Term
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Definition
| organizing & interpreting sensations into meaningful experiences |
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Term
| Doctrine of Specific Nerve Energy |
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Definition
| The quality of a sensation depends primarily on the nerve stimulated, and the stimulus itself only secondary |
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Definition
| a condition: Stimulation of one sense evokes an involuntary response in another |
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Definition
| the relationship between the physical qualities of a stimulus and the subject's experience of it. |
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Definition
| Absolute threshold, "elements of psychophysics" fechner's law |
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Definition
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Definition
| initial detection & encoding of environmental energy |
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Definition
| The very smallest amount of stimulus-energy required for an observer to reliably detect (51%) it. |
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Definition
| Signal Detection Theory: a measure of how sensitive the subject was to a stimulus. Higher d' = more |
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Definition
| a receptive field is a region of sensory neurons that, when stimulated, changes the firing rate of their attached ganglion |
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Definition
| Demonstrated that the eye uses lenses to create an image |
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Definition
| Doctrine of specific nerve energy. |
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Definition
| psychophysics, difference threshold, weber's law |
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Definition
| stevens' law, magnitude estimation experiments |
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Term
| Weber's law, and symbol identification |
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Definition
Delta-I / I = k
I=intensity of original stimulus
D-I= Just Noticeable Difference
k= a sense-dependent constant |
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Term
| Fechner's three methods for absolute threshold (& rough description of each) |
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Definition
Method of Constant Stimuli: various levels of stimuli/random order/ 50% correct = absolute threshold
Method of Limits = strong stimuli, build down til cannot be detected (and vice versa)/ repeat several times/ average of crossover points = absolute threshold
Method of Adjustment= intensity of stimulus adjusted by subject until it can just barely be detected |
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Term
| 5 reasons why it's advantageous to have two eyes? |
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Definition
1. Enhanced depth perception
2. Wider field of view
3. redundancy
4. Blind spot coverage
5. better than one at seeing in the dark |
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Term
| Difference between absolute refractory period and relative refractory period |
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Definition
Absolute refractory period: neuron CANNOT fire again
Relative: a duration where it is more difficult (and requires more than minimum input) to cause a neuron to fire again |
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Term
| Describe stevens' magnitude estimation experiments |
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Definition
| Show lights to subjects of a standard intensity (10). Show new lights of varying intensities (known to the experimenter) and have them rate them on the same scale. Graph perceived intensity vs actual. |
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Term
| How do neurons indicate their level of excitation? |
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Definition
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Term
| Why is signal detection theory better than fechner's methods for absolute threshold |
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Definition
| it's independent of subject's response criterion (or bias) |
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Term
| How is a typical signal detection theory experiment conducted? |
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Definition
| 1. Subject presented with faint or no stimulus 2. subject reports whether stimulus is present (yes/no) 3. repeat sequence many times when hits=false alarms and misses=correct rejections, we have absolute threshold (d' = zero) |
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Term
| Difference between myopia and hypermetropia |
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Definition
myopia: focus is in front of the retina - eyeball too long
hypermetropia: focus is in behind the retina - eyeball too short |
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Term
| Hit, Miss, Correct rejection, False alarm (signal detection theory) |
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Definition
hit = present/ guess present
miss = present/ guess absent
false alarm = absent/ guess present
correct rejection = absent/ guess absent |
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Term
| ganglion cells are responsible for: |
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Definition
| generate action potentials that are sent to the brain |
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Term
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Definition
| Thought the eye worked like a pinhole camera |
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Term
| Numerical resting potential of a neuron |
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Definition
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Term
| why is center-surround organization desirable in ganglion cells? |
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Definition
| because it's great for seeing the edges of things |
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Term
| names & properties of 3 kinds of ganglion cell |
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Definition
P-Cells : Form & color
M- Cells: depth, motion & simple light detection
k- cells: code overall level of illumination |
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Term
| three types of cells in v1 & what they're responsible for |
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Definition
Simple: Respond to bar shapes at a particlar location & orientation
Complex: Respond to bar shapes at a particular location, orientation and velocity
End-Stopped: respond to bars that at a particular location, orientation and length (detecting corners) |
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Term
| function of the collicular pathway |
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Definition
| retinal information carried by ganglions to the Superior Colliculus, which is involved in determining what is important to pay attention to. |
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Term
| Advantages & disadvantages of a pinhole camera |
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Definition
Adv: cannot be out of focus
Dis: images are very dim, and not as suitable for vision |
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Term
| advantages & disadvantages of a lens system |
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Definition
Adv: images are bright, plenty of light, better depth perception through oculomotor cues
disadv: easily out of focus, lens is vulnerable to damage & deterioration |
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Term
| Two assumptions of fechner's law |
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Definition
1. Weber's law was correct
2. All JND's are equal in percieved magnitude |
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Term
| Two problems common to fechner's 3 methods for absolute threshold |
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Definition
1: observer could be lying
2: relies on observer's "opinion" which fouls results |
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Term
| Sevens' law and symbol identifications |
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Definition
p=kI^b
p=perceived magnitude
I = true stimulus intensity
k&b= sense-dependent constants |
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Term
| Four main parts of a neuron & functions |
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Definition
soma (cell body): organelles & DNA
dendrites: input from other neurons
Axon: carries action potential to terminal buttons
Terminal buttons: output to next neuron in chain |
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Term
| horizontal cells are responsible for: |
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Definition
| modifies connections between the photoreceptors & ganglion cells |
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Term
| Significance of 'b' in Stevens' law (b<1), (b=1), (b>1) |
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Definition
b = 1 indicates a 1:1 increase of perceived intensity and stimulus intensity
b<1= p.magnitude increases slower than s.intensity
b>1= p.magnitude increases faster than s. intensity |
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Term
| Bipolar cells are responsible for: |
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Definition
| carry the output of the photoreceptors to the ganglion cells |
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Term
| Fechner's law, and symbol identification |
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Definition
P=k log (I)
p= perceived magnitude
I= stimulus intensity
k= sense-dependent constant |
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Term
| amacrine cells are responsible for: |
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Definition
| modifies connections between bipolar & ganglion cells |
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Term
| Draw a labeled diagram showing the sequence of events at action potential |
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Definition
Should include:
-70mv (resting potential)
-65mv (when action potential begins and Na+ channels open. NA + enters cell until...)
+50 mv (Na+ channels close, K+ channels open. K+ leaves cell, cell becomes more negatively charged.)
Also should show:Voltage (Y-axis) Time (X-axis) |
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Term
Draw diagram showing the response of an on-center off-surround ganglion cell to
1. Diffuse illumination
2. center-only illumination
3. illumination only in the surround
4.darkness. |
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Definition
(- (+) )
think of light in the outer area (the - area) SLOWING the firing rate of the cell | | | | | to | | | | |
and light in the CENTER area (the +) increasing the firing rate of the cell
| | | | | to: ||||||||.
the rest should be simple reasoning. (Darkness: no change / diffuse: + and - cancel each other out, so no change / light-center: increased firing rate / light-surround: slowed firing rate) |
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