PSY-230 Midterm: Brain and Behavior - Exam 2
Brain and Behavior - Exam 2
Vision:
●Physics of Light
○Light (and photons or a wave)
■Absorb
●Where the light is taken up then no longer
being transmitted
●Ex. putting a flashlight on a blanket then
looking on the other side and not seeing
much light at all
■Scattered
●When energy is dispersed irregularly
■Reflected
●Light redirected when it strikes a surface
●Ex. mirror selfie
■Transmitted
●Where it passes through a surface
●Ex. flashlight through a window
■Refracted
●Light energy is altered when it passes
through some other medium
●The Human Eye
○Cornea
■Transparent window into the eyeball
■Protective layer
○Aqueous humor
■Watery fluid in the anterior chamber or eye
○Crystalline Lens
■Lens that is inside the eye that focus light back
to the retina
○Pupil
■Dark circular opening at the center of the iris
■Where light is allowed in
○Iris
■Muscle where it changes size based on amount of
light
■Ex. walking outside during the daylight from the
movie theater
○Vitreous humor
■Watery fluid in the eye
○Retina
■Light sensitive membrane on the back of the eye
■Contains our rods and cones
●Cells that allow us to see
●Visual Processing
○Everything in our left field of vision is processed by
the right side of our brain
■And vice versa
●Visual Processing x2
●Visual Processing x3
●Receptive Field
○Receptive field
■Region of retina in which stimuli influence a
neuron’s firing
■Each neuron responsible for vision has one
●Responsible for different points in the
visual field
●Have a center-around organization
○ON-center ganglion cells
■Fires when light is on the center
■Excited by light that falls on their center
■Inhibited by light that falls in their surround
○OFF-center ganglion cells
■Inhibited when light falls on their center
■Excited when light falls in their surround
○ON-center and OFF-center ganglion cells are in the
retina
●Cell Layers in the Eye
○When light comes into the eye and hits the retina,
there are several layers it must pass before hitting
the rods and the cones
●Cell Layers of the Retina
○Transduction
■Any process by which a cell converts one kind of
signal/stimulus with another
○Lateral inhibition
■When an excited neuron reduces the activity of
its neighbors
○Rods/Cones
■Responsible for transduction
●Converting some sort of external stimulus
into neural code
○Translate light into something our
brain can understand
○Bipolar/Ganglion
■Carry information from the photoreceptors to the
retinal ganglion cells
●Signaling
○Activating with light - ON-center or
OFF-center
○Horizontal
■Communicating between the bipolar and ganglion
cells and adjacent parts of the retina
●Lateral inhibition
○Amacrine
■
●Contrast enhancement temporal sensitivity
○The squiggling lines are the dendrites and the axon
terminals
○If nothing is in your visual field, then it will be
inhibited vision
●Photoreceptors
○Cones/Rods
■Working to take light waves and turn it into a
neural language that our brain will understand
■Named by what they are shaped like or look light
■Chromatic/Achromatic
●Chromatic
○Cones work with color and detail
●Rods do not process color
○Excel in dimly light scenarios
■Non-saturable/Saturable
●Cones need lots of light
○Can handle as much light as needed
●If a rod is saturated, it will turn off
Document Summary
Where the light is taken up then no longer being transmitted. Ex. putting a flashlight on a blanket then looking on the other side and not seeing much light at all. Light redirected when it strikes a surface. Light energy is altered when it passes through some other medium. Watery fluid in the anterior chamber or eye. Lens that is inside the eye that focus light back. Dark circular opening at the center of the iris. Muscle where it changes size based on amount of. Ex. walking outside during the daylight from the light movie theater. Light sensitive membrane on the back of the eye. Everything in our left field of vision is processed by the right side of our brain. Region of retina in which stimuli influence a neuron"s firing. Each neuron responsible for vision has one. Responsible for different points in the visual field. Fires when light is on the center.
