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31 terms

Vision

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Vergence
movements that keep both eyes fixed on the same target
saccadic
rapid, jerky movements that shift your gaze from one point to another
pursuit
movements that allow us to maintain a moving object
fovea
highest concentration of cones is found here; specialized in visual acuity
Amacrine
cells in the retina that connect adjacent ganglion cells with bipolar cells
Horizontal
cells in the retinat that connect photoreceptors with bipolar cells
Trichromatic
theory of colour vision postulating that colour perception is a function of the relative rates of response by three types of cone photoreceptors, each sensitive to a different set of wavelenghts
trichromatic
theory of colour vision that fails to explain after images and blends of colours
Opponent Process
theory of colour vision stating that we percieve color in terms of paired opposites: red/green, yellow/blue, black/white
receptive field
the area of the visual field in which the presence of a stimulus influences the firing rate of that neuron; the part of the neuron in which light must fall to excite the neuron
ON Cell
stimulated by light falling on center; inhibited by light falling on periphery
OFF Cell
inhibited by light falling on center; stimulated by light falling on periphery
Lateral
geniculate nucleus associated in vision; of the thalamus; relay point of vision signal between retina and primary visual cortex
Orientation Sensitive
neuron in the striate cortex that responds only when a line of a particular direction appears within its receptive field
Simple
Orientation Sensitive Neuron whose receptive field is organized in an opponent fashion; inhibitory region runs parallel to receptive field
Complex
Orientation Sensitive Neuron which does not possess an inhibitory surround; respond when line moves perpendicular to its angle of orientation; movement detectors
Hypercomplex
Orientation Sensitive Neuron that has inhibitory regions at the end of a line segment
High Frequency
sharp edges provide this signal
low frequency
image looks unfocused but we can still make out the form
Ventral
the "what" stream; recognizes what the object is and the color
Dorsal
the "where" stream; recognizes where the object is and whether it is moving
TE and TEO
areas of the brain at the end of the ventral visual stream; damage here leads to difficulty in determining WHAT an object is
Visual Agnosia
the inability to recognize objects, persons, or shapes in the absences of blindness or memory loss
Prosopagnosia
deficit in recognizing faces; face blindness
Fusiform Gyrus
area of the brain with special "face-recognizing" circuits
MT
area of the extrastriate cortex that contains neurons which respond to motion
Area V5
area of the estrastriate cortex that contains neurons which respond to motion
akinetopsia
inability to percieve motion; caused by bilateral damage to MT (or Area V5)
MST
performs further motion analysis
Area V5a
performs further motion analysis
Optic Flow
the analysis of the relative movement of the visual elements around us; riding a bike, everything is moving on its own AND in relation to us