An Ocean of Sensations
- Published21 Aug 2012
- Reviewed21 Aug 2012
- Source BrainFacts/SfN
The brain perceives the world through our senses, much like an artist observes the world through windows. This animated video shows how, courtesy of Sebastian Vasquez Lopez from Newcastle University, who won third place in the 2012 Brain Awareness Video Contest.
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We are like boats floating in an ocean of sensations: a sea made of waves of several types and lengths, a place full of stimulating substances and where we constantly come into contact with all kinds of objects, living and non-living, floating on their own.
Our senses are windows through which we can perceive the ocean around us, and the brain is like an artist, living inside the boat, portraying what can be seen through the windows, making sense of it and recording it as memories.Some of the waves in this sea are of the electromagnetic type, of which we can only perceive those with a particular length, not too long or too short, and we call them light. From all the light around us only a tiny fraction enters our eyes and is absorbed by the cells in the retina, at the back of the eye.
Other types of waves exist as small, propagating differences in air pressure that we can perceive as sounds. These vibrations can penetrate into our ears where they ultimately tickle tiny hairs on specialised nerve cells inside a small coiled tube at the inner ear.Chemical substances in the air we breathe stimulate receptor cells at the top of our nasal cavity, whereas the things we put in our mouth, like food and drinks, activate specialised taste cells in the tongue.
Objects that touch our skin and even the air around us can stimulate receptors that are sensitive to pressure and temperature, and when something is causing damage to our bodies, receptors in free nerve endings are activated at the place of the injury, either on the skin or deeper inside the body.
All the stimuli captured by our body senses are transmitted, not in the form of light, sound, pressure or heat, but as tiny electrical impulses travelling along millions of nerve fibers, like information flowing through wires. And all this information is directed to the master artist: the brain.
The brain has the challenging task of making sense of all these signals and by doing so it gives us a portrait of reality. Specialised areas of the brain process visual information allowing us to distinguish the colours: the blue of the sky, the green of the fields, the white of the clouds; the shape of a smile or the letters in a book; to differentiate what is close from what is far, what is dark from what is light, as we do when we gaze at the night sky.Other areas process signals coming from our ears and then we perceive the sounds: the song of the birds, the notes of our favourite tune, peoples’ voices and the falling rain...
The brain creates the impression of smells: the aroma of the flowers, the smell of damp earth or of a blown out candle, the perfumes, the essences... and also tastes: the sweetness, the saltiness, the sourness, the bitterness...It is inside our brains where we consciously perceive touch and temperature: the surfaces, rough and smooth, hot and cold; the feeling of wind in the face, of water running down the skin, the caresses, the warmth of the sun...
As we sail through the sea of sensations that is reality we are blissfully unaware of all the intricate processes occurring in our brain and sensory organs.Our senses are the windows through which we see, hear, touch, smell and taste the world around us. Without these windows we would live in a dark, silent void, unable to perceive any light, sound or touch and even without a sense of our own bodies.