Exam 2 Flashcards
perception = ___ + ___
sensation + prediction based on experience
our visual systems quickly and efficiently represent the world with limited ___ by making use of lots of past ___
limited information ; past experience
what we perceive is a ___ of what comes into our senses, guided (or biased) by what we have seen most often in our lifetime
construction
we have so much experience viewing ___ that our visual systems can sometimes lead us to perceive anything with many face-like features as being a face, at least momentarily
faces
the visual system develops over ___ to become efficient at classifying things commonly around you
childhood
photoreceptors that are sensitive to brightness
rods
photoreceptors that are sensitive to color
cones
the ___ is concentrated with cones
fovea
central fixation of the fovea
0 degrees
rods dominate ___
peripheral vision
pathway to cortex:
- retinal input
- ‘crosses over’ at the chiasm
- left or right visual field is processed in the opposite lateral geniculate nucleus (LGN) of the thalamus and occipital cortex
the ___ is a “first order” thalamic nucleus
lateral geniculate nucleus (LGN)
the right visual field is processed solely in the ___ primary visual cortex (V1), and vice versa
right visual field - left primary visual cortex
left visual field - right primary visual cortex
the lateral geniculate nucleus (LGN) is a component of which part of the brain?
thalamus
the LGN of the thalamus transfers retinal input to ___ in successive stages
V1
when transferring retinal input from the LGN to V1, first, a coarse “gist” of the scene is sent, followed by the fine details over the next ~___ms
~10 ms
slow, detailed (“specific”)
parvo
fast, coarse (“global”)
magno
the primary visual cortex (V1) is located along the ___ fissure
calcarine fissure
the primary visual cortex (V1) receives retinal input according to the ___ of the stimulus in the visual field
location
the ___ half of your visual field is routed to right V1
left
the ___ field areas are routed to the inferior back of V1
upper field areas
the ___ fixation point is routed to posterior V1
central fixation point
___ areas route to anterior V1
peripheral areas
for every degree of the visual field, separate clusters of V1 neurons are sensitive to different ___ (edges, contrast, brightness) of objects in that location
visual features
despite considerable differences in our left and right eye’s visual field, we see ___ image
one unified image
the mystery of binocular vision: each of our eyes sees a different view, yet the image we see is uniform
how is this “convergence” accomplished?
we haven’t figured it out exactly
why do we have two eyes? there is a consistent difference across prey/predator species in ___ vs. ___ processing
peripheral vs. depth processing
___ overlap in visual field (both eyes facing ___) gives a much better account of our distance to the object
wide overlap ; both eyes facing forward
prey eyes vs. predator eyes
prey eyes - stronger peripheral vision
lateral geniculate nucleus (LGN) directs left and right visual input to V1, but keeps track of which eye the retinal input came from in layer ___
layer 4
if we present conflicting information into each eye, our perception switches back and forth between the two
binocular rivalry
according to binocular rivalry, there must be some ___ and ___ between left and right eye input, reflecting ‘higher order’ (late visual cortex and prefrontal cortex) processes that bias our perception toward one stimulus
competition and choice
binocular rivalry task: when presented a happy face, a neutral face, or an unhappy face, people have a slightly greater likelihood of reporting an __ face than a ___ face
emotional face ; neutral face
the visual system converts the light at the retina into the basic properties of visual perception including: (5 components)
- lightness
- color
- depth
- size
- motion
___ qualities can be different from the physical properties of visual stimuli as measured by purely objective methods (ex. was the dress white and gold or blue and black?)
perceived
lightness is a ___ quality, while luminance is a ___ property of an object
perceived quality ; physical property
the ___ of an object is not directly related to the ___ of an object
lightness ; luminance
lightness could be described as a ___ value, dependent upon local ___ and prior ___
calculated value ; local context ; prior experience
our visual systems have not evolved to determine the “___” nature of stimuli, only what we need to manage
“true”
through infancy and early childhood (by ___ and ___) we learn what visual features are “correct” and use this information to interpret future scenes
trial and error
around what age do we learn what visual features are correct?
around age 3 or 4
a global distinction can be made between “___” and “___” visual pathways, although recent data suggests the streams are more mixed
“what” and “where” pathways
two pathways within the primary and extrastriate visual cortex:
where pathway and what pathway
where pathway - ___ stream
dorsal stream
analysis of motion and spatial relations within this pathway
where pathway
what pathway - ___ stream
vental stream
analysis of form and color within this pathway
what pathway
ventral visual cortex: early vs. late stage:
a rough distinction can be made between early visual (“___”) and later visual (“____”) processing regions
(“simple”) and (“complex categorical”)
which part of the brain is utilized during late stage?
inferior temporal (IT) visual cortex
which part of the brain is utilized during early/mid stage?
occipital visual cortex (V1, V2, V3…)
visual cortex - general locations:
this part of the brain is medial inferior temporal
parahippocampal gyrus
visual cortex - general locations:
this part of the brain is lateral inferior temporal
fusiform gyrus
visual cortex - general locations:
this part of the brain is referred to as the “transition area”
lateral occipital
visual cortex - general locations:
this area of the brain is middle temporal
area MT
early/mid stage of visual processing occurs within:
V1, V2, V3, V3a
‘early stage’ :
‘late stage’ :
‘early stage’ : V1, V2, V3
‘late stage’ : everything else
PPA refers to:
parahippocampal “place area”
FFA refers to:
fusiform “face area”
lots of fMRI and invasive data reveals that there are multiple ventral visual regions dedicated to the processing of ___ of things like faces, body parts, words, and others
categories
where is color perceived?
lesion data suggests that color perception depends on regions of ___ visual cortex, a late stage of visual processing
ventral visual cortex
patients with damage in the ventral visual cortex (stroke, tumor) often report a ___ loss of color vision, while other visual abilities remain intact
specific
depth cues
V1 activity at central fixation, representing a small object activates:
only V1 and V2
V1 activity at central fixation and periphery, representing a large object activates:
V1-5
the illusory effect in V1 depends on feedback from ___ brain regions
because fMRI reflects average activity over seconds of time, we can see this ___ effect in V1
later brain regions ; context effect
in the ___ (a type of monkey), the organization and timing of visual processing stages is relatively well known
macaque
visual information is integrated and resolved along the ventral pathway until task-driven decisions can be made in PFC around ~___ ms
~150 ms
the first stage of visual processing in V1 is purely ___ driven (“___”)
stimulus driven ; (“bottom up”)
the first stage of visual processing in V1 occurs up to around ~___ ms after cue onset
~50 ms
later V1 activity also reflects ___ from other brain regions (“___”), such as late visual cortex and prefrontal cortex
feedback ; (“top-down”)
later V1 activity occurs ~___ ms after onset
~100 ms
feedback biases perception:
~50 ms =
~50 ms = pure sensory
feedback biases perception:
~120 ms =
~120 ms = biased
perceptual priming:
one model of this process focuses on visual context, which has been shown to churn information in a repeating cycle of ___ and ___ waves
feedforward and feedback waves
…we argue that the ventral pathway is a ___ and highly ___ occipitotemporal network linking early visual areas and the anterior IT cortex (aIT) along multiple routes through which visual information is processed
recurrent and highly interactive
the ventral visual pathway is ___, ___
reentrant, nonlinear
“…anatomical evidence indicates that the ventral pathway is actually a complex network of feedforward and feedback projections, some of which are unidirectional (ex. non-reciprocal) feedback connections and others of which ___ intermediate areas, allowing direct communication between putative early and late stages of the hierarchy”
bypass
“visual information from ‘early’ stages of the central route can be transmitted to the most rostral temporal areas or ‘final’ visual processing stages without passing through the ___ areas of the central route”
intermediate
a reentrant, nonlinear explanation of the ventral visual pathway might explain how late-stage visual cortex could rapidly ___ early visual cortex
bias
visual cues for ___ and object ___ are so convincing because feedback from late-stage visual cortex seems to activate regions of V1 that represent larger objects (the peripheral visual field)
depth and object size
because fMRI reflects average activity over seconds of time, we can see this biasing effect in V1, ___ after the feedback has arrived
long after
the feedback to V1 is limited to basic features that V1 processes, like ___ and ___
luminance and size
explicit, clear awareness of a face is most strongly tied to ___ activity
FFA (fusiform face area)
is the FFA only specific to faces?
no ; the FFA shows plenty of activity for non-face stimuli too
in some studies, the FG is the ___ selective visual area
FG
according to gauthier’s ‘greeble’ study, FFA = ___, and is not a genetic module for faces
FFA = experience
auditory information, including speech and music, can be quite powerful
true or false: science has come up with a reasonable evolutionary purpose for music
false; despite lots of trying, science hasn’t come up with a reasonable evolutionary purpose for music
the ventromedial prefrontal cortex and nucleus accumbens are referred to as the ___
reward circuit
the reward circuit runs on ___
dopamine
olds and milner (1954) demonstrated (accidentally) that a rat given the ability to self-stimulate the nucleus accumbens (NAcc) would continue to do so until ___ from thirst
death
what does NAcc stand for?
nucleus accumbens
in human fMRI studies, ___ rewards (ex. chocolate, cocaine) and ___ rewards (money) will drive reward circuit activity, including subcortical nucleus accumbens (NAcc) and ventromedial prefrontal cortex (mPFC)
primary rewards and secondary rewards
___ is a powerful driver of NAcc activity
methamphetamine (as well as all drugs of abuse and gambling)
___ music activates nucleus accumbens (vs. neutral)
pleasant (your favorite music)
___ binding = more dopamine release
less binding
are pure tones rare or common in the real world?
rare (most natural sounds are combinations of many different frequencies)
a recent meta-analysis of 47 fMRI studies of music (n=997) found that pleasant music enhances activity in reward (NAcc) and basic emotion regions (amygdala), along with increases in auditory cortex
is it clear how music became linked to this basic reward system?
no; how music became linked to this basic reward system is unclear
instruments produce sounds that contain multiple ___ (or timbre) which we use to help us discriminate between different sound sources, like a piano vs. a flute
harmonics
the upper harmonics are a doubling of the ___ (___) frequency
fundamental (lowest) frequency
with each harmonic, the energy is ___, until it dies out around the ___th or so
reduced ; 10th
fundamental frequency is always the same: ___ Hz
440 Hz
does the strength of upper harmonics remain the same or vary?
varies widely
our auditory systems keep track of all of these simultaneous frequencies by converting sound pressure variation to neuronal input via the ___
cochlea
this device contains ~48 artificial excitation points in cochlea can be enough for people to decipher speech and other complex sounds
cochlear implant
the auditory system enables selective filtering of input at the level of the ___, allowing us to focus on frequencies of interest in the moment
cochlea
from the cochlea, frequencies are sent to the ___
primary auditory cortex (A1)
sounds are ordered by ___ within A1 (like a piano)
frequency
our auditory system is hyper-sensitive in the ___-___ range
2-5K range
specialization of the auditory system may have evolved recently, adding sensitivity about ~___KHz
~3.5 KHz
the auditory system includes two subcortical circuits to ___ low (<3 Hz) and high (>3 Hz) frequency sounds
localize
is our ability to localize sound good?
no
are humans more dependent on visual or auditory input?
visual
how does the somatosensory system work? is it clear or unclear?
unclear ; we know the parts involved, but not how they really work together in real time
located along the back edge of the frontal lobe (M1) and the front edge of the parietal lobe (S1), separated by the central sulcus
location of the primary somatosensory and primary motor cortex
The ___ of SS cortex involved depends on the need for fine control and sensitivity
volume
do your eyelids occupy about the same volume of the SS cortex as do your legs? more or less?
about the same
the primary sensory cortex (S1) includes three subtypes of physical sensation from the body:
- touch
- temperature/pain
- joint/muscle position sense
different types of sensory information are channeled through three parallel pathways in the ___ and ___, ultimately feeding into the same section of S1 representing that body part
spinal cord and brainstem
the first modality of the touch subtype of the primary sensory cortex (S1)
discriminative touch (DT)
discriminative touch includes 3 categories:
touch, pressure, and vibration perception
free nerve endings =
pain
meissner corpuscles =
slow vibration
ruffini endings =
compression
pacinian corpuscles =
rapid vibration
temperature/pain includes the sensation of ___ and ___ across the body
itch and tickle
___ nerve stimulation from pepper, ammonia, tear gas also falls under this group
trigeminal
___ stimulation in mouth, nose, and eyes = pain
noxious
when you put hot sauce in your food, you are not adding taste or improving the flavor, you are adding ___, as you are stimulating the trigeminal nerve
pain
___ and ___ are critical for tickle
intensity and duration
joint muscle position sense is described by
proprioception
joint muscle position sense (proprioception) includes receptors for muscle ___, joint ___, and tendon ___
muscle stretch, joint position, and tendon tension
this modality (joint muscle position sense - proprioception) feeds into the ___, which processes real-time feedback regarding the orientation of the body
cerebellum
___ is susceptible to alcohol
proprioception
somatosensory representation in the cortex is ___ (it expands and contracts with experience)
dynamic
throughout childhood, our common actions became ‘packaged’ into functional units in ___
M1 (primary motor cortex)
in an animal model, complex multi-joint movements can be evoked by stimulation at a ___ location on primary motor cortex
single location
M1 codes ___, not single muscles
actions
many of our common motor behaviors are “___”
-we combine motor scheme so we can walk, look at our phone, and eat at the same time
automated
example of a motor expectation
walking into the kitchen to put the milk and cereal box away (you know the general direction to walk into the kitchen, but you put the cereal in the fridge, and the milk in the pantry)
locomotor behaviors are even more ___
-once begun, major transitions in locomotion pattern can be managed outside of our awareness
packaged
does awareness make major transitions in locomotion pattern better or worse?
worse
animal research shows that the ___ alone can manage transitions in locomotor behaviors via what has been called ___ (CPG) without any input from the brain
spinal cord ; central pattern generators
does controlled motor behavior require little or enormous preparation and on/off timing before M1 becomes involved to execute the action?
enormous
this part of the brain manages the preparation for action in response to external cues
premotor cortex
premotor cortex activity ___ primary motor cortex activity
precede
premotor cortex activity ___ when overt movement begins (or is aborted)
ceases
in superior medial frontal cortex, and feeds into premotor cortex
supplementary motor cortex
does the supplementary motor cortex manage well-learned movements, with or without need for explicit sensory cues?
without
does an action actually have to happen to evoke supplementary motor area (SMA) activity?
no; simply imagining that you are riding a bike will evoke SMA activity (the action does not have to actually happen)
SMA (and cerebellum) is strongly active during ___ actions, even when action is clearly impossible
-___ feedback is unnecessary
imagined ; sensory feedback
motor preparation occupies a large chunk of cortex, mostly located on surface ___
gyri
___ exploit this large premotor signal to communicate with “locked in” patients
brain-computer interfaces
to finely control the exact onset and offset of a movement, the ___ serves as a “gate” between premotor and motor cortex
basal ganglia
this part of the brain prepares and plans motor behavior
premotor cortex
the start and stop of motor behavior (“gating”)
basal ganglia
the execution of the motor behavior occurs in which part of the brain?
primary motor cortex
which part of the brain ensures that the action goes “according to plan”
cerebellum
cerebellum: movement “___” in real time
“tuning”
the cerebellum serves to ___ and ___ the balance of sensory-motor integration during a movement
coordinate and refine
cerebellum makes up ___% of total brain volume, but makes up almost ___% of neurons in the brain
10% ; 50%
this part of the brain is thought to be a huge ‘data processor’ crunching numbers to adjust motor output based on sensory feedback, thus enabling precise motor control in changing contexts
cerebellum
true or false: human brains have an oversized cortex
true; other mammals have nearly equivalent sized cortex and cerebellum
a quick neurological test of cerebellar integrity
moving your finger directly between your nose and a fixed point in space
the ___ pathways of the cerebellum are well defined, but real-time function is not
structural
the cerebellum receives huge amounts of input from the cortex (frontal, parietal), spinal cord, and midbrain, and then some sort of comparison is made between ___ and ___ action
planned and actual
after a comparison is made between planned and actual action, ___ signals are sent from the cerebellum to motor thalamus to refine movement in almost real time
error correction signals
error correction signals are sent from the ___ to motor ___
cerebellum to motor thalamus
the cerebellum is also active during many ___ tasks, which was often ignored as “noise” in early fMRI studies
non-motor
true or false: inhibiting the cerebellum (but not other areas of the brain) slows down our ability to make predictable choices
true
which 3 behavior domains appear to be associated with the largest clusters of cerebellum activity?
language, music, and working memory
dynamic behaviors (language, music, working memory) involve the most significant ___ and ___ as the behavior takes place
prediction and adjustment
one idea about the cerebellum’s contribution to no motor tasks is that its huge processing power may have been “repurposed” to ___ what might happen in future behaviors
predict
which study illustrated the flexible nature of body ownership?
the rubber hand illusion
-when a semi-realistic false hand was placed within the subject’s view (with their real hand out of view) and both hands were stimulated, most subjects soon reported feeling ownership of the false hand, reacting defensively if the false hand was threatened
the nature of body ownership is ___
constructive
