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Perception > Last minute Review > Flashcards

Last minute Review Flashcards

1
Q

Moment provides info one 4

A

> Orientation and navigation
calculating direction of heading
`avoiding/catching approaching objects
Separation of figure and ground
introduction of movement defines an object
Defining object shape
successive views can be integrated into a full percept
Called structure from motion
Attracting attention
detection of moving object is easier than detecting same target when stationary

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2
Q

Dorsal Pathway in general

A

Where/how

V2–>MT (motion)–>parietal cortex (perceiving space/motor, coordinating visual/motor interactions)

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3
Q

Psychophysical Evidence for direction circuit

A

Selective adaptation (measure contrast thresholds before and after adaptation)
-direction specific
–adapting to a gratings/bars moving in one direction, elevates the threshold for gratings/bars moving in the same direction
-velocity specific
–most threshold elevation is found for gratings moving at the same speed
Suggests populations of direction and velocity selective neurons

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4
Q

Eye movements: 2 types

A

version eye movements
-Pursuit movement - Tracking objects through space
[Slow & smooth]
-Saccades - fixating on different parts of a scene
{Saccadic suppression & transsaccadic integration (change blindness)]
[Fast, jerky & very frequent]
vergence eye movements
(shift of movement from close up to far away/vise versa)

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5
Q

Corollary Discharge Theory- 3

A

Movement perception depends on three signals
-Motor signal (MS) - signal sent to eyes to move eye muscles (from the supirior colliculous)
-Corollary discharge signal (CDS) - copy of the motor signal
-Image movement signal (IMS); movement of image stimulating receptors across the retina
Movement is perceived when comparator receives input from either corollary discharge or image movement signal
Movement is not perceived when comparator receives input from both corollary discharge and image movement signals

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6
Q

Physiological Evidence for Corollary Discharge Theory

A

Damage to the medial superior temporal area in humans leads to perception of movement of stationary environment with movement of eyes
Real-movement neurons found in monkeys that respond only when a stimulus moves and do not respond when eyes move

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7
Q

The kinetic depth effect

A

When the shadow of a rotating 3D object is cast on a screen, it looks three-dimensional, even though the shadow is flat. 


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8
Q

Bimodal neurons

A

Are sensitive not only to visual information from the space near the hand, but also to tactile stimulation of the hand
Are uniquely suited to support the execution of actions on nearby objects

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9
Q

Action-specific perception

A

Representations provided by perceptual system
Take action capabilities into account.
Capture the relationship between your environment and your abilities.

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10
Q

Visual processing in perihand space

A

Recent studies demonstrate that visual information processing about nearby objects is different when hands are near objects than when hands are far away from objects.
This difference facilitates potential actions (actions that could be performed if desired).

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11
Q

Vision Affects Action

A

Time to process visual feedback
One of first researchers to study visual feedback systematically described an elegant series of simple experiments
-Kymograph Robert S. Woodworth (1869–1962)

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12
Q

Visual feedback

A

Refers to visual information used to control an ongoing movement
Involves complex and precise coordination of incoming visual information with outflowing muscle commands

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13
Q

Physical characteristics of sound

A
  • The physical stimulus for hearing is a change in the pressure of the surrounding medium (usually air, but could be any fluid)
  • Pressure change achieved with any vibrating surface
  • Molecules of air alternately compressed and released
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14
Q

dBSPL

A

decibels of sound pressure level: SPLreference is taken as 20 micropascals, a value that is very close to the normal absolute threshold of hearing
converts a range of 0.0002 (threshold) to 2000 (jet take-off) to a range of 0 to 140 dB

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15
Q

Calculating Decibels

A
  • 20 dB = 10x increase in sound pressure
  • 100 dB = 100, 000 x more intense
  • how many decibels for a doubling in sound pressure? 6
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16
Q

Equal loudness contour

A

Curve showing the amplitude of tones at different frequencies that sound about equally loud


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17
Q

We’re best at what frequency of sound?

A

3000-5000Hz critical to human conversation.

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18
Q

Fourier analysis

A

A mathematical procedure for decomposing a complex waveform into a collection of sine waves with various frequencies and amplitudes.

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19
Q

Fourier spectrum

A

A depiction of the amplitudes at all frequencies that make up a complex waveform.

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20
Q

Timbre

A

The difference in sound quality between two sounds with the same pitch and loudness; for complex periodic sounds, timbre is mainly due to differences in the relative amplitudes of the sounds’ overtones or harmonics; the perceptual dimension of sound that is related to the physical dimension of waveform.

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21
Q

Fluid-filled inner ear has two main components:

A
  • cochlea
 (hearing)
  • semi-circular canals
(vestibular function)
  • Stapes attaches to cochlea at the oval window
  • Cochlea is snail-shaped structure with three internal canals
  • Neural transduction occurs within the cochlea
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22
Q

vestibular system

A

The sense organs used to produce neural signals carrying information about
balance and acceleration;
includes the semicircular canals and the otolith organs.

23
Q

semicircular canals

A

Part of the vestibular system; three mutually perpendicular hollow curved tubes in the
skull filled with endolymph; responsible for singling head rotation.

24
Q

The Organ of Corti:

A

the auditory analogue of the retina
Is the site of neural transduction
Rests on the basilar membrane
Contains the hair cell receptors

25
Q

Basilar Memrane Displacement: Base, Middle and Apex (end)

A
  • at thick stiff narrow base: big displace for high freq

* At thin wide loose apex: big displacement for low freq

26
Q

Stimulation Deafness Experiments

A

Experimental procedure
First, a low level test tone is presented
Then, masking tones are presented with frequencies above and below the test tone
Measures are taken to determine the level of each masking tone needed to eliminate the perception of the test tone
Assumption is that the masking tones must be causing activity at same location as test tone for masking to occur – common neural mechanism
Resulting tuning curves show that the test tone is affected by a narrow range of masking tones
Psychophysical tuning curves show the same pattern as neural tuning curves which reveals a close connection between perception and the firing of auditory fibers

27
Q

Volley Theory & Phase Locking

A

frequency could be coded by pattern of activity in a number of cells

28
Q

Conductive loss:

A 
~mechanical impediment to sound transmission~
Common causes
-blockage in external ear
-Otitis media (infection)
-Otosclerosis
Diagnosis
-Relatively “flat” loss or low -frequencies more affected
-Difference between bone and air thresholds
-maximum loss no more than about 6o dB
Treatment
-Medical/surgical
-Hearing aid
29
Q

Sensori-neural loss:

A


~damage to neural transduction (i.e. hair cells)~
Common causes
-Age: gradual deterioration (presbycusis)
-Noise: progressive cumulative effects
-Ototoxic drugs: nicotine, aspirin, streptmycin
-Infections: mumps, maternal rubella, syphilis
Diagnosis
-Similar bone and air thresholds
-Typical high frequency loss (“ski-slope”)
-Loss may be profound
Treatment
-Hearing aids very limited
-In severe cases, cochlear implants

30
Q

Problems for theories of the encoding of pitch: Change in pitch perception in noise

A
  • tones heard in background noise - pitch appears to be shifted in direction opposite to the pitch of the noise
  • tone in lower frequency noise appears higher in pitch
  • tone in noise higher in frequency appears lower in pitch
31
Q

Problems for theories of the encoding of pitch: Missing Fundamental

A
  • Most natural sounds have a fundamental frequency and harmonics, which are always some multiple of the fundamental
  • The defining characteristic of the sound is the fundamental
  • The missing fundamental phenomenon occurs when only the higher harmonics of a tone are presented
  • In this situation, the fundamental is still heard
  • Poses problems for a simple place theory
32
Q

Problems for theories of the encoding of pitch: Loudness

A
  • as the intensity of tone changes, so does the pitch
  • low frequency tones - high intensity sounds appear lower in pitch
  • high frequency tones - high intensity sounds appear higher in pitch
33
Q

Descending pathways

A

Carry signals between auditory cortex
Modulate motile response
Protect ear from damage through acoustic reflex activation
Block task-irrelevant ascending auditory signals and pass task-relevant ones
feedback-related MGB activity correlates with the ability to discriminate different syllables

34
Q

Ventral Stream Auditory

A

What or ventral stream starts in the anterior portion of the core and belt and extends to the prefrontal cortex
-It is responsible for identifying sounds

35
Q

Dorsal Stream Auditory

A
  • Where or dorsal stream starts in the posterior core and belt and extends to the parietal and prefrontal cortices
  • It is responsible for locating sounds
36
Q

Monaural Cue for Sound Location

A
  • The pinna and head affect the intensities of frequencies
  • The difference is called the head-related transfer function (HRTF)
  • This is a spectral cue since the information for location comes from the spectrum of frequencies
37
Q

Judging Distance

A

Loudness/amplitude
-familiarity
-inverse square law (Amplitude of sound decreases in proportion to the square of the distance to the source)
.
.
Spectral Cues
-“blurring” (reduction in relative loudness of higher frequency components of sound)
-Proportion of sound reflected from surfaces
-Doppler effect (The frequency of a sound emitted by a moving sound source is higher in front of the sound source than behind it)

38
Q

Auditory Grouping

A

-Heuristics that help to perceptually organize stimuli
>Location - a single sound source tends to come from one location and to move continuously
>Similarity of timbre and pitch - similar sounds are grouped together
>Auditory stream segregation - separation of stimuli into different perceptual streams

39
Q

proprioception

A

-muscle stretch and joint angle, for monitoring limb position and movement
-Three different types of sensory organs provide information about joint angles:
muscle spindles
Golgi tendon organs
joint receptors

40
Q

Simultaneous Sounds: 4

A

Grouping by Temporal Proximity
Grouping by Frequency Similarity
Grouping by Harmonic Coherence
Grouping by Synchrony or Asynchrony

41
Q

haptic

A

object shape, perceived through touch and proprioception together

42
Q

Pattern Theory

A

Distributed coding – trichromatic theory of colour vision

Population code

43
Q

duplex theory of texture perception

A
  • Spatial cues are determined by the size, shape, and distribution of surface elements
  • Temporal cues are determined by the rate of vibration as skin is moved across finely textured surfaces
  • only the adaptation to the 250-Hz stimulus affected the perception of fine textures (adapt pacinian)
44
Q

Dorsal Path Body

A
  • information used to guide actions that require tactile and proprioceptive input
  • goes from S1 to the posterior parietal cortex and then to premotor cortex
45
Q

Ventral Path Body

A
  • tactile and proprioceptive information used in perceiving and remembering object shape and identity
  • Goes from S1 to S2 and then to prefrontal cortex and hippocampus
46
Q

PET imaging while cold stimulus applied to right hand

A

Activation in the left insular cortex which varied with the temperature applied to the hand
a site where nonpainful temperature sensations are represented in a somatotopic map used for, among other things, maintaining homeostasis ( e. g., constant body temperature)
R. insular: a site where the relative intensities of temperature sensations are evaluated.

47
Q

Cortical Representation of Pain: Pain Matrix

A
  • Signals from nociceptors travel up the spinothalamic pathway and activate:
  • Subcortical areas including the hypothalamus, limbic system, and the thalamus
  • Cortical areas including S1 and S2 in the somatosensory cortex, the insula, and the anterior cingulate cortex
  • These cortical areas taken together are called the pain matrix
48
Q

Analgesia

A

reducing sensitivity to pain by modulating the intensity of pain signals

49
Q

endogenous opioids

A

Compounds that belong to a class of substances called opiates; released by the body in response to painful or stressful experiences.

50
Q

endorphins

A

Endogenous opioids that have an inhibitory effect on pain- related neural signals in many areas of the central nervous system, reducing the perceived intensity of pain.

51
Q

Gate Control Model of Pain Perception

A

-The “gate” consists of substantia gelatinosa cells in the spinal cord (SG- and SG+)
-Input into the gate comes from:
Large diameter (L) fibers - information from tactile stimuli
Small diameter (S) fibers - information from nociceptors
Central control - information from cognitive factors from the cortex
-Pain does not occur when the gate is closed by stimulation into the SG- from central control or L-fibers into the T-cell
-Pain does occur from stimulation from the S-fibers into the SG+ into the T-cell

52
Q

Haptic Tests: 8

A
  • lateral motion (Texture)
  • pressure (hardness)
  • skin contact (tempeture)
  • unsupported holding (weight)
  • enclosure (volume/global shape)
  • contour following (volume/exact shape)
  • functional test (specific function)
  • part motion test (part motion)
53
Q

Controlling Pain

A 
Pharmacological interventions
•Local or topical (e.g., lidocaine)
•Central (e.g., morphine & endogenous opiates)
Physical intervention
•Counterirritants (e.g., acupuncture)
Psychological Interventions
•Placebo effect
•Hypnosis
•Cognitive behavioural therapy
•Expectation
•Shifting attention
54
Q

Haptic perception

A

•is the active exploration of 3-D objects with the hand
•It uses three distinct systems:
–Sensory system
–Motor system
–Cognitive system
•Psychophysical research shows that people can identify objects haptically in 1 to 2 sec

Perception (23 decks)

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