Midterm Flashcards
golgi stain
silver nitrate staining of cells
Dendrites, as well as the cell soma, are clearly stained in brown and black and can be followed in their entire length, which allowed neuroanatomists to track connections between neurons and to make visible the complex networking structure of many parts of the brain and spinal cord
impregnating fixed nervous tissue with potassium dichromate and silver nitrate
only stains 1/10 of neurons
stains a limited number of cells at random
neuron doctrine
1917
Ramon y Cajal
It’s a list of important discoveries
• Neurons as individual non-continuous pieces
• The collateral and terminal ramifications of all axis-cylinders [axons] end in the grey matter
• the body and dendrites of the nerve cells, establishing a contact or articulation [synapses] between the receptor protoplasm [dendrites] and the final, tiny axonic branches
• the body and the protoplasmic processes participate in the chain of conduction, that is, that they receive and propagate the nervous impulse
• the nervous impulse is transmitted by contact, as in the articulations of electrical conductors, or by a kind of induction, as with induction coils
action potential definition
change in potential across the membrane of a cell
all or nothing
Rapid depolarization with inward current (Na+). Turning off inward current (Na+) Turning on outward current (K+) Refractory Period Return to Rest
seem to be responsible for thoughts, beliefs etc.
action potential mechanism
at resting phase all channels are closed
when voltage of cell is changing after certain threshold channel will open
–>chain reaction-other channels open
cell changes into certain conformation–>voltage change
this is a voltage dependent process
once enough Na+ is in the cell the na+ will sotp, the K+ channel will open and K+ will diffuse out of cell
central forces in action potential mechanism
flow of current through electrical circuit
diffusions
electrical attraction and repulsion
corpuscular view
Descartes and Borelli in 17thC
Nerves are hollow tubes
They carry “animal spirits.”
Vital spirits inflate muscles.
Muscles tug on bones.
swammerdam
Put frog muscle (b) in water in a syringe (a)
Stimulate (c) nerve to cause muscle to contract
Monitor movement of fluid (e)
No change in volume!
this means that contraction could not be a consequence of inflow of nervous fluid.
and that stim of nerve doesn’t cause the muscle to physically contract/expand
galvani
Electrical stimulation of the nerve causes muscular contraction
Severing the nerve prevents the contraction.
Laying the nerves across one another restores the contraction.
So it’s a kind of “animal electricity” but the “electricity” does not propagate instantaneously the way actual electricity does
squid giant axon
The action potential goes beyond zero; the cell becomes positive.
Not membrane breakdown (negates Bernstein’s theory)
Coordinated ionic fluxes combine.
bernstein’s membrane breakdown theory
Uses Differential rheotome to get “snapshots” of the passing negative variation (1868)
Membrane theory: The resting potential is explained by different ionic concentrations inside and outside the cell.
The “action potential” is a temporary but complete breakdown of the membrane.
later disproved by squid giant axon
rest potential
-70mV is the rest potential voltage (voltage differece of outside cell and inside cell)
equilibrium potential vs rest potential value comparison
eqm potential for Na+»_space;rest potential voltage
eqm potential for K+
equilibrium potential
the value of the membrane potential at the electrochemical equilibrium for a particular ion
an ion will be in electrochemical eqm if V(membrane)=V(ion)
voltage clamp does what?
allows you to assess the value of the conductance to different ions across the membrane at different voltages if we hold them constant
results from the voltage clamp
Note rapid time course of Na+ conductance change
Note delayed and prolonged effect on K+ conductance.
hodgkin and huxley’s question
Could voltage-dependent changes in membrane conductance to Na+ and K+ explain the action potential?
how can hodgkin and huxley go about answering their question: Could voltage-dependent changes in membrane conductance to Na+ and K+ explain the action potential?
: Construct a model that accurately describes all the relevant variables and their mathematical relations to one another and show that the features of the action potential follow from that
aka assume it does and use the math that would be required in this assumption and see if it follow (i think)
findings of Hodgkin and Huxley on whether voltage-dependnent changes in membrane conductance to Na+ and K+ explains action potential
Hodgkin and Huxley explain action potentials in terms of known conductance changes.
But they had only a phenomenal model of the conductance changes.
They can model this magic; but they can’t explain HOW it works.
sympathetic nervous systems
active in emergency situations
dilates pupils makes heart beat stronger and faster relaxes airways letting you breathe more deeply inhibits digestion increases blood flow to skeletal muscles
in emergency situations you ___ nervous system is active
when your body is at rest your ___ nervous system is active
sympathetic nervous system when in emergency situations
parasympathetic nervous system when body is at rest
parasympathetic nervous system
active when body is at rest
it constricts pupils makes heart beat more slowly constricts airways stimulates digestion reduces blood flow to skeletal muscles
quantal release
communication between neurons is made up of quantum packets
packets of neurotransmitters
vesicles go to wall of neuron
each quantum gives the same post synaptic response (quantal amplitude)
one vesicle=one quanta
m=np (this means that the mean quantal content=number of vesicles/quanta multiplied by the probability of release)
freeze fracture technique
neuromuscular junction is stimulated
this causes it to relase stuff
freeze at this point
then fracture it
this gives you the number of vesicles fusing at that instance and the number of quanta released
when graphed you get a 1:1 line of vesicles fused and quanta released
main categories of neurotransmitters
acetylcholine (most active at the neuromuscular junction)
biogenic amines
Amino acids
neuropeptides
simple non-associative learning
there are 2 types:
Habituation: relatively persistent waning of a response to a stimulus with repeated stimulation.
Sensitization: the enhancement of a response to a stimulus when it is noxious or paired with a noxious stimulus.
habituation
relatively persistent waning of a response to a stimulus with repeated stimulation
ex: the aplysia starting to freak out less and less when you poke it as you poke it more and more
Sensitization:
the enhancement of a response to a stimulus when it is noxious or paired with a noxious stimulus
like when you don’t notice something at first and then it gradually starts to piss you off–you become sensitive to it
neuromuscular junction
chemical synapse formed by the contact between a motor neuron and a muscle fiber. It is at the neuromuscular junction that a motor neuron is able to transmit a signal to the muscle fiber, causing muscle contraction
ACh is most active at the neuromuscular junction
basic reflex of aplysia
when scared, it freaks out and sucks everything in and releases ink
experiment with the aplysia
they don’t have many neurons so they thought they may be able to figure something out here
they scared the aplysia by squirting water at it, and kept doing this until habituation happened (aka when the aplysia started to freak out less and less)
do aplysia have brains?
basically aplysia have abdominal ganglion which is sort of like a brain but its really just a collection of nerve
the abdominal ganglion is responsible for the fear response
aplysia (experiment results)
when you scare the aplysia the sensory neuron is activated–> leads to the activation of the motor neuron which causes the aplysia’s gill to retract
when you keep scaring it the sensory neuron is still stimulated but the motor neuron gets less and less responsive to sensory neuron
abdominal ganglion in the aplysia is responsible for:
Gill and siphon movement Control of heart rate and respiration Release of ink Release of reproductive hormones Egg Laying Cells we are concerned with work on glutamate and gabba.
Otto Loewi experiment title and question
parasympathetic innervation of the heart
how does the vagus nerve (which is associated with the parasympathetic innervation of the heart) physically slow the heart down?
otto loewi experiment procedure (parasympathetic innervation of the heart), background info for experiment, and results
parasympathetic is when body is at rest
the heart generally slows heart beat down
innervation means to supply with nerves or to stimulate to action
vagus nerve that is associated with the parasympathetic innervaton
when stimulated it slows the heart down
procedure:
he put a heart in a beaker of fluid and stimulated the vagus nerve
mechanism for slowing down the heart beat involves a chemical reaction, then the chemical composition of the water will change
the water of first beaker is pumped into a second beaker with a different heart
if the heartbeat of the second heart slows down as the fluid from the stimulated heart is pumped onto it then it means that the mechanism is chemical and NOT electuric
results:
the heartbeat slowed down so the mechanism is chemical and NOT ELECTRIC
cell doctrine
Sensory consciousness is unitary.
Separate sensory mechanisms cannot give rise to a unitary consciousness
There must exist some single mechanism in which all senses converge
consciousness is unified
anterior commisure
The anterior commissure (also known as the precommissure) is a bundle of nerve fibers (white matter), connecting the two temporal lobes of the cerebral hemispheres across the midline, and placed in front of the columns of the fornix. The great majority of fibers connecting the two hemispheres travel through the corpus callosum, which is over 10 times larger than the anterior commissure, and other routes of communication pass through the hippocampal commissure or, indirectly, via subcortical connections
a MAJOR interhemispheric connection
Transfer of learning in split brain cats?
myers and sperry
they taught one side of the brain one thing and looked to see if the other side knows
the task was to hit a bar with a square while right eye is covered then see what happens when you move the patch to the other eye
results:
normal cats will know what it learned from one side of the brain with the other side of the brain
severed optic chiasm; normal–the information is probably getting to other side of brain through a different route than the optic chiasm
severed Corpus collosum and optic chiasm: these cats cannot transfer learned info from one side of brain to the other side of the brain
early split brain research
1. Perceptual Lateralization: Target sensory input to one half of the brain and not the other: Touch Smell Tachistoscope Chiasm 2. Response Control: Lateralization of response Handedness Speech
split brain and materialism
On the one hand; seem to get a divided person.
On the other, they seem to exhibit unified behavior.
Inconsistent triad (Schechter, forthcoming)
A split brain subject has two minds
A split brain subject is one person.
Each person has one mind.
myasthania gravis
Auto-immune response
Antibodies attack Ach receptors
Anticholinesterases reduce (but do not eliminate symptoms).
gould’s argument
strong critique of biological determinism (shared behavioral norms, and the social and economic differences between human groups— primarily races, classes, and sexes,— arise from inherited inborn distinctions and that society, in this sense, is an accurate reflection of biology)
critiques morton and broca
doesn’t think race class and sex are rooted in biology
he disputes the idea that biology and genes have anything to do with behavior which is perhaps an over emphasis of his message
BUT, One can accept his critique of Morton and Broca, and the primary lessons of his book, without abandoning the ideas that genes are causally implicated in behavior
Morton
talks shit on eskimos
did study of measuring cranial capacity with seed/shot
found that ethiopians have the smallest cranial volume
this experiment was done very very poorly so it is not taken to be true
this is implicit bias not conscious fraud
redoes his experiment with shot (originally with seed) and this is what created the discrepancy in volume
great chain of being
everything has some place in the hierarchy of life
some people are better than others (some races are better than others)
hypothesis myopia
collecitng evidence to support hypothesis not looking for evidence against it
texas sharpshooter
seizing on random findings and presenting as significant
mishandling samples in Crania americana
samples from different groups SHOULD be equal or weighted to account for group differences
Morton did not do this
unconscious bias
choosing one set of data because it fits your preconceived notion better but not realizing youre doing this
just-so stories
occured for broca
when you determine a method to be bad purely because it disproves your hypothesis
finding stories after the fact to rationalize whatever the results turnout to be
asymmetric attention
rigorously testing unexpected results but giving expected ones a free pass
basic cortical facts
10-15 billion neurons in the brain (cerebral cortex)
info transfer is by neurons
50 billion glia (support cells–non info transfer)
nissl stain
uses basic dyes to stain negatively charged RNA blue
used to highlight structural features
weigert stain
stains myelin deep blue
shows axonal pathways
laminar architecture of cortex
different organiazation of cells in dif parts of brain
found this out using staining techniques
molecular layer architecture (layer1 )
processes of cells
axons passing thru
dendrites of deeper cells
external granule cell layer (layer 2)
composed mainly of small spherical granulae cells
layer 3 external pyramidal cell layer
contains pyramidal cells in rows
layer 4 internal granule cell layer
densely packed stellate cells
main target of sensory input from thalmus
main target of all feed forward projections
there is no layer 4 in primary motor cortex
layer 5 internal pyramidal cell layer
large pyramidal neurons
feedback originates in deeper layers and terminate in layers 1 and 6
layer 6 multiform layer
heterogenous collection of cells
blends w/ white matter
broadman
used staining to deifine areas in 1909
categorized functional units
sometimes right sometimes nah
used laminar arch to map things
wallerian degeneration
over time if cell body is crushed then you can see degeneration
useful bc you can kill a cell and see where axons fall apart w staining
aka you can see where the cell projects
autoradiography
commandeer axonal transport to deliver dyes to the rest of the neuron
it doesn’t kill the cell and it doesn’t stain the fibers of a passage
dyes are only taken up by cell body
active connectome
more than just structures
measure all activity in all cells all at once rather than the connection of things you are looking at the activity level, action potential
they did this with calcium imaging
what question does this even answer though?
seung
i am my connectome
hypothesis is that it is solely this structure that makes and individual unique
does knowing everything about every neuron really communicate identity and personhood?
dennet’s where am i
in the body?
in the brain?
wherever dennett thinks he is?
the computer brain?
there is no unified dennet
dennett and seung together sameness of personhood and sameness of connectome
the conditions for the sameness of personhood are not the conditions for the sameness of connectome
a person is still a person if they remove a hemisphere
thought experiments
Thought Experiments are Arguments.
Arguments are used to test coherence of ideas by bringing ideas into tension with one another.
Neurophilosophy is the search for thought experiments in which one or more of the premises describe empirical findings
ROEDIGER MCDERMOTT DEESE TASK
meant to study false memory in people
youre told a bunch of words and then asked if lure word (word that fits in with group but was not presented) was said
people frequently falsely remember it being there
why do they falsely remember?
associative spread=sentation of associated words could spread activation through an associative network to the nonpresented lure word, and thus the false recognition of words could be due to residual activation
prototype theory, which claims that the presentation of patterns that match some prototype activates and increases the recognition of the prototype, even when it has never been presented
neither option explains this alone
mcgurk effect
perceptual phenomenon that demonstrates an interaction between hearing and vision in speech perception. The illusion occurs when the auditory component of one sound is paired with the visual component of another sound, leading to the perception of a third sound
reaction times of mental rotation task
Reaction time is linearly related to degree of rotation.
The best explanation is that we rotate a representation.
This also fits our perceptual experience.
Reaction times used to constrain lower-level mechanisms.
opperationalism
based on the intuition that we do not know the meaning of a concept unless we have a method of measurement for it. It is commonly considered a theory of meaning which states that “we mean by any concept nothing more than a set of operations; the concept is synonymous with the corresponding set of operations”
X has C iff (If test T is applied to X, then result R is achieved).
tolman maze
Spatial memory is not merely stim response learning; it involves the formation of a SPATIAL MAP
uses rats in mazes who form spatial maps
morris water maze
Pool for testing forms of spatial memory
Hidden maze
No problems with smell.
Factors: Vision Proprioception Working memory Attention Motor system Place learning Associative learning Reward-based learning (etc.)
Learn to swim Learn to swim toward platform Learn to swim away from walls Learn that escape is possible Learn to climb on platform Learn where the platform is in relation to distal cues Learn associations How to navigate the maze
problem with nomic measurement
We want to measure quantity X
Quantity X is not directly observable by unaided human perception so we infer it from another quantity Y, which is directly observable.
For this inference, we need a law that expresses X as a function of Y, x = f(y)
The form of this function f cannot be discovered or tested empirically, because we can’t measure X directly.
Q: How does this come up in the history of thermometry?
Q How might one apply this to brain imaging.
construct validity
the degree to which a test measures what it claims, or purports, to be measuring
Does the operational definition actually measure the construct you think it’s measuring and not some other construct?
Intelligence vs. Socio-economic status
Skull lumps vs. brain lumps.
external validity
External validity refers to the degree to which the results of an empirical investigation can be generalized to and across tasks, individuals, settings, and times
(like can it be generalized from One task to the next.
from the Sample to population.
from One species to another.
from One time to another)
theory of mind
emerges between 3-4 years old
Theory of mind is being able to infer the full range of mental states (beliefs, desires, intentions, emotions, etc.) that cause action. Having a theory of mind is to be able to reflect on the contents of one’s own and others’ minds.
we assume that others want, think, believe and the like, and thereby infer states that are not directly observable, using these states anticipatorily, to predict the behavior of others as well as our own. These inferences, which amount to a theory of mind, are to our knowledge, universal in human adults
why is theory of mind relevant to the everyday person?
Hypertrophy of human social cognition Ability to predict others’ behavior Capacity for Trust Capacities for forming alliances Standards of fairness/justice Interest in Gossip
smarties task
give kids a package that looks like smarties candy and they open it to find pencils are inside
ask them what they thought was in the box
what will your friend think is inside the box
this determines whether they have a theory of mind
looking time experiment
- Habituate to stimulus until looking time/ sucking hit baseline
- Introduce a change
- See if looking time/sucking changes
If yes, evidence of discrimination
If no, evidence of no discrimination.
Discrimination is not the same as understanding
Discrimination is not the same as “having the concept”
executive function
set of mental skills that help you get things done. These skills are controlled by an area of the brain called the frontal lobe. Executive function helps you: Manage time. Pay attention.
sally-ann task
sally (a doll) has marble and puts it in basket and walks away
ann (a doll) takes marble out of basket and puts it in a box
ask the kid where sally will look for the marble when she comes back
ask kid where the marble is now
where was it in the beginning
this also determines whether the kid has a theory of mind
most 3 year olds can’t do this
appearance reality task
Sponge/rock
E: What’s this?
C: A rock.
E: Are you sure? Here, try touching it? My gosh, it’s not really a rock, is it? What is it?
C: A sponge.
E: If your dad saw this sitting here, and he didn’t touch it like you did, what would your dad think this was?
(Pass the test if Child says dad will think it’s a rock; child says it’s actually a sponge)
ToM task
day/night stroop task
kid is told to say day when looking at a dark picture and say night when looking at a light daytime picure
expected response must be suppressed
this measures executive function
child needs to THINK about the answer in order to pass-the kid can’t just go on autopilot because their instincts must be suppressed
dimensional change card sort task
theirs a red bunny and blue boat and kids are first told to sort cards by shape (all colors of bunny go with bunny)
then told to do something else–sort cards by color (red bunnies and red boats go with the red bunny category)
little kids can do the first task successfully but can’t change do a different task
to be successful children need to be good at separating features (color and shape)
studies of support phenomena
Infants progress through the following developmental sequence:
By 3 months of age, infants expect the box to fall if it loses all contact with the platform. Any contact is sufficient. Between 3 and 6.5 months, two developments take place: 1) Awareness that type of contact matters (eg contact on side vs contact underneath) 2) Awareness that amount of contact matters (hanging over edge of support but still supported vs barely touching support at all)
chomsky and language
poverty of stimulus argument
some of languange is innate
poverty of stimulus argument
There are patterns in all natural languages that cannot be learned by children using positive evidence alone.
Positive evidence is the set of grammatical sentences that the language learner has access to, as a result of observing the speech of others.
Negative evidence, on the other hand, is the evidence available to the language learner about what is not grammatical. For instance, when a parent corrects a child’s speech, the child acquires negative evidence.
Children are only ever presented with positive evidence for these particular patterns. For example, they only hear others speaking using sentences that are “right”, not those that are “wrong”.
Children do learn the correct grammars for their native languages.
Conclusion: Therefore, human beings must have some form of innate linguistic capacity that provides additional knowledge to language learners.
chomsky
horizontal decalage
knowledge learned in one domain isnt applied in another domain
E.g., 7yo changing shape doesn’t shape amount of clay but does change weight.
E.g., Seriation: Ordering by size and ordering by weight
generalizaiotn is a distinctive form of learning
computational explosion
Determining which information is relevant to which problem.
Constrained problems are easy to solve
Unconstrained problems are very hard because we don’t even know what evidence is relevant to which beliefs.
Blank slates face this problem in spades
innateness and environment argument about computational explosion
innateness: We come with innate ideas or biases: certain conceptual categories over others, certain attentional mechanisms, and not others
environment/learning: Broadly applicable learning rules can explain the phenomenon.
environment strucutures learning so you can solve the computational explosion
U shaped developmental curves innateness and environment arguments
innateness: it is U shaped because some of it is innate, once activated learning is very fast
environment: Connectionist networks show U-shaped developmental curves.
Local Error Minima (many local minima one global minimum)
Darwin’s continuity hypothesis
“Nevertheless the difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind. We have seen that the senses and intuitions, the various emotions and faculties, such as love, memory, attention, curiosity, imitation, reason, etc., of which man boasts, may be found in an incipient, or even sometimes in a well-developed condition, in the lower animals. (“Descent of Man”
morgans cannon
In no case is an animal activity to be interpreted in terms of higher psychological processes if it can be fairly interpreted in terms of processes which stand lower in the scale of psychological evolution and development
AVOID ANTHROPOMORPHISM
Modularity of mind
notion that a mind may, at least in part, be composed of innate neural structures or modules which have distinct established evolutionarily developed functions. Somewhat different definitions of “module” have been proposed by different authors.
reductive materialism
mental events can be grouped into types, and can then be correlated with types of physical events in the brain. For example, one type of mental event, such as “mental pains” will, presumably, turn out to be describing one type of physical event
eliminative materialism
people’s common-sense understanding of the mind (or folk psychology) is false and that
certain classes of mental states that most people believe in do not exist
no coherent neural basis will be found for many everyday psychological concepts such as belief or desire, since they are poorly defined.
they argue that psychological concepts of behaviour and experience should be judged by how well they reduce to the biological level
Other versions entail the non-existence of conscious mental states such as pain and visual perceptions
soul DNE
Eliminativism about a class of entities is the view that that class of entities does not exist
propositional attitudes
mental state held by an agent toward a proposition
often assumed to be the fundamental units of thought and their contents, being propositions, are true or false.
An agent can have different propositional attitudes toward the same proposition (e.g., “S believes that her ice-cream is cold,” and “S fears that her ice-cream is cold”).
Propositional attitudes have directions of fit: some are meant to reflect the world, others to influence it
mind-brain identiy ToM
experiences (pain, or of seeing something, or of having a mental image) just are brain processes, not merely correlated with brain processes
they’re sorta like physicalists (there are some entities in physics which do not have material properties)
but call themselves materialists usually
