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232 Cards in this Set

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Large, common (80% of all neurons) and have glutamate as a neurotransmitter, making them a major ecitatory component of the cortex
Pyramidal Neurons
branching structures that carry information from other neurons
dendrites
branching structure that carries information to other neurons and transmits an action potential
axon
where neurotransmitters are released, permitting signalling between neurons
synapse
a sudden change in the electrical properties of the neuron membrane in a axon
action potential
chemical signals that are released by one neuron and affect the properties of other neurons
neurotransmitters
Name the 6 layers in the cortex
molecular
external granular
external pyramidal
internal granular
internal pyramidal
multiform
speeds up conduction. blocks the normal Na+/ransfer and so the action potential jumps, via passive conduction, down the length of the axon at the points where this is absent
myelin
consists of neuronal cell bodies
consists of axons and support cells (glia).
support cells involved in tissue repair and in the formation of myelin
glia
carries waste metabolites, transfers some messenger signals and provides a protective cushion for the brain
ventricles
the most important commisure, a large white matter tract that connects the two hemispheres
corpus collosum
____ is divides the frontal lobe from the parietal lobe.
central sulcus
front
anterior/rostral
back
posterior/caudal
top
superior/dorsal
bottom
inferior/ventral
How is blood supplied to the brain?
-brain supplied by major arteries
How is deoxygenated blood removed from the brain?
-veins remove the deoxygenated blood
constitutes the axonal tracts running between brain regions. It can be visualized postmortem, also with Diffusion Weighted Imaging.
white matter
There are several major tract pathways of the brain (association tracts, commisures, and projection tracts). They are made up of___.
white matter
52 areas based on the relative districution of cell types across cortical layers
Broadmann's areas
regulating motor activity and programming and termination of action
basal ganglia
relates organism to it's enviornment based on current needs and the present siuation and previous experience
limbic system
main sensory relay station of the brain for all the senses
thalamus
body temp, hunger thirst, sex, regulation of endocrine functions (growth)
hypothalamus
grey matter nucleus that forms part of visual pathway
superior colliculi
grey matter nucleus that forms part of the auditory pathway
inferior colliculi
dexterity and smooth execution of movement
cerebellum
receives info from visual areas to control eye and body movement
pons
vital functions...breathing swallowing, heart rate, wake/sleep cycle
medulla oblongata
higher mental processes such as thinking percieving imagiving speaking acting and planning
cognition
bridging dicipline between cognitive science and cognitive psychology (one hand) and biology and neuroscience on the other
cognitive neuroscience
How is it that a physical substance can gfive rise to our feelings thoughts and emotions?
mind body problem
brain is made up of different kinds of substance even though they may interact
dualism
___ was a proponent of dualism.
Decarte
the belief that mind and brain are two levelsof description of the same thing
Dual aspect theory
beleif that mind based concepts will eventually be replaced by neuroscientific concepts
reductionism
___ believed that cognition was a product of the heart.
Aristotle
___ believed that mental processses resided in the ventricles of the brain
Galen
FAILED idea that individual difference in cognition can be mapped on the differences in skull shape.
-different regions of brain perform different functions
-size of different regions produces distortions of the skull which reflect personality
phrenology
___ came up the idea of phrenology
Gall and Spurzheim
different regions of the brain are pseicalized for different functions
functional specialization
made a case for functional specialization
specailized area for language in the brain
huge conceptual leap in mind/brain science
broca's area
Early experimental psychology ignores the____. (despite broca's findings)
brain
started as a neurologist and neurobiologist. saw many patients and based his observations on data from introspection and free association. developed the powerful enormously popular and infulential theory of psychoanalysis
Frued
Ian Pavlov
BF skinner
Behaviorism
the study of the brain-damaged patients to inform theories of normal cognition
cognitive neuropsychology
approach in which behavior is described in terms of a sequence of cognitive steps
information processing
later sages of processing can begin before earlier stages are complete
interactivity
the influence of later stages on the processing of earlier ones
top down processing
different information is processed at the same time
Parallel processing
computational models in which information processing occursusing many interconnected nodes
neural network models
the basic units of neural network models that are acivated in response to activity in other parts of the network
nodes
accurarcy with which one can measure when an event
temporal resolution
spatial resolution
the accuracy with which one can measure where an event (physiological change) is occuring.
According to ___ psychology could only become and objective science if it was based on observable behavior in test subjects.
Behaviorism
As mental events are not publicly observable, behaviorist psychologists avoided description of ___ or the ___ in their literature.
mental processes or the mind
Cognitive psychology accepts the use of ___ and generally rejects___ unlike Fruedianism
scientific method, introspection
It explicitly acknowledges the existence of ___ unlike behaviorism
internal mental state
-no exlicit symbol processing
-massively parallel
-distributed information
-modeled on the way brain might work
connectionism
In fMRI B0 is
the main field
In fMRI xyz are the
gradient coils
-close as possible to the head
-transmits and recieves radiofrequency signals (amt of energy)
-turned on/off during particular phases of the scanning process
the head coil
In magnetic resonance, protons have ___ and can be seen as ___.
spin, "little magnets"
When a uniform magnetic field is applied protons will ___ and have ____.
line up
net magnetization
H protons spin at an angle like a top then come back to the center...this is called
precession
Basic Mag Res physics: energy states
-a proton/magnet/bar can assume a low or high energy state and relative to the large magnetic field
-protons can be pushed to a high state with radiofrequency (RF) pulse
-when they fall back to low energy state, they emit RF energy
In MRI protons will experience a ___ in longitudinal direction.
net magnetization
Push some protons to ___ with ____RF pulse
higher state
transmitted
As protons precess back again, they will yield energy which is now ____ by the RF coil
recieved
contrast is the __________ between different quantities being measured in an imaging system
intensity difference
Good contrast is produced by ______ in the quantity being measured
small differences
How does MRI measure contrast?
-the rate of relaxation of the precessing hydrogen proton is governed by -
_____ and _____.

______ signals are affected by the ________ and chemistry.
longitudinal time constal T1
transverse time constant T2

t1 and t2
tissue molecular structure
We can collect a single MR image for an entire volue (brain) by systematically turning of the _______.
different gradient fields
_____ is the application of an RF pulse that exites a proton spins within one slice but has no effect on spins outside of the slice.
slice selection
The slice is defined on its ______, _______, and _______ by application of gradient coils
location orientation and thickness
_____ tells us about gray and white matter, CSF, tumors and other kinds of brain structure
structural imaging
______ tells us (indirectly) about the excitability of neurons in particular areas of the gray matter in relation ot the perosn's cognitive state
functional imaging
Normally, oxyegenated hemoglobin (hg) is converted to deoxygenated hg at ________.
constant rate
when neurons are active there is relative _____ in oxy hg and _______ in deoxy hg.

this provides the basis for ____.
increase oxy
decreased deoxy

contrast!!!
oxy hg is_______ while deoxy hg is _______. (which has a magnetic susceptibility 20% greater)
diamagnetic
paramagnetic
increased magnetic susceptibiility causes a reduced ____.
T2 relaxation time
If you see somthing scary (while in an fMRI) brain regions that process fear will change their local oxy/deoxy ration _______ than those who do not care about fear. This will produce_______.
more
contrast diff
_________ induces change in the BOLD signal.
Sensory stimulus
_____ is like a pixel in 3D.
voxel
How fMRI study is run
-need a representative sample of people
-scan each person on one or more occasion (session)
-within each session, scan separate runs (around 6 min) each
-each run consists of multiple scans (volumes (~1 per 2sec)
For ______ images can be used ot produce a contrast volume (eg fearful faces - neutral faces) this has one value at each voxel.
single subject
_______,volumes can be combine to produce a grand average (2 #'s: mean at each voxel and variance at each voxel).
accros subjects
At each voxel, mean/variance can be used to produce a__________.
t-statistic (for the group)
t-stat of all voxel...get some false + need to do correction
multiple comparisons problem
stimuli, eg happy v sad faces, can be ____ or presented randomly as _______.
blocked in time (30 sec/block)
events (mixed up)
If a particular voxel "cares" about happy or sad faces then one can predict....
how the fMRI signal will change in that voxel
One predicts the data by convolving the ______ with the time of the stimulus
hymodynamic response fuction
What can lesions studies show us that imaging studies can't?
-lesions studies establish *necessity*
-ie that a given brain region is necessary for a given cognitive function
-imaging can't do this
-imaging can show activation in a particular region, but it does not prove that that the brain region is essential (or necessary) for the task
ways of acquiring brain damage:
(explain each of these)
1.neurosurgery for epilepsy
2.stroke
3. traumatic brain injury
4. cancerous tumors
5.neurodegenerative disorders
1.chop out part of the brain
2.arteries constrict and burst...that part of the brain=dead
3. falling
4.remove part of the brain
5. huntington's disease
parkinson's disease
above the eyes and in front
orbitofrontal
if a patient or group of patients is/are impaired on task A but spared on task B this is called...
eg. patients may be fine at coping and drawing, but impaired at seeing left side of space
single dissociation
-task a uses more of the same brain region than task B
-so not the case that diff brain regions underlie the two tasks
task resource artefect
-patient or patients perform task A badly bc there was something about the task they didnt understand
-so poor performance on task A might not be related to damage to the region as such
-make sure patients have intact general intellectual functioning (match w control subj w IQ)
task demand arefact
two diff patients, or 2 diff groups of patients
-group 1 imapaired on task A, but not at B
-group 2 impaired at task B but not at A
-this is very powerful evidence
double dissociation
--task resource artefact uses this
prob's with single cases
-enormous variability btw people:hence to make strong claims about the relation between cognitive function and the brain we need to be able to generalize
-so we need a sample of patients drawn from the population and we need statistics
-if possible, group approach is preferred
in group study, three types of grouping
1. by syndrome (schizophrenia)
2. by symptom (imulsivity)
3. by anatomical lesion (Right frontal damage)
diaschisis
remote effects elsewhere, downstream effects
prob's with group study
-for syndromes : eg schizophrenia...poor characteritics of brain damage
-for studies based on anatomical lesions
-difficult to identify lesion (blast injury)
-non overlapping brain lesions
-diaschisis
(MRI helps all of these)
problem of nonoverlapping lesions
even if all the patients have damage in left frontal cortex the location of the lesion will be diff
-almost impossible to find patients iwth damage in same place
What are the 2 solutions to nonoverlapping lesions
1. single voxel lesion symptom mapping
-normalize each person's scan into standard space
-at each voxel, group patients into
a. damage=1 or damage=0
b. perform two sample t-test using behavior as dependent variable
2. the region of interest method
-for each subject
-normalize lesion image into standard space
-compute overlap w each region of interest
-across subjects correlate amt of damage to each region of interest with behavioral variable
2. region of interest method
rodents and monkeys/non human animal models
-suck out part of the brain
ablation via suction
rodents and monkeys/non human animal models
damage a particular area
excitotic lesions
rodents and monkeys/non human animal models
put probe in brain boost brain regions temorarily turn a region off for short period
infusions
probe measures activity
neurophysiological recording
neuroransmitter recording via probe
dialysis
advantages of rodent and monkey lesion models relative to humans
-within subjet design
-complete control
-histology- sacrifice model, slice brain, confirm lesion is where they think
disadvantages of rodent and monkey lesion models relative to humans
-ethical issues
-non-human special limits generality
...rodents can't think...plan..
noninvasive simulation of the brain caused by rapidly changing electrical current in a coil held over scalp
Transcranial magnetic stimulation
a surgical procedure in which the fibers of the corpus callosum are severed
split brain
if two tasks share the same neural/cognitive resource but one task uses it more then the damage to this reource will affect one task more than the other
task resource artefact
one task is performed worse than another bc the tastk is performed suboptimally but not bc some aspect of the task is comprimised
task demand artefact
two single dissociations that have a complementary profile of abilities
double dissociation
difficulties in spelling and writing
dysgrpahia
a cluster of diff symptoms that are believed t be relationed in some meaningful way
syndrome
swelling of the brain following an injury
oedema
discrete brain lesion can disrupt the fuctioning of distant brain regions that are structurally intact
diaschisis
if there is a decrement in performance associated with doing two things at once then it suggests that these two tasks share cognitive processes
dual task interference
internal surface of the eyes containing photoreceptors that convert light into neural signals
retina
a type of photorecpetor specialized for low levels of light intensity such as those found at night
rod cells
a type of photoreceptor specialized for high levels of light intensity, such as those found during the day and specialized for the detection of diff wavelengths
cone cells
the pt at which the optic nerve leaves the eye, there are no rods and cones present there
blind spot
first stage of the visual processing in the cortex, the region retains the spacial relationships found on the retina and combines simple visual features into mroe complex ones
primary visual cortex (V1)
in vision cells that respond to light in a particular orientation
simple cells
in vision cells that respond to light in aparticular orientation but do not respnd to single points of light
complex cells
in vision cells that respond to particular orientations and particular lengths
hypercomplex cells
a failure to detect a sudden change in the visual scene
change blindness
cortical blindness resticted to one half of the visual field (associated with damgage to the primary visual cortex in one hemisphere)
hemianopia
cortical blindness resticted to a quarter of the visual field
quadrantanopia
a small region of cortical blindness
scotoma
a symptom in which the patient reports not being able to consciously see stimuli in a particular region but can nevertheless perform visual discrimations accurately
blindsight
region of the extra striate associated with color
v4
a failure to perceive color (world appears in greyscale) not to be confused with colorblindness
achromatopsia
a failure to perceive visual motion
akinetopsia
the color of a surface is percieved as constant even when illuminated in diff light conditions
color constantcy
the ability to detect wherther a stiumulus is animate or not from movement cues alone
biolgical motion
a memory representation of the three dimensional structure of objects
structural descriptions
a failure to understand the meaning of objects due to a deficit a the level of object perception
apperceptive agnosia
a failure to understand the meaning of objects due to deficit at the level of sematic memory
associative agnosia
LGN made up of __ layers
6
______ have concentric receptive fields with either on-center off surround or off center on surround.
LGN
In LGN When light covers both center and surround there is...
no change
on center off surround cells fire rapidly when light is ______ region but not when ____.
on the center
light is on surround region.
receptive fields of the striate V1 are _______
NOT CIRCLES
but elongated (stripes bars lines)
T or F... a v1 cell will respond to any line
FALSE... v1 cells show orientation tuning...cell is tuned to detect lines in a particular orientation
circular receptive fields of LGN are transformed into
elongated v1 receptive fields. multiple LGN cells line up and feed into a single v1 cell (simple cell)
everything in the visual scene is made up of
lines
complete damage to v1 leads to _______.
cortical blindness
loss of one eye or optic nerve of that eye results in....
blindness of that one eye...but other eye can still see both sides of space
when a subject can recieve visual info without awareness- it is typically because of
cortical damage
-amgydala activation to angry face even without awareness
ie. "blindsight"
earliest processes in vision gives rise to...
edges and orientations
later states group these elements into
higher order mechasnisms such as figure and ground
figures out what viewer centered descriptions mean
semantic system
grouping features into hiher order representations
gestalt psychology
the dog is not recognized by identifing its parts and then inferring the dog..the dog is percieved as a whole all at once
emergence
the experienced percept contains more explicit spaial info than the sensory stimulus on which it is based
reification
ambiguous perceptual experience pops back and forth unstably between two 2 or more alternative interpretations
multistability
objects are recognized independent of rotation translation and scale as well as elastic deformation
invariance
where does object recognition happen in the brain
-as info flows from v1 along the ventral visual pathway, more and more processing is done and the cells have larger and larger receptive fields
-we know that higher areas of occipital cortex and also the inferotemporal crtex are important because of:
patient work
neurophysiology
disorders of object recognition
agnosias
"Higher" (ie areas outside the occipital cortex) are important for
object recognition
people who can't name living objects
associative agnosia
people with this type of agnosia (HJA) would have difficulty with recognizing pics of objects..but can describe the parts.. integrating parts into wholes (Gesalt principles)
preserved copying and drawing, but couldnt tell you what he drew.. couldnt tell you if the object he drew was real or not
could draw an owl from memory
apperceptive agnosia
Infero-temporal neurons have ______ receptive fields
very large
Why is the "grandmother cell" hypothesis probably not true?
-seems unlikely that single cells could code for single objects
-instead multiple visual areas could code for diff features and these come togeher to ensemble
medial temporal lobe consists of three things
amgdala and hippocampus
parahippocampus
fusiform area
regions of the temporal cortex probably specific for
categories
-faces
-animate objects
-inanimate objects
In fMRI BOLD signal changes with
ratio of oxy/deoxy blood
-blood flow in a local region change siwth neural activity
-across time in a particular brain region one can measure how MR signal changes depending on if/when the subject saw a visual sitmulus
congential (@birth) prosapagnosics have _____FFA
smaller
From grebles experiement we can see that the FFA may just be...
not a "face area" but a configural expert processing area
similar to FFA there may be an area that specializes in recognizing places called
PPA parahippocampal place area
wound coil
placed over subject's head
current flows through the coil
generates mag field
induces current in underlying brain
alters brain funct
TMS transcranial magnetic stimulation
type of TMS: could faciitate or disrupt
single pulse
generally disruptive (rirtual lesion)
low fequency repetitive TMS (rtms) <1hz
generally facilitory...treatment for depression
high frequency rTMS >1 Hz
How do we control in tms
compare performance when stimulation is given in critical and non crital brain regions...
compare performace for same task on diff hemispheres
in tms structural and functional MRI can be used
frameless stereotaxy
in tms single pulses given to brain region __ task performance
during
excitability of corticaspinal tract monitored with
electromyography
if a brain area eg MT (V5) performs a citical function, TMS over the area may _____ performance
disrupt
if brain area eg v5 competes with another area the TMS over v5 may ______ performance
facilitate
advantages of TMS over organic lesions
1.less reorganization
2.can address timing of cognition
3. lesion is focal
4. lesion can be moved within participant
disadvantages of TMS over organic lesions
1. subcortex can't be studied
2. effects not always well understood...could be affecting remote regions or networks
-subject respnds fast to Go grials
-on some trials a stop signal occurs after the go signal
-main dependent variable is stop signal rxn time
stop signal paradigm
-900 pulses of TMS given at 1 hz to subjects before the main test
-low frequency technique is thought to depress cortical activity
-virtual lesion
-lasts ~30 min
-in L hemisphere it can produce speech arrest
low freq rTMS
R inferior frontal gyrus disruption affects
repsonse inhibition
demonstrates that attention can
operate on a spatial basis
• The cue summons attention to
a location
• On valid trials, processing at the
target location will be quicker,
relative to neutral
• On invalid trials it will be slower,
relative to neutral
The Posner orienting paradigm
The cue ‘captures’ the spotlight of attention and facilitates
processing at that location
• At delays of 300ms and above, the reverse pattern is found
• The spotlight may shift there, but if no target comes quickly, it
‘disengages’ - called
inhibition of return.
is “stimulus-driven
attention”, relates to arousal
and neurotransmitter
systems
• It interrupts current
processing, leading to
localization of cue or target in
space
Alerting
from a location
likely involves the parietal
cortex - as we’ll see soon
• If target does not appear at
cued location, attention may
move away, re-engaging with
a new location and perhaps
inhibiting the representation
of the old one
Disengaging
type of orienting that is alerting,
stimulus driven, bottom-up
• Measured by comparing
infrequent unattended targets
(invalid) vs. frequent attended
ones (valid)
Exogenous
type of orienting that is goal driven,
top-down
• Measured by contrasting cuedriven
attentional
engagement (valid) with noninformative
cue (neutral)
Endogenous
..... engages a ventral
frontoparietal network (right hemisphere)
Exogenous attention
......engages
a dorsal frontoparietal network (both
hemispheres)
Endogenous or top-down attention
.... typically associated with
working memory
Dorsolateral PFC
Perceptual features such as color and
orientation are coded in parallel PRIOR to
attention
• If the target does not share features it ‘pops
out’
• But if it does, then one needs to bring together
information about several features (color AND
orientation) = conjunction
• assumes that this occurs by allocating
spatial attention to the location of candidate
targets/objects
• If the object is not the target then the spotlight
moves on - this is a slow process
Feature Integration Theory
Evidence against feature integration
theory
FIT is an example of an early
selection model of attention
• It assumes that information is
selected at the level of individual
features
• But late selection theories
suggest that all incoming
information is processed up to
the level of meaning before
selection occurs
• The negative priming paradigm
is evidence for late selection
shows that attentional
process of distractor must have occurred up to the
level of semantic category, not just features
The negative priming paradigm
If there is a low perceptual load (just a few objects)
then subjects could process each object up to the
semantic level:
Late selection
But if there is a high perceptual, then this might be
impossible, and subjects revert to selecting at the
level of features:
Feature integration and early
selection
involves superior parietal lobe and dorsal frontal
cortex
– Could relate to memory circuits helping to modulate spatial
receptive fields
Top down attention
involves inferior parietal lobe and ventral frontal cortex
– Could relate to a circuit-braking function to stop current behavior
Alerting
can “boost” representations in fusiform face area
or hippocampal place area or other areas like V5, V4 etc.
Selective attention
Top-down attention, re-orienting,
endogenous
dorsal frontoparietal****
Bottom-up attention, stimulus driven,
alerting, exogenous,
ventral frontoparietal*****
Right temporo-parietal
damage gives....
left hemi-neglect
L hemiNeglect most likely produced by
damage to
right angular gyrus
Neglect: problem of low level
perception or attention?
not a low level problem
Neglect: problem of low level
perception or attention?
not low level
must be attention
T or F: Space is not represented in the brain as a single entity
true
T or F:Neglect can occur for spatial mental
images too
true
Bilateral parietal damage produces________
• Such patients only notice one object
at a time: ___________
Balint’s syndrome
simultanagnosia
The parietal lobe is large -
different parts may
represent different aspects of space!
Extinguished objects are
implicitly
remembered
a map of space coding relative to the position of the body
allocentric space
integrating information across sensory modialitities
cross-modal perception
a slowing of reaction time associated with going back to a perviously attended location
inhibition of return
attention that is externally guided by a stimulus
exogenous orienting
attention is guided by the goals of the periceiver
endogenous orienting
in non-lesioned brain there is over attention to the left side of space
pseudoneglect
if ignored object suddenly becomes the attended object the participants are slower at processing it
negative priming
a tendency to mislocalize heard sounds onto a seen source of potential sound
ventriloquist effecta variant of the visual search paradigm in which the patient must search for targets in a array normally striking them through as they are found
when presented with two stimuli at the same time (one in each hemisphere) then the stimulus on the opposite side of the lesion is not consciously percieved
extinction
a representational system for coding space
reference frames
test of spatial memory develped for rodents that requires learning and retaining the location of a hidden platform submerged in opague water
water maze
neurons that respond when an animal is in a particular location in allocentric space
place cells