UNC NSCI 225 FINAL EXAM (ALL LEARNING OBJECTIVES
WITH ANSWERS) WITH COMPLETE SOLUTION
2025/2026!!
What is Sensation and Perception? Answer - Stimuli and our experience with
them
What are the stages of how our perceptual experience is formed? Answer -
Environmental stimulus, Stimulus on receptors, transduction, processing,
perception, recognition, action
What is the difference between bottom-up and top-down processing? Answer
- 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? Answer -
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? Answer - 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 Answer - Dendrites - Many
taken in the signal, pretty short (passive)
Cell body
Axon - Single, long, myelinated, release signal (active)
Explain how neurons communicate Answer - 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? Answer - 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? Answer - Wavelength/frequency decides color, amplitude
decides brightness, and purity decides saturation
What are the various parts of the eye? Answer - Cornea, sclera, iris, pupil,
aqueous humor, lens, vitreous humor, retina including fovea and optic
disc/blind spot
What role does each play in vision? Answer - 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
Answer - 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? Answer -
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
WITH ANSWERS) WITH COMPLETE SOLUTION
2025/2026!!
What is Sensation and Perception? Answer - Stimuli and our experience with
them
What are the stages of how our perceptual experience is formed? Answer -
Environmental stimulus, Stimulus on receptors, transduction, processing,
perception, recognition, action
What is the difference between bottom-up and top-down processing? Answer
- 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? Answer -
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? Answer - 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 Answer - Dendrites - Many
taken in the signal, pretty short (passive)
Cell body
Axon - Single, long, myelinated, release signal (active)
Explain how neurons communicate Answer - 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? Answer - 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? Answer - Wavelength/frequency decides color, amplitude
decides brightness, and purity decides saturation
What are the various parts of the eye? Answer - Cornea, sclera, iris, pupil,
aqueous humor, lens, vitreous humor, retina including fovea and optic
disc/blind spot
What role does each play in vision? Answer - 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
Answer - 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? Answer -
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
