Sensation and Perception Flashcards
Sensation
Conversion or transduction of physical, electromagnetic, auditory, and other information from the internal and external environment into electrical signals in the nervous system
Perception
Processing of sensory information to make sense of its significance
Sensory receptors
Nerves that respond to stimuli and trigger electrical signals
Sensory ganglia
Collection of cell bodies outside the central nervous system associated with sensory neurons
Projection areas
Sensory stimuli are transmitted to projection areas in the brain, which further analyze the sensory input
Threshold
Minimum stimulus that causes change in signal transduction
Absolute threshold
Minimum of stimulus energy that is needed to activate a sensory system
Threshold of conscious perception
Minimum of stimulus energy that will create a signal large enough in size and long enough in duration to be brought into awareness
Difference threshold / just-noticeable threshold
Minimum difference in magnitude between two stimuli before one can perceive this difference
Weber’s Law
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
Signal detection theory
Effects of nonsensory factors, such as experiences, motives, and expectations, on perception of stimuli. Detection theory or signal detection theory is a means to measure the ability to differentiate between information-bearing patterns and random patterns that distract from the information
Response bias
Bias is the extent to which one response is more probable than another. That is, a receiver may be more likely to respond that a stimulus is present or more likely to respond that a stimulus is not present. It can be hits, misses, false alarms, and correct negatives
Adaptation
Decrease in response to a stimulus over time
Eye
Organ specialized to detect light in form of photons
Cornea
Gathers and filters incoming light
Iris
Divides front of eye into anterior and posterior chambers. It has two muscles, the dilator and constrictor pupillae, which open and close the pupil.
Lens
Refract incoming light to focus it on the retina and is held in place by suspensory ligaments connected to the ciliary muscles
Aqueous humor
Produced by ciliary body and drains through canal of Schlemm
Rods
Detect light and dark
Cones
short-, medium-, long- , detect color
Macula
In the retina and corresponds to central visual field. Mostly has cones
Fovea
Center of macula and contains only cones
Rods and cones synapse on __________ which synapse on _________.
- Bipolar cells
2. Ganglion cells
Horizontal and amacrine cells
Integrate signals from ganglion cells and edge-sharpening
What support bulk of eye?
Vitreous on the inside and sclera and choroid on the outside
Visual pathway
Eye->optic nerves->optic chiasm->optic tracts->lateral geniculate nucleus (LGN) of thalamus->visual radiations->visual cortex
Optic chiasm
Contains fibers crossing from nasal side of the retina (temporal visual fields) of both eyes
Visual radiations run through ___
Parietal and temporal lobes
Where is visual cortex?
Occipital lobe
Parallel processing
All senses are processed this way. This is the simultaneuous analysis and combination of information.
Parvocellular cells
Detect shape with high spatial resolution and low temporal resolution
Magnocellular cells
Detect motion with low spatial resolution and high temporal resolution
Divisions of ear
Inner, outer,middle ear
Outer ear
pinna (auricle), external auditory canal, tympanic membrane
Middle ear
Ossicles ( malleus, incus, stapes). Stapes rest on oval window of cochlea and middle ear is connected to nose via eustachian tubes
Inner ear
Has the bony labyrinth, within which is the membranous labyrinth.
Bony labyrinth
Filled with perilymph
Membranous labyrinth
Has endolymph. It has the cochela, utricle, and saccule, semicircular canals
Cochlea
Detects sound
Utricle and saccule
Detect linear acceleration
Semicircular canals
Detect rotational acceleration
Auditory pathway
Cochlea-> vestibulocochlear nerve and medial geniculate nucleas (MGN) of thalamus–>auditory cortex in temporal lobe
Superior olive
Sound information goes here for sound localization
Inferior colliculus
Sound information goes here for startle reflex
Olfactory chemoreceptors or olfacotry nerves
Detect volatile or aerosolized chemicals in olfactory epithelium
Olfactory pathway
Olfacotry nerves –> olfactory bulb and tract–> higher order brain areas
PHEROMONES
Chemicals given off by animals that have an effect on social, foraging, and sexual behavior in other members of that species
Taste
Detection of dissolved compounds by taste buds in papillae. It comes in five modalities such as sweet, sour, salty, bitter, and umami (savory).
Somatosensation
Four touch modalities: pressure, vibration, pain, 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
Normal temperature of the skin to which objects are compared to determine if they feel “cold” or “warm”
Nociceptors
Responsible for pain perception
Gate theory of pain
Pain sensation is reduced when other somatosensory signals are present
Kinesthetic sense (proprioception)
Ability to tell where one’s body is in 3D space
Bottom up (data driven) processing
Recognition of objects by parallel processing and feature detection. It is slower but less prone to mistakes
Top-down (conceptually driven) processing
Recognition of an object by memories and expectations, with little attention to detail. It is faster, but more prone to mistakes.
Gestalt principles
Way the brain can infer missing parts of a picture when a picture is incomplete
Law of proximity
Elements close to one another tend to be perceived as a unit
Law of similarity
Objects that are similar appear to be grouped together
Law of good continuation
Elements that follow the same pathway tend to be grouped together
Subjective contours
Perception of nonexistent edges in figures, based on surrounding visual cues
Law of closure
When a space is enclosed by a group of lines, it is perceived as a complete or closed line
Law of praganz
Perceptual organization will always be as regular, simple, and symmetric as possible
