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Cards In This Set
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The Problem of Perception
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1. Stimuli are inherently ambiguous
2. many different objects could give rise to the same retinal image 3. the brain must therefore make guesses or "unconscious inferences" in order to interpret the image 4. perception is therefore "indirect" because it requires "information processing" |
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Levels of Understanding Perception:
ecological or computational |
What is the goal of perception and what properties of the stimulus or the situation allow the problem to be solved?
e.g. optic flow: as we move through the environment the retinal image changes in characteristics ways that provide cues about our motion |
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Levels of Understanding Perception:
physiol psychological |
What are the processes underlying our perception and what sort of mental representations do they lead to?
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Levels of Understanding Perception:
physiological |
How are these processes and representations realized by the nervous system?
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Physiological approaches:
Nueropsychology |
Studying perceptual deficits in patients with brain damage
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Physiological approaches: nueroimaging
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fMRI and PET- examining which parts of the brain are active during a perceptual task by monitoring blood flow
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Physiological approaches : Electrical Potentials
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Examining brain responses to stimuli by measuring the electrical responses to stimuli by measuring electrical responses on the scalp (e.g. visual evoked potential) or surface of the eye (e.g. electroretinogram)
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Physiological approaches: Single Unit recording
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Measuring the responses of individual cells by recording their electrical signals
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Basics of Nuerophysiology:
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A. Neuron
1. Cell body: contains most of the machinery to keep cell functioning 2. Dendrites: fibers for receving information from other neurons 3. axon: fiber for sending information to other neurons 4. synapse: where neuron makes contact with other neurons |
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Basics of Nuerophysiology:
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B. neurons signal information through electrical activity controlled by the flow of charged ions across the cell membrane, leading to charge differences across the membrance
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Basics of Nuerophysiology:
3 important electrical potentials for understanding how a neuron works-- Resting potential |
1. resting potential: baseline charge difference when cell is at rest (not stimulated)
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Basics of Nuerophysiology:
3 important electrical potentials for understanding how a neuron works-- Graded potentials |
2. graded potentials- passive charge difference in response to stimulation
a. synaptic potential- due to influence of other neuron b. receptor potential- due to "transduction" of physical stimulus (e.g. absorption of light) |
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Basics of Nuerophysiology:
3 important electrical potentials for understanding how a neuron works-- action potential |
3. action potential: breif charge (nerve impulse or "spike" generated by a neuron to carry information along the axon.
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Basics of Nuerophysiology: Differences between action potentials and graded potentials
(Action) |
ACTION POTENTIALS:
1. size - large-fixed 2. duration- brief (1msec) 3. signal- depolarize only 4. location- axon 5. purpose- to carry fixed signal over long distances |
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Basics of Nuerophysiology: Differences between action potentials and graded potentials
(Graded) |
GRADED
1. size- small-variable 2. duration- long 3. signal- depolarization or hyperpolarization 4. location- throughout the cell 5. purpose- to sum together the inputs from other cells |
