Sensation and Perception Flashcards
1
Q
A
2
Q
What is the difference between sensation and perception?
A
Sensation is the term for transducting the information surrounding us to the nervous system
Perception is the process of understanding those signals receive to make sense of that (for exemple, making an image out of the signals the nervous system gets from the eyes
3
Q
What is a distal stimuli and a proximal stimuli?
A
A distal stimuli would be the object in the environment
A proximal stimuli would be how that objects interacts with our sensory receptors
4
Q
What is psychophysics?
A
The study of the relationship between the physical nature of a stimuli and the sensations and perceptions these stimuli evoke
5
Q
What is a ganglia?
A
A collection of neurons cells bodies found outside of the CNS
6
Q
Where a ganglia would transduce the sensory information it has receive?
A
To a projection area to further analyse the information
7
Q
Name 7 sensory receptors?
A
Photoreceptors (sight)
Mechanorecepteurs (pressure or movement)
Nociceptors (dlr)
Thermoreceptors (temperature)
Osmorecepteurs (osmolarity of the blood)
Olfactory receptors (smell - volatile compounds)
Taste receptors (taste - dissolve compounds)
8
Q
Why is perception considered a part of psychology?
A
Because each person can experience different threshold
9
Q
What are the different types of threshold?
A
Absolute threshold
Threshold of conscious perception
Difference threshold
10
Q
What is an absolute threshold?
A
The minimum of stimulus energy needed to activate the sensory system (for a signal to happen)
11
Q
What is a Threshold of conscious perception?
A
The level of intensity needed from a stimulus to be consciously perceive by the brain (a signal is send, but if it’s too small, the brain would perceive it)
12
Q
How do we call information that doesn’t cross the threshold of conscious perception?
A
Subliminal perception
13
Q
What is the difference threshold? What’s its other name?
A
Just-noticeable difference (jnd)
Is the minimum change in the stimulus needed for the CNS to know it is in fact 2 different stimuli
14
Q
What test could be done in reference to the difference threshold?
A
Discrimination testing (patient is presented with a stimulus, and then we change it a little bit and ask if they perceive a change in the stimulus)
15
Q
What is the Weber’s law?
A
The ratio putting a quantitative number on the difference threshold
16
Q
What does the Weber’s law says about threshold?
A
The bigger the stimulus is, the less our sensitivity to it would be.
In exemple, if a light is already low, if you increase it a little bit, we would see the difference easier than if the light was already very high and we would increase it of the same amount.
17
Q
What is signal detection theory?
A
Studies how the internal (psychological) and external (environmental) factors influence threshold
18
Q
What is the difference between noise and catch trials?
A
Both of which are detection experiment.
A noise trial: the participants are presented with the signal
A catch trial: the participants are not presented with the signal
19
Q
What are the 4 different outcomes for detection trials?
A
Hit: the signal was presented and the signal was detected
Miss: the signal was presented and was not detected
Fasle alarm: the subject thinks they perceived the signal, but the signal wasn’t presented
Correct negative: the subject correctly identifies that no signal was presented
20
Q
How can our ability to detect a stimulus can change over time?
A
Through adaptation
21
Q
What are the components of adaptation?
A
Physiological (sensory) and Physchological (perceptual)
22
Q
What is the only sense to which an entire lobe is devoted for?
A
Sight (occipital lobe)
23
Q
What covers most of the exposed portion of the eye?
A
The sclera (doesn’t cover the frontmost portion which is the cornea of the eye)
24
Q
What are the sets of blood vessels that supplies the eye?
A
Choroidal and retinal vessels
25
What is the innermost layer of the eye?
Retina
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Where are the photoreceptors?
In the retina
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What is the role of the cornea?
To gather and focus the incoming light
28
What are the 2 parts of the front of the eye?
The anterior and posterior chambers
Anterior = in front of the iris
Posterior = between the iris and the lens
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What are the muscles that compose the iris?
Dilator pupillae and constrictor pupillae
30
Under what type of stimulation both the muscles in the iris function?
Diatator: in sympathetic stimulation
Constrictor: parasympathetic stimulation
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What the iris is continued with?
Choroid and the ciliary body
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What is the choroid?
A vascular layer of connective tissue that provides nourishment to the retina
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What is the function of the ciliary body?
To produce the aqueous humour
34
What structure drains the aqueous humour?
Canal of Schlemm
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What is the role of the lens?
Refract the incoming light
36
What controls the ciliary muscle?
Parasympathetic nervous system
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What is the process of accomodation?
As the ciliary muscle contracts, it pulls on the suspensory ligament and changes the shape of the lens to focus on an image as the distance varies
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What structure supports the retina?
Vitreous humour
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What part of the nervous system is the retina considered a part of?
Central
40
What is the duplicity theory of vision (or duplexity)
States that the retina contains 2 types of photoreceptors (once for light-dark and one for colour detection)
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What type of photoreceptor is most common in the retina?
Rods
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What are cones for?
Color
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What are the types of cones?
Short (also called blue)
Medium (also called green)
Long (also called red)
They are named based of the wavelength at which they have highest light absorption
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What pigment cell is in a rod?
Rhodopsin
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Where is visual acuity best at?
The fovea
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Where are the concentration of cones higher than os rods?
Macula and fovea
Closer to the fovea (center) = the more cones there will be
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What is the optic disk?
Where the optic nerve leaves the eye
This is devoted of photoreceptors and give rise to the blind spot
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What type of cells are in between the photoreceptors and the optic nerve?
Bipolar cells
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What is the trail of a stimuli coming from the photoreceptor?
Photoreceptor
Bipolar cells
Ganglion cells
Optic nerve (axones of ganglion cells group together to form the optic nerve)
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Why do we say information from photoreceptors are transmitted forward?
Because the bipolar cells and the ganglion cells are all in from of the photoreceptors
51
What's the relation between the number of receptors that converge through 1 bipolar cells to the ganglion cell with resolution?
The bigger the number of receptors, the lower the resolution
52
What could explain why we have a better resolution for color than for black-white details?
On average, more rods coverage to the same bipolar cell than cones
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What are the other 2 types of cells that are important for edge detection and that increase our perception of contrast?
Amacrine and horizontal cells
54
What is a visual pathway?
Both the anatomical connection between the eyes and the brain
And the flow of visual information along these connections
55
What is the difference between temporal and nasal retinal fibers?
Which fiber of an eye will receive the information from an object
Temporal fiber = on the lateral side of either eye
Nasal fibers = on the medial side of either the eyes, in other words, the closer to the nose
56
What is the difference between temporal and nasal visual fields?
Where is the object relatively to your eye. (or what part of the front portion of the eye is passed)
Temporal fiber = on the lateral side of either eye
Nasal fibers = on the medial side of either the eyes, in other words, the closer to the nose
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What happens at the optic chiasm?
Nasal fibers from the left eye and the right eye cross path
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What are called the pathway after having crossed the optic chiasm?
Optic tracts
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What is the use of the optic chiasm?
For the info of an object that you saw will be processed by the contralateral side (the opposite side)
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Where does the information goes to after the optic chiasm?
Some nerve fibers pass through the lateral geniculate nucleus (LGN) of the thalamus where they synapse with nerves that then pass through radiation in the temporal and parietal lobes to the visual cortex in the occipital lobe
Other fibers skip the thalamus and head directly to the superior colliculi in the hindbrain (reflex response to visual stimuli and reflexive eye movements
61
The connection between what parts of the brain help create a cohesive image of the world?
Optic tract, LGN and visual cortex
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What is parallel processing?
Ability of the brain to analyze information at the same time (i.e. cooler, form, motion and depth)
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What does form refers to?
The shape of an object, but also the ability for us to discriminate an object from the background
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What cells do the neurone synapse with at the lateral geniculate nucleus?
Mostly parvocellular cells but also magnocellular cells
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What is the characteristics of parvocellular cells?
They have high spatial resolution, but very low temporal resolution (so they can only work with stationary or slow-moving objects)
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What are the characteristics of magnocellular cells?
High temporal resolution (good for in-motion objects)
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From what part of the vision does magnocellular cells get information from the most?
Periphery
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What type of cells allow us rapid detection of an object approaching from the side?
Magnocellular cells
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What is depth-perception?
Ability to discriminate the 3 dimensional shape of our environment
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What are specialized cells in the visual cortex for depth perceptions named?
Binocular neurons
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How does binocular neurone work?
They compare the inputs from both hemisphere to detect the differences in visual depth
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What type of cells detects very particular features and associate it for easier visual processing?
Feature detectors in the visual cortex
73
What is the vestibular sense?
The ability to detect rotational and linear acceleration
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What are the 3 parts of the ear?
Outer, middle and inner ear
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What does a wave sound reaches first in the auditory system?
The cartilaginous outside part, named the pinna or auricle
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What is the role of the pinna/auricle?
To direct the sound wave into the external auditory canal towards the tympanic membrane (eardrum)
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What does a louder sound does to the vibration of the eardrum?
Bigger amplitude
78
What divides the outer ear from the middle ear?
Tympanic membrane (eardrum)
79
What are the 3 ossicles names?
Malleus (hammer)
Incus (anvil)
Stapes (stirrup)
80
What is the role of the ossicles?
Transmit and amplify the vibration from the tympanic membrane
81
What part of the ear is connected to the nasal cavity via the Eustachian tube?
Middle ear
82
What connects the nasal cavity and the middle ear together?
Eustachian tube
83
What it the role of the Eustachian tube?
Help equilibrate pressure of the middle ear with the environment
84
What is the bony labyrinth?
Hollow region of the temporal bone containing the cochlea, vestibule and semicircular canals
85
What are the membranous labyrinth?
Collection of tubes and chambers that contains receptors for the equilibrium and hearing
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What are the membranous labyrinth filled with?
Endolymph, a potassium-rich fluid
87
What are the 2 fluids in the bony labyrinth?
Endolymph and perilymph
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What is perilymph?
A thin layer of fluid in the bony labyrinth that suspend the endolymph.
Its role is to transmit vibration from the outside world as well as cushion the inner ear structures.
89
What part of the ear contains the receptors?
Cochlea
90
What are scalae?
How the 3 parts of the cochlea are called
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What is in the middle scalae?
The organ of cortical (the actual hearing apparatus).
On top of the organ of Corti is a tectorial membrane (relatively immobile)
The organ of Corti rests on the basilar membrane
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What composed the organ of Corti?
Thousands of hair cells which are bathed in endolymph
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What happens when a sound enters the cochlea?
It enter via the oval window and causes vibration of the perilymph. Thos vibrations are transmitted to the basilar membrane (on top of the organ of Corti) and then to the organ of Corti
The hair cells of the organ of Corti then transforms the information into electrical signal that is carried to the CNS by the auditory (vestibulocochlear) nerve
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What is the role of the round window?
It permits the fluid (perilymph) to actually move within the cochlea
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What is the vestibule?
The portion of the bony labyrinth that contains the utricle and saccule
96
What is the role of the utricle and the saccule?
Balancing apparatus by being sensitive to linear acceleration and to determine one's orientation
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How dies the vestibule functions in balancing?
The utricle and the saccule both contains hair cells (otoliths) that will resist the motion has the body accelerate. This will then create a signal to the brain
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What type of acceleration are the utricle and the saccule sensitive to?
Linear
99
What structure is sensitive to rotational acceleration?
Semicircular canals
100
How are the semicircular canals arranged?
They are perpendicular to each other and ends in a swelling called the Ampula at their bottom where hair cells are located
101
What happens to the electrical signal from the vestibulocochlear nerve?
It ascends to the medial geniculate nucleus (MGN) of the thalamus
Then nerve fibers project the information to the auditory cortex of the temporal lobe for sound processing
Some info is also send to the superior olive (to localize the sound) and to the inferior colliculi (for the vestibule-ocular reflex and to keep the eyes fixed on a point while the head is turned)
102
What are stereocilia?
Hair cells
103
What happens because of the swaying of the stereo cilia?
Opening of ion channels and causes a receptor potential
104
What is the use for stereo cilia that are directly connected to the tectorial membrane?
They are involved in amplifying the incoming sound
105
What is the place theory?
It states that the location of the hair cell on the basilar membrane determines the perception of pitch when that hair cell is vibrated
(high frequency pitch causes vibration of the hair cells close to the oval window; low-frequency pitch causes vibration at the apex which is far from the oval window)
106
How is the cochlea organize?
Tonotopically: which location of hair cells are vibrating gives the brain an indicator of the pitch of the sound
107
What are receptors for smell?
Olfactory chemoreceptors
108
Where are olfactory chemoreceptors located?
In the olfactory epithelium in the upper part of the nasal cavity
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Do every chemical entering the nose create a signal?
No, it must bind with it's respective chemoreceptor
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What are pheromones?
Chemical secreted by an animal that once it bond with chemoreceptors they urge another animal to behave a specific way
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What is the olfactory pathway?
Once odor molecules are bonded to their respective chemoreceptors in the olfactory nerve (in the olfactory epithelium).
These receptors are activated and send signals to the olfactory bulb.
These signals are relayed via the olfactory tract to higher regions of the brain (like the limbic system)
112
What are the 5 base tastes?
Sweet, sour, salty, bitter and umami
113
What is the difference between flavour and taste?
Flavour is the complex interplay of the smell and the taste in which could be affected by non chemical stimuli like texture and someone's mood
Taste is the chemical being detected by the taste buds
114
Where are found the taste buds in the mouth?
In little bumps on the tongue called papillae
115
What are the modalities of somatosensation?
Pretium, vibration, pain and temperature
116
Name 5 different types of receptor to receive tactile information (and what the respond to)
Pacinian corpuscles: deep pressure and vibration
Meissner corpuscles: light touch
Merkel cells: deep pressure and texture
Ruffini endings: stretch
Free nerve ending: pain and temperature
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Where does the signals from the somatosensation receptors go to?
The CNS where it travels to the somatosensory cortex in the parietal lobe
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In which lobe is the somatosensory cortex?
Parietal
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What is a two-point threshold?
The minimum distance on the skin between to points to which it will be feel as 2 points and not 1
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What does the two-point threshold depends on?
The density of nerves in a particular area
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What is the physiological zero?
The normal temperature of the skin
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What are pain receptors?
Nociceptors
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What is the gate theory of pain?
There's a special mechanism that can turn pain signals on and off. The spinal cord could forward the signals for pressure and temperature to the brain thus reducing the sensation of pain
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What is another name for kinesthetic sense?
Proprioception
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Where do we usually find proprioceptors?
In muscles and joints
They play a role in hand-eye coordination, balance and mobility
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What are the types of psychological processing for object recognition?
Bottum-up (data-driven) processing
Top-down (conceptually driven) processing)
127
What is the bottum-up (data-driven) processing?
Refers to the processing in parallel and the feature detection.
The brain takes information from different stimuli and makes an image before determining what object it is
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What is the top-down (conceptually driven) processing?
Memories and expectations recognize the object and then recognize the components based off these expectations
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Are the 2 object recognition processing sufficient by itself?
No, if we only did bottom-up processing, we would be slow at recognizing objects because it would be like it was the first time every time.
If we only did top-down, we would have difficulties discriminating small differences between objects
130
What is perceptual organization?
The ability to create a complete picture or idea by combining bottom-up and top-down processing with all other sensory clues
131
What are the 2 types of cues needed for depth perception?
Monocular and binocular (requires 1 eye and 2 eyes)
132
What can be deduced from monocular cues?
Relative size (objects appear closer than they are)
Interposition (when 2 objects overlap, the one in front is closer)
Linear perspective (convergence of parallel lines - the further the convergence, the further the distance)
Motion parallax (objects closer to us seem to move faster when we change our field of vision
133
What is relative size?
Monocular - Objects appear closer than they are
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What is interposition?
Monocular - When 2 objects are superposed, the one in front is closer
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What is linear perspectives?
Monocular - The convergence of 2 parallel lines. The further the convergence, the further the distance
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What is motion parallax?
Monocular - objects closer to us then to appear as if they are going faster when we change our field of vision
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What be deduced from binocular cues?
Retinal disparity (slight difference between the 2 images projected on the 2 retinas)
Convergence (angle between the 2 eyes to perceive distance)
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What is constancy in the perception?
Our ability to perceive that certain characteristics of objects remain the same despite changes in the environment.
139
For what do we have constancy for?
Color, brightness, size and shape
140
What is the Gestalt principles?
A set of general rules that account for the fact that the brain thens to view incomplete stimuli in organized and patterned ways.
141
What are the principles of the Gestalt principles?
Law of proximity (objects close to each other tend to be seen as a unit)
Law of similarity (objects similar to each other tend to be grouped together)
Law of good continuation (elements that appear to follow the same pathway tend to be grouped together)
Subjective contours (perceiving contours and therefore shapes that are not actually present)
Law of closure (When a space is enclosed by a contour, the space tends to be perceived as a complete figure)
142
What governs the Gestalt principles?
The law of Pragnanz
143
What is the law of Pragnanz?
Says that perceptual organization will always be as regular, simple and symmetric as possible
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