CAS PS 222 Lecture Notes - Lecture 10: Receptive Field, Motion Perception, Retina
18 May 2018
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Any object that falls on the horaptor displays zero disparity.
The type of the disparity tells us relative to space where the object is.
What other information do we need to figure out where the object is?
- The magnitude of the disparity: how far apart is the location of the images of the object
on the retinae.
- The greater the disparity: the further away the object is from the object you are fixating
on
- Horoptor is defined in the physical world. If you draw this invisible sphere, it will fall on
the same location on the two retinaes.
The receptive field of a binocular cell is composed of photoreceptors.
How many discreet locations: 2 RF one in each eye. And it fires when the object is in the location
it most prefers.
Motion Perception:
Not only do we need to detect the distance of the objects from us, but also detect how it is
moving or coming towards us.
You need to identify that the object you saw in Spatial location 1 and Time 1 is the same object
that you see in spatial location 2 at time 2.
Our challenge is to identify that relationship between space and time.
So how do we do this?
The part of the brain that processes motion is MT. Earlier than that, we hear about motion
selective cells in V1. Motion processing starts in V1 with the motion sensitive neurons.
We can use the single cell recording technique.
The characteristics of one particular neuron can give us information about how the brain starts
to wire up motion selective cells.
Defining the receptive field of motion-selective neuron:
- Neuron needs to respond to particular speed, direction.
- The image of the object is also moving across the retina.
- We need at least two locations to make up the receptive field
- Can a motion selector cell can be binocular cells as well? Yes, then it would have 4 RFS
The circuit is not sufficient to give us information about the direction of the motion
The longer the delay, the slower the speed.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Any object that falls on the horaptor displays zero disparity. The type of the disparity tells us relative to space where the object is. The magnitude of the disparity: how far apart is the location of the images of the object on the retinae. The greater the disparity: the further away the object is from the object you are fixating on. Horoptor is defined in the physical world. If you draw this invisible sphere, it will fall on the same location on the two retinaes. The receptive field of a binocular cell is composed of photoreceptors. How many discreet locations: 2 rf one in each eye. And it fires when the object is in the location it most prefers. Not only do we need to detect the distance of the objects from us, but also detect how it is moving or coming towards us.
