Sensation and Perception Flashcards
Sensation
Refers to transduction, the conversion of physical, electromagnetic, auditory, and other information form our internal and external environment to electrical signals in the nervous system
Perception
The processing of sensory information to make sense of its significance
Distal stimuli
Stimuli that originate outside the body are called this before they reach the body
Proximal Stimuli
Directly interact with and affect sensory receptors, and inform the observer about the presence of a distal stimulus
Ganglia
Collections of neuron cell bodies found outside the central nervous system
Absolute Threshold
The minimum of stimulus energy that is needed to activate a sensory system
Subliminal Threshold
The perception of a stimulus below a given threshold. Usually this term refers to the threshold of conscious perception
Discrimination Testing
Used to analyze the limit in human perceptive ability. Difference between a current stimulus and an original is increased until the participant reports noticing a change.
Difference Threshold (Just Noticeable Difference)
The minimum difference in magnitude between two stimuli before one can perceive the difference
Weber’s Law
States that there is a constant ratio between the change in stimulus magnitude needed to produce and and the magnitude of the original stimulus
Signal Detection Theory
The concept that perception of stimuli can also be affected by non-sensory factors such as memory, motives, and expectations. Focuses on the changes in our perception of the same stimuli depending on both internal (psychological) and external (environmental) context
Response Bias
Refers to the tendency of subjects to systematically respond to a stimulus in a particular way due to non-sensory factors
Sclera
The white of an eye. Thick structural layer that covers most of the exposed portion of the eye
Retinal Vessel
One of two sets of blood vessels that supply nutrients to the eye
Choroidal vessels
A complex intermingling of blood vessels between the sclera and retina
Retina
The innermost layer of the eye, contains the photoreceptors that transduce light into electrical information the brain can process. Functions to convert incoming photons of light to electrical signals
Cornea
Clear, domelike window in the front of the eye which gathers and focuses the incoming light
Dilator Pupillae
One of two muscles in the iris. Opens the pupil under sympathetic stimulation
Constrictor Pupillae
Constricts the pupil under parasympathetic stimulation
Ciliary Body
Produces aqueous humor
Canal of Schlemm
The aqueous humor drains into this
Lens
Helps to control the refraction of incoming light
Accommodation
The process through which muscle contraction changes the shape of the lens
Vitreous
A transparent gel that supports the retina
Duplexity/Duplicity Theory of light
States that the retina contains two kinds of photoreceptors: those specialized for light-and-dark detection and those specialized for color detection
Rhodopsin
The color pigment found in rods
Fovea
The centermost point of the retina that contains only cones. Visual acuity is best here
Bipolar cells
Rods and cones connect with these. They highlight gradients between adjacent rods and cones
Ganglion cells
Synapse with bipolar cells. They group together to form the optic nerve
Amacrine and horizontal cells
Receive input from multiple retinal cells in the same area before the information is passed on to ganglion cells. They can accentuate slight differences between the visual information in each bipolar cells Important because they increase our perception of contrasts
Optic chiasm
Where the fibers from the nasal half of each retina cross paths. They carry the temporal visual field from each eye
Optic Tracts
The pathway between the optic chiasma and the brain
Lateral geniculate nucleus (LGN)
Region of the thalamus that relays visual information from the optic chiasma to the occipital lobe
Superior colliculus
Controls some response to visual stimuli and reflexive eye movements
Parallel Processing
The ability to simultaneously analyze and combine information regarding color, shape, and motion.
Feature Detection
The neuroscience correlate of parallel processing. The idea that our visual pathways contain cells specialized in detection of color, shape, or motion
Parvocellular Cells
Detect shape. Have good spatial resolution but bad temporal resolution