CN 530: Neural and Computational Models of Vision

Course Syllabus, Fall 2004

Professor Ennio Mingolla                                  Teaching Fellow: Arash Yazdanbakhsh

Office: 677 Beacon Street, Room 210               Office: 677 Beacon Street, Room 110

Office hours: Tuesdays, 1:00--3:00 PM, and     Office Hours: Tuesdays, 10:00 AM to noon, and

          by appointment                                                   by appointment

Tel: 617-353-9485; email: ennio@cns.bu.edu          Tel: 617-353-6426; email: yazdan@cns.bu.edu

Course overview and meeting times.

SUMMARY OF WEEKLY TOPICS

Week 1               Sep 8                Fundamental problems of vision

Week 2               Sep 15              Shunting competitive networks and representation in early vision

Week 3               Sep 22              Contrast sensitivity and spatial scales

Week 4               Sep 29              Early visual pathways

Week 5               Oct 6                Brightness and lightness perception

Week 6               Oct 13              Parallel visual pathways

Week 7               Oct 20              Boundary detection, completion, and sharpening

Week 8               Oct 27              Approaches to textural segmentation and grouping

Week 9               Nov 3                Binocular vision

Week 10             Nov 10              An in-class examination, covering topics in the readings and lectures

                                                     from the first 9 weeks, will be given during this class period.

Week 11             Nov 17              The phenomena of motion perception

Week 12             Dec 1                Models of motion perception   

Week 13             Dec 8                 Visual attention

Overview: This course explores the psychological, biological, mathematical and computational foundations of visual perception. Lectures and readings combine with simulation and essay assignments to provide an intensive and self-contained examination of core issues in early and middle visual processing. Mathematically specified neural and computational models elucidate the structure and dynamics of the mammalian visual system. Emphasis is placed on understanding the psychophysics and physiology of mammalian vision, both as a means of better understanding our own human intelligence, and as a foundation for tomorrow's machine vision architectures and algorithms. While some of the models developed in recent years at Boston University's Center for Adaptive Systems (CAS) and Department of Cognitive and Neural Systems (CNS) are covered in depth, selected models by a variety of researchers are compared and contrasted.

Meeting times: Lectures will be given on Wednesdays, beginning on September 8 and ending on December 8, from 1:00-4:00 PM in Room B02 of 677 Beacon Street. An additional hour-long discussion period at a different time will be arranged.

COURSE REQUIREMENTS AND GRADES: All students must complete three simulation assignments , an in-class midterm examination , and a written final course report . Students will also turn in weekly updates of a personal journal , as described below. Course grades will be based on a conventional 100 point scale, with A = 93 or better, A-minus = 90-92, etc. The weighting of assignments and exams on the final grade is:

          30%           Three simulation assignments: Each counts 10% of the total for the course.

          30% In-class midterm examination ( Week 10, Nov. 10 )

          10%           Final report (Due on Thursday, Dec. 16, 4:00 pm)                               

          10%          Discussion meeting participation

          20%          Professional growth, as documented in a personal journal

ASSIGNMENTS (OVERVIEW): Credit for participation in discussion meetings will be based on the student's understanding of core topics from readings and lectures, as expressed in comments initiated by students or in response to questions from the professor. Written assignments are of three kinds: (1) Simulation assignments involve performing short computer simulations; facility for graphical plotting of black-and-white data curves or line segments will be required. One of the assignments will involve the numerical solution of ordinary differential equations. All enrolled students have access to facilities adequate for doing the assignments. In the past many students have successfully used their own personal computers or machines provided at their place of employment. If you anticipate difficulties in performing simulations (programming, graphical plotting, machine access), see the course teaching fellow immediately. ) (2) The final report will be an essay that summarizes the fruits of personal research on a topic to be negotiated. Details about the format and content of the final report will be provided after the in-class exam. (3) Each student will keep a personal journal ; individual journal entries can be turned in weekly, on Wednesdays, at the start of class.

Details of personal journals: You must turn in exactly 10 journal units, with each unit being two or three pages long – no more, no less – using 1.5 line spacing between lines and a legible font of at least 10pt size. No more than one journal unit can be turned in per week. You will have 12 opportunities to turn in units, including the week that you have your in-class exam and including weeks that simulation assignments are due. You will thus have to plan your time carefully.

In the upper right hand column of each journal unit, write your name, the date that you turn the unit in, and “Unit N,” where N is an integer from 1 to 10, corresponding to the number of that unit. Each journal unit has two parts: (1) a short essay , and (2) an annotated reading list. The essay should start with a descriptive title and be closely based on required readings for the course, though it may also refer to supplementary readings or to readings of your choosing that are not on the syllabus. Readings that you cite in your essay must be included in the annotated reading list. You must choose a standard citation style and stick to it throughout the semester. For example, see http://library.osu.edu/sites/guides/apagd.html , though you are free to choose a different style. The essay should be one to two pages in length. The topic does not have to correspond to any of the topics of the upcoming lecture, but try to vary your topics from week to week. Strive to improve your writing throughout the semester. Review Strunk & White (described below) or some other style reference. Consult the handout given out at the first class.

The annotated reading list should include full citations of readings that your have done, followed by a one or two sentence description of that reading. Over the course of the semester, your annotated list should include most of the required readings for the course, and at least a few supplementary readings.

Journal units must be turned in at the start of class; I will take a dim view of any student arriving late “because” that student needed extra minutes to finish a journal assignment. Electronic submission of journal units is not an option. Please note that the effect on your grade of turning in less than 10 journal units is almost certain to be noticeable: With each unit accounting for 2% of your total course grade, you will slip quickly from (say) an A to an A-minus to a B-plus if you fail to turn in 10. At the end of the semester, I will review all of your journal entries for evidence of professional growth, and possibly adjust your final grade point credits by one or two points (plus or minus, on a 100 point scale) based on this evidence.

Journals will be grade on a “check” system, with each unit that is turned in on time counting for two points (out of 100 total points of your final grade). Most units will earn this default scoring, and I will not in general return journal units to you throughout the semester. I will contact individuals directly if performance on journal units deviates significantly from the default. I will often share with the class points raised by individuals in their journals, and my reaction to those points. The student's identity will not be disclosed in these cases.

SIMULATION ASSIGNMENT SUBMISSION, CONTENTS, AND FORMAT:

1) Due dates and submission: Simulation assignments are due by 4:00 pm on Mondays, not Wednesdays. Do not even THINK of asking me if it is “okay” to submit an assignment late; it is not okay, not even by a few minutes, and your assignment grade will suffer. Please assume that printers will not work in the hours just before an assignment is due, that the subway will run late, etc., and get your assignments turned in on time anyway. My preference is to receive hardcopies at my office; assignments may be placed under my door if I am not in. If you are unavoidably physically distant from CNS on a due date, you may submit assignments electronically in Adobe Acrobat “PDF” format only.

2) Cover sheet and anonymous grading: Turn in all simulation assignments on 8 1/2” x 11” paper, and include your name, the course number, the date of submission, and the words “Simulation Assignment N” (N = assignment number) on the upper right corner of the first page only. These assignments are to be evaluated based on their content only, so do not include information about your identity on any other pages.

3) Length: Simulation reports are expected to be brief. “Brief” means up to 2500 words for total report text; simulation assignments will have additional pages for graphs and diagrams. Software such as MSWord or LaTeX typically generates approximately 250 to 350 words per page, depending on settings for margins and line spacing.

4) Abstracts and titles: Simulation reports and the Final Report, must include abstracts of approximately 200-300 words. Abstracts should be specific enough in their wording that a person reading only the abstract should come away with a reasonably accurate idea of the content of your report. The simulation and final reports must begin with a short title that is descriptive of the content of the report. Possible titles do not include “simulation assignment 2” but do include concise phrases like “simulations of brightness filling-in by boundary-gated diffusion.”

5) Graphical plots: Describe simulation results in words, but with the help of graphical plots whenever possible. Include scales on all axes, and explicitly label the quantities being plotted on all axes . Your plots can be generated by computer or by hand, or in combination. (For example, you may be able to plot locations of points by computer, but prefer to label the scale of axes by hand.) Be judicious in choosing which outputs to display overall. Choose figures that contribute materially to the reader's understanding (by showing crucial “before and after” or “with-crucial-parameter-value-equals-this-or-that” juxtapositions), rather than showing dozens of simulations. A typical mistake made by novice simulators is to display the results of many computer runs that vary only by a single parameter on several pages, making it nearly impossible for the reader to discern the overall impact of parameter variation on simulation results. Often, some manual “cut and paste,” perhaps with photocopier reduction, is necessary to get a coherent graphical presentation. Note that it is almost never sufficient to report results only by showing plots; some accompanying verbal description -- well keyed to the plots -- is generally necessary . Irrespective of the contents of the data plots, a “sprawling” presentation where the relevant variation occurs across pages or with insufficient labeling (of axes and parameter variations) will be awarded reduced credit. Listing of computer code is not desired.

ASSIGNMENT DUE DATES AND GRADING POLICY: Simulation assignments and the final report are to be turned in to Prof. Mingolla's office; please slip them under the door by 4:00 PM on the following dates. Note that all are Mondays , except for May 6, which is a Thursday:

          Simulation Assignment 1                  Monday     Sep 27          Week 4

          Simulation Assignment 2                  Monday     Oct 25          Week 8

          Simulation Assignment 3                  Monday     Nov 29          Week 12

          Final report                                                Thursday          Dec 16

NOTE: Simulation assignments turned in late are eligible for a maximum of 80% credit. Assignments will not be accepted more than 2 calendar weeks after their due date. Simulation assignments will be graded on a 15-point scale, with 15 indicating “excellent” work, 12 indicating “good” work, and less than 12 indicating a “less than B-minus trajectory”, which is inadequate for graduate work. Do not underestimate the effect of missing a single assignment deadline on your final course grade. For example, a 20% decrement from the 10 points available from a single simulation assignment accounts for 2% of total available course credit, which is enough to change an “A-” to a “B+”. On rare cases, a credit score slightly greater than 10 may be awarded for an assignment containing elaboration beyond that specified in the assignment's requirements. NOTE: “Elaboration” means that once you have completed all required aspects of the assignment , you may -- time and your own enthusiasm permitting -- do additional simulations, mathematical analysis, or prose argument. It does not mean that you may substitute something that you would rather do for the requirements of the assignments.

SIMULATION SOFTWARE: While it is assumed that every student in this course is capable of writing simple applications programs for coding assigned simulations, this is not a programming course, and programming will not be taught. The assignments are not meant to burden students with days of software development, and they have been constructed in such a way as to minimize program development time. Many students in past courses have found that MATLAB or comparable packages offer a useful development environment. In any case, sophistication in programming and the use of software tools varies widely among students, and sometimes the best programmer runs into an unanticipated and stubborn quirk. If this happens, feel free to ask the Teaching Fellow (TF) for assistance. You many use any commercially available software that you feel enhances your productivity. You may legitimately ask questions of me or of the course TF while doing the assignments. You may discuss simulation development with fellow students, up to the point of exchanging programming “tips” or information about available resources (for graphics, word processing, etc.), but you are not to work in groups for “division of labor.”

WRITING STYLE: Imagine being the reader of your document. It is not enough to ask “Have I put down what I know?” or “Is this what I mean to say?” Ask yourself also: “Would someone who cannot read my thoughts understand what I have written?” and “Are there equally probable interpretations of what I have written other than what I mean?” Considerations of proper usage (spelling, margins, etc.) pertain both to human decency -- why subject the reader to your sloppiness? -- and to good professional practice. Do not take the attitude that “I'll turn in something proper only when it really matters,” insofar as bad habits are easy to establish and hard to break. For those who may need additional motivation, I assure you that “it really matters” right here and now. The impact on your grade of stylistic lapses of the sorts described in this syllabus can be UP TO 20% of the total.

SIMULATION ASSIGNMENT FORMAT AND STYLE: All assignments must include an abstract, a short introduction, and a short concluding section, each designated by an appropriate header. Your introductions should be sufficiently self-contained to make sense to someone besides me or the course teaching assistant. That is, you should not use jargon or assume familiarity with terms not expected to be in general use in the field of vision research. For simulation assignments you must explicitly label which part of which question (e.g. 3a or 1b) a given section of your report addresses. All assignments must be produced on a word-processor. Clear handwritten annotation is acceptable in small amounts, including correction of typos, insertion of notation in mathematical equations, graphs, or figures. Assignments containing extensive handwritten passages will be returned ungraded. You are expected to employ proper English spelling and grammar, and to adhere to reasonable stylistic conventions (such as the use of margins, references, headings and so forth.) I am aware that for many of you English is not a first language, and I do not expect you to become accomplished authors overnight. I am referring to basic requirements that can and should be met by all: Make sure that your sentences contain verbs and end with a period. If you use a pronoun in a sentence, make sure its antecedent is unambiguous. Do not employ slang. Check your writing for clarity; do not expect to be given “the benefit of the doubt” if your words are ambiguous or vague.

PLAGERISM: What you write is to be the original expression of your own learning. If you must employ a phrase or more of words written by another person, clearly mark the passage used as a quotation , and cite the source in full. This requirement applies even if the source is the course lecture notes, or any “study guide” informally circulated among students, whether in paper or electronic form.

“EXTRA CREDIT” WORK: There will be none. The course already contains many pointers for “extra” work within its assignments. The answer to any request that a student be allowed to bring their grade up to some level (say, B-) through work not already described in course materials -- as opposed to doing a proper job on the regular assignments -- will be “NO.”

MAKE-UP” WORK: (a) Assignments: Simulation assignments turned in after the due date for whatever reason are eligible for a maximum of 80% credit. For example, a student receiving less than a 12 on a given simulation assignment may resubmit a corrected version of that assignment within 5 weeks of the original due date, in order to bring the grade up to 12 (i.e. 80% of full credit). If a less-than- perfect assignment is submitted on the second round, the grade will be 80% of what that assignment would have earned on the first round. No amount of subsequent extra work on that assignment can make the resulting grade higher than 12. (b) Examinations: Students who are unavoidably absent from the in-class examination will take a special make-up examination consisting of written and oral portions as soon as one can be scheduled.

EMAIL: An alias called cn530@cns.bu.edu has been set up in order to broadcast information of interest to people in this class. Email will never be used as the sole source of important information, but may serve to speed up administrative matters. The accounts of the professor and teaching fellow are included. Any student may send a message to the account, for items likely to be of general interest.

CONFIDENTIALITY OF PERSONAL WORK: All students using University computers for doing simulations, word processing, or figure generation for assignments or take-home examinations are expected to read-protect their files.

LECTURE NOTES AND MISCELLANEOUS READINGS: Copies of all lecture notes for the course are available for download from the course web site. Required readings that are not contained in the textbooks will be made available for photocopying, as will be explained during the first class. Some readings will be available via electronic means.

BU POLICY: The syllabus, course descriptions, and handouts created by Professor Mingolla, and all class lectures, are copyrighted by Boston University and/or Professor Mingolla. Except with respect to enrolled students as set forth below, the materials and lectures may not be reproduced in any form or otherwise copied, displayed or distributed, nor should works derived from them be reproduced, copied, displayed or distributed without the written permission of Professor Mingolla. Infringement of the copyright in these materials, including any sale or commercial use of notes, summaries, outlines or other reproductions of lectures, constitutes a violation of the copyright laws and is prohibited. Students enrolled in the course are allowed to share with other enrolled students course materials, notes, and other writings based on the course materials and lectures, but may not do so on a commercial basis or otherwise for payment of any kind. Please note in particular that selling or buying class notes, lecture notes or summaries, or similar materials both violates copyright and interferes with the academic mission of the College, and is therefore prohibited in this class and will be considered a violation of the student code of responsibility that is subject to academic sanctions.

BOOKS MOST RELEVANT TO THE COURSE: One book has been ordered for CN 530:

Palmer, S. E. (1999). Vision science: From photons to phenomenology . Cambridge, MA: MIT Press. (Approx. $80.00). The bookstore lists it as “required,” in the sense that many required readings can be found there. You may choose to use the CNS library edition of this book, or to purchase it. In the weekly listing of required readings, this book is designated as " SEP ." Note that all chapters of this book may be available for downloading with a subscription to Cognet: http://cognet.mit.edu/

You may wish to consider additional purchases, which have not been ordered for CN 530. Some comments are included below to help you make purchasing decisions. Books are interest in the order in which they are most likely to be useful for most students.

Strunk, W., Jr., and White, E.B. The Elements of style . 4th edition. Boston, Allyn & Bacon, 2000. At $6.95 (paperback) this may be the best book, on a price/performance basis, you ever purchase. One cannot overstate the importance of being able to communicate your ideas in forceful and direct English.

Wandell, B. A. (1995). Foundations of vision. Sunderland, Massachusetts: Sinauer Assoc., Inc. The bookstore lists this book as “optional.” This book contains an overview of current research issues in visual perception. Several chapters of this book were required reading in past editions of CN 530; in the weekly listing of supplementary readings, this book is designated as “ BAW .” This book is tutorial in organization, with a clear emphasis on “vision science,” rather than visual perception. (Please ask me if you do not know the difference.) (Approx. $50.00).

Kandel (Editor) E. R., Schwartz, J. H., and Jessell, T. M. (Eds), Principles of Neural Science, 4 th Edition. New York: McGraw-Hill. (hardcover $85.00) Do insist on the 4 th edition of “ KSJ .” While only five chapters pertain to vision, many other chapters are assigned readings in other CNS courses.

Bruce, V. and Green, P. R. (1997). Visual perception: Physiology, psychology, and ecology . (3rd Ed.) Hillsdale, NJ: Lawrence Erlbaum Assoc. (paperback, $29.95, new; $22.50, used.) Earlier editions of this “easy” book were an undergraduate-level text. The " B & G " 3rd edition is a bit more advanced. It is recommended primarily as remedial reading for those with limited backgrounds in visual perception.

Kosslyn, S. M. & Anderson, R. A. (Eds.) (1992). Frontiers in cognitive neuroscience. Cambridge, MA: MIT Press. ($70.00, hardbound) This collection reprints “classic” papers in many in areas besides vision. Several chapters are required reading in CN 530; in the weekly listing of required readings, this book is designated as “ K & A .”

Grossberg, S. (Ed.) (1987). The adaptive brain II: Vision, speech, language, and motor control. Amsterdam: North Holland. ($61.50, paperback) This book includes core papers describing the work on vision done at the Center for Adaptive Systems. It also contains many other papers that will be used for other courses in CNS.

Answers to CN 530 FAQs:

Question 1: Why is there so much required reading? (In other words, what do I really have to do to get an A? What parts of this stuff can I skip?)

Answer: I have tried, through points raised in lectures, notes interspersed throughout the syllabus, the creation of a study guide, and the providing of ready access to prior examination questions to be as explicit as I know how to be about what you are expected to know. Further suggestions are welcomed. There's simply a lot to know about vision before you can even start to model it.

Question 2: Aren't you really making us read more than is really important? Couldn't you tell us more explicitly which sections, figures, equations, paragraphs, sentences, or phrases really matter?

Answer: Yes, it's true. There remain a few places where I could have been even more explicit than I have been about how you should separate wheat from chaff. By electing to take this course, however, you have embarked on study of an area of research so new, so unformed, and so controversial that -- for many topics -- consensual “textbook” knowledge can hardly be said to exist. Soon enough you will have to confront primary source material without any of the aids provided in this course! Part of my job is to train you to meet the challenge of transitioning from “undergraduate mode” to “researcher mode.” I have done this in part by assigning -- in relatively few places -- entire chapters or articles for which I know that whole sections could be skipped without undue harm! Part of your task is to figure out which are those sections, and not to worry about them.

Question 3: Some of the contents of readings contradict parts of other readings. What's going on?

Answer: Welcome to the real world of science.

Question 4: Why do I have to bother with all this silly psychology and complicated physiology? How is this going to help me design real world vision applications?

Answer: Let's talk about this during our discussion periods.

Question 5: Why are so many of the course readings from primary sources (original research articles or research book chapters, as opposed to textbook chapters)? The authors use different terminology for the same concepts, and often contradict one another, and they take way more pages to explain things than a textbook does.

Answer: No single textbook appropriate for the entire course exists. The books that exist are either too elementary, too detailed, or too narrow in scope, and they barely cover much of the core material in the course. For certain ideas, there simply is no present substitute for primary sources. (Remember, that's correlated with our department being involved in emerging, new, exciting, interdisciplinary, lemon-scented research!) Even in the case of psychophysics, and physiology, which the textbooks cover at least moderately well, I have asked you to read some primary sources. I believe that the extra effort required to read them will be rewarded by deeper understanding than can be gotten from textbooks. In any case, I encourage you to go back and forth, between the two types of readings, until you have satisfied yourself that you can master the material outlined in the study guide and presented in class.

Question 6: How will I know when I'm “getting it,” given how amorphous and confusing some of the readings are? How do I know which version of several descriptions of, for example, physiological functions of some visual area, is right?

Answer: Where experts disagree, you are entitled to make an informed choice among reasonable alternatives. You are, however, expected to understand the issues underlying the disagreement.

Question 7: How should I study for the in-class midterm?

Answer: During the mid-term, you will not be reading long articles, or reviewing lecture notes, so do not spend all of you preparation time in those activities! During the exam you will primarily be writing . You should practice writing . You should practice writing concise answers to short questions in limited time. I will do my best to make the exam less a measure of your rate of expression and more a matter of assessing your mastery of content. You can help avoid unpleasant surprises by giving yourself one or two “practice” tests based on the study guide, without notes or readings, and in a realistically short amount of time. I would be happy to give you feedback on sample answers that you show me.

Question 8: Much of this course seems rigidly laid out; what if we want to do things differently (e.g. read unassigned articles, or do different simulations than required in assignments.)

Answer: Everything about this course is evolving, and everything is negotiable. Remember, though, that any proposed improvement has a cost (in human effort) that must be budgeted. If your suggestion involves the whole class, remember that the class motto is: “To suggest is to volunteer.”

WEEKLY TOPICS AND READINGS

The readings are listed along with a short synopsis of the theme of each week's lecture. Readings for each week are designated under the headings Required Reading , Supplementary Reading , and BONUS Reading . You will be responsible (in the sense of possibly being tested) for material covered under the “required” heading only. Material listed as supplementary generally falls into one of two categories. The first includes “enrichment” or “remedial” readings of relatively broad interest; these are generally followed by short parenthetical comments. The second category includes technical or scholarly citations. Those supplementary readings that are indicated by a bullet (•) are likely to be the most useful to you, ask me about them if you have any trouble locating copies. BONUS readings are listed only because reading them might be fun; these will also be available in the CNS library. (Those contemplating careers as university professors can use these as a diagnostic; if you do not enjoy a significant portion of the bonus readings, you may wish to explore another line of work!) NOTE: Students will be expected to have read all of the required readings listed for a given week by the time that lecture is given , in the sense that the contents of the lecture will assume some familiarity with the readings. That is, the lectures will often comment upon the readings, rather than acting as a substitute for doing the readings.

Week 1: Fundamental problems of vision

1) Unit formation and grouping

2) Seeing and recognizing -- form/color interactions

3) Retinal veins and blind spot

4) Perceiving surface color: Constancy, contrast, and discounting the illuminant

5) Stabilized images: Boundaries and featural color and brightness

6) Complementary processing: Unoriented and oriented detectors

Required Reading:

Supplementary Reading:

• Marr, D. (1982). Vision. New York, Freeman. Read “lightly” Chapters 1 and 2, pages 3 - 98. Alternatively, read Marr and Nishihara's paper in K & A, Ch. 14. If you do the latter, note that Marr and Nishihara speak of four “levels” of analysis where Marr (1982) speaks of three. Marr argues clearly and persuasively for a point of view that has enjoyed considerable popularity in recent years. Much of the CAS/CNS work in vision can be cast in counterpoint -- explicit or implicit -- to Marr's views. Download PDF.

Gibson, J. J.(1966) The senses considered as perceptual systems . New York: Houghton Mifflin. Read pages 1-15, 187-223, and 263. This is not “urgent;” you can read it later in the course.

Week 2: Shunting competitive networks and representation in early vision

1) The noise--saturation dilemma

2) Reflectances and ratios; shunting and mass action

3) Brightness: Constancy and contrast

4) Shift property and Weber law

5) Retinal physiology

6) Hyperpolarization and featural noise suppression

7) Distance--dependent shunting networks

Required Readings: (To be read BEFORE class)

SEP . Read Chapters 1 and 2 for “background.” Also read Ch. 4, Sec. 3.

Grossberg, S. (1982). Why do cells compete? UMAP Unit 484, The UMAP Journal, Vol. III, No. 1. (Education Development Center, 0197-3622/82/010101.) (This is by far the “easiest” introduction to shunting inhibition Grossberg has ever written.) Download PDF.

KSJ . Read Ch. 25 and Ch. 26. Also, skim Ch. 21 if you have had no undergraduate introduction to perception or cognition. Ch. 26 contains some details of the pharmacology of receptor phototransduction that will not be “on the test for CN 530,” as clarified in class.

Supplementary Reading:

Note: While not “required,” the first article listed below will be of particular interest to those of you concerned with computer vision (and is very short!)

• Boyer, K. L., and Sakar, S. Computer Vision and Image Understanding. Perceptual Organization in Computer Vision: Status, Challenges, and Potential. Vol. 76, No. 1, October, pp. 1–5, 1999, Article ID IV990797. Download PDF. Also available online at http://www.idealibrary.com .

Cornsweet, T. (1970). Visual Perception . New York, Academic Press. Chapter XI, “The psychophysiology of brightness -- I”, 268-310. (While this discussion is somewhat dated, it is lucid; also, Cornsweet's views about subtractive inhibition are illustrative of views that many of Grossberg's discussions of shunting inhibition are directed against.)

Borg-Graham LJ, Monier C, Fregnac Y (1998). Visual input evokes transient and strong shunting inhibition in visual cortical neurons, Nature, 393 (6683), 369-373.

Week 3: Contrast sensitivity and spatial scales

1) Marr and Grossberg: Symbols, patterns, and the principle of least commitment

2) Recurrent networks

3) Structural scales: functional scales: kernels: receptive fields

4) Peak shifts and lateral inhibition

5) Detectors and filters

6) Contrast sensitivity and spatial scales

Required Reading: (To be read BEFORE class)

SEP . Ch. 4.

Kiper, D. and Carandini, M. The neural basis of pattern vision. Encyclopedia of cognitive science , 2000, Macmillan Reference, Ltd. Download PDF.

Kaufman, L., (1974). Sight and Mind . New York, Oxford University Press. Chapter 5, “Contrast and contour”, 128-152. (This is a good overview of some classic issues in spatial vision. Don't worry if a few parts seem obscure.) Download PDF.

Grossberg, S. (1983). The quantized geometry of visual space: The coherent computation of depth, form, and lightness. Behavioral and Brain Sciences, 6 , 625-692. Reprinted as Chapter 1 of Grossberg, S. (Ed.) (1987). The adaptive brain II: Vision, speech, language, and motor control. Amsterdam: North Holland. Read Sections 1-3 and 21-25, 27, and 28, and the commentaries of Grimson and Stevens and Grossberg's reply to those commentaries. Note that the Commentary section appears only in the journal article and is not reprinted in the book. Sections 21-25 restate and extend the discussion of the “UMAP Module” reading, and discuss some issues of relevance to Assignment 1. If you have not had CN 510, sections 27 and 28 may seem obscure -- if so, do not panic; subsequent work in CN 530 will clarify this material. Download PDF.

Adelson, E.H. (2000). Lightness Perception and Lightness Illusions, in M. Gazzaniga, M.S., ed., The New Cognitive Neurosciences, 2nd Ed.Cambridge, MA: MIT Press, pp. 339-351. Download PDF.

This is a clearly written article that explains much of the important terminology used in the study of lightness perception. (Download of this article may be slow!)

Supplementary Reading:

• Levine, D. and Grossberg, S. (1976). Visual illusions in neural networks: Line neutralization, tilt after-effect, and angle expansion. Journal of Theoretical Biology, 61 , 477-504. Levine was Grossberg's first Ph.D. student; this reading is also relevant to Simulation Assignment 1.

BAW : Read Chapter 5, but first, skim chapters 1, 2 and 3, noting the discussion of any words printed in boldface that have also appeared in class or in other readings.

Gaudiano P. (1994). A nonlinear model of spatiotemporal retinal processing: simulations of X and Y retinal ganglion cell behavior. Vision Research, 34, 1767--1784.

BONUS READING

Daugman, John. (1990) Brain metaphor and brain theory. Chapter 2 of Eric Schwartz (Ed.) Computational Neuroscience . Cambridge, MA: MIT Press. Reprinted as Chapter 2 in Philosophy and the Neurosciences , edited by W. Bechtel et al. Oxford: Blackwell Publishers. (Scanned .PDF file here ). (This essay is a timely and entertaining polemic on the meaning of the word “computational.”)

Week 4: Early visual pathways

1) Anatomical and physiological techniques

2) Retinal structure and function

3) ON and OFF channels

4) Anatomy and physiology of the early visual pathways

Required Reading: (To be read BEFORE class)

KSJ. Read Ch. 27.

Schiller, P. H. On the specificity of neurons and visual areas. Behavioural Brain Research , 1996, 76 (21-35). Download PDF.

Gilbert, C. D. Plasticity in visual perception and physiology. Current Opinion in Neurobiology 1996, 6:269-274. Download PDF.

Supplementary Reading:

Bullier, J. and Nowak, L. G. Parallel versus serial processing: new vistas on the distributed organization of the visual system. Current Opinion in Neurobiology , 1995, 5:497-503. Download PDF.

BAW : Read Chapter 7.

• Callaway EM Local circuits in primary visual cortex of the macaque monkey Annual Review of Neuroscience 21 , 47-74 1998. Comprehensive review.

• Schiller, P. H. (1986). The central visual system. Vision Research , 26 , (9), 1351-1386. This is a scholarly and entertaining review of 25 years of work in visual neurophysiology. Read Part A, pages 1351-1362.

Grossberg, S. (1973). Contour enhancement, short term memory, and constancies in reverberating neural networks. Studies in Applied Mathematics LII, 213-257. Reprinted in S. Grossberg, Studies of mind and brain (1982), Boston, Reidel.

Ellias, S. and Grossberg, S. (1975). Pattern formation, contrast control, and oscillations in the short term memory of shunting on-center off-surround networks. Biological Cybernetics, 20 , 69-98.

Werblin, F. S. (1971). Adaptation in a vertebrate retina: Intracellular recordings in Necturus. Journal of Neurophysiology, 34 , 228-241.

BONUS Reading:

Sacks, O. (1995). The case of the colorblind painter. Pages 3-41 in O. Sacks, An anthropologist on Mars . New York: Alfred Knopf.

Week 5: Brightness and lightness

1) Brightness perception: Quantifying percepts

2) Isomorphistic and nonisomorphistic theories

3) Craik-O'Brien-Cornsweet (COCE) effect

4) Integration models and the Retinex algorithm

5) Brightness assimilation

Required Reading: (To be read BEFORE class)

SEP . Skim Ch 3. Read Sec. 3.3 carefully.

Todorovi , D. (1987). The Craik--O'Brien--Cornsweet effect: New varieties and their theoretical implications. Perception & Psychophysics, 42 , 545-560. Download PDF. Concentrate on the distinction between isomorphistic and nonisomorphistic theories.

Marr, D. (1982). Vision . New York, W.H. Freeman. Pages 250-258. Marr gives a lucid overview of Land's Retinex theory; read this before Land (1986). Download PDF.

Land, E. H. (1986). Recent advances in Retinex theory. Vision Research , 26 (1), 7-21. You will be expected to understand this approach, an example of an “integration theory,” in excruciating detail. Download PDF.

Check out Retinex-based commercial image processing at: http://dragon.larc.nasa.gov/retinex/

Compare Simon Hong's results by following “projects” link at: http://cns-alumni.bu.edu/~yhong/

Supplementary Reading:

For Retinex Matlab code, go to: http://www.cs.sfu.ca/~colour/publications/IST-2000/       

Zaidi Q, Spehar B, Shy M.(1997). Induced effects of backgrounds and foregrounds in three-dimensional configurations: the role of T-junctions. Perception;26(4): 395-408. Link. This paper rejects an important hypothesis about lightness perception, read the abstract first, if you are interested in the topic, then read the rest.

Gilchrist A, Kossyfidis C, Bonato F, Agostini T, Cataliotti J, Li X, Spehar B, Annan V, Economou E. An anchoring theory of lightness perception. Psychological Review, 1999 Oct;106(4):795-834.

Cornsweet, T. (1970) . Visual Perception. New York, Academic Press. Chapter XII, “Psychophysiology of brightness -- II, Modulation transfer functions,” 311-364.

Graham, N. (1980). Spatial frequency channels in human vision: Detecting edges without edge detectors. In C. S. Harris, Ed., Visual coding and adaptability. Hillsdale, NJ, Earlbaum, 215-262. The experiment described in Figure 6 (page 226) and the accompanying text is of fundamental importance to understanding issues related to “spatial frequency channels” in human vision.

BONUS Reading:

Barlow, H. B. (1972) Single units and sensation: A neuron doctrine for perceptual psychology? Perception 1 :371-394. Reprinted as Chapter 14 of J. A. Anderson, A. Pellionisz, and E. Rosenfeld (Eds.) Neurocomputing 2, Directions for Research. Cambridge, MA, MIT Press, 1988. This is one of the foundational papers from the recent “single unit” era in physiological psychology.

Week 6: Parallel visual pathways, boundaries and surfaces

1) A simple BCS-FCS model

2) Diffusion and time

3) Symbolic models and energy models

4) Edge detection?

5) How thin is “thin”?

6) Spatial and orientational competition

7) Hyperacuity

8) Neon color spreading

Required Reading: (To be read BEFORE class)

Grossberg, S. and Todorovi , D. (1988). Neural dynamics of 1-D and 2-D brightness perception: A unified model of classical and recent phenomena. Perception & Psychophysics, 43 , 241-277. Reprinted in Grossberg, S. (Ed.) (1988). Neural Networks and Natural Intelligence. Cambridge, MA: MIT Press. Download PDF. (Concentrate on the role of boundaries and diffusion in the explanation of percepts.)

SEP . Ch 6.

Neumann, H. and Mingolla, E. (2003). Contour and surface perception. In M.A. Arbib, Ed., Handbook of brain theory and neural networks, II. Cambridge, MA: MIT Press. Download PDF.

Supplementary Reading:

Pessoa, L., Thompson, E., & Noe, A. Finding out about filling-in: a guide to perceptual completion for visual science and the philosophy of perception. Behavioral and Brain Sciences, 1998 Dec;21(6):723-48.

• Neumann H. (1996). Mechanisms of neural architecture for visual contrast and brightness perception. Neural Networks, 9(6) , 921-936. NOTE: You may wish to consult this paper while doing Simulation Assignment 2. (Downloadable at: http://www.sciencedirect.com .)

Davey, M. P., Maddess, T., and Srinivasan M. V. (1998). The spatiotemporal properties of the Craik-O'Brien-Cornsweet effect are consistent with “filling-in”. Vision Research, 38 (13), 2037-2046. The title speaks for itself.

BAW : Read Chapter 6.

Paradiso, M. A. and Nakayama, K. (1991). Brightness perception and filling-in. Vision Research, 31 , 1221-1236.

Hung CP, Ramsden BM, Chen LM, Roe AW., Building surfaces from borders in Areas 17 and 18 of the cat., Vision Res. 2001;41(10-11):1389-407. Download PDF. Take a look for some electrophysiological evidence regarding the effect of boundary contrast on surface lightness.

Gerrits, H. J. M., and Vendrick, A. J. H. (1970) Simultaneous contrast, filling-in process and information processing in man's visual system. Experimental Brain Research, 11 , 411-430.

<<Week 6 readings continue on the next page >>

Week 6 (Continued)

Supplementary Reading (continued):

Grossberg, S. and Mingolla, E. (1985). Neural dynamics of form perception: Boundary completion, illusory figures, and neon color spreading. Psychological Review , 92 (2), 173-211. Reprinted as Chapter 2 of Grossberg, S. (Ed.) (1987). The adaptive brain II: Vision, speech, language, and motor control. Amsterdam: North Holland. Download PDF. Concentrate on the arguments for making the Boundary/Feature distinction in the first place; on the conditions that produce neon color spreading, and on the mechanisms of the theory's explanation of neon color spreading. Skim lightly over the sections on cooperative completion of boundaries. In other words, concentrate on Sections 1-15. The Appendix of this article is subsumed by that of a subsequent article.

Bressan, P., Mingolla, E., Spillmann, L. and Watanabe, T. (1997). Neon color spreading: A review . Perception, 26 (11), 1353-1366.                                             

Badcock, D. R., and Westheimer, G. (1985). Spatial location and hyperacuity: The center/surround localization contribution function has two substrates. Vision Research, 25 , 1259-1267.

BONUS Reading:

Westheimer, G. (1983). Herman Helmholtz and the origins of sensory physiology. Trends in Neurosciences , Jan., 5-9. (Did you know that Helmholtz is considered by many to be the greatest sensory psychologist who ever lived?)

Week 7: Boundary detection, completion, and sharpening

1) Cooperative-Competitive (CC) Loop

2) Bipole cells, then and now

3) Spatial impenetrability

4) Boundary webs

5) von der Heydt, Peterhans, & Baumgartner, 1984

7) Autonomy of perception; cognitive impenetrability

Required Reading: (To be read BEFORE class)

Grossberg, S. and Mingolla, E. (1985). Neural dynamics of perceptual grouping: Textures, boundaries, and emergent segmentations. Perception & Psychophysics, 38 , 141-171. Reprinted as Chapter 3 of Grossberg, S. (Ed.) (1987). The adaptive brain II: Vision, speech, language, and motor control. Amsterdam: North Holland. Download PDF. Yes, this is one of those articles containing paragraphs that “won't be on the test.” Use the study guide and lecture notes for clues about which. (What is the difference between an “invisible” boundary and an “illusory” one?)

KSJ . Read Ch. 28.

Lamme VAF, Super H, Spekreijse H Feedforward, horizontal, and feedback processing in the visual cortex. CURR OPIN NEUROBIOL 8: (4) 529-535 AUG 1998. Download PDF.

von der Heydt, R., Peterhans, E., and Baumgartner, G. (1984). Illusory contours and cortical neuron responses. Science, 224 , 1260-1262. Download PDF. (This paper describes some striking evidence for long- range cooperative interactions in early vision. Reprinted as Ch. 12 of K & A . You are expected to understand the reported experiments in detail.)

Supplementary Reading:

Spillmann, L., Werner, J.S. Long-range interactions in visual perception. TRENDS NEUROSCI 19: (10) 428-434 OCT 1996. Download PDF.

Fitzpatrick,D. Seeing beyond the receptive field in primary visual cortex. CURR OPIN NEUROBIOL 10: (4) 438-443 AUG 2000. Download PDF.

Takeichi H, Shimojo S, Watanabe T. (1992). Neon flank and illusory contour: interaction between the two processes leads to color filling-in. Perception 21(3):313-24. Download PDF. This shows how psychophysics can help localize the areas responsible for boundary and surface formation.

Daugman, J. (1985). Uncertainty relation of resolution in space, spatial frequency, and orientation optimized by two-dimensional visual cortical filters. Journal of the Optical Society of America A, 2, 1160-1169. (This paper includes some key observations on uncertainty in filtering.)

• Sarti A, Malladi R, Sethian JA Subjective surfaces: A method for completing missing boundaries

P NATL ACAD SCI USA 97: (12) 6258-6263 JUN 6 2000. (Of interest to students concerned with computer vision .)

Neumann, H. and Mingolla, E. 2001 Computational neural models of spatial integration in perceptual grouping. In From Fragments to Objects: Grouping and Segmentation in Vision. T.F.Shipley & P.J. Kellman, Editors. Amsterdam: Elsevier, 353-400. Download PDF. Note: For reasons surpassing human understanding, this PDF file will print on some printers and not on others.

<<Week 7 readings continue on the next page >>

Week 7 (Continued)

Supplementary Reading (continued):

Gove, A., Grossberg, S., and Mingolla, E. (1995). Brightness perception, illusory contours, and corticogeniculate feedback. Visual Neuroscience, 12 , 1027--1052. Available as gzipped postscript from http://cns-web.bu.edu/Profiles/Grossberg/onlinepub.html

Grossberg, S. Mingolla, E. & Ross, W. D. (1997). Visual brain and visual perception: A corticogeniculate model of perceptual grouping. Trends in Neurosciences (TINS), 20(3) , 106-111.

Lesher, G. W. (1995). Illusory contours: Toward a neurally based perceptual theory. Psychonomic Bulletin and Review, 2(3) , 279-321. (This is the recent literature review on illusory contours.)

Lesher, G. W. & Mingolla, E. (1993). The role of edges in line-ends in the formation of illusory contours. Vision Research, 36(16) , 2253--2270. B & G: Chapter 5.

Redies, C. and Spillmann, L. (1981). The neon color effect in the Ehrenstein illusion. Perception, 10, 666-681.

S. Petry and G. E. Meyer, Eds. (1987), The perception of illusory contours . New York, Springer- -Verlag. (This is the book on illusory contours.)

Koffka, K. (1935/1963). Principles of Gestalt psychology . New York, Harcourt, Brace, and World. Chapter 4, “The environmental field,” 106-176, contains many of the seminal notions of Gestalt psychology. See especially pages 148-176.

Yen SC, Finkel LH. Extraction of perceptually salient contours by striate cortical networks. Vision Research , 1998 Mar;38(5):719-41.

Horn, B. K. P. (1986). Robot vision . Cambridge, Massachusetts, MIT Press. Chapter 8, “Edges and edge finding,” 161-184.

Ullman, S. (1984). Visual routines. Cognition, 18 , 97-106. Reprinted in M. A. Fischler and O. Firschein, Eds., Readings in computer vision. 1987, Los Altos, CA, Morgan Kaufman, 298-328.

Zucker, S. W. (1985). Early orientation selection: Tangent fields and the dimensionality of their support. Computer Vision, Graphics, and Image Processing, 32(1) , 74-103. Also in M. A. Fischler and O. Firschein, Eds., Readings in computer vision. 1987, Los Altos, CA, Morgan Kaufman, 333- 348.

Ramsden BM, Hung CP, Roe AW. (2001). Real and illusory contour processing in area V1 of the primate: a cortical balancing act., Cereb Cortex. Jul;11 (7):648-65. This article shows the difference between V1 and V2 units in response to illusory contours. Reading the abstract, figure legends and discussion suffices.

BONUS Reading:

Bateson, G. (1979). Every schoolboy knows... Chapter 2 of Mind and Nature . Toronto, Bantam. Bateson was weird; do you know the definition of “sacrament” as given in the Baltimore Catechism of the Roman Catholic Church? If not, how will you ever understand “emergent” behavior of neural networks? For that matter, how will you ever know what remarks in a course syllabus to take seriously?

Week 8: Approaches to textural segmentation and grouping

1) What is texture?

2) Textural segmentation -- textons?

3) Representations for segmentation

Required Reading: (To be read BEFORE class)

Mishkin, M. Ungerleider, L. G., and Macko, K. A. (1983). Object vision and spatial vision: Two cortical pathways. Trends in Neurosciences, 6 , 414-417. Reprinted as Ch. 2 of K & A. Download PDF. This classic paper launched decades of research and debate.

Beck, J. (1993). The British Aerospace Lecture: Visual processing in texture segregation. In D. Brogan, A. Gale and K. Carr, Eds. Visual Search 2 . London: Taylor and Francis. Download PDF. Read 1-11, 21-25.

Malik, J. and Perona, P. (1990). Preattentive texture discrimination with early vision mechanisms . Journal of the Optical Society of America A, 7 (5), 923-932. Download PDF.

Supplementary Reading:

BAW , Chapters 8.

• Beck, J. (1983). Textural segmentation, second-order statistics, and textural elements. Biological Cybernetics, 48, 125-130.

• Julesz, B. and Bergen, J. R. (1983). Textons, the fundamental elements in preattentive vision and perception of textures. Bell Systems Technical Journal, 62(6) Part II: 1619-1645. Reprinted in M. A. Fischler and O. Firschein, Eds., Readings in computer vision . 1987, Los Altos, CA, Morgan Kaufman, 243-256.

Zucker, S. W., Dobbins, A., and Iverson, L., (1989). Two stages of curve detection suggest two styles of visual computation. Neural Computation, 1 (1), 68-81.

Beck, J., Prazdny, K. and Rosenfeld, A. (1983). A theory of textural segmentation. In J. Beck, B. Hope, & A. Rosenfeld (Eds.), Human and machine vision. New York: Academic Press, 1-38.

Sutter, A., Beck, J., and Graham, N. (1989). Contrast and spatial variables in texture segregation. Perception & Psychophysics, 46 (4) , 312-332.

BONUS Reading:

Stevens, P. S., (1974). Basic patterns (Chapter 2) and Spirals, meanders, and explosions. Chapter 4 of Patterns in Nature . Boston: Little, Brown, and Co. (Visual contours are also among the “patterns in nature,” more complex and more beautiful than even Stevens's examples.)

Week 9: Binocular vision

1) Disparity and depth

2) Projection theories

3) The correspondence problem

4) Matching algorithms

5) Prazdny's algorithm

6) Grimson's wedding cake

7) Kaufman's stereogram: Rivalry

8) Occlusion, depth, and da Vinci stereopsis

9) Modal and amodal perception

Required Reading: (To be read BEFORE class)

SEP . Ch 5, Secs. 1-3.

Kaufman, L. (1974). Binocular stereopsis. In L. Kaufman, Sight and Mind . New York, Oxford University Press, 269-321. Download PDF.

Grossberg, S. 1983. The quantized geometry of visual space: The coherent computation of depth, form, and lightness. Behavioral and Brain Sciences, 6 , 625-692. Reprinted as Chapter 1 of Grossberg, S. (Ed.) (1987). The adaptive brain II: Vision, speech, language, and motor control. Amsterdam: North Holland. Read lightly Sections 1 to 34, pages 625-647, and the commentaries and reply to the commentaries of Grimson and Stevens. Note that the Commentary section appears only in the journal article and is not reprinted in the book. Yes, parts of this reading have been assigned before.

DeAngelis GC Seeing in three dimensions: the neurophysiology of stereopsis TRENDS COGN SCI 4: (3) 80-90 MAR 2000. Download PDF.

Blake R, Wilson HR. Neural models of stereoscopic vision. Trends in Neurosciences , 1991 Oct;14(10):445-52. Download PDF.

Supplementary Reading:

Nakayama K, & Shimojo S. (1990). da Vinci stereopsis: depth and subjective occluding contours from unpaired image points. Vision Res. 30(11): 1811-25 This paper a good example of how psychophysical techniques can constrain the search for physiological substrates.

I.P. Howard & B. J. Rogers, Seeing in depth: Vol. II. Depth perception. Toronto: Porteous Publisher.

Grossberg, S. (1993) A solution of the figure-ground problem for biological vision. Neural Networks, 6 , 463-493.

Blake, R. (1989) A neural theory of binocular rivalry. Psychological Review, 96(1) , 145-167. Read for gist.

Nakayama, K. Shimojo, S. and Ramachandran, V.S. (1990) Transparency: relation to depth, subjective contours, luminance, and neon color spreading. Perception, 19 , 497-513.

<<Week 9 readings continue on the next page >

Week 9 (Continued)

Dev, P. (1975). Perception of depth surfaces in random-dot stereograms: A neural model . International Journal of Man-Machine Studies, 7 , 511-528.

Marr, D. (1982). Vision . New York, W.H. Freeman. Pages 111-158.

Sperling, G. (1981). Mathematical models of binocular vision. In S. Grossberg, Ed. Mathematical Psychology and Psychophysiology . Hillsdale, NJ, Earlbaum, 281-300.

Prazdny, K. (1985). Detection of binocular disparities. Biological Cybernetics, 52 , 93-99. Also in M. A. Fischler and O. Firschein, Eds., Readings in computer vision . 1987, Los Altos, CA, Morgan Kaufman, 73-79.

Prazdny, K. (1985). On the disparity gradient limit for binocular fusion. Perception and Psychophysics, 37 (1), 81-83.

Grossberg, S. and Marshall, J. (1989). Stereo boundary fusion by cortical complex cells: A system of maps, filters, and feedback networks for multiplexing distributed data, Neural Networks, 2 , 29- 51.

Yeshurun, Y. and Schwartz, E. L. (1987). An ocular dominance column map as a data structure for stereo segmentation. Proceedings of the IEEE First International Conference on Neural Networks, San Diego, CA.

Grossberg, S. (1987). Cortical dynamics of three-dimensional form, color, and brightness perception: II. Binocular theory. Perception & psychophysics, 41(2), 117-158. Reprinted as Chapter 2 of Neural Networks and Natural Intelligence. Cambridge, MA: MIT Press. Sections 1-9 contain some useful background material.

BONUS Reading:

Schwartz, E. (Ed.) (1990). Computational Neuroscience . Cambridge, MA: MIT Press.

Introduction, ix-xiii. Schwartz offers unvarnished statements of contrasting presuppositional attitudes.

*** Week 10 ***

There will be an in-class EXAMINATION, covering the topics in the readings and lectures from the first 9 weeks, during the class period.

BONUS Reading:

Thompson, D. A., (1917/61). On magnitude. Chapter 2 of On growth and form (Abridged edition). Cambridge: Cambridge University Press. (For a system such as the BCS to be automatically “scaled up” to deal with large images requires a deeper understanding of the Principle of Similitude for nonlinear dynamics than we seem presently to possess.) If you read only one bonus reading all year, make it this one.

Week 11: The phenomena of motion perception

1) What is motion? Apparent motion and real motion

2) Long-range motion: Arguments for short and long range mechanisms

3) Korte's laws and figural affinity

4) Short and long-range motion

5) Fourier and non-Fourier stimuli

6) Gradient models (Marr/Ullman)

7) Energy models (Adelson/Bergen)

8) Correlation models (Reichardt; van Santen/Sperling

Required Reading: (To be read BEFORE class)

SEP . Ch 10.

Grossberg, S. and Rudd, M. E. (1989). A neural architecture for visual motion perception: Group and element apparent motion. Neural Networks,2, 421-450. Read pages 421-433. Download PDF.

Supplementary Reading:

BAW , Chapter 10

• Cavanagh, P. and Mather, G. (1990). Motion: The long and the short of it. Spatial Vision, 4, 103- 129.

Nakayama, K. (1985). Biological image motion processing: A review. Vision Research, 25(5), 625-660. Read 625-651.

Kolers, P. A. (1972). Aspects of motion perception . Oxford: Pergamon Press. Read pages 1-58.

Adelson, E. H. and Bergen, J. R. (1985). Spatiotemporal energy models for the perception of motion. Journal of the Optical Society of America A, 2(2) , 284-299.

Anstis, S. (1988). Motion perception in the frontal plane. Chapter 16 of K. R. Boff, L. Kaufman, and J. P. Thomas, Eds., Handbook of perception and performance, Volume I, Sensory processes and perception , pages 16-1 to 16-27.

van Santen, J. P. H. and Sperling, G. (1985). Elaborated Reichardt detectors. Journal of the Optical Society of America A, 2(2) , 300-321.

Watson, A. B. and Ahumada, A. J. (1985). Models of human visual-motion sensing. Journal of the Optical Society of America A, 2(2) , 322-342.

BONUS Reading:

Gibson, J. J. (1966). The visual system: Environmental information. Chapter 10 of

The senses considered as perceptual systems. Gibson was the most important perceptual psychologist of the 20th century. The force of his arguments was so great that many today subscribe to important aspects of his views without realizing the source! Find out in his own words what was so much in need of justification in 1966.

Week 12: Models of motion perception

1) Group and element motion

2) Motion pooling and aperture problem

3) Motion detection, segmentation and grouping

Required Reading: (To be read BEFORE class)

Grossberg, S., Mingolla, E. and Viswanathan, L. (2001). Neural dynamics of motion integration and segmentation within and across apertures. Vision Research , 41(19), 2521-53. Download PDF.

Simoncelli, E. P., & Heeger, D. J. (1998). A model of neuronal responses in visual area MT. Vision Res ,earch 38(5) , 743-61. Note: This reading is only “quasi-required,” in the sense that you should read it carefully enough to get the gist of the modeling effort, without worrying about every last implementation detail. Download PDF.

Pack CC, Born RT. (2001). Temporal dynamics of a neural solution to the aperture problem in visual area MT of macaque brain. Nature. Feb 22;409(6823):1040-2. Download PDF. This is a great paper.

Supplementary Reading:

• Allman, J., Miezin, F., & McGuiness, E. (1985). Direction- and velocity-specific responses from beyond the classical receptive field in the middle temporal visual area (MT). Perception, 14 , 105- 126. Reprinted as Ch. 11 of K & A.

Grossberg, S. and Rudd, M. E. (1992). Cortical dynamics of visual motion perception: Short-range and long-range apparent motion. Psychological Review, 99(1), 78-121. Read pages 78-82 and 90- 96.

Marshall, J. A. (1990) Self-organizing neural networks for perception of visual motion. Neural Networks, 3(1) , 45-74.

Livingstone MS, Pack CC, Born RT. (2001). Two-dimensional substructure of MT receptive fields. Neuron. Jun;30(3):781-93. Download PDF. This article teaches you experimental techniques in motion electrophysiology with classic citations about each aspect of the technique. Figure captions are clear, therefore you can use the abstract-figure captions-discussion strategy again!

Mingolla, E., Todd, J. T., & Norman, J. F. (1992). The perception of globally coherent motion. Vision Research, 32(6), 1015--1031.

Albright, T. D., Desimone, R., and Gross, C. G. (1984). Columnar organization

of directionally sensitive cells in visual area MT of the macaque. Journal of Neurophysiology, 51, 16-31.

Burt, P. and Sperling, G. (1981). Time, distance, and feature trade-offs in visual apparent motion. Psychological Review, 88(2) , 171-195.

BONUS Reading:

Gregory, R. L. (1991). What is caught in neural nets? Perception, 19, 5 61-568. Gregory is the most influential exponent of the “cognitivist” position in vision today, though his views resist simple categorization. Regardless of whether you agree or disagree with him, this essay is fun!

Week 13: Visual attention

1) Facets of attention: Bottom-up and top-down

2) Feature integration theory

3) Search rate asymmetries: Pop-out and slow search

4) Guided search and iconic bottleneck

5) Surfaces and features

6) Attentional modulation of receptive fields

7) Change blindness

Required Reading:

SEP . Ch 11.

Kastner, S. and Ungerleider, L. G. Mechanisms of visual attention in the human cortex. Annu. Rev. Neurosci. 2000. 23:315-341. Hypertext.

Duncan J, Humphreys G, Ward R Competitive brain activity in visual attention CURR OPIN NEUROBIOL 7: (2) 255-261 APR 1997. Download PDF.

Supplementary Reading:

Grossberg, S., Mingolla, E. & Ross, W. (1994). A neural theory of attentive visual search: Interactions of visual, spatial, and object representations. Psychological Review, 101(3), 470-489.

Eriksen, C. W. (1990) Attentional search of the visual field. In Visual search , D. Brogan, Ed. London: Taylor and Francis.

Duncan, J. (1995). Target and nontarget grouping in visual search . Perception & Psychophysics, 57 , 117-120.

Wolfe, J. M. (1994). Guided Search 2.0: A revised model of visual search. Psychonomic Bulletin and Review, 1(2), 202-238.

Moran, J. & Desimone, R. (1985). Selective attention gates visual processing in the extrastriate cortex. Science, 229, 782-784. Reprinted as Ch. 26 of K & A.

Crick, F. (1984). Function of the thalamic reticular complex: The searchlight hypothesis. Proceedings of the National Academy of Science USA, 81 , 4586-4590. Reprinted as Ch. 28 of K & A.

He S, Cavanagh P, Intriligator J. (1996). Attentional resolution and the locus of visual awareness. Nature. Sep 26;383(6598):334-7. Download PDF. Arash says: The experiment in the paper is doable by yourself when you read the paper, and the explanation seems exciting, however it worth trying a simpler null hypothesis to interpret the result.

The great beyond

Hochstein S & Ahissar M. View from the top: hierarchies and reverse hierarchies in the visual system. Neuron 2002 Dec 5;36(5):791-804. Download PDF.

Bar, M. (2004) Visual objects in context. Nature Reviews Neuroscience 5 , 617 -629.   Download PDF.

Sacks, O. (1995). The case of the colorblind painter. Pages 3-41 in O. Sacks, An anthropologist on Mars . New York: Alfred Knopf.