Lesson 5 Flashcards
Translation of external information (light, sound, touch, odor, time) into neural codes
sensation
The organization and interpretation of sensations into a coherent percept of the world
perception
Cells specialized to detect certain kinds of
stimuli
sensory receptors
Process for converting physical stimulus energy into electrochemical messages for transmission as nerve impulses to the brain
transduction
what are the two sensory areas we have in the brain?
primary and secondary
All sensory inputs reach cortex via the thalamus
except for _______
olfaction
Bees perceive distinct color patterns on flowers that are invisible to the human eye. Why is that?
The color patterns are in ultraviolet light, which humans cannot see
vision begins where and with what?
at the eye with sensation
electromagnetic energy that travels in waveforms that have intensity and wavelength
light
intensity is related to what?
brightness
wavelength is related to what?
colors
distance in crest between two waves - relates to perceived color
wavelength
what type of cells are located in the retina (the back part of the eye)?
photoreceptors
how much types of photoreceptors are there in the eye? what are they?
2; RODS and CONES
high-sensitivity, but low-resolution vision (poor acuity),
no color (black & white), good for low-light conditions
RODS
good for high-resolution vision, and for color vision
CONES
Where are cones most concentrated in?
the fovea
where are rods absent from?
the fovea
true or false? if false, correct the statement
both rods and cones exist in the blind spot of the eye
False; No receptors at all exist in the blind spot
true or false? if false, correct the statement
there are actually many pathways from the eye to the brain
true
what principle aligns with there being a gradual decline in the reaction to any stimulus if the stimulus persists unchanged
adaptation
Sensory systems respond more to change in _______
stimulation
what type of cells don’t respond to light/dark per se, but local transitions from light to dark, or dark to light (i.e., edges)
retinal ganglion cells
bright in the center and dark in the immediate surround elicits strongest increase in activity
on-center
dark in the center and bright in the immediate surround elicits strongest increase in activity
off-center
Left visual field images are communicated to ____ visual cortex.
right
Right visual field images are communicated to ____ visual cortex.
left
Contra Eye: Layers ___,____ & ___
1, 4 & 6
Ipsi Eye: Layers ____, ____ & ___
2, 3 & 5
some ‘vision’ via a subcortical visual pathway
blindsight
Perception combines ____ stimuli (bottom-up)
and ______ (top-down)
visual; expectations
what is one “rule” the visual system use to arbitrate between possible interpretations?
“non-accidental view”
(the one that’s simplest, most probable, as opposed to least probable)
When in visual processing do ‘top down’ processes influence perception?
Attention to regions of space can alter or enhance responding in V1 (and even LGN), but the response properties are the same
what area responses to ‘illusory’ lines?
V2
what areas have dorsal and ventral components, after which the visual pathways split?
V2 and V3
The highest density of ________, or color-sensitive photoreceptors, can be found in the ________ of the retina.
cones; fovea
Due to a defect in one type of photoreceptor, Sheena has poor vision at night, when light levels are relatively low. Which type of photoreceptor is defective?
rod
The primary visual pathway is best described as
retina –> optic nerve –> optic chiasm –> thalamus –> occipital lobe
the “what” pathway is located in the
temporal lobe
the “where” pathway is located in the
parietal
V4 is important in
shape and color perception
V5 is important in
movement perception
V4 color vision depends on what two things?
wavelength (cones) and luminance (or presumed luminance)
how can we assess functional role of visual areas?
by examining behavior in patients with lesions that result in specific deficits in perception.
what disorder impairs motion perception due to cortical damage? where do they have damage?
Akinetopsia; damage in V5
Impaired color perception due to cortical damage
Achromatopsia
what does the dorsal pathway of vision offer us?
-Where/How computations
-Spatial perception
-Dynamics/motion
-Vision for action
what does the lateral pathway of vision offer us?
-What computations
-Shape, color, texture
-Object recognition
-Object categorization:
-Links with memory
Optic ataxia is impairment of visually guided reaching despite normal object recognition.
Impaired vision for action. What type of lesion would a patient have?
dorsal lesion
Visual agnosia (without knowledge) is impairments in object recognition/spared action vision also, impaired vision for color.What type of lesion would a patient have?
Ventral lesion
Brain regions selectively responding to faces
Fusiform Face Area
what do patients have difficulty with when there is damage to the Fusiform Face Area
recognizing faces
area that responses to body parts
EBA, extrastriate body area
area that responses to objects and shapes
LOC, lateral occipital complex, and IT, inferior temporal, cortex in general
area that responses to places
PPA, parahippocampal place area
area that responses to faces
FFA, fusiform face area; FFB, fusiform body area
Which of the following is a brain region that would likely be implicated in processing spatial relations in an outdoor scene?
the parahippocampal place area (PPA)
With regard to the two main output pathways from the occipital lobe, ________ is to ________ as dorsal is to ventral.
“where”; “what”
If you were to conduct a single-cell recording from a neuron in the MT region of the extrastriate visual cortex, you would probably find that the cell fires most vigorously to a
bar of light that moves across the cell’s receptive field.
