What if you lost all sense of self? You know you have a body - you can see it there beneath you, but you can't feel it. You aren't paralyzed, per se, just unaware that your body is moving unless you are looking at it. And then, only under intense concentration and your own watchful eye, can you reach out toward something and grasp it. But if you don't look or pay close attention, the object will either slip out of your hand because you are holding it too loosely, or you'll squeeze it with such intensity your knuckles will turn bone white. This ability to feel our bodies, to unconsciously sense them is known as proprioception. It's sometimes referred to as the secret sense - or "sixth sense." Unlike our five senses - sight, sound, smell, touch and taste - which are open and obvious to us, the sense of controlling and owning our own bodies is otherwise hidden. Proprioception is, simply put, the awareness of where your body is in space.

For example, while walking, sensor receptors on your skin, joints and muscles send signals to the brain that make you aware that your right foot is in front of you even if your eyes are closed or you're not looking down at your feet, explains Dr. Jack Shelley-Tremblay, professor and chair of the department of psychology at the University of South Alabama. Proprioception is sometimes used interchangeably with the term "kinesthesia," but they are actually very different perceptions. Kinesthesia is the sense of movement of our muscles, tendons and joints. For example, while walking, the brain picks up on the sensations of force, velocity and the propelling of your body forward from the inner ear, which oversees balance orientation, to sense movement. You are aware of the sensation of your body being in motion even if you are focused on the scenery around you and not your body. Proprioception and deep sleep solution kinesthesia, while different, work together to make us cognizant of our own bodies in space.

Combined, they can be considered the sixth sense or, respectively, as the sixth and seventh senses. Proprioception plays a vital role in balance and orientation, enabling us to stand upright or walk, Orthopedic Sleep Pillow especially on uneven surfaces. It allows golfers to perfect their swings and dancers to move with the grace of a butterfly. Sometimes people feel a temporary impairment of this sixth sense. Think of someone who's intoxicated taking a field sobriety test, for instance. With their vestibular system impaired by too much alcohol, they have a sense of proprioception loss and thus have a difficult time walking in a straight line or balancing on one foot. A more precise example is when your arm falls asleep and, as a result, it feels numb and is difficult to move. British neurologist Oliver Sacks describes in a chapter of his book "The Man Who Mistook His Wife for a Hat" a patientbook, "Pride and a Daily Marathon". The book focuses on Ian Waterman who, at the age of 19, lost all sense of his body from his neck down after suffering a brief illness. Waterman described feeling as if he were just a head floating on a pillow.