Sensation and perception Flashcards
The conversion or transduction of physical, electromagnetic, auditory, and other information into electrical signals in the nervous system
Sensation
The processing of sensory information to make sense of its significance
Perception
Nerves that respond to stimuli by triggering electrical signals that carry information to the CNS
Sensory receptors
Studies the relationship between the physical nature of stimuli and the sensations and perceptions they evoke
Psychophysics
Collections of neuron cell bodies found outside the CNS which send information to projection areas to further analyze sensory input
Sensory ganglia
Receptors that respond to electromagnetic waves in the visible spectrum (sight)
Photoreceptors
Receptors that respond to pressure or movement. Hair cells for example, respond to movement of fluid in the inner ear structure (movement, vibration, hearing, rotational, and linear acceleration)
Mechanoreceptors
Receptors that respond to painful or noxious stimuli (somatosensation)
Nociceptors
Receptors that respond to changes in temperature (thermosensation)
Thermoreceptors
Receptors that respond to the osmolarity of the blood (water homeostasis)
Osmoreceptors
Receptors that respond to volatile compounds (smell)
Olfactory receptors
Receptors that respond to dissolved compounds (taste)
Taste receptors
The minimum amount of a stimulus that renders a difference in perception
Threshold
The minimum of stimulus energy that is needed to activate a sensory system and evoke an action potential
Absolute threshold
The level of intensity (large enough in size and long enough in duration) that a stimulus must pass in order to be consciously perceived by the brain (signal is transductance)
Threshold of conscious perception
Information received by the CNS the does not cross the threshold of concious perception
Subliminal perception
The minimum change in magnitude required for an observer to perceive that two difference stimuli are different
Difference threshold (just noticeable difference)
The just noticeable difference for a stimulus is proportional to the magnitude of the stimulus, and that this proportion is constant over most of the range of possible stimuli
Weber’s law
A thoery that studies how internal (psychology) and external (environmental) factors influence thresholds of sensation and perception
Signal detection theory
Trials in which the signal is presented
Noise trials
Trials in which the singal is not presented
Catch trials
A signal is presented and correctly perceived in a trial
Hit
A subject fails to perceive the presented signal in a trial
Miss
A subject indicates that they perceived a signal even through the signal was not presented in a trial
False alarm
A subject correctly identifies that no signal was presented in a trial
Correct negative
A decrease in response to stimulus over time
Adaptation
Examined using signal detection experiments with four possible outcomes: hits, misses, false alarms, and correct negatives
Response bias
Covers the exposed portion of the eye (except the cornea) for structural support
Sclera
Located between the sclera and retina and provides nourishment and support to the retina
choroidal vessels (choroid)
Contains the photoreceptors that transduce light into electrical information
Retina
A clear, domelike, window in the front of the eye, which gathers and focuses incoming light
Cornea
Allows the passage of light from the anterior to posterior chamber
Pupil
The coloured part of eye - controls size of pupil - divides the front of the eye into the anterior and posterior chambers
Iris
The muscles of the iris that open pupil under sympathetic stimulation
Dilator pupillae
The muscles of the iris that constrict the pupil under parasympathetic stimulation
Constrictor pupillae
Produces AQUEOUS HUMOR that bathes the front part of the eye before draining into the canal of Schlemm.
Ciliary body
Right behind iris, controls the refraction of incoming light to focus it on the retina and is held in place by suspensory ligaments and connected to ciliary muscles
Lens
A part of ciliary body that is under parasympathetic control. Pulls on the suspensory ligaments and changes the shape of the lens to focus an image ~ accommodation
Ciliary muscle
The fluid behind the lens that supports the retina
Viterous humor
The back of the eye that acts as a screen and consists of neural elements and blood vessels that convert incoming light to electrical stimuli
Retina
The theory that the retina contains two kinds of photoreceptors, those specialized for light and dark detection and those for color detection
Duplexity (duplicity theory of vision)
Assoicated with colour vision and the detection of fine detail and work best in bright light. They come in three wavelengths: short, medium, and long
Cones
Contain rhodopsin and respond to any wavelenth of light but only detect light and dark. Function best in low light.
Rods
The area of high cone concentraion in the retina
Macula
The central part of the macula that only contains cones. Visual acuity is best in daylight
Fovea
The part of the retina that is devoid of photoreceptors
Blind spot
The location where rods and cones synapse
Bipolar cells
A group of axons that form the optic nerve and synapse with bipolar cells converging information from rods and cones
Ganglia cells
Cells that integrate signals from ganglion cells and perform edge-sharpening
Amacrine and horizontal cells
The brain’s ability to analyze information regarding color, form, motion, and depth simultaneously using independent pathways in the brain to form cohesive picture.
Parallel processing
Shape, ability to discriminate object from background by detecting its boundaries. Detected by parvocellular cells
Form
Found in the LGN and have high color spatial resolution ~ detect very fine detail of form. Only work with slow-moving objects because these cells have very low temporal resolution
Parvocellular cells
Cells in the LGN that detect motion b/c they have very high temporal resolution Detect information from periphery but have very low spatial resolution (no rich detail). Provide blurry picture of object moving by
Magnocellular cells
The ability to discriminate 3D shape and judge distance. Performed by bionocular neurons which compare inputs from both hemispheres and compares the differences
Depth perception
Cells that detect very specific details
Feautre detectors
The ability to detect rotational and liner acceleration and use this information to inform our sense of balance and spatial orientation
Vestibular senses
The pinna (auricle) channels sound waves into the external auditory canal which directs sound waves to the tympanic membrane (eardrum). Frequency of wave determines vibration of drum and amplitude determines the intensity.
Outer ear
Three smallest bones in body and transmit and amplify vibrations of drum ~ located in the middle ear
Ossicles
The three ossicles in the middle ear
Malleus (hammer), incus (avil), stapes (stirrup)
Connects the middle ear with the nasal cavity and equilizes the pressure between the middle ear and the external enviornment
Eustachian tube
Sits in the bony labyrinth, the hollow region of the temporal lobe, and contains the membraneous labyrinth which contain receptors for the sense of equilibrium and hearing and are filled with potassium rich fluid called endolymph which is suspended by perilymph which transmits vibrations from the outside and provides cushion
Inner ear
The fluid that fills the bony labyrinth
perilympth
The fluid that fills the membraneous labyrinth
endolympth
Spiral shaped organ that contains hearing receptors and is divided into three parts called scalae
Cochlea
The middle scalae of the cochlea that rests on a thin basilar membrane and is composed of hearing cells that are bathed in endolympth
Organ of Corti
Allows the perilymph to move within cochlea and respond to vibrations
Round window
Hair cells transmit physical stimulus into electrical signal which is carried to CNS by auditory ———- nerves
vestibulocochlear
The portion of bony labyrinth that contains utricle and saccule ~ sensitive to linear acceleration ~ contains modified hair cells covered with otoliths which resist motion and send signals to brain
Vestibule
Three canals that are sensitive to rotational acceleration and each ends in a swelling called an ampulla where hair cells are locate
Semicircular canals
The auditory pathway starts from the cochlea and travels through the —— and —— of the thalamus to get to the —– in the temporal lobe. Some information projects to the —–, which localizes the sound, and the —–, which is invovled in the startle reflex
vestibulocochlear nerve, medial geniculate nucleus (MGN), auditory cortex, superior olive, inferior colliculus
The location of the hair cell on the basilar membrane determines the perception of pitch when that hair cell is vibrated
Place theory
Smell is the detection of volatile or aerolized cheimcals by the —– —– on the olfactory epithelium in the upper part of the nasal cavitiy
olfactory chemoreceptors (olfactory nerves)
chemicals given off by animals that have an effect on social, foraging, and sexual behvaiour in other members of the species
Pheromones
The olfactory pathway starts from the olfactory nerve and travels through the olfactory —- and olfactory —- to get to higher order brain areas, such as the limbic system
bulb, tract
The five taste modalities
sweet, sour, salty, bitter, and umami (savoury)
Taste is the detection of dissolved compounds by — — in —.
Taste buds, papillae
The four modalities of somatosensation
Pressure, vibration, pain and temperature
Receptors that respond to deep pressure and vibration
Pacinian corpuscles
Receptors that respond to light touch
Meissner corpuscles
Receptors that respond to deep pressure and texture
Merkel cells (discs)
Receptors that respond to streach
Ruffini endings
Receptors that respond to pain and temperature
Free nerve endings
The minimum distance necessary between two points of stimulation on the skin such that the points are felt as two distinct points ~ depends on nerve density
A two-point threshold
Temperature is judged relative to normal temperature of skin
Physiological zero
Receptors responsible for pain perception
Nociceptors
States that pain sensation is reduced when other somatosensory signals are present. The spinal cord can preferentially forward signals from touch modalities to the brain
The gate theory of pain
Refers to the ability to tell where one’s body is in three-dimensional space. Uses proprioceptors found primarily in muscle and joints and play role in hand-eye coordination, balance, and mobility
Kinesthetic sense (proprioception)
The ability to recognize and object by parallel processing the feature detection. Takes individual stimuli to form cohesive picture. Slower but less prone to mistakes.
Bottom up (data driven) processing
The process driven by memories and experiences which allows the recognition of the whole object, with little attention to detail. Faster but more prone to mistakes
Top-down (conceptually driven) processing
The ability to create a complete picture or idea by combining top-down and bottom-up processing with all of the other sensory clues including, depth, form, motion, and constancy gathered from an object
Perceptual
Cues that require one eye and include relative size, interposition, linear perspective, motion parallax, and their minor cues
Monocular cues
Objects appear larger the closer they are (monocular cue)
Relative size
When two objects overlap, the one in front is closer (monocular cue)
Interposition
The greater the convergence of parallel lines, the further the distance (monocular cue)
Linear perspective
The perception that objects closer to us seem to move faster when we change our field of vision (monocular cue)
Motion parallax
Involve retinal disparity which refers to the slight difference in images projected on the two retinas
Binocular cues
The brain detects the angle between the two eyes required to bring an object into focus (binocular cue)
Convergene
Our ability to perceive that certain characteristics of objects remain the same, despite changes in the environment (binocular cues)
Constancy
A set of general rules that account for the fact that the brain tends to view incomplete stimuli in organized, patterned ways
Gestalt principes
Elements close to one another tend to be perceived as a unit
Law of proximity
Objects that are similar tend to be grouped together
Law of similiarty
Elements that appear to follow in the same pathway tend to be grouped together
Law of good continuation
Perceiving shapes that are not actually present
Subjective contours
When space is enclosed by a contour, the space tends to be perceived as a complete figure
Law of closure
Perceptual organization will always be as regular, simple, and symmetric as possible
Law of pragnanz
