Final (death) Flashcards
(139 cards)
1
Q
what are interlevel experiments used for?
A
to assess relevance to components and to integrate levels
2
Q
bottom up experiment
A
intervene in some aspect of the part and map what it does to the whole (excitatory or inhibitory)
3
Q
top down experiment
A
change behavior of whole zoom in and detect the parts (excitation)
4
Q
cognitive neuropsychology
A
aims to understand how the structure and function of the brain relates to specific psychological processes
5
Q
examples of how cog neuropsychology could be used
A
used psychiatric case-studies to make inferences about how healthy cog mechs work
use models of healthy cog mechs to draw inferences about mechs underlying disease
6
Q
lumping strategy
A
things that you think are unrelated are actually one thing (ex-breathing and rusting are both oxidation)
essentially strategy of association
7
Q
example of lumping strategy
A
boyer showed that ritualistic behavior shares qualities and have the same mechanism as the actions of people with OCD
8
Q
splitting strategy
A
dissociation
things you thought were all one sort of thing are not just one sort of thing
9
Q
example of splitting strategy
A
emotions dont really all hold together
(simple emotions cluster; social emotions cluster but they dont cluster with each other)
memory isn’t all the same-declarative and non-declarative memories are causally independent
10
Q
two branches of memory
A
declarative and non-declarative
they are causally independent
11
Q
declarative memory
A
explicit
breaks down into episodic and semantic (has a “that” clause) memories
12
Q
non-declarative memory
A
implicit
breaks down into priming, classical conditioning and motor skills
13
Q
association studies
A
lesion to single structure impairs performance on task A and B
infer mechanism for task A and mech for task B have either a component in common or both are causally dependent on a third thing
14
Q
the projection system
A
episodic memory and imagination of future are thought to be related
people who have deficits in ep mem also have deficits in imagining self in future
the thought is that maybe there is ONE cognitive system, a single projection system, that is responsible for both things
this is a lumping hypothesis
15
Q
problem with association
A
(or the lumping hypoth)
it may be hard to damage one part of brain without damaging another
i may be hard to damage JUST one cog faculty without damaging others so it could be that theres just more than one damaged thing
16
Q
single dissociation
A
subject S is impaired on task A but not taks B
infer that A requires some component (damage in S) that B does not
17
Q
Ex of single dissociation with KC
A
he can define words (generally), but cant remember or recognize what words he defined 3 minutes earlier
he has a digit span but once hes distracted the info is gone
there is therefore a single dissociation between semantic (which is intact) and episodic memory (which is gone)
18
Q
multi task dissociation
A
id a set of tasks on which subject succeeds (Ts)
ID set of tasks where the subject fails (Tf)
conjecture that some cognitive faculty is required for Tf but not Ts
19
Q
example of multi task dissociation with HM
A
declarative memory-
he fails at consciously recognizing facts and events (regardless of the type of test or material or sensory modality)
he succeeds at perceptual and motor skills, IQ tests, mirror drawing, priming, classical and operant conditioning and language
20
Q
KC
A
motorcycle accident that left him with severe memory probs
no new semantic memory
no episodic memory
Unlike other patients (patient HM, for example), KC has his semantic memory intact
21
Q
HM
A
had a bilateral medial temporal lobectomy to surgically resect the anterior two thirds of his hippocampi, parahippocampal cortices, entorhinal cortices, piriform cortices, and amygdalae in an attempt to cure his epilepsy
no semantic memory
able to complete tasks that require recall from short-term memory
no long-term episodic memory
22
Q
modularity
A
cognition composed of separable capacites-not just a homogenous jelly
23
Q
universality
A
all normal subjects share the same or similar cognitive architectures
24
Q
subtractivity
A
brain damage can impair or delete esisting components in the system but not add cognitive abilities
25
no de novo reorganization
not reorganization following brain damage in a way that masks or unmasks certain symptoms
26
transparency
one can easily infer the function of the independent processing unit from the pattern of impaired performance
27
limitations of using impaired/lesioned people
n=1
premorbid psych condition often unknown
psych eval is rarely clean
damaged in only one function? (doubtful)
28
capgras delusion
delusion that loved ones have been replaced with replicas (imposter syndrome)
and that homes have been replaced with replicas
self as an imposter
29
assumptions of dissociation
```
modularity
universality
subtractivity
no de novo reorganization
transparency
```
30
double dissociation
ability to do A without B exists
ability to do B without A also exists
leads to a more full conclusion that A and B are independent
31
resource problem single dissociation
if Task B requires more cognitive capacity that Task A and S can do task A but not B than the results could look like A and B are independent when in fact they may use the same cog system but B requires more cog ability
32
double dissociation with crossover
Task A: Patient S performs better than patient T
| Task B: Patient T performs better than Patient S
33
localization
Find the brain area or set of brain areas that are damaged in the case at hand; posit that the damaged area is responsible for the missing faculty
this goes back to GALL who believed in modularity
Broca later agreed saying language center is right behind the eyes
34
double dissociation without crossover
Patient S performs Task A better than Task B;
Patient T performs task B better than task A.
this is without crossover because patient S could be better than T on both
35
what happens with brocas apashia
this can happen from a stroke-there is speech comprehension but NO language prooduction
36
where is brocas area?
look it up
37
wernickes aphasia
no speech comprehension but TONS of language production-the words they say dont make sense
38
where is wernickes area
look it up but its toward the back of the brain
39
difficulties with localization
damage to one area or many? direct damage of diaschesis(-secondary effects of a primary lesion due to loss of connectivity or damage to the vasculature)
we can not know exactly where a cog function is developped
40
non-invasive lesions with TMS(benefits ad what it is)
TMS stands for transcranal magnetic stimulation
this is one solution to the difficulties with localization
current through a coil that makes a magnetic pulse which induces a magnetic field pulse
the changing mag field induces an Efield
E field induces current in the tissue which creates virtual patients
41
TMS problems
localization can be an issue, lateral spread of current and connection spread can be problems
no cell type receptor type specificity
can only hit surface level areas
inferential distance (models vs target)
42
how to target a location with TMS
use EEG electrode locations
guide with fMRI
deine area by its function
use control stimulation (the click of the machine during the pulse and a muscle twitces or whatever)
43
TMS compared to other lesion techniques (benefits)
```
humans
short duration
temporal control
more precision
moveable
theres recovery of function
valence
lon term study
As many people as you want (high N)
```
44
caramaza
responsible for noting the assumptions that dissociation studies have:
```
modularity
universality
subtractivity
no de novo reorganization
transparency
```
45
advantages using animal models in deficit studies
more control over location and extent of lesions
better pre and post mortem comparisons
n>1
more exacting controls
46
lesion techniques
1. Aspiration and Cauterization
2. Transection of Fiber Bundles
Corpus callosum.
Fornix.
White matter temporal stem.
3. Cooling
47
how might animal models fail
1) Overly Simple (Sensitization vs. Episodic)
2) Sample Bias (mice and genetics)
4) Inbreeding of Strains
5) Comparing Behavioral Tasks
Is it a simplified task? To what extent does it capture key features of the phenomenon? Does it presume idealized conditions?
How much training is required in target and model?
Is the task enviornmentally adequate?
Do we use the same or similar mechanisms to solve the same or similar tasks?
48
limitations of animal models
1. Indirect interference
Connecting fibers
Collateral damage
Diaschesis
Specific Cell/Receptor population
2. Compensation: Redundancy and Recovery.
3. Comparison:
Are humans and monkeys engaged in the same cognitive processes when they do the same task?
How do you decide, given inevitable differences?
4. LESION EXPERIMENTS ARE ONLY AS GOOD AS THE PSYCHOLOGICAL TASKS THAT GO WITH THEM.
Battery versus focused
49
timing of TMS stimulation
????
50
single unit recording (SUR)
top-down techinique
you engage the organism in behavior of interest
"method of measuring the electro-physiological responses of single neurons using a microelectrode system. When a neuron generates an action potential, the signal propagates down the neuron as a current which flows in and out of the cell through excitable membrane regions in the soma and axon. "-wikipedia
invasive
put electrode in brain
measures electrical activity in certain part of brain of a single neuron
we are measuring action potential
51
trilogy of techniques used in SUR
recording
stimulation within injecting current
inactivation of a whole bunch of neurons
52
how to do SUR
finding a cell-base w a grid, microdrive, microelectrode of metal or glass,oscillosocpe/audio amplifier
insert microelectrode/audio amplifier while behavior of interest taking place
tetrode-search of all or none amplitude of consistent shape
53
connectivity-orthodromic activation
the neuron recorded from it synaptically driven
54
antidromic actication
the neuron recorded is driven through its own axon
55
SUR vocab: prefferred stimulus
stim type that elicits the strongest effects on the activity of the neuron
56
SUR vocab-parametric variations
changing aspects of the stim so as to narrow down the neurons preferred stim and its physiological profile
57
sur vocab-receptive field
the region of sensory space within which stim presentations affect neuron activity
58
sink
????
59
wide dynamic range neuron
most populous type of those neurons whose cell bodies are located in the dorsal horn of the spinal cord
WDR neurons are responsive to all somatosensory modalities (thermal, chemical and mechanical) and a broad range of intensity of stimulation from peripheral nerves
They steadily increase their firing rate as the stimulus intensity rises into the noxious range.
There are, for example, wide dynamic range neurons that respond to benign stroking as well as to painful heat and mechanical damage in the cell's receptive field
60
lateral geniculate nucleus (LGN)
in the thalmus between neurons
relay center in the thalamus for the visual pathway
It receives a major sensory input from the retina.
The LGN is the main central connection for the optic nerve to the occipital lobe.
In humans, each LGN has six layers of neurons (grey matter) alternating with optic fibers (white matter).
61
who worked on the lateral geniculate nucleus and how
Hubel and wiesel doing SUR from cat neruons
62
lateral geniculate nucleus what was found
hubel and weisel found that LGN has an ON center and an OFF center using SUR on cat neurons
63
lateral geniculate nucleus ON center vs OFF center cells
the ON center is excited when illumination is in center of receptice field-inhibited with illlumination anywhere else
OFF center neurons-exact opposite pattern of illumination and activity
64
Hubel and Wiesel SUR from cat neurons
basically what they did is prevent movement of a cat's head and had illumination and tracked the action potentials as they moved the illumination
they tracked the action potentials of simple cortical cells, complex cells
and hyper-complex cells
65
simple cortical cell tracking illumination
elongated receptive field of a certain orientation
66
complex cell function w/ illumintation
responsible for tracking the motion and orientation of the receptive field
67
hyper complex cell w illumintaion
responsible for tracking the size direction and motion of receptive field
68
what did we learn from hubel and wiesels SUR cat neuron study?
the system contains neurons with very different receptive fields and v different physiological profiles
neuron in the visual system have larger receptive fields and are responsive to more complex/abstract stim the further they are from the source of illumination
complex response characteristics and receptive fields of cells down stream can be understood as direct function of response characteristic and receptive fields of cells up-stream
69
advantages of SUR
```
looking at individual cells
looking at individual action potentials
direct measure of activity
connectivity of neurons
distribution of def cell typeds in the investigated region
```
etc etc
70
disadvantages of SUR
```
difficulty to do technically
ethically diffifult
cant be done in humans
only 1 cell-cog functions seem to involve 100s of neurons
purely correlational
```
etc etc
71
optogenetics
biological technique which involves the use of light to control cells in living tissue, typically neurons, that have been genetically modified to express light-sensitive ion channels
72
how to make brain light sensitive-(set up for optogenetics)
1) piece together genetic construct-promoter drives expression and gene encoding opsin (which is a light sensitive ion channel)
2) insert construct into virus
3) inject virus into animal brain-opsin is expressed in targeted neurons
4) insert optrode fibre optic cable plus electrod
5) laser light of specific wavelength opens ion channel in neurons
73
elevated plus maze
so its a giant plus shaped maze
one of the perpendicular intersecting linees of the plus has a wall, while the otherdoes
aka one part is enclose and one part isnt
74
elevated plus maze used in part to...
measure anxiety in rats
| less anxious rats are more willing to go to unenclosed platform-more anxious rats will tend to stay in the enclose part
75
optogenetics in action
since you made the neuron light sensitive, you can use light to drive a mouse to run around
rats explore non-enlclosed platform in elevated plus maze in amygdala which is thought to be responsible for anxiety
76
optogenetics vs pharmacology
optogenetics more specific b/c you can target specific cells-anything that you can distinguish can alone be targeted
optogenetics is very temporally precise because it "brings optical control to the temporal regime occupied by the fundamental building blocks of neural computation"
something about speed
optogenetics give fine grain and large range this means it has more control and more exacting controls
77
Valence def
valency of optogenetics
Can the intervention increase and decrease the value of the putative cause variable from its rest value?
optogenetics is bivalent
with optogenetics one can raise and lower the value of a variable and explore the space of possible switchpoints
78
advantages of optogenetics
```
Precision among variables
Physiological Relevance
Within variables
Range
Grain
Valence
Reversibility
High Level of Control
Efficacy
Dominance
Determinism
Repeatability
```
79
optogenetics and physiology
optogenetics is physiologically relevant because:
the intervention tech allows one to target variables that are relevant ot physiological function
set target to variables to to values in a range observed under physiological conditions
80
Modeler’s knowledge
looked at with TMS, lesion studies, SUR?
Central Problem: To understand physiological systems in normal conditions.
Central Exemplars: Hodgkin and Huxley: Kandel (aplysia)
Ideals of Explanation: Ability to Predict and Save Phenomena
Ideals of Justification: Ability to Predict and Save Phenomena
Aim of Science: To build empirically adequate models
Benchmarks of Success: Prediction, Coverage.
81
makers knowledge
looked at with optogenetics
Central Problem: To control brain function.
Central Exemplars: Optogenetic Manipulation, Genetic manipulation, BMI
Ideals of Explanation: Mechanics understanding
Ideals of Justification: Manipulation and control a direct test.
Aim of Science: The betterment of the human condition.
Benchmarks of success: Ability to solve problems: experimental, practical.
82
optogenetics as progress?
Making as Demonstration:
Viruses, genes, gene regulation, and ion channels (cf. Hacking)
Electrophysiology and anatomy (Looping the brain into our control).
Knowing how to control or tweak the brain without necessarily being able to model it (e.g., write down structural equations)
Maker’s Progress:
Increasing ability to control the brain and to make it subserviant to our will.
83
reversability and optogenetics
optogenetics is reversable
all in one organism not a control gorup
removes inference that experimental and control group are the same
compared to lesioning this is a dream
84
efficacy of intervention of optogenetics
v efficacious 90-95% efficacious
85
repeatability of optogenetics
v high
86
francis bacon
invented science
| wrote new atlantis
87
new atlantis
by francis bacon
sailors get stuck everyone is dying etc
boat takes them to new atlantis
this island has crazy shit-everyone gets healthy
very sciientific because there is hierarchical society of thought
bacon is therefore the one that thought of this hierarchy of science
88
the extended mind
by Andy Clark and David Chalmers
the mind is partly constituted by things outside the sull/brain/body-dynamic coupling
points:
1. if we carve things at the mind/world boundary we see a difference between Otto and Inga but by using 'belief' in a wider way we use something more natural--belief becomes more unified, deeper and more useful in explanation
2. epistemic action demands spread of epistemic credit dont get held up on the functional ins and outs-cog processes not all in the head
often cognition isn't just n unaided brain-the dynamic worldly combos are what is important
89
the extended mind characters
otto and inga
90
otto
character in the extended mind by andy clark and david chalmers
otto has alzheimers and writes down everything and can therefore function somewhat normally by referring to notes
91
inga
character in the extended mind by andy clark and david chalmers
just a regular person with a normally functioning memory-doesn't need to write everything down
92
active externalism
objects within the environment function as a part of the mind
argument presented in the extended mind thought experiment
external objects play a significant role in aiding cognitive processes, the mind and the environment act as a "coupled system".
mind is extended into the external world.
93
passive externalism
semantic features change but behavior does not
the world determines our thoughts about things?
example of twin earth...
this is flawed because its missing out on the conversation of meaning
94
twin earth thought experiment
?
95
implications of externalism
?
96
top down activation experiments
fMRI
PET
Single Unit Recording
EEG
97
fMRI what it detects
focus on BOLD signal
BOLD is blood oxygen level dependent
there is an increase in blood flow
and an increase in oxygenated hemoglobin
the activation is due to the stimulus
98
fMRI detecting BOLD signals how?
well the protons in the atomic nuclei of the blood cells have spin and polarity
the behavior of spin changes when oxygentation happens-fMRI can detect this
99
magnetic resonance neurons fMRI
before the fMRI the spins and orientation of neurons is unorganized
when you apply an external field they get organized and will change orientation so that their fields align
with the external field they are in the same phase of bold signal and have the same orientation
100
mag resonance as it applies when the field is no longer there
the neurons dephase (T2 imaging)
the neurons recover their longitudinal orientation (T1 imaging)
orientation (go back to being un organized)
101
when there is a higher oxy/deoxy ration in fMRI
there is slower dephasing
more synchroning in precession lasting longer
stronger radio signal because:
youre detecting the dendritic field potentials
indicative of the cells in that area recieving input
102
T1
the neurons recover their longitudinal orientation in fMRI after external field is turned off
103
T2
the neurons dephase after the external field goes away in fMRI
104
PET
measures blood flow in the brain.
injecting subject with a radioactive isotope (i.e. an unstable atom, usually a variation of oxygen that has a short-half life); this isotope will quickly decay
positron will collide with an electron and they will annihilate each other, sending two gamma ray particles in exactly opposite directions which are detected by detector around brain
many gamma rays emitted allow lines to be drawn
at the intersection of those lines is the radioactive isotope-allows for localization of blood flow?
105
PET vs fMRI
both measure blood flow in the brain
PET scans are advantageous in that a person does not have to remain as still as he or she would for the fMRI
resolution of the PET scans is lower.
fMRI’s can be done at many hospitals around the world with little or no extra cost because of the prevalence of MRI scanners
PET scans need radioactive isotopes to work. This isotope can be given only a few times before it is unsafe
106
subtraction technique
finds parts of the brain unique to one task by subtraction
task 1 needs X-->Y-->Z
task 2 needs X-->Z
Y is unique to task 1 and not 2
107
assumptions of subtraction
Decompositional Validity
Decompositions are theories. Correct?
Specificity
The performance of a task places specific demands on specific brain regions.
Activity
Cognitive Demands are Met by Changes in Neural Activity.
Additivity
Do brain regions do the same thing in different task contexts?
108
petersen et al what did they do
study of language processing
it was a lexical access experiment
used PET
essentially studied lang prcessing by having subjects do a passive task, repeat a word and generating vocab
109
methods of petersen et al language processsing study
cognitve operations:
sensory prcessing, word level coding-in this section the controls fixated on a point while the experimental group passively viewed/listened to words
for articulatory coding and motor output--the control group told to passively view/ listen to words while the experimental group read aloud/repeat words
for semantic association--the control group read words while the experimental group told to generate verbs
110
results of petersen et al language processing study for the passive task
for the passive task-activation in Visual cortex. (Visual word codes) activation in Auditory and temporo-parietal, including Wernicke. (Phonological codes)
111
results of petersen et al language processing study for repeat word
activation in Inferior pre-motor cortex, Cerebellum
Activation of Wernicke’s area (only in auditory version of the task)
In visual version, Wernicke’s area is by-passed.
No activation in Broca’s area
112
results petersen et al language processing study for generate verb
Left frontal areas (incl. Broca)
Left posterior temporal
Activation in Wernicke’s area in auditory version of task.
But there is activation close to it in visual version of the task.
113
assumptions made before fMRI or PET can be done
decpositional validity
specificity of brain region
activity (there is activity when there is cognitive demands met)
additivity
114
geschwind model
Visual and auditory codes (sensory cortices)
- ->Semantic codes (Wernicke’s area)
- ->Articulatory codes (Broca’s area)
- ->Motor ouput (Motor cortex)
115
is imaging correlational or causal
correlational
116
strengths of imaging
Non-invasive
No diaschesis/indirect damage and healing/compensation
3d view of whole brain
Medical Relevance even if functional mapping has problems
117
limitations of imaging
```
Spatial resolution
Temporal resolution
BOLD signal is indirect
Mapping across brains
Complexity of statistical interpretation
```
118
limitation of imaging-mapping across the brain
we use the Talairach atlast which is essentially a grid
119
limitation of imaging-statistical interpretation
```
Distinguish voxels within slice
Brain Mapping
Movement Artifacts
Latency Correction
Filter Noise
Locate region of interest
Tests for significance
```
these are all the steps between raw data and final image
120
network analysis
Mathematics of pairwise relations.
Classification of kinds of networks.
Concepts for describing network organization.
Mathematics for proving formal results about networks (e.g. vulnerability)
Algorithms for detecting/discovering network properties.
121
network models are...
1. Very general
Can be applied to any kind of relation, and kind of network
2. Very abstract
Only tell you the network structure
122
nodes and edges
nodes are the things or concepts or whatever-edges connect the nodes
123
node degree
the number of nodes one node is connected to
124
hub
connects modules of nodes
125
path length and distance
the number of edges needed to connect two nodes (can look at max or min)
126
clustering coefficients
the amount of clustering of nodes around one node
127
computing modularity
Modularity is a matter of degree
Typically measured as deviation from expected modularity in random networks.
But random networks tend to have some Simon near-decomposability as a matter of chance
128
sub-module
component with greater connection within itself that outside
cut things with weak connection between sub-module
129
applying network analysis to the brain
```
Discovering large-scale cortical networks
Carving the brain into parts
Comparing brains
Discovering new causal properties
Strengths and Limitations
```
130
resting state fMRI
looks at BOLD at rest
signals with peiods between 10 and 100 seconds which is v slow
determind correlation coefficients for each voxel pair
correlations will become edges in the network
rest is the task condition
these show signals may or may not have anything to do with rest cog activity
131
what is rest?
Rest is not a priveleged state.
Individual Differences may result from different sub-behavioral tasks
I’m mind-wandering
You’re doing math
Differences may result from state differences between subjects
E.g., people with autism fixate on tasks more and might be likely to move less in the scanner
Resting networks can differ from task networks
132
structural connectivity
physical connections
133
functional connectivity
NOT causal
| correlation in BOLD signals
134
effective connectivity
which structural connections are actually doing work
135
areal analysis
chunking in corse grain way
uses 264 brain regions
20mm spheres
gives the pearson correlation matrix of the brain
136
voxel-wise analysis
~15,000 voxels, each correlated with all the others.
| Not task related at all
137
areal vs voxel-wise
get the same results with either method
138
modular density
number of unique modules within X mm of a voxel
speculated that higher modular density has a worse outcome of a lesion in that area-that makes sense
139
relationship between rs-fMRI and anatomy
Areas with anatomical connections tend to show functional connectivity.
Primary hand representations fluctuate with midline motor structures and to hand areas of the cerebellum.
Damage to anatomical connections disrupts functional connectivity.
Corpus callosum lesions disrupt interhemesiphereic coupling.
BUT-
They are just correlations in BOLD
V1-V1 connections without interhemisphereic synapses
Preserved interhemispheric coupling in people born without a corpus callosum
