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Neurophysiology > Visual cortex and perception > Flashcards

Visual cortex and perception Flashcards

1
Q

What happens at the optic chiasm

A

Fibres from the nasal portion of both the left and right retina cross over- this means all info from the left visual field is directed to the right side of the brain, and vv

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2
Q

Where is info from each hemifield processed

A

All info from the left visual hemifield is processed by the right hemisphere, while all info from the right visual hemifield is processed by the left hemisphere

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3
Q

Summarised pathway of visual info through the brain

A

Retina -> Optic chiasm -> Optic tract -> LGN -> Optic radiation -> V1-> Other subcortical visual nuclei

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4
Q

How is the LGN divided

A

Split into 6 layers, magnocellular/parvocellular/ koniocellular info goes to different layers
For P and M cells, each layer gets a precise retinotopic input from one eye (ipsi vs contra)

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5
Q

Where does M vs P vs nonMnonP info project to in the LGN

A

M- layers 1-2
P- layers 3-6
nonMnonP- ventral to each principal layer, called layers K1-6

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6
Q

How are the electrophysiological properties of LGN cells similar to the ganglion cells supplying them

A

ON and OFF cells remain independent, P cells retain colour opponancy, circular receptive fields with surround antagonism
eg magnocellular LGN neurons have similar properties to M cells

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7
Q

Is there retinotopic mapping in the LGN?

A

Yes, precise retinotopic map in each layer

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8
Q

Experimental lesion monkey study, effect of damage to magnocelllar layers of LGN

A

Merrigan et al (1991)- sharp reduction in ability to perceive rapidly changing stimuli, no effect on visual acuity or colour vision

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9
Q

Experimental lesion monkey study, effect of damage to parvocelllar layers of LGN

A

Merrigan et al (1991)- no effect on motion perception, severely impaired visual acuity and colour perception

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10
Q

Experimental lesion monkey study LGN- conclusion about role of parvocellular stream

A

Merrigan et al (1991)-Important for high spatial resolution- size, shape and colour of objects

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11
Q

Experimental lesion monkey study LGN- conclusion about role of magnocellular stream

A

Merrigan et al (1991)-Critical for tasks that require high temporal resolution- location, speed and direction of a rapidly moving object

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12
Q

Why is the striate cortex considered to be the primary visual cortex (V1)

A

Most LGN axons terminate in V1, all V1 neurons respond exclusively to visual stimuli, ablating V1 causes blindness, electrical stimulation of v1 elicits visual sensations

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13
Q

What is the result of a stroke destroying neurons in the right V1

A

Loss of left (contralateral) visual field, as V1 is needed for initial cortical processing of visual info necessary for visual perception

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14
Q

Study showing effect of shrapnel wounds on visual field

A

Holmes- studied different visual field losses caused by different shrapnel wounds causing different V1 lesions in WW1 soldiers.. could map out the whole of the visual field in V1 in these individuals

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15
Q

What is a scotoma

A

An area of blindness in the visual field- the region of the scotoma is characteristic of the area of the lesion, showing the retinotopic organisation of the visual pathways

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16
Q

What distortion is there in the cortical retinotopic map

A

Cortical magnification of area receiving and analysing foveal input aka it is disproportionately large
Peripheral areas have much smaller areas for cortical processing

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17
Q

What is the retinotopic map in the cortex based on

A

No of receptors present in fovea vs periphery, and no of ganglion cells that output that info

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18
Q

What important research did Hubel and Wiesel provide us- development of the visual system?

A

Critical periods and descriptions of ocular dominance columns

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19
Q

What important research did Hubel and Wiesel provide us- bases for understanding visual physiology

A

How the brain interprets visual info to generate edge detectors, motion detectors, stereoscopic depth detectors and colour detectors

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20
Q

How is V1 divided

A

9 layers with distinct cytoarchitecture- I (ventral-most), II, III, IVA/B/Ca/Cbeta, V, VI
Different pathways dock in different layers

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21
Q

What do stellate cells do in v1

A

Receive info streams from the LGN and pass it to the dendrites of pyrAmidal cells

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22
Q

What carries info from the LGN to V1

A

Optic radiations

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23
Q

Where does info from the magnocellular pathway terminate in v1

A

Layer IVCa

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24
Q

Where does info from the parvocellular pathway terminate in V1

A

Principally IVCbeta

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25
Q

Where does info from the koniocellular pathway terminate in V1

A

Layers II and III

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26
Q

What do pyramidal cells do in V1

A

Send info out of V1 to form connections with others areas of the cortex (extrastriate and subcortical areas), allowing horizontal processing by branching within each layer and forming local connections in the cortex

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27
Q

Where is info sent downwards from v1 by pyramidal cells

A

Some sent to superior colliculus involved in saccadic eye movement, and LGN for intention and arousal to a particular visual scene

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28
Q

What experiment did Hubel and Wiesel carry out into the physiology of V1

A

Hubel and Wiesel (1950)- systematically did microelectrode recordings of individual neurons in the striate cortex in cats/monkeys to determine their receptive fields, what they responded to etc

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29
Q

What columns did Hubel and Wiesel discover in V1

A

Info from each eye is segregated in ocular dominance columns in layer IV

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30
Q

What did Hubel and Wiesel discover about neurons in V1 and their receptive field properties

A

Different neurons showed binocularity, orientation selectivity, direction sensitivity, colour processing

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31
Q

Hubel and Wiesel study evidencing the existence of ocular dominance columns- procedure?

A

Hubel and Wiesel (1969)- Radioative proline injected into one eye, terminations in V1 visible by putting old fashioned film over it to develop, producing a collection of silver grains- autoradiogram shows terminations as bright bands

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32
Q

Hubel and Wiesel study evidencing the existence of ocular dominance columns- results

A

Hubel and Wiesel (1969)- Autoradiogram shows white stripes (terminations) are organised into columns
When the experiment was repeated with the other eye, the black and white stripes switched, suggesting they come from the different eyes

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33
Q

What is ocular dominance

A

The tendency to prefer visual input from one eye over the other

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34
Q

What do electrical recordings confirm about ocular dominance columns

A

Neurons in layer IV of V1 respond to stimulation of either the left or right eye ie show ocular dominance

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35
Q

What is the retinotopic map in the cortex based on

A

No of receptors present in fovea vs periphery, and no of ganglion cells that output that info

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36
Q

What important research did Hubel and Wiesel provide us- development of the visual system?

A

Critical periods and descriptions of ocular dominance columns

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37
Q

What important research did Hubel and Wiesel provide us- bases for understanding visual physiology

A

How the brain interprets visual info to generate edge detectors, motion detectors, stereoscopic depth detectors and colour detectors

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38
Q

How is V1 divided

A

9 layers with distinct cytoarchitecture- I (top), II, III, IVA/B/Ca/Cbeta, V, VI
Different pathways dock in different layers

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39
Q

What do stellate cells do in v1

A

Receive info streams from the LGN and pass it to the dendrites of pyrAmidal cells

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40
Q

What carries info from the LGN to V1

A

Optic radiations

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41
Q

Where does info from the magnocellular pathway terminate in v1

A

Layer IVCa

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42
Q

Where does info from the parvocellular pathway terminate in V1

A

Principally IVCbeta

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43
Q

Where do binocular neurons first appear

A

Projections from layer IV of V1 to layers above or below show convergence of info from both eyes- most neurons in layers II, III, V and VI are binocular

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44
Q

What do pyramidal cells do in V1

A

Send info out of V1 to form connections with others areas of the cortex (extrastriate and subcortical areas), allowing horizontal processing

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45
Q

Where is info sent downwards from v1 by pyramidal cells

A

Some sent to superior colliculus involved in saccadic eye movement, and LGN for intention and arousal to a particular visual scene

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46
Q

What experiment did Hubel and Wiesel carry out into the physiology of V1

A

Hubel and Wiesel (1950)- systematically did microelectrode recordings of individual neurons in the striate cortex in cats/monkeys to determine their receptive fields, what they responded to etc

How well did you know this?
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47
Q

What columns did Hubel and Wiesel discover in V1

A

Info from each eye is segregated in ocular dominance columns in layer IV

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48
Q

What did Hubel and Wiesel discover about neurons in V1 and their receptive field properties

A

Different neurons showed binocularity, orientation selectivity, direction sensitivity, colour processing

How well did you know this?
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49
Q

Hubel and Wiesel study evidencing the existence of ocular dominance columns- procedure?

A

Hubel and Wiesel (1969)- Radioative proline injected into one eye, terminations in V1 visible by putting old fashioned film over it to develop- autoradiogram shows terminations as bright bands

How well did you know this?
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50
Q

Hubel and Wiesel study evidencing the existence of ocular dominance columns- results

A

Hubel and Wiesel (1969)- Autoradiogram shows white stripes (terminations) are organised into columns
When the experiment was repeated with the other eye, the black and white stripes switched, suggesting they come from the different eyes

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51
Q

What is ocular dominance

A

The tendency to prefer visual input from one eye over the other

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52
Q

What do electrical recordings confirm about ocular dominance columns

A

Neurons in layer IV of V1 respond to stimulation of either the left or right eye ie show ocular dominance

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53
Q

Hubel and Wiesel blindfolded kitten experiment- results in kittens with 1 eye blindfolded to 6 months

A

Hubel ad Wiesel (1963)- Blind in deprived eye even once blindfold was removed, non-deprived eye assumes control of the whole column

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54
Q

Hubel and Wiesel blindfolded kitten experiment- results in kittens with both eyes blindfolded to 6 months

A

Hubel ad Wiesel (1963)- vision never improved once blindfold was removed (severely impaired), no ocular dominance columns formed so would never form
Normal LGN connections, normal receptive fields etc

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55
Q

Hubel ad Wiesel (1970)- study blindfolded adult cats results

A

Had no effect on their vision as ocular dominance columns had already formed

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56
Q

What did Hubel and Wiesel say about the critical window for ocular dominance column development

A

Lack of environmental stimulation in the critical window severely and irreversibly affects the circuitry in visual cortex, causing an inability to process info from the affected eye
FIRST 3 MONTHS

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57
Q

Study into development of ocular dominance columns with binocular vision vs monocular vision- normal binocular vision

A

Adams et al (2007)- following normal development of ocular domiance columns, there is an equal no of black and white stripes in immunohistochemistry

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58
Q

What is revealed by inserting a microelectrode perpendicularly down through the various layers of the visual cortex

A

Reveals neurons of the same orientation preference in a column, regardless of whether they have simple or complex receptive fields

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59
Q

What is revealed by inserting a microelectrode parallel to the surface of the visual cortex

A

The microelectrode passes through several columns in the same layer revealing a gradual change in orientation preference as the microelectrode progresses

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60
Q

What is retina disparity

A

Each eye receives a slightly different image when looking at the same point in visual space

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61
Q

Where do binocular neurons first appear

A

Projections from layer IV of V1 to layers above or below show convergence of info from both eyes

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62
Q

What does binocular fusion form

A

A single stereoscopic perception of depth and distance

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63
Q

What can result from improper binocular fusion

A

Double vision- brain may ignore info from weaker eye to prevent this

64
Q

What is amblyopia

A

Poor or indistinct vision in an otherwise normal eye- can be caused by strabismus (eye pointing in wrong direction), congenital cataract or refractive errors

65
Q

What happens in the brain as a result of amblyopia

A

In children, the brain learns to ignore the vision from the weaker eye and the ocular dominance columns are not properly formed

66
Q

How can amblyopia be treated

A

Manipulating V1’s plasticity by forcing stimuli to be received in the poorer eye- patching the good eye, atropine eye drops cause blurring of the good eye, blinding contact lenses in the good eye

67
Q

When is the critical window for effective amblyopia treatment

A

Up to 8 years old

68
Q

How are the compelx cell receptive fields of cells in parvointerblob pathway formed

A

Stellate cells in layer IV are innervated by parvocellular layers of LGN to form simple cell receptive fields…projections to the interblob layers in layers II and III show complex cell receptive fields

69
Q

What selectivity do simple cells show

A

Orientation selectivity- respond to bars of light in a specific orientation (Hubel and Wiesel, 1959)

70
Q

Describe how simple cells show orientation selectivity

A

Hubel and Wiesel (1959)- clearly defined ON and OFF regions within the elongated receptive field
Prefer a specific orientation- bars, slits or edges

71
Q

Which V1 layers are complex cells found in

A

Layers II, III and V

72
Q

What do complex cells show selectivity for

A

Hubel and Wiesel (1959)- Give responses to stimul throughout the receptive field in the correct orientation

73
Q

How do the receptive fields of complex cells difer from simple cells

A

Hubel and Wiesel (1959) Complex cells have no distinct excitatory/inhibitory regions, larger more complex receptive fields

74
Q

How are the receptive fields of simple cells created

A

Linear receptive fields formed from converging cumulative input from >3 LGN neurons with receptive fields aligned along one axis (so centre ON regions form a line), obvious ON and oFF regions

75
Q

How are the receptive fields of complex cells created

A

Composed of several like oriented simple cells, but no obvious ON and OFF regions

76
Q

What is revealed by inserting a microelectrode perpendicularly down through the various layers of the visual cortex

A

Reveals neurons of the same orientation preference in a column, regardless of whether they have simple or complex receptive fields

77
Q

How did Hubel and Wiesel describe orientation columns in V1

A

The cortex is organised into adjacent columsn with an orientation preference that differs by 15degrees
All 180degrees is represented every 1mm of cortex- represents all orientations for a particular area of visual space

78
Q

What are the blobs in V1

A

Layers II and III are segregated into blobs surrounded by interblobs, with each blob centred on an ocular dominance column- response properties of neurons in the blobs are different

79
Q

Evidence for the blob and interblob regions

A

Carrol and Wong-Riley (1984)- immunohistochemical labelling for cytochrome oxidase (enzyme for cell metabolism) reveals cytochrome-rich BLOBS surrounded by interblob regions

80
Q

What does horizontal processing in the LGN lead to the formatino of

A

A full visual perception of the visual field

81
Q

What do blobs receive info from

A

Direct LGN input from single opponent koniocellular layers, parvocellular and magnocellular input from layer IVC of the striate

82
Q

What do the interblob regions receive info from

A

Parvocellular input from layer IVC

83
Q

Why do people criticse the hypercolumn nodel

A

It does not allow for obvious inclusion of other properties such as colour, optical images of V1 activity show the regions of V1 responding to different eyes and orientations are not nearly as regular as the hypercolumn model

84
Q

What is the parvointerblob pathway responsible for

A

Discriminative ‘form or shape’ processing cells of V1

85
Q

How are the compelx cell receptive fields of cells in parvointerblob pathway formed

A

Stellate cells in layer IV are innervated by parvocellular layers of LGN to form simple cell receptive fields…projections to the interblob layers in layers II and III show complex cell receptive fields

86
Q

What are the properties of interblob neurons

A

Orientation-selective necessary for fine detail processing, wavelength insensitive, respond to achromatic contrast, binocular

87
Q

What sort of cells are the cells in the blobs in V1

A

Concentric double-opponent cells

88
Q

What are the concentric double-opponent cells in the blobs in V1

A

Respond selectively to colour contrast eg excited by green and inhibited by red in its receptive field centre, and excited by red and inhibited by green in its receptive field surround
Don’t respond well to uniform illumination or achromatic contrast

89
Q

What are the 4 classes of double opponent cels in the blob pathway

A

G+R- centre/G-R+ surroudn and vv

B+Y-centre/B-Y+surround and vv

90
Q

What are the properties of neurons in the blob areas

A

Wavelength sensitive, detect colour contrast via double colour opponent receptive fields, insensitive to achromatic contrast, monocular, orientation/direction INSENSITIVE

91
Q

What are double opponent cells formed from

A

Opponent cells

92
Q

What are the 3 pathways that follow the Parvocellular magnocelular and koniocellular pathways

A

Blob pathway, parvointerblob pathway, magnocellular pathway

93
Q

What does direction sensitivity mean

A

With a moving bar stimulus presented at the optimal orientation, the neuron responds strongly when the bar is swept to the right, but weakly when the bar is swept to the left

94
Q

What is the magnocellular pathway involved in

A

Analysis of moving stimuli, control of visual attention and gaze, stereopsis (depth perception)

95
Q

What innervates the magnocellular pathway

A

Layer IVCa receives input from M layers of LGN forming simple cell receptive fields, projects to layer IVB which is made up of simple and complex cells

96
Q

Akinetopsia case study- how was the patient’s visuomotor coordination impaired

A

Zihl (1983)- Asked to move her finger along a wire as fast as possible- performance was much poorer in visual than tactile conditions, as the woman reported she could not follow her finger with her eyes if she moved too fast

97
Q

How is info from the M pathway output to control visual attention and gaze reflexes

A

Via layer V outputs to the pulvinar (thalamic nucleus involved in visual attention), superior colliculus (saccadic eye movements) and pons

98
Q

What model do Hubel and Wiesel propose to explain how the visual scene is broken down and processed

A

Hypercolumn model- hypercolumns are functional modules

99
Q

How did Hubel and Wiesel demonstrate the hypercolumn model experimentally

A

Using microelectrodes to explore the receptive fields of the neurons in V1, they showed it can be divided into essentially identical columns
The columns differ in the portion of the visual field assigned to them

100
Q

What does achromatopsia suggest about visual processing

A

Results from damage to temporal and occipital lobes, with normal LGN and V1- suggests disorder of processing in ventral stream

101
Q

What does each column in Hubel and Wiesel’s hypercolumn model contain

A

Cells of every direction orientation selectivity possible, right and left eye, info from different layers etc

102
Q

Where does visual processing occur beyond V1

A

In over 30 retinotopically mapped areas

103
Q

Where do layers II III and IVB of V1 provide output to

A

Project to other cortical layers

104
Q

Where does layer VI OF V1 provide output to

A

Projects back to LGN

105
Q

What 2 parallel streams is info processed in after V1

A

Dorsal stream and ventral stream

106
Q

What is the dorsal stream fed by

A

Magnocellular neurons in V1

107
Q

What is the dorsal stream involved with

A

WHERE PATHWAY- motion recognition, visual motion, control of actions

108
Q

What is the ventral stream fed by

A

Parvointerblob and blob neurons in V1

109
Q

What is the ventral stream involved with

A

WHAT PATHWAY- object/form recognition, perception of the visual world

110
Q

What is area V5 also known as

A

MT- medial temporal

111
Q

What is V5 involved in

A

Detection of motion

112
Q

What is the result of bilateral damage to V5

A

Akinetopsia, inability to perceive visual motion

113
Q

Akinetopsia case study- how was the patient’s visuomotor coordination impaired

A

Asked to move her finger along a wire as fast as possible- performance was much poorer in visual than tactile conditions, as the woman reported she could not follow her finger with her eyes if she moved too fast

114
Q

What is area V4 involved in

A

Shape and colour recognition

115
Q

What does electrophysiology suggest about selectivity of V4 neurons

A

V4 neurons are both orientation and colour selective

116
Q

What is achromatopsia

A

Loss of colour vision despite normal functioning cones, also associated with deficits in form perception

117
Q

What does achromatopsia suggest about visual processing

A

Results from damage to temporal and occipital lobes, but normal LGN and V1- suggests disorder of processing in ventral stream

118
Q

What lobes do the dorsal and ventral streams project to

A

Ventral stream- temporal lobe

Dorsal stream- parietal lobe

119
Q

Case study into blindsight- what was the case

A

Weiskrantz(1986)- Man had blindsight after complete bilateral loss of V1- registered as blind by all physiological tests, imagingi studied showed inactive V1

120
Q

Case study into blindsight- what were the findings

A

Weiskrantz (1986)- man was able to walk down a cluttered hallway avoiding objects
He has a pathway where info from LGN and thalamus is used to achieve this, without it passing through V1 meaning he can’t perceive it

121
Q

How do the ganglion cells first leave the eye

A

Optic nerves exit the optic disks and travel thruogh the fatty tissue behind the eyes

122
Q

Why is the crossing over in the optic chiasm called partial decussation

A

Only the axons from the nasal retinas decussate

123
Q

What are the receptive fields of cells in the koniocellular LGN layers like

A

Centre-surround, light/dark or colour opponency

124
Q

How much of the LGN’s input comes from V1

A

80% of excitatory synapses

125
Q

What is a possible role for projections from V1 to LGN

A

‘Top-down’modulation from V1 to LGN gates ‘bottom-up’ input back to cortex eg suppressing inputs coming from outside an area in our visual field we wish to fixate i

126
Q

Where does the LGN receive input from other than the retina and V1

A

Brain stem neurons involved in alterness and attentiveness- input can modulate the magnitude ot LGN responses to visual stimuli

127
Q

What are other names for V1

A

Brodmann’s area 17, striate cortex

128
Q

In which lobe is V1 located

A

Occipital lobe

129
Q

How is there retinotopy in the projections from retina to LGN and V1

A

Neighbouring retinal cells feed info to neighbouring places in LGN and V1, so 2D surface of retina is mapped onto the 2D surface of the subsequent structures

130
Q

What are the 2 types of neurons in V1

A

Spiny stellate cells and pyramidal cells

131
Q

Where are stellate cells found in v1

A

Found in the 2 tiers of layer IVC

132
Q

Where are pyramidal cells found in V1

A

Outside layer IVC

133
Q

What is the structrue of stellate cells

A

Small with spine-covered dendrites that radiate from the cell body

134
Q

What is the structure of pyramidal cells

A

Covered in spines also, single thing apical dendrite that branches as it ascends towards layer, and multiple basal dendrites that extend horizontally

135
Q

In which V1 layer do most axons from the LGN terminate

A

IVC

136
Q

Why does layer IVC contain 2 overlapping retinotopic maps

A

One from the magnocellular LGN, one from the parvocellular LGN

137
Q

What is the consequence of most V1 intracortical connections extending perpendicular to the cortical surface along radial lines

A

Maintains the retinotopic organisation in layer IV, meaning a cell in layer VI receives info from the same part of the retina as the cell perpendicular to it in layer IV

138
Q

Where does info from the left and right eye mix for the first time

A

Layers IVB and III, where they are innervated by stellate cells projecting from layer IVC

139
Q

What do recent studies suggest about the blob/interblob theory

A

Recent V1 studies have found overall neurons in blobs and interblobs are similar, with both showing orientation and colour selectivity- no simple way to distinguish the receptive field properties of blob cells from interblob cells

140
Q

How is the reality of the blob/parvointerblob/magnocellular pathways mroe complicated

A

The 3 pathways don’t keep m/p/nonMnonP signals separate as they mix, striate cortex output has a different form of parallel processing (ventral vs dorsal streams)

141
Q

What did Hubel and Wiesel argue would be the result of removal of one hypercolumn

A

Would leave a blind spot in the visual field, as each of the 1000s of hypercolumns analyse a small point of light from the image

142
Q

Which of the previous 3 pathways are the dorsal and ventral stream pathways similae to

A

Dorsal stream- magnocellular

Ventral stream- blob, parvointerblob

143
Q

How does visual info progress as it leaves V1

A

Projects to V2, V3, ….progression of areas where more complex specialised visual representations develop

144
Q

What are the receptive fields of neurons in MT

A

Large receptive fields that respond to stimulus movement in a narrow range of directions- almost all cells are direction selective

145
Q

Evidence for role of MT in movement

A

MT has been shown to be activated by some optical illusions that produce illusory motion, suggesting its neurons tell us perceived motion rather than actual present motion

146
Q

How is MT organised similar to V1

A

Arranged into direction-of-motion columns- perception of motion presumably depends on a comparison of the activity across columns spanning a full 360 degrees of preferred directions

147
Q

Study showing role of MT in monkeys

A

Newsome- weak electrical stimulation in MT in monkeys appears to alter the direction small dots of light are perceived to move - monkey behaviourally reports a perceived direction of motion based on COMBINATION of MT stimulation and visual motion input

148
Q

What is area MST

A

Area beyond MT, medial superior temporal, contains cells sensitive for linear motion, radial motion and circular motion

149
Q

What appears to be the farthest extent of visual processing in the ventral stream

A

An area in the inferior temporal lobe called area IT

150
Q

What is the fusiform face area

A

Kanwisher et al (1995) found the fusiform face area, an area on the fusiform gyrus especially sensitive to faces- propopagnosia associated with damage to an area that may include the fusiform face area

151
Q

Evidence against idea of ‘grandmother cells’

A

No evidence for this region, coutner to broad tuning, too risky

152
Q

Evidence against idea of ‘grandmother cells’- no evidence for this region

A

No evidence a portion of the cortex has different cells tuned to each of the millions of objects we all reconise

153
Q

Evidence against idea of ‘grandmother cells’- counter to broad tuning

A

Such great selectivity is counter to the general principle of broad tuning that exists throughout the nervous system- photoreceptors respond to a range of wavelengths, simple cells to many orientations

154
Q

Evidence against idea of ‘grandmother cells’- too risky?

A

Too risky for the nervous system to rely on extreme sensitivity- a blwo to the head might kill all 5 grandmother cells, meaning we instantly lose the ability to recognise her

155
Q

How many LGNs are there

A

2, one in each hemisphere

156
Q

How much of the LGN represent the fovea and the region just around it

A

Half the neural mass of LGN

157
Q

How do the local interconections of cels in the V1 columns allow a new level of abstracion

A

Each column contains many complex cells that receive direct connections from the simple cells in the column

Neurophysiology (23 decks)

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