Chapter 2: Sensation and Perception Flashcards
1
Q
Sensation
A
aligned with transduction, which means seeing the physical, electromagnetic, auditory, and other information from our internal and external environment and converting this information into electro signals in the nervous system. Raw signal, which is unfiltered and unprocessed until it enters the central nervous system.
2
Q
Perception
A
Refers to processing this information within the central nervous system in order to make sense of the information significance. It helps us make sense of the world.
2
Q
Sensory receptors.
A
Neurons that respond to stimuli by triggering electrical signals that carry information to the central nervous system.
3
Q
Proximal Stimuli.
A
Sensory stimulating byproducts
3
Q
distal stimuli
A
Physical objects outside of the body.
4
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Psychophysics
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The relationship between the physical nature of stimuli and the sensations and perceptions these stimuli evoke.
5
Q
Ganglia
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Collections of neurons, cell bodies found outside the central nervous system.
6
Q
Projection areas.
A
Electrical chemical energy is sent along neuropathways to various projection areas.
7
Q
Photoreceptors
A
Respond to electromagnetic waves in the visible spectrum.
8
Q
Mechanoreceptors
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Respond to pressure or movement.
9
Q
Nociceptors
A
Respond to painful or nauseous stimuli.
10
Q
Thermal receptors.
A
Respond to changes in Temperature.
10
Q
Threshold
A
The minimum amount of stimulus that renders a difference in perception.
11
Q
Osmoreceptors.
A
Respond to the osmolarity of the blood.
11
Q
Olfactory receptors.
A
Respond to the volatile compounds.
11
Q
Taste receptors.
A
Respond to dissolved compounds.
11
Q
Action potentials.
A
All sensory information is sent to the central nervous system in the form of action potentials, which the central nervous system must then interpret and act upon.
12
Q
Threshold of conscious perception.
A
This lack of conscious perception may be because this stimulus is too subtle to demand our attention. The level of intensity that a stimulus must pass to be consciously perceived. Information that is received by the central nervous system but that does not cross this threshold is called subliminal perception. Stimulus below the absolute threshold will not be transduced, and thus never reaches the central nervous system. A stimulus below the threshold of conscious perception arrives at the central nervous system but does not reach the high order brain regions that control attention and consciousness.
12
Q
Absolute threshold.
A
Minimum Of stimulus energy that is needed to activate a sensory system. It is the minimum intensity which stimulus will be transduced.
12
Q
A
12
Q
Difference threshold OR just noticeable difference
A
Refers to the minimum change in magnitude required for an observer to perceive that two different stimuli are different.
12
Q
Discrimination testing.
A
In a comment discrimination testing experiment, a participant is presented with a stimuli. The stimulus is then varied slightly and researchers asked the participant to report whether they perceive a change period. Often, the difference continues to be increased until the participant reports they noticed the change, and this interval is recorded, as should the just noticeable difference.
12
Q
Weber’s Law.
A
He’s credited with the observation that differences thresholds are proportional and must be computed as percentages.
12
Q
Signal detection theory.
A
studies how internal and external factors influence thresholds. During each trial, families may or not be presented. Trials in which the signal is presented are called noise trials, whereas those in which the trial is not presented are called catch trials.
A hit is a trial in which the signals is presented and the subject correctly perceives the signal; And miss is a trial in which the subject fails to perceive the presented signal. A false alarm is a trial in which the subject indicates perceiving the signal, even though the signal was not presented; A correct negative is a trial in which the subject correctly identifies that no signal was presented.
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Adaptation.
Our ability to detect a stimulus can change over time. Adaptation can have both the psychological component and Physiological Component. It is one way the mind and body try to focus attention on only the most relevant stimuli, which are usually changes in the environment around us.
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Vision
The only sentence to which an entire lobe of the brain is devoted, the occipital lobe.
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Eye
Specialized organ used to detect light in the form of photons.
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Sclera
Thick structural layer or the white in the eye
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The eye is supplied with nutrients by two sets of blood vessels:
Choroidal vessels and retinal vessels
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Retina
The innermost layer of the eye, It contains the actual photoreceptors that transduce light into electrical information the brain can process.
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Cornea
The clear, doom like window in the front of the eye, which gathers and focuses the incoming light.
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Anterior chamber.
Lies in front of the iris.
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Posterior Chamber.
Between the iris and the lens.
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Iris
Colored part of the eye, is composed of two muscles: dilator pupillae, which opens the pupil under sympathetic stimulation; And the constrictor pupillae, which constricts the pupil under parasympathetic stimulation. The iris is continuous with the choroid, which is a vascular layer of connective tissue that surrounds and provides nourishment to the retina.
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Ciliary body.
Produces the aqueous humor that baits the front part of the eye before draining into the Canal of Schlemm.
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Lens
Lies right behind the iris and helps control the refraction of the incoming light.
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Accommodation
As the muscles contract, it pulls on the suspensory ligaments and changes the shape of the lens to focus on the image as the distance varies.
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Vitreous humor.
Transparent gel that supports their retina.
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Duplexity or duplicity theory of vision.
States that the retina contains two kinds of photoreceptors: those specialized for light and dark detection and those specialized for color detection.
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Cones
Are used for color vision into sense fine details. Most effective in bright light incoming 3 forms: Short also called blue, medium also called green, and long also called red.
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Rods
They are used in reduce illumination. Are more functional than cones because each rod cell is highly sensitive to photons and in somewhat easier to stimulate than a cone cell. All rods contain only a single pigment called rhodopsin. Route only allows sensation of light and dark, period. Less useful for detecting fine details because rods are spread over a much larger area of the retina. There are more rods than cones in the human eye.
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Macula
The central section of the retina. It has high concentrations of cones.
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Fovea
Center most region of the macula. It contains only cones.
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Blind spot.
Some distance away from the center of the retina, the optic nerve leaves the eye. This region of the retina which is devoid of photoreceptor is called the optic disc and it gives rise to a blind spot.
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Pathway of synapse.
Rods and cones synapse directly with bipolar cells, then with ganglion cells, the axons of which grouped together to form the optic nerve.
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Arrangement of nerves.
Photon must actually navigate past several layers of cells to reach the rods and cones at the back of the retina; The information is then transmitted forward into the form of action potentials from the rods anc cones cells until the signal reaches the ganglion cells.
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Amacrine and horizontal cells
Receives input from multiple retinal cells in the same area before the information is passed on to ganglion cells. These cells are important for edge detection, as they increase our perception of contrast.
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Visual pathways.
If an object is to your left, then photons from that object stimulate the right side of the retina in each eye. If an object is to your left, the photons enter your eyes and continue traveling to the right, thereby stimulating the right side of each of your eyes's retina. Visual information from objects to your left is preceded by the right side of your brain.
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Temporal and nasal retinal fibers
Temporal fibers are closer to your temple, nasal fibers are close to your nose.
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Temporal in nasal visual fields.
Placement of the object in space, relative to your eyes.
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Optic chiasm
Here come the nasal fibers from the left and right eyes crossed paths.
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Optic tracks.
Pathways after leaving the optic chiasm.
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Rule about the nasal and temporal.
The temporal field of each eye stimulates the nasal fibers of each eye, and vice versa. Second, The nasal fibers cross at the optic chiasm.
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Pathway after the optic chiasm.
Some nerve fibers passed to the lateral geniculate nucleus (LGN) of the thalamus, where they synapse with nerves that then pass through radiation in the temporal and parental lobe to the visual cortex in the occipital lobe. Some nerve fibers go strictly to the superior colliculi in the mid brain, which controls some reflective responses to visual stimuli.
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Parallel processing.
Brains ability to analyze information regarding color, form, motion, and depth simultaneously.
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Form
Refers not only to the shape of an object, but also our ability to discriminate an object of interest from the background by detecting its boundaries.
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Parvocellular cells
Neurons carry information from the fovea In surrounding central portion of the retina synapse. They are located in the lateral geniculate nucleus. These cells have very high color spatial resolution and very low temporal resolution. These cells can only work with stationary or slow moving objects.
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Magnocellular cells.
Are responsible for detecting motion because these cells have very high temporal resolution. It is also located in the lateral geniculate nucleus. These cells have very low spatial resolution, so much of the rich detail of an object can no longer be seen once the object is in motion.
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Depth perception.
Specialized cells in the visual cortex, known as binocular neurons, are responsible for comparing the inputs to each hemispheres and detecting these differences.
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Feature Detectors.
Exists in the visual cortex each feature detector cell types detects a very particular individual feature of an object in the visual field
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Vestibular Sense.
Our ability to both detect rotational and linear acceleration and to use this information to inform our sense of balance and spatial orientation.
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Pinna or auricle
Outside part of the ear. It’s main function is to channel sound waves into the external auditory canal, which directs the sound waves to the tympanic membrane (eardrum).
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The Tympanic membrane divides_____
the outer ear from the middle ear.
42
Three smallest bones in the body are called ____ and are:_______
Ossicles / malleus, incus and stapes
The baseline of the staples rests on the Oval window of the cochlea, which is the entrance to the inner ear.
43
Eustachian tube.
Helps equalize pressure between the middle ear and the nose environment
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Bony Labyrinth.
The hollow region of the temporal bone contains the cochlea, vestibule, and semicircular canals. Inside the Bony labyrinth rests a continuous collection of tubes and chambers called the Membranous labyrinth, filled with the potassium rich fluid called endolymph. While the Bony labyrinth is filled with perilymph.
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Cochlea
Spiral shaped organ that contains the receptors for hearing; It is divided into three parts called scalae. The middle scala houses the actual hearing apparatus, called the organ of Corti, which rests on a thin, flexible membrane called the basilar membrane. The organ of Corti is composed of thousands of hair cells, which are based in the endolymph. On top of the organ of Corti. It is a relatively immobile membrane called the tectorial membrane.
The sound entering the cochlea through the oval window causes vibrations in the perilymph, which are transmitted to the basilar membrane.
46
Round window.
A membrane covered holding the cochlea, It permits the perilymph to actually move within the cochlea. That is because fluids are not compressible.
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Auditory (vestibulocochlear) nerve
Hair cells in the organ of Corti Transduced the physical stimulus into an electrical signal, which is carried to the central nervous system by the auditory nerve.
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Vestibule
Refers to the portion of the Bony labyrinth that contains the utricle and saccule. They are sensitive to linear acceleration. The utricle and saccule Contain modified hair cells covered with otoliths. As the body accelerates, these otoliths will resist their motion. This bands and stimulates the underlying hair cells, which sends a signal to the brain.
49
Semi circular canals.
Are sensitive to rotational acceleration. They are arranged perpendicular to each other, and each ends in a swelling called an ampulla. When the head rotates, endolymph in the semicircular canals resist this motion., bending the underlying hair cells, which sends a signal to the brain.
50
Auditory pathways.
Most sound information spaces through the vestibulocochlear nerve to the brainstain, where it ascends to the medial geniculate nucleus. From there, nerve fibers project to the auditory cortex in the temporal lobe. For sound processing. Some information is also sent to the superior olive, which localizes the sound, and the inferior colliculus, which is involved in the start reflex and helps keep the eyes fixed on a point while the head is turned.
50
Hair cells.
Our names for the long Tufts of stereocilia on their top surface. Movement of fluid inside the cochlea leads to depolarization of the neuron associated with the hair cell.
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Place theory.
The location of a hair cell on the basilar membrane determines the perception of pitch when the hair cell is vibrated. The highest frequency pitches cause vibrations on the basilar membrane very close to the oval window, whereas low frequency pitches caused vibrations at the apex away from the oval window.
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Tonotopically
Which hair cells are vibrating gives the brain an indication of the place of the sound.
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Smell
Smell responds to volatile compounds. Olfactory chemoreceptors are located In olfactory epithelium in the upper part of the nasal cavity. Chemical stimuli must bind
to their respective chemoreceptor to cause a signal.
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Pheromones
Small can also carry interpersonal information. There are chemicals secreted by one animal, and which, once bonded with chemo receptors compelled, urge another animal to behave in a specific way.
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Olfactory pathways.
Odor molecules are inhaled into the nasal passages and then contact the olfactory nerves in the olfactory epithelium. These receptor cells are activated, sending signals to the olfactory bulb. The signals are then relayed via the olfactory track. to higher regions of the brain, including the limbic system.
56
There are five basic tastes:
Sweet, sour, salty, bitter, and umami which is savory.
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Flavor
Complex interplay between smell and taste, which can be affected by non chemical stimuli like texture in their individuals mood.
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How are taste detected?
Chemoreceptors, which are sensitive to dissolved compounds.
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What are the receptors for taste?
Taste buds, which are found in the little bumps of the tongue called papillae.
60
Taste pathway.
Taste information travels from taste buds to the brainstem, and innocence to the taste center in the thalamus before travelling to higher order brain regions.
61
Somatosensation is often reduced to:
Touch
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Pacinian corpuscles
Respond to deep pressure and vibration.
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What are the four modalities of touch?
Pressure, vibration, pain, and temperature.
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Meissner corpuscles
Respond to light touch.
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Merkel cells
Respond to deep pressure and texture.
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Ruffini ending
Respond to stretch.
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Free nerve endings.
Respond to pain and temperature.
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Two-point threshold.
Refers to the minimum distance necessary between two points of stimulation on the skin such that the points will be felt as distinct stimuli. Below the two-point threshold, the two stimuli will be felt as one.
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Physiological zero
Temperatures judge relative to physiological 0, or the normal temperature of the skin. Thus, an object feels cold because it is under Physical logical 0, An object feels warm because it is above physiological 0.
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Gate theory of pain.
Proposes that a special gating mechanism can turn pain signals on or off, affecting whether or not we perceive pain. The spinal cord is able to preferentially forward the signals from other touch modalities. Thus reducing the sensation of pain.
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Nociceptor
Pain perception.
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Kinesthetic sense is also called
proprioception
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Proprioception
Ability to tell where one's body is in space. The receptors for proprioception, called proprioceptors, are found mostly in muscles and joints and play critical roles in hand, eye, coordination, balance, and mobility.
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Constancy
Refers to our ability to perceive that certain characteristics of an object remain the same, despite changes in the environment.
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Gestalt Principles
Are a set of general rules that account for the fact that the brain tends to view incomplete in stimuli in organized, patterned ways.
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Perceptual Organization.
Refers to the ability to create a complete picture idea by combining top down and bottom up processing with all of the other sensory clues gathered from an object.
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Bottom-up processing
Refers to an object recognition by parallel processing and feature detection. Essentially, The brain takes the individual sensory stimuli and combines them together to create a cohesive image before determining what the object is. If we only performed bottoms up processing, we would be extremely inefficient in recognizing objects. Every time we looked at an object, it would be like looking at the same object for the first time.
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Top-down processing.
Driven by memories and expectations that allow the brain to recognize the whole object and they recognize the components based on these expectations. If we only perform top, bottom processing, we would have difficulty discriminating slight differences between similar objects.
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Depth perception relies on a number of visual cues that are interpreted by the brain to deduce an object's distance. These visual cues are separated into:
Monocular and binocular cues.
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Law of proximity
Elements close to one another tend to be perceived as a unit.
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Binocular cues
Primarily involves retinal disparity which refers to the slight difference in images projected on the two retinas. A second is convergence in which the brain detects the angle between the two eyes required to bring an object into focus.
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Law of similarity
Says that objects that are similar tend to be grouped together
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Monocular cues
Require one eye and include relative size, interposition, linear perspective, motion, parallax, and other minor cues.
Relative size: Refer to the idea that objects appear larger the closer they are.
Interposition: Means that when two objects overlap, the one in front is closer.
Linear perspective: refer to the convergence of parallel lines at a distance, the greater the convergence the further the distance
Motion parallax: objects closer to us seem to move faster when we change our field of vision
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Subjects contours
Perceiving contours and therefore the space tends to be perceived as a complete figure.
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Law of good continuation
Elements appear to follow in the same pathway tend to be grouped together.
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Law of closure
When a space is enclosed by a contour, the space tends to be perceived as a complete figure.
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Law of pragnanz
Perceptual organization will always be as regular, simple and symmetric as possible.
