand the science taking place inside our brains that govern these reactions. It’s a fascinating confluence of electrical impulses and chemistry whose internal workings scientists and medical professionals are spending a great deal of time exploring. Furthermore, to understand the inner workings of our brain is to gain a deeper appreciation and awareness of the internal forces influencing our acts of thought and motion.

thebeautyofneurons

It’s best to think of our brains as a network of circuits, a mesh of interconnected points that send messages to each other via electrical impulses whose strength and frequency determine the mood we’re in and the extent to which we react to external stimuli. If these signals are in any way impeded or the paths they travel along damaged (by drugs or disease), then our very identity and self-awareness is compromised.

Diffusion spectrum MRI image of the human brain showing three dimensional grid structure of white matter tracts. From Wedeen, et al (2012).

The points embedded and scattered across the neural web are called neurons, the cells that contain the source of each signal in the form of neurotransmitters (more on these later), while the connecting strands that make up the web are called axons and dendrites.

neuron

Axons are covered in myelin, a protective and electrical impulse-friendly fatty layer, and are the longest strands extending from each neuron. It’s along these axons that the electrical impulses a neuron initiates travels (up to 250 miles per hour!).

National Academy of Sciences

The ends of each axon connect to other nerve strands called dendrites, the receiving branches of other neurons. The meeting point between an axon and a dendrite is called a synapse, and when the electrical impulse reaches the end of an axon, it triggers the release of a chemical messenger called a neurotransmitter. Once these neurotransmitters are released, they must travel across a region of space called the synaptic cleft, and eventually absorbed by specialized receptors lining the surface of a dendrite’s membrane.

Synapse

Philosophers, artists, and social scientists spend countless hours analyzing human behavior, and the consequences they have not only on other humans, but also in the way they shape the identity and dynamic of towns, cities, and nations. In sum, the perceived world is the outward expression of the processes governing neurons that provide all living things the opportunity to interact with each other.

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Featured image credit: TINA CARVALHO

About Author

Kristian strives to enlighten and entertain readers. In addition to his teaching and editorial responsibilities, he is working on a science-fiction novel that promises not to include exoskeleton suits and anemic aliens floating in mysterious vats of green-tinted goop.

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