Glossary
Embodied Cognition
The idea that bodily sensations and physical states can influence our psychological states, thoughts, and judgments.
Example:
Holding a warm drink might make you perceive a stranger as more friendly, an example of embodied cognition where physical warmth influences social warmth.
Endorphins
Natural opiate-like neurotransmitters produced by the brain in response to pain or vigorous exercise, which can reduce the perception of pain and produce feelings of euphoria.
Example:
After a long run, the 'runner's high' is often attributed to the release of endorphins, which naturally alleviate pain.
Gate-Control Theory
A theory by Melzack and Wall proposing that the spinal cord contains a neurological 'gate' that either blocks pain signals or allows them to pass to the brain.
Example:
According to the Gate-Control Theory, rubbing a sore muscle can reduce pain by activating large nerve fibers that close the 'gate' in the spinal cord.
Hair Cells
Sensory receptors found in the inner ear (both in the cochlea for hearing and in the vestibular system for balance) that convert mechanical vibrations or movements into electrical signals.
Example:
In your inner ear, tiny hair cells bend with the movement of fluid, sending signals to your brain that help you maintain balance.
Kinesthesis
The sense of the position and movement of individual body parts, allowing us to know where our limbs are without looking.
Example:
A dancer relies heavily on their kinesthesis to execute complex moves, knowing exactly where their arms and legs are in space.
Large Nerve Fibers
Nerve fibers that transmit non-painful sensations like pressure or touch, and when activated, they tend to close the 'gate' in the spinal cord, inhibiting pain signals.
Example:
Massaging a bruise stimulates large nerve fibers, which can help close the pain 'gate' and reduce discomfort.
Medulla
A part of the brainstem that helps regulate vital functions like breathing, heart rate, and blood pressure, and serves as a relay station for sensory information.
Example:
Before touch information reaches the thalamus, it passes through the medulla in the brainstem.
Pain
An unpleasant sensory and emotional experience associated with actual or potential tissue damage, serving as a crucial alarm system for the body.
Example:
The sharp pain you feel after stubbing your toe is your body's way of telling you to be more careful.
Phantom Limb Sensations
The experience of feeling sensations, including pain, in a limb that has been amputated, caused by the brain misinterpreting activity in the central nervous system.
Example:
Even years after an amputation, some individuals report feeling as though their missing hand is itching, a phenomenon known as phantom limb sensations.
Proprioception
The broader sense of the body's position in space, encompassing both static position and movement, often used interchangeably with kinesthesis but sometimes referring more generally to body awareness.
Example:
Your proprioception allows you to walk across a room in the dark without bumping into furniture, as you're aware of your body's location.
Semicircular Canals
Three fluid-filled canals in the inner ear that are part of the vestibular system, responsible for detecting rotational movements of the head.
Example:
When you turn your head quickly, the fluid in your semicircular canals shifts, signaling your brain about the movement.
Sensory Interaction
The principle that one sense may influence another, demonstrating how our senses work together to create a complete perception of the world.
Example:
When you have a cold, food often tastes bland because your sense of smell, crucial for flavor perception, is impaired, illustrating sensory interaction.
Small Nerve Fibers
Nerve fibers that primarily transmit pain signals, and when activated, they tend to open the 'gate' in the spinal cord, allowing pain to be perceived.
Example:
When you get a paper cut, the small nerve fibers are activated, sending pain signals that open the spinal cord's 'gate'.
Somatosensation
The body's sense of touch, encompassing pressure, warmth, cold, and pain, which allows us to perceive the physical world through our skin.
Example:
When you feel the soft fur of a cat, your somatosensation is actively processing the pressure and texture.
Somatosensory Cortex
An area in the parietal lobe of the brain that processes sensory information from the skin, muscles, and joints, including touch, temperature, and pain.
Example:
When you accidentally touch a hot stove, your somatosensory cortex quickly registers the burning sensation.
Spinal Cord
A long, thin, tubular bundle of nervous tissue and support cells that extends from the brainstem to the lumbar region of the vertebral column, serving as a major pathway for sensory and motor information.
Example:
Sensory signals from your fingertips travel up your spinal cord to reach your brain, allowing you to feel the warmth of a mug.
Synesthesia
A neurological phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway.
Example:
Someone with synesthesia might literally 'see' the color blue whenever they hear the note C sharp played on a piano.
Thalamus
A brain structure located in the forebrain that acts as a sensory relay station, directing most incoming sensory information (except smell) to the appropriate areas of the cortex.
Example:
The thalamus acts like a central switchboard, sending the sensation of a cool breeze from your skin to the correct processing area in your brain.
Vestibular Sacs
Structures in the inner ear that are part of the vestibular system, responsible for detecting linear acceleration and the head's position relative to gravity.
Example:
As an elevator starts to ascend, your vestibular sacs detect the upward acceleration, contributing to your sense of movement.
Vestibular Sense
The sense of body movement and balance, which monitors the head's position and movement, allowing us to maintain equilibrium.
Example:
Your vestibular sense is what helps you stay upright and not fall over when you spin around rapidly.