Psych 159: Physiological Basis of Perception

Psych 159: Physiological Basis of Perception

Instructor: Don MacLeod

Class meetings: Lectures, Tuesday and Thursday 11am to 12.30, 1507McGill

Office Hours: Wednesdays, 10-12, Room 5121 McGill; Tel 534-3975.

Email: dmacleod@ucsd.edu

Web: http://www-psy.ucsd.edu/~dmacleod  (and click on “courses” link)

 

Aims and scope: We consider the process of perception as a causal chain that starts with the sensory stimulus and continues through successive stages of neural representation, culminating finally in the construction of a behaviorally useful representation of the environment. We will be aiming for a research-level treatment of current understanding of selected topics. To make this job easier, we consider mainly visual perception, and select a limited number of problems within that field for in-depth treatment, especially those for which the nature of physiological constraints on perception is clearest. The inquiry focuses particularly on how both subjective (or "psychophysical") and objective (electrophysiological, neuroanatomical) approaches can be brought to bear on the same issues about visual processing, and on the difficulties and successes in achieving consistency between the findings of the two approaches.

Text: Fundamentals of Sensation and Perception

by Mike Levine. (Oxford University Press, 2000)

This text is a 3rd edition. It is, I understand available at the Bookstore. The price is about $75. Earlier editions are unfortunately not good substitutes (though better than nothing I suppose). The book includes a CD-ROM (for a Windows PC  with at least 9MB of disc space free—sorry, MacIntosh aficionados). The CD has a useful demo or two for each chapter. To use the CD, run its setup.exe program to install the software to some directory on your hard disc (look at readme.txt on the CD first if you like), and then run Sensperc.exe in the installation directory.

We will (tentatively) be leaving out the speech perception chapter, which leaves Chapters 1-17, 19 and 20. Some of this material is less important than other parts, though. Lectures will indicate, and emphasize, the parts of the material that are most critical, but chapters 2, 12, 17, 19 and 20 will be among the less critical parts of the text.

I strongly encourage review of the material in the text before the associated lecture, as listed below. This will make it easier to deal with the more advanced material that will often be introduced in the lectures.

Prerequisites and desiderata: Psych 102, Introduction to Perception, is ordinarily required. Confident students are not necessarily excluded, however, especially if they have some background in neurobiology or physiological psychology. Quite a few of the topics we consider will be treated quantitatively, so an enthusiasm for thinking quantitatively, or some background in physics or engineering, is also a great advantage…and an aversion to thinking quantitatively is a corresponding handicap.

Format: The lectures will use the topics in the text as a starting point. But they will not necessarily follow the text very closely—they will leave out some topics, and often introduce new material to update and elaborate the discussion in the text. So you should consider the lectures mandatory rather than optional, if you want to do well.

Evaluation (tentative plan):

We plan to have a midterm and a final.  Besides these you are asked to produce one substantial paper  and one 15 minute presentation to the class.

The paper will be due at the beginning of class on Thursday of Week 7. A recommended length is 10 pages (double spaced type please). The choice of topic is up to you, provided it's relevant to the themes of the course. Discuss it with us first if you're uncertain. Originality will be appreciated, but it isn't mandatory. Possible topics will be discussed in class. You should choose a topic and tell me your choice at least a week before the paper is due. You are expected to consult the research literature beyond the recommended readings in preparing your paper.

Format of the paper is flexible, but: use citations in your paper to justify your claims. Cite authors by name and date, e.g. (Smith & Jones, 1922). Include complete references at the end of the paper in any standard format, e.g. APA format. Include an abstract (a summary of the key points, in less than 1 page). You are encouraged to replace one of the papers with a more concrete project: for instance you could conduct a perception experiment, do a computer simulation, or create an informative visual demonstration. A project could also be accompanied by a short written report if you like.

The presentation should be a short and snappy but comprehensible (to your classmates) account of some topic that the text discusses. Please discuss your choice of topic with me beforehand. One possible choice (though not the best one) is to just summarize and clarify part of the textbook chapter we are dealing with on the day of your presentation, perhaps developing your own understanding of that topic using other sources like the recommended readings. Much better is to introduce some new material that has a connection to the material in the text (for instance, briefly summarize a recent piece of research that has something to say about the topic of the day). 

It’s a good idea to use some graphics for your presentation. PowerPoint is a good way to go. I will be bringing a computer graphics projector. If you can use your own laptop for that, that will be fine. Otherwise, I will need notice the day before so I can bring mine. If we have to use my laptop, you can email your .ppt file to me the day before, or bring it to class on a CD. Alternatively, I will bring a projector for overhead transparencies if that’s your preference (N.B. 16 point minimum font size for legibility!).

Tentative distribution of points: Midterm (25%), paper/project/presentations (15% for each of two) and final (45%). Midterm and final exams will be include essay type questions as well as short answer/multiple choice questions—about a 50/50 split between essay type and short answer questions in the total grade. Tentative format for essay questions: you will be asked to answer 2 (midterm) or 3 (final) out of 5 questions. These 5 questions will be selected by us from a list of up to 20 questions that we will give out at the lectures, at least a week in advance of the exam. Questions and grading will try to reward understanding rather than detailed factual knowledge. Of the material in the text, the most important topics will be the ones emphasized in the lectures, and the most important material within each topic is the material that is esssential to our understanding of the subject, rather than specific facts. Answers will require thoughtful consideration of text and lectures. Feel free to help me (and yourself) by providing me with candidate questions that you think would be appropriate for inclusion in the exam. I expect to use only a small proportion of questions that are submitted this way, but formulating (and answering) questions is in any case a productive way of organizing high-level study.

SCHEDULE (TENTATIVE)

Week 1 Tuesday: The problem of perception

Week 1 Thursday: How the retinal image is formed

Reading: Chapter 3

Week 2 Tuesday:       Lecture topic: optical limitations on the quality of vision

Week 2 Thursday: Retinal organization

Reading: Chapter 4

Lecture topic: How photoreceptors respond to light

Week 3 Tuesday: Functional organization of the retina: receptive fields

Reading: Chapter 5

Lecture topic: Why isn't vision perfect? Resolution and receptive fields

Week 3 Thursday: Light and Dark adaptation: how sensitivity is regulated

Reading: Chapter 6

Week 4 Tuesday:  Color vision: Why we are all partially color blind

Reading: Chapter 14 (can be read out of sequence),  to p319

Week 4 Thursday: Physiological Basis of Color Appearance

Reading: Chapter 14, pp319-end

Lecture topic: Color and lightness constancy

Week 5 Tuesday: Primary visual cortex and form vision

 

Reading: Chapter 7; also preview chapter 9

Lecture topic: Illusions, aftereffects and the brain

Week 5 Thursday: Higher cortical areas and form vision

Reading: Chapter 8  

Lecture topic: Parallel streams and functional specialization in the cortex

Week 6 Tuesday:  TBA

Week 6 Thursday: MIDTERM

Week 7 Tuesday: Spatial frequency representation

Reading: Chapter 9  

Week 7 Thursday: Physiological Basis of Depth Perception

Reading: Chapter 11  

Week 8 Tuesday:  Constancies and Illusions

Reading: Chapter 12  

Week 8 Thursday: Motion

 

Reading: Chapter 13  

Week 9 Tuesday: Hearing and the ear PAPER DUE

Reading: Chapter 15 and 16  

Week 9 Thursday:  TBA

Week 10 Tuesday:  Touch and Pain, Taste and Smell

Reading: Chapters 19 and 20

Week 10 Thursday:  Form Perception

Reading: Chapter10  

Lecture topic: The Symbolic Representation and its Computation

 

MIDTERM: Tentatively Thursday, 13 February, Week 6 (in class)

FINAL: as in schedule of classes.

 

Additional recommended reading: general

The text will not be terribly challenging to those who have already done Psych 102. I will distribute copies of a few other readings during the quarter as they are relevant. There are no other required readings, but if you want to do well (and still more, if you are keen to advance your understanding of the subject) you will want to read further. For a start, anyone who hasn’t completed Psych 102 might find it useful to look over a more introductory (Psych 102 or equivalent) text for review of background. Two good examples:

R. Sekuler and R.Blake, Visual Perception, Knopf, 1985

E.B.Goldstein, Sensation and Perception, Wadsworth, 1989 ( a little more physiologically oriented, and so marginally preferable here, to Sekuler and Blake).

T.N.Cornsweet, Visual Perception, Academic Press, 1970 is that rarity: a thinking person’s textbook. Fun, but limited to low levels of visual processing that can be understood in physiological (or at least in mechanistic) terms.

Richard Gregory, Eye and Brain, Princeton, 1990 is shorter, more selective, less technical and even more fun than Cornsweet.

S. E. Palmer, Vision Science: From Photons to Phenomenology, MIT 1999 is an excellent and comprehensive survey of our understanding of visual perception, encompassing phenomenological and cognitive as well as physiological viewpoints.

Useful for a more advanced and up to date, mathematically oriented survey of most of the course material: Wandell B.A. Foundations of Vision. Sinauer Associates Inc., 1995.

Still more advanced, but useful for getting into current issues in preparing papers, are the proceedings of recent scientific symposia:L. Spillmann & J.S. Werner (Eds.) Visual Perception: The Neurophysiological Foundations. Academic Press 1990 and C. Blakemore (ed.). Vision: Coding and Efficiency, Cambridge (1990).  These are sophisticated summaries of current thinking at the frontiers of research.

 

Recommended reading: specific topics

Other books recommended for a clear and comprehensive account of part of the material:

P.K. Kaiser and R.M.Boynton, Human Color Vision, Optical Society of America, 1996. This discusses not only color vision but also visual sensitivity (altogether, about 1/3 of the course material) in a sufficiently advanced but understandable way. Most useful are chapters 1-7 and 10, especially chapters 5, 6 and 7.  For a state-of-the-art discussion of current issues in color vision you could also try R. Mausfeld and D. Heyer, Colour Perception: Mind and the Physical World, Oxford, 2003.

D. Marr, Vision, Freeman, 1982 is the most influential book on vision written this century, outlining what has become known as the "computational" approach, which unites the artificial intelligence and physiological points of view on vision. Especially good on stereo.

Chapter 4 of The Computational Brain, by Pat Churchland and Terry Sejnowski, is a good briefer treatment along Marr's lines, again concentrating on depth and 3D shape.

S. Zeki, A Vision of the Brain, Blackwell, 1993 is a beautifully illustrated but peculiarly one-sided and controversial discussion of the special role of different regions of the cerebral cortex in vision. A broader and less idiosyncratic, but less up-to-the minute, account of the physiological basis of vision with a focus on the cortex is D.H.Hubel, Eye, Brain, and Vision, Freeman, 1988.

R. W. Rodieck, The First Steps in Seeing, Sinauer, 1998. is a challenging in its rigor and attention to detail, but it is written clearly so that an interested and thoughtful reader can understand it without much prior knowledge. Focus is heavily on early stages in vision, mainly the eye and the retina. Complements Zeki, where the focus is on cortex.

   

D.B. Dusenbery, Sensory Ecology, Freeman 1992 is an interesting survey of sensory processes in animals.

 

David M. Regan, Human Perception of Objects, Sinauer, 2000 discusses in some depth the early visual processing of spatial form defined by luminance, color, texture, motion, and binocular disparity.

 

Some student presentations

presentations05\AaronGanglion Cells.ppt

presentations05\AndreaLaser Eye Surgery.ppt

presentations05\andrewCol.ppt

presentations05\BenPitch.ppt

presentations05\CathyVisionTherapy.ppt

presentations05\DanEvolution of the Eye.ppt

presentations05\DusanSound Compression.ppt

presentations05\EricDepth Perception.ppt

presentations05\jenniferglaucoma.ppt

presentations05\MichaelSound Localization of Humans.ppt

presentations05\RachelHearing.ppt

presentations05\Ryan05Evolution of multiple retinal rod pigmentation.ppt

presentations05\AnaPain.ppt

presentations05\KamilleILLUSIONS.ppt

 

A few of the many useful Web resources: