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  • PROFESSOR: This is our first introductory meeting

  • of the course, which is 9.04.

  • And we are going to cover vision and audition in this course,

  • and there are going to be two of us lecturing.

  • My name is Peter Schiller, and this is Chris Brown.

  • And I will be talking about the vision portion,

  • and Chris will be lecturing about the auditory portion.

  • Now, what I'm going to do is I'm going

  • to hand out the syllabi that we have, in this case,

  • for the first half of the course.

  • And that we are going to discuss in some detail

  • today for the first half of the lecture,

  • and Chris is going to discuss it for the second half.

  • So that is the basic plan for today.

  • And I will go through some of the basic procedures and issues

  • that we may want to deal with at this very introductory portion.

  • So first of all, let me talk about the reading assignments.

  • If you have the handout, they are ready for you.

  • If you look at the second page, that's

  • where we have the assigned readings for the vision

  • half of the course.

  • Now, for that half of the course,

  • the top eight assignments are all articles

  • in various journals.

  • We don't have a textbook for this portion of the course.

  • And then in addition to the assigned readings,

  • we have recommended readings that are listed there.

  • And then another important factor

  • that is listed there-- let me first

  • say that the lectures will be put on Stellar, in most cases,

  • after each lecture.

  • And in addition, the videos that we are now recording

  • will also become available, but they will not

  • be available until well after each lecture.

  • So I would advise each of you to come to the lectures

  • rather than hoping to read the assigned material only

  • or to eventually look at the videos.

  • The reason I'm telling you this is

  • that our analysis has shown that those students who

  • attend the lectures regularly get

  • much better grades on the exams than the students who do not.

  • So I strongly will urge all of you

  • to come to as many lectures as you possibly can.

  • Now, the additional requirement that you're

  • going to have for this course is to write two research reports,

  • one for vision and one for audition.

  • And the assigned written report that you need to put together

  • is in a paper at the bottom of the second page.

  • In this case, it's going to be a paper that

  • was written quite some years ago,

  • a very important and remarkable paper that has been published

  • by Oster and Barlow, as you can see.

  • And the task for you will be to not just report

  • what they had reported, because that's repetitious,

  • but to do a bit of research and write

  • about what has been discovered since the remarkable findings

  • that these two people had made at the time.

  • All right.

  • So that's the research report.

  • And then I want to specify the exams.

  • We are going to have a midterm exam,

  • and the exact date for this has already been set on October 23.

  • All right?

  • But as I say, you can find this, and I

  • will specify that in more detail in just a minute.

  • And then we are going to have a final exam

  • at the end of the term.

  • The exact date for this, as always at MIT,

  • will not have been set until probably sometime in November.

  • So now let me also specify the grade breakdown.

  • I think that's important for all of us.

  • The written report for each half of the course--

  • there's going to be one report, as I've already said,

  • for vision and one for audition--

  • and that will constitute 10% of the grade for each.

  • And the midterm exam, this constitutes 25%.

  • The final exam constitutes 55% of the overall grade.

  • And in that, 15% will be on vision and 40% on audition.

  • So if you add that up, you can see that vision and audition

  • are set up to be exactly equally weighed for the exams.

  • MICHELLE: Hi.

  • I'm Michelle.

  • I'll be helping the professors, especially with [INAUDIBLE].

  • PROFESSOR: So I'm Chris Brown, and I'm one of the instructors.

  • I'll be teaching the second half.

  • And my research is on two areas, brain stem auditory reflexes,

  • like the startle reflex and the middle ear muscle reflex.

  • And I also work on animal models of the auditory brain stem

  • implant, which is a neural prosthesis that's

  • used in deaf individuals.

  • PROFESSOR: All right.

  • And I'm Peter Schiller, and I work on the visual system.

  • And I'm a professor here in our department.

  • So that's very nice.

  • Thank you for the introductions.

  • And I hope, you guys, we all get to know each other.

  • I'm very impressed that there's so many seniors here.

  • That's actually unusual.

  • I don't remember having this high a percentage

  • of seniors in the class.

  • That's really very nice, very nice.

  • OK.

  • So now we are going to talk, for the first part

  • of today's lecture, about what aspects of visual processing

  • we are trying to understand and, therefore,

  • what we are going to try to cover

  • in this course in terms of topics.

  • OK?

  • So first of all, what we are going

  • to do for several lectures is to talk about the layout

  • and organization of the visual system itself.

  • Most of it we will discuss as it applies to higher mammals,

  • in particular monkeys and primates and humans.

  • Then we are going to talk about specific aspects

  • of visual processing.

  • We're going to try to understand how we adapt in vision,

  • and, very interestingly, how we are

  • able to perceive colors and process them accurately.

  • Another fascinating topic is how we

  • are capable of analyzing motion.

  • That's a complex, very interesting topic,

  • as is depth perception.

  • And the reason depth perception is particularly

  • interesting is because, as you know,

  • the retinal surface is essentially

  • a two-dimensional arrangement.

  • And yet from whatever falls on these two dimensions

  • in the left and right eyes, somehow the brain

  • needs to convert to be able to see the third dimension.

  • And as a result, several mechanisms

  • have evolved to accomplish that, and we

  • are going to discuss them.

  • Then, again, another very complex topic

  • is how we can recognize objects.

  • Perhaps the most complex of those

  • is our incredible ability to recognize faces.

  • And that is highlighted, of course,

  • by the fact that if you look at more simple organisms,

  • like, I don't know, monkeys, they all look the same to you.

  • But human beings, who are actually

  • more similar to each other than perhaps monkeys are,

  • we are really capable of telling them

  • apart and readily recognize them over long periods of time.

  • So it's a very interesting topic.

  • And yet another topic that we will discuss

  • is how we make eye movements.

  • As you probably know, or you're aware of,

  • that we are constantly moving your eye.

  • You make saccadic eye movements about three times a second,

  • thousands of times a day, hundreds of thousands of times,

  • to be able to see things clearly in the world.

  • So we are going to try to understand

  • how that incredible ability has evolved

  • and how it is realized by the brain.

  • OK.

  • So now to look at exactly how we are going to cover this,

  • let me go through this.

  • During the next lecture, which is September 9,

  • we are going to look at the basic layout of the retina

  • and the lateral geniculate system,

  • as well as how the visual system in general is wired.

  • Then on September 11, we're going

  • to look at the visual cortex, then

  • at the ON and OFF channels, so-called,

  • that you'll realize what they are once we talk about it.

  • And then there's another set of channels

  • that originates in the retina, which

  • are the midget and parasol channels.

  • We'll discuss those, try to figure out why did they evolve

  • and what is their role in being able to see

  • the world in realistic fashion.

  • Then we're going to talk about adaption and color, depth

  • perception, form perception.

  • And then we're going to have a lot of fun on October 2,

  • and we're going to look at illusions and also

  • visual prosthesis, because one of you,

  • in particular, is interested in that topic.

  • Then we are going to talk about the neural control of visually

  • guided eye movements.

  • That's going to consist of two sessions.

  • And then we're going to talk about motion perception

  • and another aspect of eye movements

  • when we pursue something with smooth eye movements.

  • And then we're going to have an overview.

  • And then, lastly, on October 23rd,

  • we are going to have the midterm exam.

  • That's going to cover questions from all of these lectures.

  • I should tell you right now that the midterm exam is going

  • to consist of multiple-choice questions.

  • So you're not going to, maybe, asked to write anything.

  • You're going to have to just pick

  • from each of the questions the correct answer.

  • All right.

  • So now what I would like to talk about next in a summary fashion

  • are what we call the tools of the trade.

  • What has happened over the many years

  • that scientists tried to understand

  • how the visual system and, for that matter the brain, works,

  • what kinds of methods have been employed.

  • And so I'm going to talk about each of these just very briefly

  • this time, and then they will come up repeatedly

  • during all of the lectures.

  • Now, the first method I'm going to talk about

  • is called psychophysics.

  • I'm sure most of you know what that is.

  • It's a scientific way to study behavior of humans and animals

  • to determine how well they can see.

  • Now, there are several procedures with this.

  • I'm going to describe one that's used

  • both in humans and monkeys.

  • And what you can do nowadays, you can use a color monitor,

  • and I will describe that in just a second.

  • After that, I will talk about anatomy.

  • I will talk about electrophysiology,

  • pharmacology, brain lesions, imaging, and optogenetics.

  • So now let's start with psychophysics in more detail.

  • So here is a color monitor, and either monkeys or humans

  • can be trained to first look at a fixation spot.

  • And that's important because we want to always

  • be able to present stimuli in selected

  • locations of the visual field or selected

  • locations along the retina.

  • This is particularly important, because when

  • you study the brain, different regions of the visual field

  • representation are located in different areas,

  • for example, in the visual cortex.

  • So what you do then is you can present a single stimulus

  • like this, and the task of the human or the monkey

  • is to either make a saccadic eye movement to it,

  • say that's where it is, or to press

  • a lever that's in front of them.

  • And then on each trial, it appears someplace else.

  • You can present it in many different locations,

  • and maybe one of those locations will

  • be relevant to what part of the brain you are studying.

  • And then what you do, you can systematically

  • vary all kinds of aspects of the stimulus.

  • You can vary the color.

  • You can vary the contrast.

  • You can vary the size.

  • You can vary the shape.

  • And by systematically varying this,

  • you can create curves to describe exactly how well you

  • can see any particular thing like,

  • for example, just how much contrast you