UNC NSCI 225 Final Exam Questions and Answers Already Passed
What is Sensation and Perception? - Answers Stimuli and our experience with them
What are the stages of how our perceptual experience is formed? - Answers Environmental
stimulus, Stimulus on receptors, transduction, processing, perception, recognition, action
What is the difference between bottom-up and top-down processing? - Answers Follows the
perceptual pathway vs interchanges the last 4 steps direction (using knowledge to shape
processing/perception)
Where within the perceptual process is knowledge integrated? - Answers Knowledge is
integrated in the last 4 steps (list by memory)
How can we study the relationship between physical stimuli, our perception of those stimuli, and
the physiological response? - Answers We can use neural recording, brain imaging, Fechner's
methods, recognition tests, reaction time, phenomenological report, and physical
tasks/judgment
Absolute Threshold - Smallest amount of stimulus energy needed to detect it
Fechner's Methods - Limits (Ascend/descend, vary starting point), Adjustment (Continuous,
done by pt until undetectable), and Constant Stimuli (Random, threshold is stimuli right 50%,
least bias)
Forced Choice Procedure - Gets rid of bias. Two time intervals, one with stimulus (can be
combined with limits or constant stimuli)
Difference threshold - JND b/w 2 stimuli that can be detected (increases with stimuli)
Neuronal Recording - Microelectrode reads AP of cells which can find receptive fields
Compare and contrast the main parts of a neuron - Answers Dendrites - Many taken in the signal,
pretty short (passive)
Cell body
Axon - Single, long, myelinated, release signal (active)
Explain how neurons communicate - Answers Neurons receive chemical or physical signal
(receptor cells, interneurons)
Sodium diffuses through dendrites/body
Electrical signals activate and go quickly down the axon if strong enough, determined by APs
which occur at axons, travel up to 100 m/s, remain constant. Myelin slows conduction of AP
which allows regeneration at Nodes of Ranvier. They are all or nothing
, Neurotransmitter release at synapse starts process again at next neuron
What are the steps of an action potential? - Answers Depolarization - Na + channels then K+
channels open during
Repolarization - Na+ channels refractory, K+ channels close at the baseline, absolute
Hyperpolarization - Below baseline for a little as Na+ resets and extra K+ diffuses
Depolarization to baseline
What are some of the main properties of light waves and how do they affect perception of light?
- Answers Wavelength/frequency decides color, amplitude decides brightness, and purity
decides saturation
What are the various parts of the eye? - Answers Cornea, sclera, iris, pupil, aqueous humor, lens,
vitreous humor, retina including fovea and optic disc/blind spot
What role does each play in vision? - Answers Cornea focuses 70-80% of light on retina
Pupil lets light into eye
Lens is the transparent muscle behind pupil focusing light all the way (contracts for closer
objects since light is closer, need less)
Humors are just fluids
Retina starts transduction and processing, sending signal to optic nerve
Explain why the "blind spot" exists and why we are not usually aware of it - Answers This is
because the retina in front of the optic nerve has no receptors but it is taken care of by double
vision, filling in gaps
What are the causes/sx/treatments for some Eye disorders? - Answers Astigmatism caused by
misshapen cornea causing blurry vision fixed by glasses
Cataracts caused by protein buildup over the lens treated by surgery
Myopia/hyperopia/presbyopia is caused by problems of the eyeball being a bad size or bending
light badly due to the lens (they become stiff in old age)
Glaucoma is nerve damage causing tunnel vision fixed by draining the aqueous humor since it's
obstructed and pressure builds on the optic nerve
Diabetic retinopathy is splotchy vision due to leaky weak blood vessels
Macular degeneration obstructs the focus of vision
What is Sensation and Perception? - Answers Stimuli and our experience with them
What are the stages of how our perceptual experience is formed? - Answers Environmental
stimulus, Stimulus on receptors, transduction, processing, perception, recognition, action
What is the difference between bottom-up and top-down processing? - Answers Follows the
perceptual pathway vs interchanges the last 4 steps direction (using knowledge to shape
processing/perception)
Where within the perceptual process is knowledge integrated? - Answers Knowledge is
integrated in the last 4 steps (list by memory)
How can we study the relationship between physical stimuli, our perception of those stimuli, and
the physiological response? - Answers We can use neural recording, brain imaging, Fechner's
methods, recognition tests, reaction time, phenomenological report, and physical
tasks/judgment
Absolute Threshold - Smallest amount of stimulus energy needed to detect it
Fechner's Methods - Limits (Ascend/descend, vary starting point), Adjustment (Continuous,
done by pt until undetectable), and Constant Stimuli (Random, threshold is stimuli right 50%,
least bias)
Forced Choice Procedure - Gets rid of bias. Two time intervals, one with stimulus (can be
combined with limits or constant stimuli)
Difference threshold - JND b/w 2 stimuli that can be detected (increases with stimuli)
Neuronal Recording - Microelectrode reads AP of cells which can find receptive fields
Compare and contrast the main parts of a neuron - Answers Dendrites - Many taken in the signal,
pretty short (passive)
Cell body
Axon - Single, long, myelinated, release signal (active)
Explain how neurons communicate - Answers Neurons receive chemical or physical signal
(receptor cells, interneurons)
Sodium diffuses through dendrites/body
Electrical signals activate and go quickly down the axon if strong enough, determined by APs
which occur at axons, travel up to 100 m/s, remain constant. Myelin slows conduction of AP
which allows regeneration at Nodes of Ranvier. They are all or nothing
, Neurotransmitter release at synapse starts process again at next neuron
What are the steps of an action potential? - Answers Depolarization - Na + channels then K+
channels open during
Repolarization - Na+ channels refractory, K+ channels close at the baseline, absolute
Hyperpolarization - Below baseline for a little as Na+ resets and extra K+ diffuses
Depolarization to baseline
What are some of the main properties of light waves and how do they affect perception of light?
- Answers Wavelength/frequency decides color, amplitude decides brightness, and purity
decides saturation
What are the various parts of the eye? - Answers Cornea, sclera, iris, pupil, aqueous humor, lens,
vitreous humor, retina including fovea and optic disc/blind spot
What role does each play in vision? - Answers Cornea focuses 70-80% of light on retina
Pupil lets light into eye
Lens is the transparent muscle behind pupil focusing light all the way (contracts for closer
objects since light is closer, need less)
Humors are just fluids
Retina starts transduction and processing, sending signal to optic nerve
Explain why the "blind spot" exists and why we are not usually aware of it - Answers This is
because the retina in front of the optic nerve has no receptors but it is taken care of by double
vision, filling in gaps
What are the causes/sx/treatments for some Eye disorders? - Answers Astigmatism caused by
misshapen cornea causing blurry vision fixed by glasses
Cataracts caused by protein buildup over the lens treated by surgery
Myopia/hyperopia/presbyopia is caused by problems of the eyeball being a bad size or bending
light badly due to the lens (they become stiff in old age)
Glaucoma is nerve damage causing tunnel vision fixed by draining the aqueous humor since it's
obstructed and pressure builds on the optic nerve
Diabetic retinopathy is splotchy vision due to leaky weak blood vessels
Macular degeneration obstructs the focus of vision
