PAST C26/C44/C3045/ANAT 3045/NEUR 3045 EXAM PAPERS (note that the course code changed between 2002/3 and 2005/6 and 2011/12)

 

Note also that between 2010 and 2011 the course content was reduced slightly in scope. In 2017 we will change to three questions in two hours rather than three.

 

 


C26: NEUROBIOLOGY OF VISION (1996)

 

Answer THREE questions. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered.

 

BEGIN EACH ANSWER IN A NEW ANSWER BOOKLET

 

(1) What is the role of retinal horizontal cells in vision?

 

(2) Discuss the role of calcium in the modulation of the phototransduction current.

 

(3) Describe physiological experiments to determine the receptive field properties of retinal ganglion cells.

 

(4) Discuss the role of screening pigments in the vertebrate eye. In which cells are they located? How do they function in adaptation to light and darkness in different vertebrates?

 

(5) At what level in the visual pathway does fusion of the input from the two eyes take place? What is the evidence for segregation of the input from the two eyes at earlier stages in the pathway?

 

(6) Discuss the anatomical connections from the retina to the lateral geniculate nucleus, the superior colliculus and the pre-tectal areas. What functions are subserved by these different visual pathways?

 

(7) What mechanisms are involved in the detection and analysis of luminance contrast and colour contrast in the visual system?

 

(8) Discuss the occurrence of direction selectivity at different levels of the visual system. Are any models of directional selectivity supported by evidence?

 

(9) Describe the effects of localised lesions to the primary visual cortex (V1).

 

(10) Describe an experiment to study the role of the visual cortex in the generation of subjective mental states.

 

(11) How has the study of colour vision helped us to understand the organization of the visual cortex?

 

(12) Discuss the syndrome of akinetopsia, emphasising the insights it has given us into the functioning of the visual cortex.


C26: NEUROBIOLOGY OF VISION (1997)

 

Answer THREE questions. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered.

 

BEGIN EACH ANSWER IN A NEW ANSWER BOOKLET

 

(1) How do retinal bipolar cells process the information they  receive from the photoreceptors? Why is this processing functionally advantageous?

 

(2) How may differences in the phototransduction cascade account for the different properties of the light response in rods and cones?

 

(3) How do ganglion and amacrine cells transform the visual signal they receive from the cells in the outer plexiform layer?

 

(4) What pathways linking visual and motor areas in the brain might be involved in catching a ball?

 

(5) Vertebrate eyes have special adaptations for dealing with a great range of light intensity. Discuss the classes of adaptation that are photomechanical rather than neural. In your answer consider the degree to which they can solve the problem of using vision at different light intensities.

 

(6) Discuss the course of optic nerve fibres from the retina to the cerebral cortex. What sort of visual functions remain anatomically segregated from the eye to the primary visual cortex?

 

(7) Write an account of area V5, emphasising in particular the new insights into the functioning of the visual brain that it has given us.

 

(8) "Colour is always a consequence, never a cause" (Edwin Land). Discuss critically this statement.

 

(9) In what ways has the demonstration of parallelism in the cerebral cortex modified our views of the functioning of the visual brain?

 

(10) Discuss the role of luminance contrast in vision, and the role of neural mechanisms in transforming intensity into contrast.

 

(11) Discuss the reasoning behind computational models of EITHER motion perception OR stereoscopic vision; and consider the  relevant psychophysical and physiological evidence.

 

(12) What has been learned about the neural basis for vision from studies of the effects of brain damage in people?

 


C26: NEUROBIOLOGY OF VISION (1998)

 

The paper is divided into two sections, Section A and Section B.  Answer THREE questions, NOT MORE THAN TWO FROM ANY ONE SECTION.  Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered.

 

Section A

 

(1) Discuss the factors that limit the rate of recovery of photoreceptors from a bright light flash.

 

(2) Describe the pathways by which rods and cones drive ganglion cells. Discuss the extent to which bipolar cells determine the receptive field properties of ganglion cells.

 

(3) How would you use voltage recording with sharp microelectrodes to study the mechanism of lateral inhibition by horizontal cells in the outer retina?

 

(4) Discuss the blood supply of the human retina in relation to the cells that it serves. How could the distribution of blood supply help to interpret regional differences in retinal structure?

 

(5) Why is it difficult to read in dim light?

 

(6) What properties of the receptive fields of retinal ganglion cells might help to explain brightness illusions in human vision?

 

Section B

 

(7) What evidence is there for directionally selective mechanisms in the human brain? Describe a model of how a directionally selective cell might be constructed.

 

(8) What is meant by the notion of a 'Grandmother cell'? How far does the nervous system go toward constructing such an entity?

 

(9) You encounter a visual stimulus presenting  red vertical bars to one eye and  green  horizontal bars to the other, at corresponding retinal locations. What would  you expect to see, and what cortical neuronal mechanisms might be responsible?

 

(10) How parallel are the primate visual pathways?

 

(11) Under laboratory conditions, lights of very different spectral composition are confused by normal human observers (metamerism). Explain why this is so, and speculate about the evolution of a system that is so prone to error.

 

(12) A patient has difficulty in recognising faces after a stroke.  Devise a series of psychophysical tests to discover the nature of the lesion that might be responsible.


C26: NEUROBIOLOGY OF VISION (1999)

 

The paper is divided into two sections, Section A and Section B.  Answer THREE questions, NOT MORE THAN TWO FROM ANY ONE SECTION.  Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered.

 

Section A

 

(1)Discuss the notion: 'cGMP is the messenger of light absorption by photoreceptors and caclium ions the messenger of light adaptation'.

 

(2) EITHER write an essay discussing the relationship between the morphology of ganglion cells and their physiological roles OR write an essay explaining the roles played by amacrine cells in shaping the visual signal as it passes through the inner plexiform layer.

 

(3) How does the outer retina process components of the image on the retina of  (i) different temporal frequency, and (ii) different spatial frequency?

 

(4) How do the different types of eye movement help us to see clearly?

 

(5) Write an essay on the functions of the pupil.

 

(6) Explain the use of  sinusoidal gratings in  measuring the contrast sensitivity of the visual system.

 

Section B

 

(7) What mechanisms are responsible for the perception of motion?

 

(8) What cortical functions depend on input from the geniculo-cortical P pathway in primates?

 

(9) Evaluate the similarity of human visual cortex to monkey visual cortex.

 

(10) Describe the organization of feedback connections in visual cortex.

 

(11)Write an essay on the evolution of colour vision, paying particular. attention to function.

 

(12) After an illness, a patient has lost the capacity to name colours.  Describe the psychophysical and functional brain imaging investigations that you would carry out to determine the cause of the deficit, and comment on the potential significance of the findings for theories of colour vision.


C26:  NEUROBIOLOGY OF VISION (2000)

 

Section A

 

(1)  Describe the cellular mechanisms by which the visual signal is segregated into ON and OFF pathways at the retinal photoreceptor to bipolar cell synapse?

 

(2)  Describe the biochemical and ionic changes that occur in the outer segment of a human rod photoreceptor following an increase in background illumination.  How do these changes differ from those seen in human cones?

 

(3)  Compare and contrast the morphology and physiology of the ganglion cell types found in the mammalian retina.

 

(4) What are the visual functions of the cerebellum?

 

(5) What are the functions of the pupil?

 

(6)  How would you measure the contrast sensitivity function of a retinal ganglion cell?  What features of the results might help to explain phenomena in human vision?

 

Section B

 

(7)  How do psychophysical experiments on human subjects help us to understand the biological basis of motion perception?

 

(8)  How do forward and feedback connections in the primate visual system differ in structure and function?

 

(9)  What neural mechanisms allow primates to distinguish red from orange?

 

(10)  What is an 'area' of visual cortex?  How can different areas be identified in humans?

 

(11)  What is the relationship between parallel organization and specialization of function in the visual cortical visual pathways?

 

(12)  Are the results of brain injury to people too complicated to aid our understanding of the mechanisms of vision?  Discuss in relation EITHER to colour vision OR 'Blindsight'.


C26: NEUROBIOLOGY OF VISION (2001)

 

1. Discuss the role of ganglion cells in vision at high and low light intensities.

 

2. Describe the changes that occur in the operation of the phototransduction cascade in rods and cones that enable vision to extend over a wide range of background intensities.

 

3. How can the same transmitter (GABA), conveying lateral inhibitory signals from horizontal cells, produce voltage changes of opposite sign in ON and OFF bipolar cells? What effect does lateral inhibition have on the processing of different spatial frequencies of light intensity in the visual image?

 

4. Discuss the roles of the inert pigments (i.e. not the photopigments) in the vertebrate eye.

 

5. Outline the general scheme for the projection from the eye to the visual cortex in all mammals. To what extent does the anatomical organisation of the projection reflect a functional segregation?

 

6. What would be the effect of a complete cerebellectomy on eye movements?

 

7. Discuss the problem of colour constancy. What difficulties does the visual system have to surmount to encode the colour of surfaces?

 

8. Describe the psychophysical evidence for spatial frequency filters in the human visual system.

 

9. Describe one model of motion perception and discuss its adequacy as a model of human motion processing.

 

10. Why do some (perhaps all) visual areas have modules inside them? Give examples.

 

11.'Agnosia' is a condition following brain injury in which human subjects lose the capacity to recognise specific items, or specific categories of items.  How far can this phenomenon be explained by reference to the organisation of the primate visual system?

 

12.What has the damaged brain taught us about colour vision?


C26: NEUROBIOLOGY OF VISION (2002)

 

SECTION A

 

1.  You are given a set of microscopic sections through the eye of a vertebrate. What might you infer about the life that the animal leads from studying those sections?  Give some examples of different specializations.

 

2.  Phototransduction can be conceptually separated into three divisions; activation, termination and modulation. Explain, with reference to the recent literature, the chemical reactions involved in each of these.  Give examples, drawn from psychophysical experiments, of how these reactions limit the capabilities of our rod and cone visual systems.

 

3.  Describe the organization of the inner plexiform layer and how amacrine and ganglion cells modify the signal they receive from bipolar cells.

 

4.  How do the anatomy and synaptic connections of retinal horizontal cells determine their effect on the processing of spatial information by the outer retina?

 

5.  Individual cones are colour blind.  Discuss this statement and its implications for normal and deficient colour vision.

 

6.  What do the psychophysical changes that occur with light adaptation (e.g., changes in contrast sensitivity, or changes in the temporal and spatial modulation transfer functions) tell us about the ways in which the cone visual system light adapts?

 

 

SECTION B

 

7.  What special mechanisms exist for the perception of motion?

 

8.  How do forward and backward pathways differ in structure and function?

 

9.  Why are there so many visual  areas of cerebral cortex?

 

10.  Seeing is not always believing.  Illustrate this statement with examples of visual illusions.  Speculate as to why you might design a visual system that makes such mistakes.

 

11.  How does attention influence neural responses to visual stimuli?

 

12.          What has the study of the "motion blindness" patient L.M. taught us about motion processing in normals?


 

C44 Neurobiology of Vision (2003)

 

Answer THREE questions, not more than TWO from each section. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered.

 

SECTION A

 

1.  Discuss the regional variability in receptor density in the mammalian eye in relation to diurnality/nocturnality, visual sensitivity, and acuity.

 

2.  Describe the mechanisms that prevent the saturation of the phototransduction machinery in rods and cones in bright light.

 

3.  Describe the pathways by which rods and cones drive ganglion cells. Explain how background light affects the synapses and gap junctions via which rods communicate signals to the brain.

 

4.  What are the cellular mechanisms by which bipolar cells process visual information as it passes through the retina?

 

5.  How does the visual system adapt to changes in light level?

 

6.  How many colours do you really need to make a rainbow, and why?

 

SECTION B

 

7.  Two eyes are better than one. Compare binocular and monocular depth cues.

 

8.  What do the mistakes that the human visual system makes tell us about how it works? Discuss using several examples.

 

9.  'For every (visual) cortical connection there is an equal and opposite back connection'.  Discuss.

 

10.  Compare and contrast the properties of primate visual areas V1 and V5.     

 

11.  Does the primate visual system process colour and form separately?  Give supporting evidence for your views.

 

12.  How successful have attempts to build models of motion perception been in explaining neural systems for motion processing?

 


C44 Neurobiology of Vision 2004

 

Time allowed: 3 hours

 

Answer THREE questions, not more than TWO from each section. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered.

 

 

SECTION A

 

1.  How does the visual system deal with the great range of light intensity it encounters?

 

2.  Can  patterns of retinal cell production be related to the configuration of the mature visual system?

 

3.  How do the anatomy and synaptic connections made by horizontal cells allow them to filter spatially the visual signal in the outer retina? What is the functional significance of this spatial filtering?

 

4.  Discuss the nature and purpose of the parallel pathways from the retina to the brain.

 

5.  Describe the phototransduction cascade present in rod and cone photoreceptors. Go on to explain the role of Ca2+ ions in mediating light adaptation in these cells.

 

6.  Discuss the properties and causes of the more common colour vision deficiencies.

 

 

SECTION B

 

7.  Seeing is believing. Discuss with example.

 

8.  What is an 'area' of visual cortex?

 

9.  How, and why, does the brain separate colour and motion processing?

 

10.  'What's up' in higher level visual areas?  

 

11. How have experiments on second order motion influenced models of human motion detection?

 

12. Discuss the neural mechanisms of motion perception. How have studies of the “motion blind” patient LM contributed to our knowledge of human motion analysis?

 


 

C44 Neurobiology of Vision 2005

 

Time allowed:  3 hours

 

Answer THREE questions, not more than TWO from each section. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered.

 

 

SECTION A

 

1.     Discuss how the retina and eye can be optimized for the visual needs of different species.

 

2.     Describe the molecular mechanisms of phototransduction in a rod, including the role of calcium ions in photoreceptor adaptation.

 

3.     What spatial frequency components of the visual image do retinal bipolar cells respond to?  What cellular mechanisms generate this spatial frequency response, and what is its functional significance?

 

4.     Compare and contrast the morphology and function of retinal P and M ganglion cells.

 

5.     Discuss the nature of the more common types of colour deficiency, and their relationship to normal colour vision.

 

6.     Describe the visual functions of the cerebellum.

 

 

SECTION B

 

7.     What can we learn about vision by studying visual illusions?

 

8.     How do two eyes help us to see in depth?

 

9.     Of what relevance is the lateral geniculate nucleus to higher visual function?

 

10.  What is area V2? How does it contribute to vision?    

 

11.  How does visual processing change as a serial cortical pathway is ascended?

 

12. Combine evidence from psychophysics, neuroscience and brain imaging to provide an account of human motion perception.

 


C3045 Eye and Brain 2006

Time allowed: 3 hours

Answer THREE questions, not more than TWO from each section. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered. Use separate answer books for each question.

 

 

SECTION A

 

1.     Describe the mechanisms involved in the conversion of photon energy into a receptor potential.

 

2.     Write an essay on the evolution of visual pigments and colour vision in vertebrates.

 

3.     How do light-evoked changes in the release of glutamate from rods or cones lead to depolarization of ON bipolar cells but hyperpolarization of OFF bipolar cells? What effect does GABA released from horizontal cells have on each class of bipolar, and what is the functional significance of this?

 

4.     Describe the organisation of the inner plexiform layer.  How do ganglion cells and amacrine cells modify the input they receive from bipolar cells?

 

5.     Colour is a property of biology not physics. Discuss.

 

6.     How does the visual system regulate its sensitivity as the light level increases?

 

 

SECTION B

 

7.     How can visual illusions give us insights into visual processing?

 

8.     How do we reconstruct depth from the two-dimensional retinal images?

 

9.     What, anatomically, is feedback? What functions might it serve?

 

10.  How does area V5 differ from area V1? Are there any similarities?        

 

11.  What is the ventral visual pathway? What does it do?

 

12. Discuss the role of direction selectivity in visual motion processing.

 


C3045 Eye and Brain 2007

Time allowed: 3 hours

Answer THREE questions, not more than TWO from each section. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered. Use separate answer books for each question.

 

 

SECTION A

 

1.   A rod photoreceptor can respond to a single photon.  Describe the transduction mechanism involved, and the significance of calcium ions in regulating the response.

 

2.   Normal human colour vision is limited by trichromacy.  Discuss this statement with reference to the evolution of colour vision in vertebrates.

 

3.   Explain how the receptive field organization of bipolar cells is produced by the wiring of cells in the outer retina. How does this organization leads to an enhancement of signals associated with edges in the visual world (step changes of light intensity) in the bipolar cells?

 

4.   Discuss the human and monkey lateral geniculate nucleus in terms of its laminar structure, its input from the two eyes, and the receptive field properties of its cells.

 

5.   What mechanisms does the visual system use to regulate its sensitivity as the light level changes?

 

6.   Discuss the organisation and functions of retinal ganglion cells.

 

 

SECTION B

 

7.   Two eyes are better than one. Discuss.

 

8.   Are colour and form processed in parallel?

 

9.   Why do visual illusions occur? Discuss, giving several examples.

 

10. How do forward and backward pathways differ in structure and function?   

 

11. What is the evidence for a 'magnocellular' pathway?

 

12. How can we characterise the motion perception deficit in akinotopsia?

 


C3045 Eye and Brain 2008

Time allowed: 3 hours

Answer THREE questions, not more than TWO from each section. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered. Use separate answer books for each question.

 

 

SECTION A

 

1.   Write an essay on the comparative anatomy of the vertebrate retina. In your answer you should discuss those features that are common to all vertebrates, and differences among animals in types and distribution of receptors, and links to ganglion cells.

 

2.   How can the absorption of a single photon produce a viable photoreceptor response?

 

3.   How is the human visual system able to operate over the enormous range of light levels to which it is exposed in the environment?

 

4.   Relate the adult organisation of the visual system to its development.

 

5.   How are signals from rods and cones thought to be transmitted to mammalian retinal ganglion cells?

 

6.   In what sense is colour vision trichromatic and why?

 

 

SECTION B

 

7.   Describe the characteristics of the three components of the Lateral Geniculate Nucleus. How far are their outputs integrated within area V1, and subsequent levels of processing?

 

8.   What is an 'area' of visual cortex? Why are there so many?

 

9.   Discuss the workings of the ‘ventral visual pathway’ in object and face recognition.

 

10. How do we see in depth?

 

11. How do visual illusions help us to understand more about visual processing?

 

12. What has akinotopsia told us about normal human motion perceptual mechanisms?


ANAT3045 Eye and Brain 2009

Time allowed: 3 hours

 

Answer THREE questions, not more than TWO from each section. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered. Use separate answer books for each question.

 

 

SECTION A

 

1.   Describe the molecular mechanisms of phototransduction. What is the role of calcium ions?

     

2.   How is the electroretinogram (ERG) generated and recorded, and what does it tell us?

 

3.   How are the signals from cones processed to generate the receptive fields of retinal ganglion cells?

 

4.   How and why does the visual system regulate its sensitivity?

 

5.   How does normal colour vision differ from the commoner forms of red-green colour vision deficiency?

 

6.   Discuss the size of cells in the retina and the lateral geniculate nucleus of mammals. How might differences in size be related to differences in function?

 

SECTION B

 

7.   What makes a visual illusion an illusion? Why are visual illusions interesting to the vision scientist? Give examples.

 

8.   What do you understand by the term 'parallel visual processing'?

 

9.   Imagine that a new area of visual cortex has been reported. What experiments might be performed in order to confirm its existence, to investigate its connections, and to determine its function?

 

10. What neural mechanisms might allow you (or a monkey) to recognise a face?

 

11. Why is integration necessary to allow us to see form?

 

12. How do we encode the direction and speed of visual motion?

 

 


ANAT3045 Eye and Brain 2010

Time allowed: 3 hours

 

Answer THREE questions, not more than TWO from each section. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered. Use separate answer books for each question.

 

 

SECTION A

1.    How does the structure of the visual system reflect its development?
      
2.    Describe the molecular mechanisms of sensitivity regulation in the transduction cascade.

3.    Discuss the role of horizontal cells in retinal circuitry.

4.    How do signals from rod and cone photoreceptors reach retinal ganglion cells?

5.    Contrast the properties of the parvocellular and magnocellular systems.

6.    Why is normal colour vision trichromatic? What are the implications of trichromacy for the reproduction of colour?

SECTION B

 

7.    What is the significance of having two eyes with overlapping visual fields?

8.    What are the pathways through the brain that are involved in catching a ball?

9.    What can be learnt about vision by studying the connectivity of visual cortex?

10.  Why are there so many visual areas of cerebral cortex?

11.  What is the neural basis of visual recognition?

12.   Discuss psychophysical and brain imaging investigations of motion processing in akinetopsia.

 


ANAT3045 Eye and Brain 2011

Time allowed: 2 hours

Candidates should answer TWO questions. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered. Use separate answer books for each question.

1.     Describe the main steps in the visual transduction cascade.
       
2.     How is the electroretinogram (ERG) generated and recorded, and what does it tell us?

3.     How are the signals from cones processed to generate the receptive fields of retinal ganglion cells?

4.     What can visual illusions reveal about brain function?

5.     “Form and movement are processed by independent systems in the eye and the brain" Discuss.

6.     What can "visual crowding" tell us about spatial vision?

7.     How have scientists attempted to clarify the 'neural correlate of consciousness'?

8.    Compare and contrast chromatic and achromatic vision.

 


NEUR3045 Visual Neuroscience 2012

Time allowed: 2 hours

Candidates should answer TWO questions. Credit will be given for imaginative and critical discussion of experimental evidence relevant to the question being answered. Be sure to use a separate answer booklet for each question.

1.    How is visual acuity measured? What limits it?

2.    How does the retina generate distinct ON and OFF responses to light?

3.    How are opponent centre-surround receptive fields of retinal ganglion cells formed?

4.    What mechanisms underlie our perception of motion?

5.    How does it help to understand the workings of visual cortex by defining separate 'areas'?

6.    What is the best way to assess if someone can detect a visual object?

7.    How do we see in depth?

8.    What kind of serial processing steps might lie between the retinal image and a face selective neuron in inferotemporal cortex?


NEUR3045 Visual Neuroscience 2013

Time allowed: 2 hours

Answer TWO questions.

Use a separate answer book for each question

1.    How does the absorption of a single photon produce a clearly measureable photoreceptor response?

2.    How does the human visual system code the shape of objects?

3.    How does the output from cone photoreceptors give rise to distinct ON-centre and OFF-centre responses in retinal ganglion cells?

4.    How are the rods and the rod retinal pathways optimized for vision at low light levels? What are the limitations of vision mediated by rods?

5.    Why is the organisation and function of the visual cortex said to be 'hierarchical'?

6.    What do you understand by the term 'neural correlate of consciousness'? Describe two experiments (one human, one non-human) that address this topic and discuss their implications.

7.    How is second order motion encoded?

8.    What can illusions tell us about how the visual system works? Give specific examples to support your discussion.

 


NEUR3045 Visual Neuroscience 2014

Time allowed: 2 hours

Answer TWO questions.

Use a separate answer book for each question

1.    Describe the steps of the visual transduction cascade. What are the main events at each step and how are they modified by light adaptation?

2.    You are an expert witness in a criminal trial and you are conducting a psychophysical experiment to measure the greatest distance at which someone could reliably identify the face of a suspect. Describe the experiment and discuss its strengths and weaknesses.

3.    How do we see depth in the visual scene?

4.    Ascending visual pathways are found to generate increasingly elaborate response selectivity at higher levels. Citing specific examples, explain how this might be achieved.

5.    “All we are hypothesizing is that the activity in V1 does not directly enter awareness” (Crick & Koch, 1995): what experimental evidence has been used to address this issue?

6.    Discuss the evidence for, and properties of, direction-selective neurons at different levels of the visual system.

Answer either 7a or 7b.

7a.  How does the output from cone photoreceptors give rise to distinct ON-centre /OFF-surround and OFF-centre /ON-surround responses in retinal bipolar cells?

7b.  How are achromatic and chromatic signals encoded and processed in the retina?

 


NEUR3045 Visual Neuroscience 2015

Time allowed: 2 hours

Answer TWO questions.

Use a separate answer book for each question

1.    What does Weber’s Law tell us about visual perception, and how would you design an experiment to test whether it occurs for judgements of size?

2.    Discuss how the anatomy of the vertebrate eye varies across species. Consider those features that are common to all vertebrates, and those that differ. Can the differences be related to the life that the animal leads?

3.    How is visual acuity measured? What limits visual acuity?

4.    What is an ‘area’ of cortex? How do areas interact in a hierarchical fashion?

5.    What is the aim of research addressing the ‘neural correlate of consciousness’? How has it exploited the phenomenon of binocular rivalry?

6.    Should we distinguish between short range and long range motion?

7.    How do the signals from cone photoreceptors give rise to the receptive fields of retinal ganglion cells under photopic conditions?

8.    How do visual Illusions inform our understanding of visual processing? Give several examples.


NEUR3045 Visual Neuroscience 2016

Time allowed: 2 hours

Answer TWO questions.

1.    How does the absorption of a single photon produce a reliable rod photoreceptor response?

2.    What anatomical and physiological characteristics of cortical visual pathways justify their description as ‘hierarchical’?

3.    Drawing on relevant literature, discuss the different ways that a stationary visual stimulus can be made to appear to move.  How can these effects be explained, and what do they tell us about motion perception?

4.    Compare and contrast the encoding, processing and transmission of achromatic and chromatic signals up to visual cortex.

5.    How does the output from cone photoreceptors give rise to distinct ON-centre /OFF-surround and OFF-centre /ON-surround responses in retinal bipolar cells?

6.    How does crowding affect our peripheral vision, and why might it do so?

7.    Define the characteristics of areas V1 and V5/MT and compare their processing of moving stimuli. What happens to human visual motion perception if either area is damaged?