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
Spatial Resolution
The ability to see very fine detail when thoroughly examining an object
Temporal resolution
The ability to detect fast moving objects
Magnocellular cells
Detect motion because they have very high temporal resolution. They have low spatial resolution
Pinna/Auricle
The cartilaginous outside part of the ear where sound first enters. It’s main function is to channel sound into the external auditory canal
External auditory canal
Directs sound waves to the tympanic membrane
Tympanic Membrane (Eardrum)
Vibrates in phase with the incoming sound waves. The frequency of the sound wave determines there ate at which the tympanic membrane vibrates
Ossicles
Help transmit and amplify the vibrations from the tympanic membrane to the inner ear. The malleus, incus, and stapes
Malleus (Hammer)
Affixed to the tympanic membrane and acts on the incus
Incus (anvil)
Acts on the stapes
Stapes (stirrup)
Rests on the oval window of the cochlea, the entrance to the inner ear
Eustachean tube
Connects the middle ear to the nasal cavity. Serves to equalize pressure between the middle ear and the environment
Bony labyrinth
Contains the cochlea vestibule, and semicircular canals. The inner ear sits within it
Membranous labyrinth
Fills the cochlea, vestibule, and semicircular canals. Is filled with endolymph
Perilymph
Suspends the membranous labyrinth within the bony labyrinth. Transmits vibrations from the outside world and cushions the inner ear structures
Cochlea
The entrance of sound into this thing through the oval window causes vibrations in the perilymph. Eventually transmitting the vibrations to the hair cells on the organ of Corti.
Organ of Corti
The actual hearing apparatus. Composed of thousands of hair cells, bathed in endolymph
Basilar membrane
The thin, flexible tissue upon which the organ of Corti rests
Tectorial membrane
Sits on top of the organ of Corti
Round window
A membrane-covered hole in the cochlea that permits the perilymph to actually move within the cochlea
Auditory (vestibulocochlear) nerve
Carry electrical auditory signal to the CNS
Vestibule
The portion of the bony labyrinth that contains the utricle and saccule
Utricle and Saccule
Sensitive to linear acceleration and are used as a part of the balancing apparatus, and to determine orientation in 3D space
Otoliths
Hair cells found in the utricle and ssaccule with resist motion as the body accelerates, bending and stimulating the underlying hair cells, sending a message to the brain
Semicircular canals
Sensitive to rotational acceleration,
Ampulla
Swellinga the the end of the semicircular canals
Medial geniculate nucleus (MGN)
Relay system between the brainstem and the auditory cortex
Superior olive
Localizes sound
Inferior colliculus
Involved in the startle reflex and helps keep the eyes fixed on a point while the head is turned
Place theory
Accepted theory of sound perception. Hypothesizes that the location of a hair cells on the basilar membrane determines the perception of pitch when that hair cells is vibrated. The highest frequency pitches cause vibrations of the basilar membrane very close to the oval window, whereas low frequency pitches cause vibrations at the apex, away from the oval window
Tonotypical organization
Which hair cells vibrate gives the brain and indication of the pitch of the sound
Olfactory bulb
Activated olfactory effectors signal this structure.
Olfactory tract
Relays signal to higher regions of the brain, including the limbic system
Taste buds
Groups of cells that serve as taste receptors. Found on papillae
Papillae
Bumps on the tongue
Pacinian corpuscles
Respond to deep pressure and vibration
Meissner Corpuscles
Respond to light touch
Merkel Cells (discs)
Respond to deep pressure and texture
Ruffini Endings
Repsond to stretch
Free nerve endings
Respond to pain and temperature
Two-point threshold
Minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli
Physiological zero
The normal temperature of the skin (86-95 deg. Fahrenheit)
Nociceptors
The receptors most commonly responsible for sending pain signals
Gate Theory of Pain
Proposes that there is a special gating mechanism that can turn pain signal on or off. The spinal cord is able to preferentially forward the signals from touch modalities to the brain, reducing the sensation of pain
Proprioception (kinesthetic sense)
The ability o tell where one’s body is in space
Bottom-up (Data-driven) processing
Refers to object recognition by parallel processing and feature detection. The brain takes individuals sensory stimuli and combines them together to create a cohesive image before determining what the object is
Top-down (conceptually driven) processing
Driven by memories and expectation that allow the brain to recognize the whole object and then recognize the components based on these expectations
Perceptual organization
The ability to use top-down and bottom-up processing in tandem with all of the other sensory clues about an object to create a complex picture or idea
Object form
Determined through parallel processing and feature detection
Constancy
The idea that we perceive certain objects to remain the same, despite differences in the environment
Gestalt principle
The idea that there are ways for the brain to infer missing parts of a picture when a picture in incomplete
The law of proximity
Says that elements close to one another tend to be perceived as a unit
The law of similarity
Says that objects that are similar tend to be grouped together
The law of good continuation
Says that elements that appear to follow in the same pathway tend to be grouped together. There is a tendency to perceive continuous patterns in stimuli rather than abrupt changes
Subjective contours
Perception of contours (and shapes) that are not actually present in the stimulus
Law of closure
Says that when a space is enclosed by a contour it tends to be perceived as a complete figure.
Law of Pragnanz
Says that perceptual organization will always be as regular, simple, and symmetric as possible
