Vision Flashcards
Accommodation
The process through which the lens is adjusted by contracting/relaxing the muscles around the lens
Aerial perspective
A pictorial depth cue caused by the visual effect of light when passing through the atmosphere that causes distant objects to appear hazy/blue
Brightness / Amplitude
The height of the wave; describes the level of energy present
Centre-surround antagonism
The centre and surround produce opposite responses
Complex cells
Cells located in the visual cortex that respond to the orientation of a bar of light as well as the direction of its movement
Compound eye
Consists of many tiny light capturing elements known as ommatidia
Convergence
Depth cues provided by feedback from the extra ocular muscles in the eye
Cornea
Transparent layer at the front of the eye that allows light to pass into the eye; responsible for 80% of eyes focusing power
Dorsal pathway
The “where pathway”, information processed along the parietal lobe
Electromagnetic spectrum
The range of wavelengths over which electromagnetic radiation extends
Fovea
Section of the retina where most cones are present and visual acuity is highest
Ganglion cell
Type of cell in the retina, receives input from the rods/cones
Hue / wavelength
The distance between the crests of the wave, generally refers to what most people mean by colour
Hypercomplex cells
Cells in the visual cortex that have all the features of a complex cell but are also sensitive to the length of the bar of light
Hyperopia
Farsightedness; able to see things far way but not close
Interposition
A pictorial depth cue where one object overlaps and thereby occludes another object
Iris
Donut-Shaped ring that controls the diameter of the pupil, gives the eye colour
Lateral geniculate nucleus (LGN)
Located at the end of the optic track on both sides of the brain, acts as the primary relay station for visual information
Lens
Curved and flexible structure in the eye that is responsible for about 20% of the eye’s focusing power
Linear perspective
Pictorial depth cue where parallel lines will appear to converge on a single vanishing point in the horizon
Magnocellular
Cells in layers 1 and 2 of the LGN
Motion parallax
Cue to depth based on the apparent speed of near and far object while you are in motion
Muller-Lyer illusion
Where two identical lines are made to look like they are different lengths by the placement of arrows on the line ends
Myopia
Nearsightedness; able to see up close but not far away
Nasal
Area of the retina closest to the nose
Necker cube
A line drawing of a transparent cube that has an ambiguous perception with regards to its 3D shape
Ocular dominance columns
Stripes of neurons in the visual cortex that respond preferentially to input from the right or left eye
Ommatidia
Light capturing element of a compound eye
Optic chiasm
Point in the brain where the optic nerve from the nasal part of the retina crosses
Optic disk / blind spot
Point of entry on the retina for the optic nerve, contains no photoreceptors
Optic flow
The perceived motion of the visual field that results from an individuals own movement through the environment
Optic nerve
Retinal ganglion axons exit through the optic nerve, pathway before the optic chiasm
Optic tract
Pathway after the optic chiasm
Orientation columns
Stripes of neurons in the visual cortex that respond preferentially to stimuli of a specific angle
Parvocellular
Cells located on layers 3-6 of the LGN
Perception
The ability to become aware of something through our senses
Photoreceptor
Cell that responds to light; rods/cones
Pinwheels
Areas of the visual cortex that do not have an orientation preference, but show a preference for other features such as brightness/colour
Preferential looking paradigm
Method used to determine grating acuity in infants
Primary visual cortex
First part of the cerebral cortex that is responsible for processing visual information
Receptive field
Area where a stimulus elicits a response
Rhodopsin
Light sensitive pigment in the retina
Saturation
Purity of hue
Sclera
The white of the eye, continuous with the cornea
Sensation
The transformation of physical characteristics of the world into electrical signals in our NS
Shading
Pictorial depth cue that can help to indicate the direction of light; which typically comes from ABOVE
Simple cells
Cells located in the visual cortex that respond to the orientation of bars of light
Simple eye
Eye with a single lens
Stereopsis
Perception of depth through the use of binocular disparity
Stereoscope
Device that creates the illusion of depth from two photographs taken of the same thing from different angles
Temporal
Area of the retina closest to the temples
Transduction
The transmission of electrical signals down the optic nerve
Ventral pathway
The “what pathway”, information processed along the temporal lobe
Ventriloquism
The production of sound so that it seems to be coming from a source other than the speaker
Visual capture
The dominance of vision over other sensory modalities
Visual spectrum
The range of electromagnetic spectrum that can be seen by humans
