Sensation and Perception Flashcards
1
Q
What is synaesthesia?(1)
A
Experiencing one sense from the activation of another.
2
Q
What was Ramas hypothesis on why synaesthesia occurs?(1)
A
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.
3
Q
Define psychophysics. (1)
A
Methods that measure the strength of a stimulus and the observers sensitivity to that stimulus.
4
Q
What is the absolute threshold usually described has?(1)
A
The value of a stimulus said to have been perceived 50% of the time.
5
Q
What is the Just noticeable difference(JND)? What effects this?(3)
A
The minimal change in a stimulus that can just barely be detects.
Depends on how intense the stimuli is and the particular sense.
6
Q
Define Weber’a Law.(1)
A
The JND of a stimulus is a constant proportion despite variations in intensity.
7
Q
Signal detection theory.(1)
A
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.
8
Q
What is d-prime(d’)?(2)
A
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.
9
Q
Perception definition.(1)
A
Organise, identify and interpret sensory information.
10
Q
What are the properties of light waves and their corresponding perceptual dimensions?(3)
A
Length-hue/colour (with shorter wavelength appearing blue and longer appearing red)
Amplitude-brightness
Purity (number of wavelengths that make up the light)-saturation.
11
Q
What is accommodation in the context of the eye?(1)
A
The maintenance of a clear image on the retina (through muscle contraction/relaxation).
12
Q
Myopia and hyperopia.(1)
A
Myopia (short sighted) distant objects are blurred
Hyperopia (long) near objects are blurred, eyeball too short.
13
Q
What are dark and light adaptation respectively?(1)
A
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.
14
Q
Describe the 3 layers of the retina.(3)
A
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.
15
Q
What is the receptive field?(1)
A
The region of the sensory surface that when stimulated caused a change in the firing rate of that neuron.
16
Q
What’s the difference between on-centre and off centre ganglion cells?(1)
A
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.
17
Q
What is trichromatic colour representation?(1)
A
The pattern of responding across the 3 types of cones that provides a unique code for each colour.
18
Q
3 diff types of cones.(3)
A
S-cones respond to blue (OPN1SW)
M-cones green (OPN1MW)
L-cones red (OPN1LW)
19
Q
Colour blindness.(2)
A
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.
20
Q
Why does a colour afterimage occur?(1)
A
Due to exhaustion of cone cells resulting in the colour-opponent system producing an image of the opposite colour.
21
Q
What is the colour-opponent system?How does it work if there are only 3 cones?(2)
A
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.
22
Q
Why is lateral inhibition important?(1)
A
It increases acuity and edge detection by increasing contrast. What happens is an excitatory neuron inhibiting neighbouring neurones.
23
Q
Describe the visual pathways from the eye through to the brain.(6)
A
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.
24
Q
V1 is said to have a topographic visual organisation. What does this mean? What is v1 mainly involved in?(2)
A
Adjacent neurones process adjacent portions of the visual field.
Perceiving shapes and edges through diff neurones perceiving diff orientations of edges.
25
Describe the two visual streams.(2)
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.
26
What is visual form agnosia? Give an example of a patient with it.(3)
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.
27
What is optic ataxia?(2)
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.
28
What is the binding problem?(1)
How features are linked together so we perceive unified objects rather than free-floating or miscombined features.
29
What is an illusory conjunction?(1)
Perceptual mistake where features from multiple objects are incorrectly combined.
30
What is the feature integration theory?(1)
A theory that proposes that attention bonds individual features together to comprise a composite stimulus.
31
What is the Mcgurk effect?(1)
Auditory stimuli overridden by visual stimuli showing the integration of the two senses.
32
What is the updated version of the feature integration theory? Give evidence.(3)
-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.
33
Where is brain activity found in synaesthesates?(1)
Parietal lobes responsible for colour and shape perception, also for attention which is required for the experience as found by experiments with dots.
34
Where is the specific region of the brain responsible for recognition of faces?(1)
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.
35
What are the arguments for modularisation?(2)
Natural pre-set recognition system
Other argument is that it is due to exposure to faces etc
Both appear to have there credits.
36
What is perceptual constancy?(1)
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.
37
What are the 6 gestalt principles?(6)
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
38
What factors effect the separation of figure from ground?(3)
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.
39
What are the contrasting proposals regarding object perception? State limitations of each too.(4)
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.
40
Describe the Bruce and Young theory for facial recognition.(3)
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.
41
What are monocular depth cues?List them.(6)
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).
42
What are Binocular depth cues? List them.(3)
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.
43
What is the motion parallax? How does it differ from binocular disparity?(3)
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)
44
Describe the Ames room.(1)
1946 creation whereby retinal size alterations give the illusion of depth when both are the same distance apart.
45
What was interesting about pupil dilation experiments on landscapes?(1)
Even just thinking about landscapes caused dilation and constriction showing that there is a memory aspect to it even those which are involuntary.
46
What is the waterfall effect? Why?(2)
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.
47
What are the 3 different physical perceptions of an audio wave? What are our precepts on the?(3)
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).
48
How is sound perceived (from outside to brain)?(5)
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.
49
Which hemispheres respectively are thought to be responsible for hearing?(2)
Left associated with language
| Right associated with music and rhythmic sounds.
50
What is the place code and temporal code?(2)
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).
51
How to we locate sounds?(1)
As a result of stereophonic hearing.
52
What is visual orienting? What is it an example of?(1)
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.
53
What is haptic perception?(1)
Perception from touch and grasping.
54
Name a genetic disorder regarding pain receptors?(1)
Congenital insensitivity to pain, can’t feel pain (children with this are at increased risk of death due to hurting themselves without realising).
55
What is the difference between A-delta fibres and C fibres?(1)
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.
56
What are the two diff pain pathways in the brain?(2)
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.
57
How can phantom limbs occur?(1)
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.
58
What is referred pain?(1)
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.
59
What is gate-control therapy?(1)
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.
60
Where does the neural feedback involved in pain perception occur?(2)
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.
61
What is the vestibular system?(1)
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.
62
What is interesting about the olfactory system when compared to other sensory systems?(1)
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).
63
How are smells detected up to brain regions.(4)
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).
64
What did a positron emission tomography (PET) scan show regarding the relation of smell and sexual orientation.(2)
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.
65
What are pheromones?(1)
Biochemical products that are released by their own species that effects the behaviour or physiology of an animal.
66
What is interesting about the role pheromones play in menstrual cycle syncing?(1)
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.
67
How is taste detected up to the brain?(3)
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
68
What are the 5 different types of tastes?(5)
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.
69
What is interesting about taste with ages?(1)
Lose about half by the age of 20.
70
What is the perceptual process cycle?(3 main stages)
1) Stimulus-Environmental stimuli, Attended stimuli, Stimuli on receptors
2) Electrical-Transduction and transmission and processing (fed into by knowledge)
3) Recognition Perception action.
71
What are the 3 parts where you can observe the perceptual process?(3)
The stimulus-perception of psychophysical (PP)
The stimulus-physiological (PH1)
The physiological to perception (PH2)
All are interconnected.
72
Difference between dorsal and ventral in anatomy?(1)
Ventral towards stomach, dorsal towards back (brain is described as dorsal in position)
73
Anterior v posterior?(1)
Front and back same as dorsal and ventral.
74
Superior v inferior.(1)
Above below.
75
Lateral v medial.(1)
Toward the side away from midline, toward the midline.
76
What are the different plane views of the brain?(3)
```
Sagittal Plane (side on)
Coronal plane (front on)
Horizontal plane (above looking down).
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77
What other brain elements are in the 3 brain regions?(3:7,2,3)
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).
78
What are the 3 main functions of the medulla?(3)
- Regulation of cardiovascular and respiratory systems
- Control of reflexes such as swallowing, coughing & vomiting
- Balance control through controlling head and limb positioning.
79
What are the main roles of the Pons?(2)
- Integration of sensory information from faical muscles, eyes tongue and ear
- Brain attentiveness and sleeping and dreaming.
80
What is main role of the cerebellum?(1)
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.
81
Describe the anatomy of the pre-frontal cortex.(3)
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.
82
What is the role of the precentral gyrus?Postcentral gyrus?(2)
It is the primary motor cortex
| It is the somatosensory cortex.
83
What are the 4 lobes of the pre-front cortex responsible for?(4)
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.
84
Where in the prefrontal cortex does the olfactory bulb have connections to?(2)
hippocampus & amygdala & mamillary body
| cingulate gyrus
85
What are the functions of the thalamus and hypothalamus?(3)
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.
86
What sub-cortical structures compose the limbic system?(2)
The amygdala and hippocampus, surround thalamus and is important for emotion, motivation, learning and memory.
87
What are primary sensory projection areas and primary motor projection areas?(2)
Sensory are points for receiving sensory info
| Motor are departure points for signals to muscles.
88
What are the 12 cranial nerves?(10)
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.
89
What is the difference between white and grey matter?(1)
White matter is a myelinated axon
| grey matter is unmyelinated, or a dendrite or cell body.
90
How fast can a AP travel?(1)
260mph
**neurones are small at 50-100microns
damage to myelination leads to MS.
91
How do APs occur (describe the graph of one).(5)
- 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.
92
What are EPSPs and IPSPs?(2)
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+
93
How is a camera different from a camera obscura?(1)
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.
94
When does visual transduction occur?(1)
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.
95
What wavelengths do rods and cones absrob?(3)
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
96
What is the principle of univariance?(1)
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.
97
What are colour-matching experiments and what do they show?(2)
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.
98
What are the 3 types of dichromatism?(3)
Tritanopia (S cones) least common
Deuteranopia (M cones)
Protanopia (L cones) most common.
99
What oculomotor cues give rise to depth perception?(2)
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.
100
What is stereoopsis?(1)
The perception of depth as a result of visual disparity.
101
What is the horopter?(1)
a line or surface containing all those points in space of which images fall on corresponding points of the retinas of the two eyes.
102
What was the Holway and Boring experiment.(2)
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)
103
What are the 2 main pressure receptors closer to the surface of the skin?(2)
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.
104
What are the 2 main pressure receptors located further in the dermis?(2)
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.
105
What are the different type of tongue papillae and where are they found?(4)
Filliform (no taste buds, cone shape and found everywhere)
Fungiform (side and tip)
Foliate (back and sides, series of folds)
Circumviliate (trench at back).
106
What are the different pathways for taste cells to brain?(4)
Chroda tympani nerve (front)
Glossopharyngeal nerve from back
Vagus fro throat and back
Superficial petronasal nerve from soft palate (top back).
107
What is the difference between macrosmatic and microsmatic? Which are humans?(1)
Macrosmatic animals have keen sense of smell for survival, micro do not.
Humans are microsmatic.
108
How is flavour perceived?(2)
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.
109
What are the 2 potential explanations for the moon illusion?(2)
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.
110
What is the size constancy theory for depth?Give an equation.(1)
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
111
What are the main types of eye movements?(4)
Vergence(conjugate)
Saccadic
Pursuit
Vestibular ocular reflex (VOR).
112
What are vergence eye movements?(1)
Both fovea aim at near or far target, eyes move in diff directions eg left eye right and right eye left.
prevents double vision.
113
What are saccadic eye movements?(1)
Move fovea to object of focus, blind between them and cannot control their speed.
114
What are pursuit movements?(1)
Cannot voluntarily do in absence of a mobile target, track a moving object-focus to keep fovea poiting at the target.
115
What are vestibular ocular reflex movements?(1)
Keep world stationary despite head movement and eye movement.
116
Following the optic nerve, where does the signal travel?(4)
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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.
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