Week 8 Flashcards
Opponent Process
The representation of colours by the rate of firing of two types of neurones: red/green and yellow/blue
Opponent Process Theory
The theory that the perception of colour is the result of the activity of three opponent-process channels. (Red/Green, Blue/Yellow, Black/White)
Photoreceptor
A receptive cell for vision in the retina; a rod or a cone
Cone
A photoreceptor that is responsible for acute daytime vision and for colour perception
Rod
A photoreceptor that is very sensitive to light but cannot detect changes in hue
Perception
The detection of the more complex properties of a stimulus, including its location and nature
Transduction
The conversion of physical stimuli into changes in the activity of receptor cells of sensory organs
Receptor Cell
A neuron that directly responds to a physical stimulus, such as light, vibrations, or aromatic molecules
Anatomical Coding
A means by which the nervous system represents information; different features are coded by the activity of different neurons
Temporal Coding
A means by which the nervous system represents information; different features are coded by the pattern of activity in neurons
Psychophysics
A branch of psychology that measures the quantitative relation between physical stimuli and perceptual experience
Just-Noticeable Difference (JND)
The smallest difference between two similar stimuli that can be distinguished; also known as difference threshold
Weber Fraction
The ratio between a JND and the magnitude of a stimulus; reasonably constant over the middle range of most stimulus intensities
Threshold
The point at which a stimulus, or a change in the value of a stimulus, can just be detected
Difference Threshold
The smallest difference between two similar stimuli that can be distinguished; also known as JND
Signal Detection Theory
A mathematical theory of the detection of stimuli, which involves discriminating a signal from the noise in which is it embedded and which takes into account participants’ willingness to report detecting the signal
Receiver Operating Characteristic Curve (ROC Curve)
A graph of hits and false alarms of participants under different motivational conditions; indicates people’s ability to detect a particular stimulus
Wavelength
The distance between adjacent waves of radiant energy; in vision, most closely associated with the perceptual dimension of hue
Cornea
The transparent tissue covering the front of the eye
Sclera
The tough outer layer of the eye; the “white” of the eye
Iris
The pigmented muscle of the eye that controls the size of the pupil
Lens
The transparent organ situated behind the iris of the eye; helps focus an image on the retina
Accommodation
Changes in thickness of the lens of the eye that focus images of near or distant objects on the retina
Retina
The tissue at the back inside surface of the eye that contains the photoreceptors and associated neurons
Optic Disc
A circular structure located at the exit point from the retina of the axons of the ganglion cells that form the optic nerve
Ganglion Cell
A neuron in the retina that receives information from photoreceptors by means of bipolar cells and from which axons proceed through the optic nerves to the brain
Bipolar Cell
A neuron in the retina that receives information form photoreceptors and passes it on to the ganglion cells, from which axons proceed through the optic nerves to the rain
Fovea
A small pit near the centre of the retina containing densely packed cones; responsible for the most acute and detailed vision
Photopigment
A complex molecule found in photoreceptors; when struck by light, it splits and stimulates the membrane of the photoreceptor in which it resides
Rhodopsin
The photopigment contained by rods
Dark Adaptation
The process by which the eye becomes capable of distinguishing dimly illuminated objects after going from a bright area to a dark one
Vergence Movement
The co-operative movement of the eyes, which ensures that the image of an object fals on identical portions of both retinas
Saccadic Movement
The rapid movement of the eyes that is used in scanning a visual scene, as opposed to the smooth pursuit movements used to follow a moving object
Pursuit Movement
The movement that the eyes make to maintain an image of a moving image upon the fovea
Hue
A perceptual dimension of colour, most closely related to the wavelength of a pure light
Brightness
A perceptual dimension of colour, most closely related to the intensity or degree of radiant energy emitted by a visual stimulus
Saturation
A perceptual dimension of colour, most closely associated with purity of a colour
Colour Mixing
The perception of two or more lights of different wavelength seen together as light of an intermediate wavelength
The Trichromatic Theory
The theory that colour vision is accomplished by three types of photoreceptors, each of which is maximally sensitive to a different wavelength of light
Negative Afterimage
The image seen after a portion of the retina is exposed to an intense visual stimulus; a negative afterimage consists of colours complementary to those of the physical stimulus
Protanopia
A form of hereditary anomalous colour vision, caused by defective “red” cones in the retina
Deuteranopia
A form of hereditary anomalous colour vision; caused by defective “green” cones in the retina
Tritanopia
A form of hereditary anomalous colour vision; caused by a lack of “blue” cones in the retina
Hertz (Hz)
The primary measure of the frequency of vibration of sound waves; cycles per second
Ossicle
One of the three bones of the middle ear (the hammer, anvil and stirrup) that transmit acoustical vibrations from the eardrum to the membrane behind the oval window of the cochlea
Cochlea
A snail-shaped chamber set in bone in the inner ear, where auditory transduction takes place
Oval Window
An opening in the bone surrounding the cochlea. The stirrup presses against a membrane behind the oval window and transmits sound vibrations into the fluid within the cochlea
Basilar Membrane
One of two membranes that divide the cochlea of the inner ear into three compartments; the receptive organ for audition resides here
Round Window
An opening in the bone surrounding the cochlea. Movements of the membrane behind this opening permit vibrations to be transmitted through the oval window into the cochlea
Auditory Hair Cell
The sensory neuron of the auditory system; located on the basilar membrane
Cilium
A hair-like appendage of a cell; involved in movement or in transducing sensory information. Cilia are found on the receptors in the auditory and vestibular systems
Tectorial Membrane
A membrane located above the basilar membrane; serves as a shelf against which the cilia of the auditory hair cells move
Chemosense
One of the two sense modalities (gustation and olfaction) that detect the presence of particular molecules present in the environment
Gustation
The sense of taste
Papilla
A small bump on the tongue that contains a group of taste buds
Taste bud
A small organ on the tongue that contains a group of gustatory receptor cells