Lecture 1: Sensation Vs Perception Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is the difference between sensation and perception

A
  1. Sensation: real /collection of information
  2. Perception: interpretation of reality based on individual
  3. Pathway of sensation to perception:
    3a. Sensory stimulus->sensory receptors->neural impulses->interpretation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Psychophysics

A
  1. Attempts to quantify the relationship between sensation and perception
  2. Has 3 elements
    2a. Simple responses by the subject
    2b. Extensive data collection from each subject
    2c. Precise manipulation of experimental stimuli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Top down vs bottom up processing

A
  1. Top down (old situations): uses prior knowledge/experience to influences answers which can lead to bias (ex: pattern recognition)
  2. Bottom up processing (new situations): perception is created by sensory stimuli, is data driven and happens in real time
  3. Need both to be effective
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Perceptual organization

A
  1. When the brain makes inferences to organize sensory information from vision (in the form of electromagnetic waves)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Perceptual organization: depth perception: Binocular cues

A
  1. Depth perception that requires 2 eyes
  2. Types
    2a. Retinal disparity: 2 retina each make a slightly different image (due to coming in from different angles), eyes compare these images creating depth perception
    2b. Convergence: when we focus on an image, we cross our eyes slightly (greater convergence for closer images): our brain registers how much our eyes turn in which tells us how close the image is
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Perceptual organization: depth perception: Monocular cues

A
  1. Relative size: larger images look closer
  2. Relative height: objects higher look distant
  3. Overlap/interposition: object overlapped in front=looks closer
  4. Shading/contour: darker(contour)= closer , lighter(shaded)=farther
  5. Motion parallax: more distant objects move slower as we pass them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Perceptual organization: Subjective Constancy

A
  1. Subjective constancy: people assume size, Color and shape of things remains constant
    1a. Size constancy: perception that object has a fixed size regardless of the size of its in the retina
    1b. Color constancy: perception that object doesn’t change colour
    1c. Shape constancy: perception that object has a fixed shape, no matter its position (ex: closed vs open door)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Perceptual organization: Gestalts grouping principles: main principles

A
  1. Emergence: we put things into patterns without realizing it
  2. Reification: perception has more information than sensation (abstract is perceived as real)
  3. Invariance: simple objects are perceived in the same way regardless of their direction, rotation, scale etc.
  4. Multistability: tendency for ambiguous perceptual experiences to alternate in unstable fashion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Perceptual organization: Gestalts basic principles

A
  1. Figure ground: multistability/ Humans organize their perceptions into figures and backgrounds
  2. Pragnanz: Brain interprets images in the simplest manner possible
  3. Law of proximity: close=grouped
  4. Law of similarity: similar=grouped
  5. Law of closure: gaps=closed
  6. Law of continuity: aligned objects=continue behind obstructions (weird lines)
  7. Law of symmetry: objects create symmetry
  8. Law of past experience: objects based on past experience
  9. Law of common fate: objects that move together=grouped
  10. Law of common region: objects in same region=grouped
  11. Law of parallelism: objects aligned parallel to one another=grouped
  12. Law of connectedness: objects connected=grouped
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sensory processing: Absolute threshold of sensation

A
  1. Definition: Minimal intensity of stimulus that is detected (detected 50% of the time)
  2. Subliminal stimulus: stimulus below absolute threshold
    2a. has no effect on conscious perception, but still affects brain activity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Sensory processing: Just noticeable difference (JND)

A
  1. Definition: the smallest noticeable difference in intensity of a stimulus while its being experienced
  2. Webers law=K=(^I)/I
    2a. ^I: just noticeable difference
    2b. I: first stimulus
  3. Higher intensity of original sound, the greater the difference needed to notice it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Signal detection theory (SDT)

A
  1. How individuals differentiate signals (important stimuli) from a noise (unimportant stimulus)
  2. 4 possibilities
    2a. Hit (good): correct identification of signal
    2b. Miss: identification of signal as noise
    2c. False alarm: identification of noise as signal
    2d. Correct rejection (good): identification of noise
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Unbiased SDT in histogram

A
  1. If put noise and signals in a histogram:
    1a. Criterion in middle: unbiased criterion
    1b. Anything less intense than criterion=no response
    1c. Anything more intense than criterion=response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Biased SDT histogram

A
  1. Conservative/+/strict: move criterion to right (histograms shift to left)
    1a. Reduce hit/false alarms: good if brave/thirsty
    1b. Increase miss/correct rejection: bad bc likely to get eaten
    1c. Increases specificity: positive identification is more likely correct
    1d. Conservative strategy: prefers correct rejection over hits
  2. Liberal/-/relaxed: move criterion to left
    2a. Increase hit/false alarm
    2b. Decrease miss/correct rejection
    2c. Increases sensitivity: negative identification is more likely correct
    2d. Liberal strategy: prefer hits over correct rejection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Sensory Receptor types

A
  1. Free nerve ending : dendrites embedded in tissues
  2. Encapsulated endings: dendrites encapsulated by connective tissue that enhances their sensitivity
  3. Receptor cell: distinct cells (not neurons) that activate neurons. Each kind of receptor cell is designed to recieve and transducer a specific type of physical stimulus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Sensory Receptor location

A
  1. Exteroceptor: located near external environment (skin)
  2. Interoceptors: located internally (organs sensing blood pressure)
  3. Proprioceptor: located in moving body part because they sense position and movement (muscle movement)
17
Q

Sensory Receptor functions

A
  1. Mechanoreceptors: touch such as pressure, distraction or vibration
    1a. Pacinian corpuscles: vibration and heavy touch
    1b. Meissner corpuscles: light touch
  2. Thermoreceptors: temperature change
  3. Nociceptors: pain
  4. Photoreceptors: light
  5. Chemoreceptors: taste, small, blood chemistry
18
Q

Transient receptor potential (TRP) channels

A
  1. Receptors that respond to pain and changes in temperature
  2. TRP channels are located on the surfaces of Nociceptors and thermoreceptors: if damaged by a stimulus they undergo conformational changes which activate action potentials that travel 3 types of nerve fibres
    2a. AB (A-beta) nerve fibres: high diameter, thick myelination, fastest signal conduction
    2b. A-delta nerve fibers: medium all
    2c. C nerve fibers: smallest, unmyelinated, slowest conduction speed
19
Q

Tonic vs phasic receptors

A
  1. Tonic receptors: when receptors adapt slowly to stimuli and fire as long as stimulus is present
  2. Phasic receptor: quickly adapt to stimuli and dire when intensity or rate of stimulus changes
20
Q

Primary somatosensory cortex (PSC)

A
  1. Sensory receptors->primary somatosensory cortex (PSC) in post central gyrus of parietal lobe
  2. Homounculus: representation of how much space different areas of the body take up in PSC
21
Q

Sensory adaptation

A
  1. Occur in response to short continuous exposure to stimuli
  2. Temporary
22
Q

Structure of eye

A
  1. Path of light:
    1a. Cornea->anterior chamber->lens->vitreous chamber->retina->fovea
  2. Assisting parts:
    2a. anterior chamber & posterior chamber: filled with aqueous humor (nutrients, maintains inocular pressure) from ciliary bodys leaked out of the canal of Schlemm
    2b. Accommodation: ciliary muscle contract=lens sphere=brings focal point close to lens
    2c. vitrous chamber: has vitrous humor that focuses light to be projected on retina
    2d. Choroid: blood vessels
    2e. Sclera: white of eye
23
Q

Rods and cones

A
  1. Rods: rhodopsin is the pigment in rods which is a form of vitamin A (light/dark)
  2. Cones in fovea of retina:
    2a. 3 types for Color: trichromatic theory of vision
24
Q

Iris and autonomic control

A
  1. Creates opening called pupil
    1a. Sympathetic /dark: contracts radical muscles of iris, dilates pupil
    1b. Parasympathetic/light: contracts circular muscles of iris, constricts pupils
25
Q

Types of sight

A
  1. Nearsighted: myopia
    1a. Can’t see far
    1b. Image is in front of retina
  2. Farsighted: hyperopia
    2a. Can’t see close
    2b. Image is behind retina
  3. Just right: image is on retina
26
Q

Phototransduction cascade

A
  1. Light->ganglion cells->bipolar cells-> rods/cones (photoreceptors)
    1a. Ganglion cells become optic nerve
  2. Photoreceptors at rest (polarized): releases glutamate (excitatory)
    2a. Photons activate retinal from cis to trans retinal in rhodopsin->GPCR activated ->activates phosophodiesterase->hyperpolarizes->no glutamate->active
27
Q

Visual processing

A
  1. When signal crosses optic chiasm ->LGN in thalamus ->primary visual cortex in occipital lobe
28
Q

Parallel processing /feature detection

A
  1. Parallel processing is efficient, allows specialization, integration, and redundancy
  2. Cell types
    2a. Parvocellylar pathway: responds to fine detail, Color, size, shape
    2b. Magnocellular: location, speed, direction of movement
29
Q

Feature detection

A
  1. Describes how brain perceives external world by dividing it into specific features
30
Q

Structure and function of the ear

A
  1. Outer ear
    1a. Auricle/pinna directs sound into external auditory canal which carries wave to tympanic membrane/eardrum
  2. Middle ear has 3 bones (ossicles)
    2a. Malleus, incus, stapes which translate wave into physical vibration which is conveyed into oval window
  3. Inner ear:
    3a. Oval window -> scala vestibuli -> cochlea -> scala tympanic -> round window ->movement of wave causes organ of corti to vibrate (organ of corti sits on basilar membrane)
    3b. Hair cells in organ of corti have stereocilia which cause action potentials to be fired ->auditory nerve ->brain
31
Q

Inner ear: vestibular system

A
  1. semicircular canals: detect angular acceleration (twist of head)
  2. otoliths: linear acceleration: up down or tilt
32
Q

Auditory processing

A
  1. Hairs in organ of corti are mechanoreceptors…when they depolarize after binding they release a neurotransmitter that causes electrical signal to go to brain
    1a. Sound information: auditory nerve->cochlear nuclei in medulla ->inferior colliculus -> Medial geniculate nucleus of thalamus ->auditory cortex in temporal lobe
33
Q

Basilar tuning

A
  1. Humans hear from 20 Hz to 20 000 Hz
  2. We distinguish high and low frequencies from high frequency waves stimulating the narrow cochlear base and low frequency waves stimulating the wider cochlear apex
34
Q

Gustation

A
  1. Relies on chemoreceptors calledgustatory cells in taste buds
  2. There are 5 tastes: bitter, sour, salty, sweet, umami (savoury) and each gustatory cell detects all 5 tastes
35
Q

Olfaction

A
  1. Relies on chemoreceptors that bind to odorants
  2. Axons of olfactory chemoreceptors form olfactory nerve and when it’s GPCR binds to chemicals it triggers AP to be sent from olfactory nerve to olfactory bulb ->piriform (olfactory) cortex in temporal lobe ->orbitofrontal cortex
  3. Only sense that doesn’t relay into thalamus
36
Q

Pain

A
  1. Detected by nociceptors
    1a. Bottom up processing detects pain
    1b. Top down processing: impacts how people experience pain
37
Q

Kinesthetic sense

A
  1. Knowing bodies position and motion
  2. Ex: muscle memory
38
Q

Vestibular sense

A
  1. Feeling of balance and spatial orientation
  2. Located in inner ear