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PSY255 Exam 2 Questions with Detailed
Verified Answers (100% Correct Answers)
/Already Graded A+
What is the path of light through the eye and onto the retina?
Ans: light passes through the cornea and is restricted by the iris, then the light passes through
the pupil, and then the light shines through the lens that focuses the image on the retina
What are retinal ganglion cells?
Ans: they pass information from the eye to the brain
What are bipolar cells?
Ans: they carry information from the photoreceptors to the retinal ganglion cells
What are rods and cones and what do they do?
Ans: Rods and cones are the two kinds of photoreceptors
What is the fovea?
Ans: a region of the retina (central vision)
What is the blind spot?
Ans: it is where the optic nerve attaches to the eye
What is the optic nerve?
Ans: it transmits information from the retina to the brain
What is transduction?
Ans: the process of converting signals and information from the outside world into the
electrical and chemical signals of our nervous system
Where and how does transduction happen in the eye?
Ans: The rods and cones, sensory receptors help
What are some of the properties of rods and cones? Where are they distributed in the retina?
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Ans: Rods are highly sensitive to light and are therefore ideal for vision in dim environments.
They are more concentrated in the periphery.
Cones come in three types, and are more sensitive to the fine details of a stimulus than rods
are. They are more concentrated in the fovea.
What is convergence?
Ans: multiple rods/cones can connect to one ganglion cell
Which one has more convergence, rods or cones? What are some of the consequences of this fact?
Ans: Rods have more
- Many rods connect to one ganglion cell, while few cones connect to one ganglion cell
- This is one reason rods are more sensitive to light than cones are
What is the center-surround organization of retinal ganglion cells?
Ans: lateral inhibition - inhibition that spreads laterally across a neural circuit
How does center-surround organization create the Mach band illusion?
Ans: lateral inhibition explains the Mach bands
What is the path of information through the visual system to the point where it splits into the dorsal
and ventral streams?
Ans: Retina >> Retinal ganglion cells >> LGN >> V1 >> V2 >> V3
How does lateralization of visual information work?
Ans: left visual field projects to the right hemi-retina and the right brain, while the right visual
field projects to the left hemi-retina and the left brain
How is the lateral geniculate nucleus structure organized?
Ans: - Each eye has a separate layer
- Each type of retinal ganglion cell has a separate layer.
- Layers have retinotopic maps
- Corresponding locations on the retina form columns across the layers
What are examples of simple and complex cells in V1?
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Ans: simple cells: respond to oriented bar of light
complex cells: respond to bar in correct orientation at many locations, often respond to
oriented bar moving across the receptive field
How are simple cells built up out of inputs from center-surround cells in the LGN?
Ans:
Retinotopic map and cortical magnification in V1?
Ans: Retinotopic map - receptive fields of adjacent cells correspond to adjacent points on the
retina
cortical magnification - retinotopic map devotes more space to stimuli in the fovea
What are the dorsal and ventral pathways and what visual tasks are they responsible for?
^ What is some evidence for this in brain-damaged patients and in normal subjects?
Ans: Dorsal pathway - involved with processing the object's spatial location
Ventral pathway - involved with object and visual identification and recognition
Evidence in brain-damaged patients:
- Patient DF: carbon monoxide poisoning damaged her ventral pathway --> no object
recognition; but perfectly able to reach for objects
- Patient LM: stroke patient had damage in dorsal pathway, could not perceive object's
locations in space
Evidence in normal subjects:
- Ebbinghaus illusion affects perceived size.
- Accurate grip size during reaching
What lobes are involved in the dorsal and ventral pathways?
Ans: Dorsal: occipital lobe, parietal lobe, temporal lobe
Ventral: medial temporal lobe, inferior temporal lobe
What is a double dissociation?
PSY255 Exam 2 Questions with Detailed
Verified Answers (100% Correct Answers)
/Already Graded A+
What is the path of light through the eye and onto the retina?
Ans: light passes through the cornea and is restricted by the iris, then the light passes through
the pupil, and then the light shines through the lens that focuses the image on the retina
What are retinal ganglion cells?
Ans: they pass information from the eye to the brain
What are bipolar cells?
Ans: they carry information from the photoreceptors to the retinal ganglion cells
What are rods and cones and what do they do?
Ans: Rods and cones are the two kinds of photoreceptors
What is the fovea?
Ans: a region of the retina (central vision)
What is the blind spot?
Ans: it is where the optic nerve attaches to the eye
What is the optic nerve?
Ans: it transmits information from the retina to the brain
What is transduction?
Ans: the process of converting signals and information from the outside world into the
electrical and chemical signals of our nervous system
Where and how does transduction happen in the eye?
Ans: The rods and cones, sensory receptors help
What are some of the properties of rods and cones? Where are they distributed in the retina?
, Page |2
Ans: Rods are highly sensitive to light and are therefore ideal for vision in dim environments.
They are more concentrated in the periphery.
Cones come in three types, and are more sensitive to the fine details of a stimulus than rods
are. They are more concentrated in the fovea.
What is convergence?
Ans: multiple rods/cones can connect to one ganglion cell
Which one has more convergence, rods or cones? What are some of the consequences of this fact?
Ans: Rods have more
- Many rods connect to one ganglion cell, while few cones connect to one ganglion cell
- This is one reason rods are more sensitive to light than cones are
What is the center-surround organization of retinal ganglion cells?
Ans: lateral inhibition - inhibition that spreads laterally across a neural circuit
How does center-surround organization create the Mach band illusion?
Ans: lateral inhibition explains the Mach bands
What is the path of information through the visual system to the point where it splits into the dorsal
and ventral streams?
Ans: Retina >> Retinal ganglion cells >> LGN >> V1 >> V2 >> V3
How does lateralization of visual information work?
Ans: left visual field projects to the right hemi-retina and the right brain, while the right visual
field projects to the left hemi-retina and the left brain
How is the lateral geniculate nucleus structure organized?
Ans: - Each eye has a separate layer
- Each type of retinal ganglion cell has a separate layer.
- Layers have retinotopic maps
- Corresponding locations on the retina form columns across the layers
What are examples of simple and complex cells in V1?
, Page |3
Ans: simple cells: respond to oriented bar of light
complex cells: respond to bar in correct orientation at many locations, often respond to
oriented bar moving across the receptive field
How are simple cells built up out of inputs from center-surround cells in the LGN?
Ans:
Retinotopic map and cortical magnification in V1?
Ans: Retinotopic map - receptive fields of adjacent cells correspond to adjacent points on the
retina
cortical magnification - retinotopic map devotes more space to stimuli in the fovea
What are the dorsal and ventral pathways and what visual tasks are they responsible for?
^ What is some evidence for this in brain-damaged patients and in normal subjects?
Ans: Dorsal pathway - involved with processing the object's spatial location
Ventral pathway - involved with object and visual identification and recognition
Evidence in brain-damaged patients:
- Patient DF: carbon monoxide poisoning damaged her ventral pathway --> no object
recognition; but perfectly able to reach for objects
- Patient LM: stroke patient had damage in dorsal pathway, could not perceive object's
locations in space
Evidence in normal subjects:
- Ebbinghaus illusion affects perceived size.
- Accurate grip size during reaching
What lobes are involved in the dorsal and ventral pathways?
Ans: Dorsal: occipital lobe, parietal lobe, temporal lobe
Ventral: medial temporal lobe, inferior temporal lobe
What is a double dissociation?
