COGS 101A Lecture Notes - Lecture 7: Agnosia, Neuropsychology, Temporal Lobe
● Receptive fields
○ Retinal ganglion cells and lgn neurons
○ V1
■ Features detectors
● Simple cortical cells
○ Responsive to oriented lines and specific location
● Complex cells
○ Oriented lines but in different location and respond to
movement
○ Also prefer certain size
● End stop
○ Hubel and Wiesel
■ Discovered receptive fields in v1 by measure relationship between
physiology and stimulus
■ Studied cats
○ Feature detectors and perception
■ Adaptation: reduction in the response of a neuron because of fatigue;
psychologist’s electrode
● Neurons tuned to specific features will fire most when presented
with this stimuli
● If stimulus remain for a long period these neurons will start to
fatigue
● Selective adaptation is a short-term effect
■ Testing: how dim can it get and still be visible
● Increase of threshold after selective adaptability
■ Tilt aftereffect
● After adapting to grating slanted ight, a vertical grating with appear
to slant left
○ Right tilt neurons get fatigued but you still have the
spontaneous firing of the left tilt
■ Selective adaptation in motion is the same idea (but different neurons)
■ Plasticity
● Early exposure is crit for feature detectors to develop
● Experience-dependent plasticity (neural plasticity)
○ Response properties of neurons are shaped by experience
○ Selective rearing
■ Raising an animal in an environment that only
contains certain orientations
■ blackman and cooper 1970
○ Extrastriate cortex
■ Functional organization
● Neurons with similar function are segregated in brain
■ Dorsal Stream
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Document Summary
Responsive to oriented lines and specific location. Oriented lines but in different location and respond to movement. Discovered receptive fields in v1 by measure relationship between physiology and stimulus. Adaptation: reduction in the response of a neuron because of fatigue; psychologist"s electrode. Neurons tuned to specific features will fire most when presented with this stimuli. If stimulus remain for a long period these neurons will start to fatigue. Testing: how dim can it get and still be visible. After adapting to grating slanted ight, a vertical grating with appear to slant left. Right tilt neurons get fatigued but you still have the spontaneous firing of the left tilt. Selective adaptation in motion is the same idea (but different neurons) Early exposure is crit for feature detectors to develop. Response properties of neurons are shaped by experience. Raising an animal in an environment that only contains certain orientations. Neurons with similar function are segregated in brain.
