Sensation and Perception

Question 1

What is synaesthesia?(1)

Answer 1

Experiencing one sense from the activation of another.

Question 2

What was Ramas hypothesis on why synaesthesia occurs?(1)

Answer 2

In early postnatal brains all diff modalities are connected but this usually segregates following this, expected to not segregate is synaesthates hence why there is crosswiring.

Thought that synaesthesia helps memory and creativity.

Question 3

Define psychophysics. (1)

Answer 3

Methods that measure the strength of a stimulus and the observers sensitivity to that stimulus.

Question 4

What is the absolute threshold usually described has?(1)

Answer 4

The value of a stimulus said to have been perceived 50% of the time.

Question 5

What is the Just noticeable difference(JND)? What effects this?(3)

Answer 5

The minimal change in a stimulus that can just barely be detects.
Depends on how intense the stimuli is and the particular sense.

Question 6

Define Weber’a Law.(1)

Answer 6

The JND of a stimulus is a constant proportion despite variations in intensity.

Question 7

Signal detection theory.(1)

Answer 7

An observation that the response to the stimulus depends on a persons sensitivity to the stimulus in the presence of noise and on a persons response criterion.

Question 8

What is d-prime(d’)?(2)

Answer 8

A statistic that gives a relatively pure measurement of the observers sensitivity or ability to detect single
Based on relative proportion of hits to misses and the group variability in detecting the phenomenon under consideration.

High d’ means more certainty.

Question 9

Perception definition.(1)

Answer 9

Organise, identify and interpret sensory information.

Question 10

What are the properties of light waves and their corresponding perceptual dimensions?(3)

Answer 10

Length-hue/colour (with shorter wavelength appearing blue and longer appearing red)
Amplitude-brightness
Purity (number of wavelengths that make up the light)-saturation.

Question 11

What is accommodation in the context of the eye?(1)

Answer 11

The maintenance of a clear image on the retina (through muscle contraction/relaxation).

Question 12

Myopia and hyperopia.(1)

Answer 12

Myopia (short sighted) distant objects are blurred

Hyperopia (long) near objects are blurred, eyeball too short.

Question 13

What are dark and light adaptation respectively?(1)

Answer 13

Dark adaptation is adaptation to dark whilst light is adaptation to light environments.

Takes approx 8 mins for rods to adapt to dark and 30mins for cones.

Question 14

Describe the 3 layers of the retina.(3)

Answer 14

Photoreceptors (rods&cones)
Bipolar neurones that connect photoreceptors to RGCs
Receptor ganglion cells (RGCs) which connect retina to brain and bundle together to form the optic nerve.

Question 15

What is the receptive field?(1)

Answer 15

The region of the sensory surface that when stimulated caused a change in the firing rate of that neuron.

Question 16

What’s the difference between on-centre and off centre ganglion cells?(1)

Answer 16

On centre have an excitatory centre surrounded my doughnut inhibitory whilst off-centre has the opposite
If the receptive field spills over into the other field then the optimum response acehived by full coverage will be diminished and if the entire receptive field is covered through later inhibition the excitatory and inhibitory responses cancel leading to no overall change.

Question 17

What is trichromatic colour representation?(1)

Answer 17

The pattern of responding across the 3 types of cones that provides a unique code for each colour.

Question 18

3 diff types of cones.(3)

Answer 18

S-cones respond to blue (OPN1SW)
M-cones green (OPN1MW)
L-cones red (OPN1LW)

Question 19

Colour blindness.(2)

Answer 19

Sex linked disorder more prevalent in men and is Linked to X
Don’t have full complement of cones hence have dichromatic or monochromatic vision (or none at all)
Those with dichromatic may not even notice.

Question 20

Why does a colour afterimage occur?(1)

Answer 20

Due to exhaustion of cone cells resulting in the colour-opponent system producing an image of the opposite colour.

Question 21

What is the colour-opponent system?How does it work if there are only 3 cones?(2)

Answer 21

Pairs of visual neurones that work in opposition (blue against yellow and red against green).
Red-green cells excited in response to red and inhibit in geeen whilst blue-yellow increase in response to blue and decrease in response to yellow.

Question 22

Why is lateral inhibition important?(1)

Answer 22

It increases acuity and edge detection by increasing contrast. What happens is an excitatory neuron inhibiting neighbouring neurones.

Question 23

Describe the visual pathways from the eye through to the brain.(6)

Answer 23

Left and right visual fields are found on the back of each refina respectively

The left receptive field goes to the right of the brain whilst the right goes to the left of the brain with cross over occurring at the optic chiasm

This then travels to the lateral geniculate nucleus in the thalamus

This then travels to the primary visual cortex in the rear of the occipital lobe

Initial processing occurs in area v1

Further processing then occurs in potentially 30-50 other areas predominantly located in the occipital or temporal lobes.

Question 24

V1 is said to have a topographic visual organisation. What does this mean? What is v1 mainly involved in?(2)

Answer 24

Adjacent neurones process adjacent portions of the visual field.
Perceiving shapes and edges through diff neurones perceiving diff orientations of edges.

Question 25

Describe the two visual streams.(2)

Answer 25

1) Ventral stream, travels across the occipital love into the lower levels of the temporal lobes and includes brain areas that represent shape and identity (what it is)
2) Dorsal stream, travels up from occipital to the parietal lobes (inc some middle and upper temporal lobes) connecting areas that identify location and motion was originally called the “where” pathway as a result but due to it being crucial for guiding movements also has been renamed the “how” pathway.

Question 26

What is visual form agnosia? Give an example of a patient with it.(3)

Answer 26

Inability to recognise objects by sight

Patient DF could no longer recognise objects by sight but could still by touch (showing memories still intact) after CO poisoning resulting in damage to lateral occipital cortex (central stream)

When asked to hold hand at the orientation of a slot she could not but when asked to put a block in a slot as if posting a letter she could do fine and fMRI showed activation of dorsal stream as a result of guided movement despite impairment in conscious understanding of the movement.

Question 27

What is optic ataxia?(2)

Answer 27

Damage to the parietal regions of the brain result in damage to dorsal stream hence impairment in ability to do guided movements.
These people however could still conceptually understanding what it was they were grasping despite being unable to move correctly showing the ventral and dorsal streams are distinct from one another.

Question 28

What is the binding problem?(1)

Answer 28

How features are linked together so we perceive unified objects rather than free-floating or miscombined features.

Question 29

What is an illusory conjunction?(1)

Answer 29

Perceptual mistake where features from multiple objects are incorrectly combined.

Question 30

What is the feature integration theory?(1)

Answer 30

A theory that proposes that attention bonds individual features together to comprise a composite stimulus.

Question 31

What is the Mcgurk effect?(1)

Answer 31

Auditory stimuli overridden by visual stimuli showing the integration of the two senses.

Question 32

What is the updated version of the feature integration theory? Give evidence.(3)

Answer 32

-Feature integration theory states that attention effects the perception of visual images and results in features binding to create a composite.
-This was found to be true with parietal lobes in the dorsal stream influential in illusory conjunctions. Patient with strokes effecting this area found unable to do visual search
Further found with TMS (transcranial magnetic stimulation) found that turning off parietal section after presentation of images still had an effect showing attention plays a part with increased number of illusory conjunctions.

Question 33

Where is brain activity found in synaesthesates?(1)

Answer 33

Parietal lobes responsible for colour and shape perception, also for attention which is required for the experience as found by experiments with dots.

Question 34

Where is the specific region of the brain responsible for recognition of faces?(1)

Answer 34

Subregion in the temporal lobe, one for landscapes found nearby.
Known as modularisatjon as specific areas of brain for particular perceptions.

(Fustiform gyrus)

However seen that a distributive approach has been found with activation of other brain regions also responsible.

Question 35

What are the arguments for modularisation?(2)

Answer 35

Natural pre-set recognition system
Other argument is that it is due to exposure to faces etc
Both appear to have there credits.

Question 36

What is perceptual constancy?(1)

Answer 36

The principle that despite changes to sensory information we still recognise things and have the same perception

Eg experiment with pictures and words of same thing had same neuronal firing in the temporal lobe.

Question 37

What are the 6 gestalt principles?(6)

Answer 37

Simplicity/Pragnanz, simple forms are usually the best therefore is how they are perceived
Closure- close things that weren’t there
Continuity- follow the line of bf
Similarity-group simular things (eg colour shape etc) together as wholes
Proximity-close together things grouped together
Common fate-elements moving in the same direction are viewed as one object

Question 38

What factors effect the separation of figure from ground?(3)

Answer 38

Edges (example being Rubin or face-vase with subregion in temporal lobe responsible for facial recognition showing greater activation when viewed as face over vase)
Size eg smaller things tend to be said to be figures
Motion things tend to be figured.

Question 39

What are the contrasting proposals regarding object perception? State limitations of each too.(4)

Answer 39

Image-based theory and parts-based theory.

Image based suggests memories of specific images are stored as a template much like a barcode
Drawback: Doesn’t explain how we can make sense of unseen objects, doesn’t explain how we understand different orientations

Parts-based suggests individual geometric representations called geons are stored in memory and grouped together and their spatial relations to one another and these compose objects
Drawback: doesn’t explain how we can tell different faces apart (who would have similar geons).

Still a dispute between the two with new hybrid theories being developed.

Question 40

Describe the Bruce and Young theory for facial recognition.(3)

Answer 40

1Structural encoding (way pattern is represented):
Recognise faces
Then arrangement of said faces
2)Then look for expressions or movements or individual marks
3)Then familiarity and maybe a name etc.

Question 41

What are monocular depth cues?List them.(6)

Answer 41

Aspects of depth perception that are from only one eyes info often referred to as pictorial depth cues as present even in 2D

1) Retinal image size or relative size (plays into familiar size too as this information is fed to the brain hence relative size would be indicative of depth if you already know the normal height of something)
2) Linear perspective (parallel lines converge into distance)
3) Texture gradient (becomes smaller as surface recedes)
4) Interposition (object partly blocks another therefore appearing closer-doesn’t indicate how far the object themselves are from one another)
5) Relative height (depends on field of vision with those in the lower visual field being closer and vice versa).

Question 42

What are Binocular depth cues? List them.(3)

Answer 42

Exist because of stereoscopic vision (space between the eyes mean each have diff views)
Binocular disparity (diff in retinal images providing info about depth with greater disparity meaning an object is closer)
Wheatstone idea used this with drawings in diff locations.

Question 43

What is the motion parallax? How does it differ from binocular disparity?(3)

Answer 43

Depth cues based on the movement of the head over time (things closer appear to move slower than far away-think when on train or car)
Differs as whilst binocular disparity focuses on diff retinal images in viewpoints, motion parallax is on diff images in time
Optic flow-particular type whereby closer images appear the periphery whilst those central are furthest away (think driving in snow with windscreen)

Question 44

Describe the Ames room.(1)

Answer 44

1946 creation whereby retinal size alterations give the illusion of depth when both are the same distance apart.

Question 45

What was interesting about pupil dilation experiments on landscapes?(1)

Answer 45

Even just thinking about landscapes caused dilation and constriction showing that there is a memory aspect to it even those which are involuntary.

Question 46

What is the waterfall effect? Why?(2)

Answer 46

Optical illusion that if watching a mobile object and then watching a stationary one, the object will move in the opposite direction.

Similar to the colour afterimage, it’s due to motion sensitive neurones for upward angles tiring resulting the opposite taking over, increased activity during illusion in the MT( V5) temporal region as shown by fMRI which is responsible for movement.

Question 47

What are the 3 different physical perceptions of an audio wave? What are our precepts on the?(3)

Answer 47

Frequency-corresponds to pitch with high pitch being from high freq n vice versa
Amplitude-Loudness (high amplitude=loud)
Complexity- perception of timbre ie sound quality/resonance (pure simple tone or combination).

Question 48

How is sound perceived (from outside to brain)?(5)

Answer 48

1) Hits pinna which direct sound wave into auditory canal up to the tympanic membrane (ear drum)
2) this then goes to the ossicles (malleus, incus and stapes) which act to amplify sound
3) this then goes to the cochlea and the cochlea fluid across the basilar membrane which undulates (waves) up the cochlear when hit
4) this causes movement of cilia in the basilar membrane to bend upon vibration against the tectonic membrane with low at the apex and high frequency at the base which results in the release of impulses via neurotransmitters to the brain *also note that movement toward the largest cilia ^AP transducer whilst to the smallest one decreases it
5) From here these APs travel to the thalamus in the brain and then to the contralateral hemisphere of the cerebral cortex in a part of the temporal lobe known as A1.

Question 49

Which hemispheres respectively are thought to be responsible for hearing?(2)

Answer 49

Left associated with language

Right associated with music and rhythmic sounds.

Question 50

What is the place code and temporal code?(2)

Answer 50

The place code is the fact that the cochlea encodes diff freq at diff areas (low freq at apex and high at base).
The place code is less accurate in sound perception for lower frequencies who travel further as it relies on detecting where the cilia move the most
Temporal code then handled lower freq by detecting the AP from the auditory nerve thus supplementing the place code. (Alternating the temporal code can only work effectively for roughly 1000 spikes per min in perception and hence isn’t as a effective as the place code for detecting high freq).

Question 51

How to we locate sounds?(1)

Answer 51

As a result of stereophonic hearing.

Question 52

What is visual orienting? What is it an example of?(1)

Answer 52

A behavioural response to move eyes toward a target, integration of sound and sight systems hence also multi sensory integration.

Another example of this is the ventriloquist effect where they can throw their voices by emphasising a dummy’s movement whilst minimising mouth movement this gives the impression of a talking dummy with sight predominantly taking over.

Question 53

What is haptic perception?(1)

Answer 53

Perception from touch and grasping.

Question 54

Name a genetic disorder regarding pain receptors?(1)

Answer 54

Congenital insensitivity to pain, can’t feel pain (children with this are at increased risk of death due to hurting themselves without realising).

Question 55

What is the difference between A-delta fibres and C fibres?(1)

Answer 55

Both are pain detecting free nerve endings in the skin, c fibres act more slowly and are the full pain after an incident whilst a-delta are the initial sharp pain you get.

Question 56

What are the two diff pain pathways in the brain?(2)

Answer 56

One through the somatosensory cortex identifying where the pain is and what kind of pain it is
The next sends signals to the emotional and motivational areas (eg hypothalamus and amygdala and frontal lobe) this makes sure we don’t find it a pleasant experience and actively seek to avoid it.

Question 57

How can phantom limbs occur?(1)

Answer 57

The pain pathways aren’t at the sight of the pain they are in the brain, therefore those pathways are still able to occur despite the limb no longer existing.

Question 58

What is referred pain?(1)

Answer 58

When sensory pain information from internal and external sources converge at the same nerve cells on the spinal cord, why those about to experience a heart attack will feel it in their left arm and not their chest.

Question 59

What is gate-control therapy?(1)

Answer 59

Can block pain via interneuronal interference (feedback from two directions) eg rubbing a stubbed toe helps stop the pain can also occur in thalamus.

Offer evidence that perception is both bottom up and top down.

Question 60

Where does the neural feedback involved in pain perception occur?(2)

Answer 60

Periaqueductal grey (PAG)

In high stress situations endorphins can act to suppress this and also shown opiates such as morphine effect the PAG pathway too.

Question 61

What is the vestibular system?(1)

Answer 61

The 3 fluid-filled semicircular canals and adjacent organs next to cochlea responsible for balance-movement of hairs here detects motion. If visual cues oppose the motion cues this results in motion sickness.

Question 62

What is interesting about the olfactory system when compared to other sensory systems?(1)

Answer 62

Only one with direct connection to fore brain with connections to amygdala and other fore-brain structures suggesting has an emotional tie (other senses connect to thalamus firstly).

Question 63

How are smells detected up to brain regions.(4)

Answer 63

1) Odourant molecules in the air travel up nasal cavity to the olfactory epithelium
2) Here there are olfactory receptor neurones (ORNs) where the molecules bind and ORN binding sites (about 350 diff ones to discriminate around 10k molecules)
3) If threshold is met then these signals are sent to the olfactory bulb to their respective glomureli
4) This then has a direct connection to the fore-brain via the olfactory nerve (cranial nerve one).

Question 64

What did a positron emission tomography (PET) scan show regarding the relation of smell and sexual orientation.(2)

Answer 64

Samples of testosterone high male sweat and oestrogen high urine sample:
Heterosexual men and lesbian women experienced activation of the hypothalamus (responsible for sexual behaviour) for urine and not sweat
Whilst opposite was said for heterosexual women and gay men showing pheromones are related to sexual orientation.

Question 65

What are pheromones?(1)

Answer 65

Biochemical products that are released by their own species that effects the behaviour or physiology of an animal.

Question 66

What is interesting about the role pheromones play in menstrual cycle syncing?(1)

Answer 66

Study found that sweat transferred to upper lip of women who had not had contact experienced menstrual cycles syncing, mechanism is not understood but known it is a thing.

Question 67

How is taste detected up to the brain?(3)

Answer 67

1) Papillae on tongue containing taste buds detect chemicals in food
2) the microvilli in the taste pores (50-100 per taste bud) that fill the taste buds (approx 10k in humans) react with molecules
3) these travel down taste receptor cells to the nerve fibres (facial, glossopharyngeal and vagus) depending on where in the mouth they are
4) They all converge at the solitary nucleus in the medulla and then head to the ventral posterioir nucleus in the thalamus
5) From the thalamus neurons then send impulses to the primary and secondary Gastatory cortex’ including: insula, frontal operculum cortex & orbital frontal cortex

Question 68

What are the 5 different types of tastes?(5)

Answer 68

Sweet (more complex with more than sugar activating them)
Salty (NaCl activation)
Bitter (more complex with 50-80 distinct binding sites responsible)
Sour (acid activation)
Umami (savoury meat sensation, respond to glutamate which is a major excitatory NM).

Monosodiumglutamate (MSG) often used to season Asian foods particularly activated umami receptors but can often cause headaches.

Question 69

What is interesting about taste with ages?(1)

Answer 69

Lose about half by the age of 20.

Question 70

What is the perceptual process cycle?(3 main stages)

Answer 70

1) Stimulus-Environmental stimuli, Attended stimuli, Stimuli on receptors
2) Electrical-Transduction and transmission and processing (fed into by knowledge)
3) Recognition Perception action.

Question 71

What are the 3 parts where you can observe the perceptual process?(3)

Answer 71

The stimulus-perception of psychophysical (PP)
The stimulus-physiological (PH1)
The physiological to perception (PH2)
All are interconnected.

Question 72

Difference between dorsal and ventral in anatomy?(1)

Answer 72

Ventral towards stomach, dorsal towards back (brain is described as dorsal in position)

Question 73

Anterior v posterior?(1)

Answer 73

Front and back same as dorsal and ventral.

Question 74

Superior v inferior.(1)

Answer 74

Above below.

Question 75

Lateral v medial.(1)

Answer 75

Toward the side away from midline, toward the midline.

Question 76

What are the different plane views of the brain?(3)

Answer 76

Sagittal Plane (side on)
Coronal plane (front on)
Horizontal plane (above looking down).

Question 77

What other brain elements are in the 3 brain regions?(3:7,2,3)

Answer 77

Fore-brain: prefrontal (cerebral) cortex & sub-cortical regions: corpus callosum, thalamus, hypothalamus, amygdala, pituitary gland, hippocampus
Mid-brain: Tegmentum and tectum
Hindbrain: Pons, cerebellum, medulla (oblongata).

Question 78

What are the 3 main functions of the medulla?(3)

Answer 78

• Regulation of cardiovascular and respiratory systems
• Control of reflexes such as swallowing, coughing & vomiting
• Balance control through controlling head and limb positioning.

Question 79

What are the main roles of the Pons?(2)

Answer 79

• Integration of sensory information from faical muscles, eyes tongue and ear
• Brain attentiveness and sleeping and dreaming.

Question 80

What is main role of the cerebellum?(1)

Answer 80

FINE control of movements and coordination (approx 30bill neurones hence size) effected during alcohol consumption, diff to medulla as this is FINE not balance as a result of body position.

Question 81

Describe the anatomy of the pre-frontal cortex.(3)

Answer 81

1)Contains 6 distinct laminae that are parallel to the cortex, cells divided into columns that are perpendicular
2)Has four lobes:
Parietal(up), occipital(back), temporal(side), frontal (fornt)
3)Central sulcus divides frontal and parietal lobes whilst lateral (sylvian) divides parietal and temporal.

Question 82

What is the role of the precentral gyrus?Postcentral gyrus?(2)

Answer 82

It is the primary motor cortex

It is the somatosensory cortex.

Question 83

What are the 4 lobes of the pre-front cortex responsible for?(4)

Answer 83

Frontal-planning of movements (particularly the precentral gyrus), recent memories, aspects of emotion (particularly with relation to olfactory connections)
Parietal-sensory (postcentral gyrus) & body sensations
Temporal-heairng, advanced visual processing (ventral stream)
Occipital-visual.

Question 84

Where in the prefrontal cortex does the olfactory bulb have connections to?(2)

Answer 84

hippocampus & amygdala & mamillary body

cingulate gyrus

Question 85

What are the functions of the thalamus and hypothalamus?(3)

Answer 85

Thalamus important for relaying sensory information to pre-frontal cortex
Hypothalamus is important for controling fight/flight/mating responses and the regulation of the endocrine system.

Question 86

What sub-cortical structures compose the limbic system?(2)

Answer 86

The amygdala and hippocampus, surround thalamus and is important for emotion, motivation, learning and memory.

Question 87

What are primary sensory projection areas and primary motor projection areas?(2)

Answer 87

Sensory are points for receiving sensory info

Motor are departure points for signals to muscles.

Question 88

What are the 12 cranial nerves?(10)

Answer 88

1) Olfactory
2) Optical
3) (3)Oculomotor, (4)Trochlear and (6)Abducens (eye movements)
4) (5)Trigeminal (largest and branches into 3, responsible for facial sensation& chewing)
5) (7)Facial-taste&expressions
6) (8)Auditory
7) (9)Glossopharyngeal (swallowing&taste)
8) (10)Vagus (cardiovascular,respiratory & digestive)
9) (11) Spinal Accessory (movement of neck& shoulders)
10) (12)Hypoglossal-tongue movements,speech&swallowing.

Question 89

What is the difference between white and grey matter?(1)

Answer 89

White matter is a myelinated axon

grey matter is unmyelinated, or a dendrite or cell body.

Question 90

How fast can a AP travel?(1)

Answer 90

260mph
**neurones are small at 50-100microns
damage to myelination leads to MS.

Question 91

How do APs occur (describe the graph of one).(5)

Answer 91

• Slow rising phase, SOME Na+ VGC open and Na+ influx occurs
• reaches -65mV threshold voltage, Rapid rising phase, SOME K+ VGC open and K+ moves out of cell leading to further depolarisation, ALL Na+ VGC open!
• Early repolarisation, ALL K+ VGC open, SOME Na+ VGC become inactivated as max 30mV has been met
• Hyperpolarisation, ALL Na+ VGC become inactivated, SOME K+ VGC close but some still open so overshoot
• Resting state -70mV, both Na+ and K+ VGC close.

Question 92

What are EPSPs and IPSPs?(2)

Answer 92

Excitatory post-synaptic potentials-require multiple to achieve AP
Inhibitory post-synpatic potentials decrease likelihood of AP (postsynaptic inibition)-usually by Cl- influx or efflux of K+

Question 93

How is a camera different from a camera obscura?(1)

Answer 93

Both solve the many to many problem by allowing for 1:1 mapping, but cameras use a lens rather than small hole and have greater aperture (hole) therefore brighter images can be produced.

Question 94

When does visual transduction occur?(1)

Answer 94

Receptors have opsin (large protein) and retinal (sandwiched in opsin at the disk end of the photoreceptor) which is a light sensitive molecule, when this absorbs a photon of light transduction occurs due to this chanign the structure of retinal by isomerisation.

Question 95

What wavelengths do rods and cones absrob?(3)

Answer 95

Difference in spectral sensitivity is due to
absorption spectra of visual pigments
•Rod pigment absorbs best at 500 nm.
•Cone pigments absorb best at 419nm, 532nm, and
558nm (easier to remember as Short (420 nm),
Middle (530 nm)& Long (560 nm)
*Absorption of all 3 cone type together equals the peak of 560nm in the spectral sensitivity curve

Question 96

What is the principle of univariance?(1)

Answer 96

Individual cones are colour blindn so despite brightness or wavelength they all elicit the isomerization which results in transduction hence only monochromatic indivually, need comparison among eachother for colour.

Question 97

What are colour-matching experiments and what do they show?(2)

Answer 97

Have one wavelength colour on left and vary other wavelengths on right to match
Show that normal vision require 3 diff wavelengths to match whilst colour blind people only required 2 by principle of uni-variance.

Question 98

What are the 3 types of dichromatism?(3)

Answer 98

Tritanopia (S cones) least common
Deuteranopia (M cones)
Protanopia (L cones) most common.

Question 99

What oculomotor cues give rise to depth perception?(2)

Answer 99

Convergence-the inward movement of our eyes as we look at nearby objects
Accomodation-lens accom also gives indication of depth.
*note these are only beneficial for around arms length.

Question 100

What is stereoopsis?(1)

Answer 100

The perception of depth as a result of visual disparity.

Question 101

What is the horopter?(1)

Answer 101

a line or surface containing all those points in space of which images fall on corresponding points of the retinas of the two eyes.

Question 102

What was the Holway and Boring experiment.(2)

Answer 102

Had observers in a split hallway look down each corridor (one with a control light of fixed distance and size) and were asked to adjust the other light to the right size(tests with both cues, solely monocuar cues, no cues)
results showed that there was little imrpovement from all cues following monocular, no cues led to very poor estimate (giving a lot smaller a circle to match)

Question 103

What are the 2 main pressure receptors closer to the surface of the skin?(2)

Answer 103

Merkel-sustained activity (fine detail detection)
High amount of these in fingertips as shown by 2point test and grate test
Meissner-active on initial encounter and when stopped and responsible for grasping.

Question 104

What are the 2 main pressure receptors located further in the dermis?(2)

Answer 104

Ruffini-continuous firing and associated with skin stretching
Pacinian-only at beginning and when stopped does it fire and is for vibrations and fine texture.

Question 105

What are the different type of tongue papillae and where are they found?(4)

Answer 105

Filliform (no taste buds, cone shape and found everywhere)
Fungiform (side and tip)
Foliate (back and sides, series of folds)
Circumviliate (trench at back).

Question 106

What are the different pathways for taste cells to brain?(4)

Answer 106

Chroda tympani nerve (front)
Glossopharyngeal nerve from back
Vagus fro throat and back
Superficial petronasal nerve from soft palate (top back).

Question 107

What is the difference between macrosmatic and microsmatic? Which are humans?(1)

Answer 107

Macrosmatic animals have keen sense of smell for survival, micro do not.
Humans are microsmatic.

Question 108

How is flavour perceived?(2)

Answer 108

1) Smell (olfactory bulb) and taste (primary taste cortex in thalamus) combine in the orbital frontal cortex (OFC)
2) this has input from the primary somatosensory cortex and also the inferotemporal (V4) cortex (involved in the visual ventral stream or “what” pathway through bimodal neurons-firing is also effected by hunger.

Question 109

What are the 2 potential explanations for the moon illusion?(2)

Answer 109

No depth cues in sky=smaller appearance than on horizon (apparent-distance theory)
Angular size contrast theory argues it may be because the sky is so large therefore the moon appears smaller
**suggested both are explanation for this.

Question 110

What is the size constancy theory for depth?Give an equation.(1)

Answer 110

Perception of an object’s size remains
relatively constant (when all learned cues are
available).
•This effect remains even if the size of the
retinal image changes.•Size-distance scaling equation (Gregory, 1966)
• S = K (R X D)
S – perceived size; R – Retinal image size; D- perceived distance.
• Namely, changes in distance and retinal size balance each other

Question 111

What are the main types of eye movements?(4)

Answer 111

Vergence(conjugate)
Saccadic
Pursuit
Vestibular ocular reflex (VOR).

Question 112

What are vergence eye movements?(1)

Answer 112

Both fovea aim at near or far target, eyes move in diff directions eg left eye right and right eye left.
prevents double vision.

Question 113

What are saccadic eye movements?(1)

Answer 113

Move fovea to object of focus, blind between them and cannot control their speed.

Question 114

What are pursuit movements?(1)

Answer 114

Cannot voluntarily do in absence of a mobile target, track a moving object-focus to keep fovea poiting at the target.

Question 115

What are vestibular ocular reflex movements?(1)

Answer 115

Keep world stationary despite head movement and eye movement.

Question 116

Following the optic nerve, where does the signal travel?(4)

Answer 116

Lateral geniculate nucleus (has retinotopic map ie diff parts stimulate diff parts due to diff parts of stimulation on retina)
Occipital lobe (v1)
Then travels either through ventral or dorsal stream 
To frontal lobe.