Unit-1-Vocab-1.6-Sensation

Sensation

The process by which sensory receptors detect stimuli from the environment.

Transduction

The conversion of sensory energy into neural signals that the brain can process.

Absolute threshold

The minimum stimulus intensity detected 50% of the time.

Just-noticeable difference

The smallest difference between two stimuli that a person can detect 50% of the time.

Weber’s law

The smallest change in a stimulus that a person can detect is a constant proportion of the original stimulus, rather than a fixed amount.

Sensory adaptation

A decrease in sensitivity to an unchanging stimulus over time.

Sensory interaction

The way one sense influences or affects another sense.

Synesthesia

A condition in which stimulation of one sense automatically triggers an experience in another sense, such as seeing colors when hearing sounds.

Retina

The light-sensitive layer at the back of the eye that converts light into neural signals.

Blind spot

The point where the optic nerve exits the eye, containing no rods or cones.

Accommodation

The lens changing shape to focus near or distant objects clearly on the retina.

Rods

Retinal receptors that detect dim light and support black-and-white and peripheral vision.

Cones

Retinal receptors responsible for color vision and fine detail, especially in bright light.

Fovea

The central area of the retina with the highest concentration of cones, providing the sharpest vision.

Ganglion cells

Retinal neurons that collect visual information and send signals toward the brain through the optic nerve; opponent-color processing helps explain afterimages.

Trichromatic theory

Color vision results from three types of cones sensitive to red, green, and blue wavelengths.

Opponent-process theory

Color vision is processed in opposing pairs: red-green, blue-yellow, and black-white; this helps explain afterimages.

Dichromatism

Color vision involving only two functioning types of cones instead of three.

Monochromatism

Color vision involving only one functioning type of cone, or no functioning cones, resulting in little or no color discrimination.

Feature detectors

Specialized neurons in the visual cortex that respond to specific features, such as edges, lines, angles, and movement.

Prosopagnosia

The inability to recognize faces, despite being able to see them.

Blindsight

The ability to respond to visual stimuli without consciously experiencing sight, often due to damage to the primary visual cortex.

Pitch

How high or low a sound seems, determined mainly by its frequency.

Loudness

How loud or soft a sound seems, determined mainly by its amplitude.

Place theory

The theory that pitch depends on where the cochlea’s basilar membrane vibrates most strongly; it best explains high pitches.

Volley theory

The theory that groups of auditory neurons take turns firing in rapid patterns to encode sound frequencies too fast for one neuron to match alone.

Frequency theory

The theory that the rate of neural impulses matches the frequency of a sound wave; it helps explain low pitches.

Sound localization

The ability to determine where a sound is coming from by comparing differences in its arrival time and intensity between the ears.

Conduction deafness

Hearing loss caused by problems conducting sound through the outer or middle ear.

Sensorineural deafness

Hearing loss caused by damage to the cochlea’s hair cells or the auditory nerve.

Olfaction

The sense of smell, which detects airborne chemical molecules.

Pheromones

Chemical signals released by an organism that can influence the behavior or physiology of other members of the same species.

Gustation

The sense of taste, which detects chemicals dissolved in saliva.

Umami

The savory taste associated with glutamate and protein-rich foods.

Oleogustus

The taste sensation associated with fatty acids, often described as the taste of fat.

Gate control theory

The theory that the spinal cord can regulate pain signals traveling to the brain, allowing some signals to be blocked or reduced.

Phantom limb sensation

The feeling that a missing limb is still present, sometimes including sensations such as pain, because the nervous system continues to represent it.

Vestibular sense

The sense of balance and spatial orientation, which helps the body detect movement and maintain equilibrium.

Semicircular canals

Fluid-filled structures in the inner ear that detect rotational head movements and help maintain balance.

Kinesthesis

The sense of the position and movement of body parts, using receptors in muscles, tendons, and joints.