FroSci Midterm

What is the white matter in the brain?

myelin for transmitting signals

insulation wrapped around axons

degeneration causes MS

What causes MS?

degeneration of myelin

What is the gray matter in the brain?

cell bodies for processing

hemispheres in brain

right and left sides

left: language

right: logic and creativity

corpus collosum

connects two hemispheres of brain, people with damaged ones have "split brain syndrome"

cortex

the layer of tissue on the outside of the brain, 2 mm thick, wrinkles and folds,

gyrus=a ridge or fold between two clefts on the cerebral surface in the brain

sulcus=a groove or furrow, especially one on the surface of the brain.

lobes

parietal, occipital, frontal, temporal. structure is linked to function!

Explain what it means that brain function is localized, and how different stimuli can lead to different perceptions. Summarize the relationship between brain function, our experiences, and reality.

Broca's Aphasia (1861) links structure to function. He realized that all these people couldn't produce language all had to damage to the same part of their brain (left side). Showed that part of the brain was specifically linked to producing language.

optogenetics

light can turn specific types of neurons/dopamine receptors? on or off

letting us see what parts of brain do what

very precise

only in animals for now

Consider why convergence is important for studying the relationship between mind and brain.

Convergence: when multiple methods of study (Ex: FMRI, damage to brain, optogenetics) come to the same conclusion, making you more confident in results. This is very necessary when studying the relationship between mind and brain because it is hard to get at the truth so need to confirm via different methods.

Compare and contrast three different techniques used to study the brain. Specify the assumptions and limitations that underlie fMRI measurements.

fMRI: blood flow is a proxy for brain activity, speed of blood flow vs. speed of brain activity not the same, but an advantage is the relationship between signals and behavior. Not invasive, very accessible.

Optogenetics: very specific, know what you are turning on/off, can't do on humans

Light can turn specific types of memory on or off, letting us see what part of the part of the brain does what

Very precise

People with damage to the brain

People with brain damage: makes us able to observe exceptional things we would not be able to otherwise. The difficulty is what if it does not apply to others. A case study isn't as good as a large-scale study.

Benjamin Libet

showed that unconscious actions occur before conscious awareness

--first your chemical readiness potential goes up, then you experience the urge to move your finger

Discuss initial attempts to determine whether ability to remember things is localized to one or more brain structures or distributed throughout the brain. Describe our current understanding.

KARL LASHLEY: tried to localize the engram: the single location of a memory

Taught rat how to do a maze, took out a part of rat's brain, tried to see which part of brain stored memories.

Conclusion: memories don't live in one particular place, memory lives throughout the brain

BRENDA MILNER AND SUE CORKIN: discovered patient H.M.

H.M. had life-learning epilepsy, a doctor tried to localize the source of his epilepsy by removing a big part of the hippocampus, surgery at age 27

Outcomes: *ANTEGRADE AMNESIA*: no new memories of people, places, moments. Could learn how to do new things like improve at mirror tracing even though he couldn't remember having done it the day before.

Treated seizures

Healthy recovery in general

Couldn't create new EPISODIC memories

Patient HM fundamental insights:

1. Different parts of brain support different types of memory (A Taxonomy of Memory, now kind of disproven)

2. A specific role for the Medial Temporal Lobe (MTC) in memory and memory for feedback

Now we think memory is both localized and throughout brain I think. For example, hippocampus is essential for creating new episodic memories.

What we've learned:

Hippocampus is necessary for building long-term episodic memories, but not building habits etc

Process of creating memories involves long-term changes to synapses--strength of neural connections

Define the role of the hippocampus in memory, and articulate how we know using examples from lecture and reading.

Hippocampus is necessary for building long-term episodic memories, but not building habits etc. Hippocampus is also the brain's GPS (place cells). People use the hippocampus for future thinking, to remember and to imagine. Hippocampus is used to imagine future things and remember past things. Lonnie Sue as an example of anterograde amnesia too.

Patient HM

showed how essential hippocampus is in creating new episodic memory, which is why he got antegrade amnesia

Lonnie Sue

antegrade amnesia

Eric Kandel

Long-Term Potentiation

researcher at COlumbia

aplasia (sea slugs), poke them until they get used to it showing neural plasticity

neural plasticity

idea that there are changes in neurons' activity based off of experience

Eric Kandel's aplasia poking experiment

long-term potentiation

activating a synapse can make it stronger

an increase in a synapse's firing potential after brief, rapid stimulation. Believed to be a neural basis for learning and memory.

shown by Eric Kandel's aplasia experiment

List the functions, other than its role in memory, that the hippocampus appears to have, and describe the supporting evidence. Discuss the relevance of these additional functions of the hippocampus to the hypothesis that the hippocampus "binds elements of experience in time and space."

IN MEMORY: hippocampus necessary for creating episodic memories but not habits

NOT IN MEMORY: navigation (place cells)

future thinking/imagination

NEED TO FIND EVIDENCE

Is memory distributed or localized?

BOTH

Distinguish between habitual and deliberative decision-making.

1) Habitual, reflexive, automatic

Dopamine: food, sex, drugs

--every time something good happens, see response of domamine neurons

Then realized: if there was a ding played before got the reward every time, the dopamine neurons would start responding at the ding, not at the reward itself

REALITY: dopamine is trackign surprise, not reward itself

--a learning signal. It's not about the reward, it's about what you predict vs. what actually happens

Loss of dopamine creates Parkinson's Disease

2) Deliberative, goal-directed, rational

Describe experiments using monkeys that investigate what happens to individual neurons in the parietal cortex as evidence is accumulated towards a decision. Summarize the conclusions of these experiments.

Monkeys learn which target (Red or green) to look at based off of predicitive cues. If they look at correct target, they get reward. Accumulation of evidence: monkeys get many clues they should look at green target, then visual acuity looking at red target decreases.

Define reward prediction error, and explain how dopamine facilitates learning of habits and habitual behavior. Identify how we know and what part of the brain appears to be involved.

Reward Prediction Error: is when you expect a reward but don't get one OR when you receive an unexpected reward. When this occurs, you adjust your expectations (ie you learn from feedback).

Experiment #1: people show elevated fMRI signal in striatum (target of dopamine release) while learning from feedback that involves figuring out which of 2 options is consistently more likely to be the "correct choice"

Experiment #2: Dr. Shahamy's research on dopamine deficient Parkinson's patients shows that they have worse learning from feedback, when take medication that restores dopamine levels, the impairment goes away

--every time something good happens, see response of domamine neurons

Then realized: if there was a ding played before got the reward every time, the dopamine neurons would start responding at the ding, not at the reward itself

REALITY: dopamine is tracking surprise, not reward itself

--a learning signal. It's not about the reward, it's about what you predict vs. what actually happens

Loss of dopamine creates Parkinson's Disease. Worse at predicting and learning. Can't just give patients dopamine because it wont enter brain, will just go into body. Different drug does help increase dopamine, leads to learning from prediction errors

Converging evidence: fMRI and patients

Shows that it is important for reward prediction errors during learning

Daniel Kahneman experiment

subjects put hand in icy water. Group A: 60 sec in water. Group B 90 sec but for last 30 sec it is slightly warmer by a few degrees. People in group b were more likely to recommend the experiment to friends and come back and do it again

--because prediction error, going from awful to slightly less awful was satisfying

Use "peak" (best part of the worst part) and endings to form your opinion of the activity

Discuss applications of decision-making research, with specific examples from lecture and reading.

Daniel Kahneman experiment: subjects put hand in icy water. Group A: 60 sec in water. Group B 90 sec but for last 30 sec it is slightly warmer by a few degrees. People in group b were more likely to recommend the experiment to friends and come back and do it again

--because prediction error, going from awful to slightly less awful was satisfying

Use "peak" (best part of the worst part) and endings to form your opinion of the activity

Which part of the brain does accumulation of evidence?

neurons in parietal cortex

Describe the difference in speed, mass, and size scales that we experience in daily life vs. what exists in the Universe as a whole.

Explain why the observation that the speed of light is constant puzzled physicists in the late 19th and early 20th century and how Einstein resolved this puzzle.

Elaborate on the implications of the constancy of the speed of light for simultaneity and describe the example of the peace-signing treaty.

Evaluate qualitatively and quantitatively what happens to time and space for observers moving relative to one another at a constant velocity. Identify the conditions under which special relativity effects on time and space must be accounted for.

it will always seem like the other person is traveling more slowly relative to you

ASK ABOUT THIS

Summarize the significance of the equation E=mc2 and the effects that moving fast has on mass.

E=mc^2 shows how energy is the same as mass

Discuss the main features and limitations of Newton's Gravitational Law.

Newtonian Gravity force of attraction between two massive objects: G x m1 x m2

t2

The issue is that if the sun disappeared, gravity would show effects instantaneously, whereas we wouldn't see the sun gone for days. Problem: nothing can go faster than the speed of light, so how can gravity?

Describe Einstein's Theory of General Relativity qualitatively, and explain how it addresses the limitations of Newton's Gravitational Law.

space (and time) itself communicates gravity

Einstein's Standard analogy: the rubber sheet, replace sheet by spacetime, lots of space warps the environment

gravity slows the passage of time

Explain the Equivalence Principle and its importance to the development of Einstein's theory.

Einstein's happiest thought: that if a painted fell of a ladder, the scale falling with him would record him as having zero mass. This means gravity=acceleration. And since Acceleration=warped spacetime, gravity is warped spacetime

Enumerate the evidence in support of the Theory of General Relativity.

In familiar situations, these equations yield the same predicted trajectory of distant starlight should bend as it passes the sun--solar eclipse 1919

GR is confirmed by observations

GR resolves conundrum regarding speed of gravity

SPEED OF GRAVITY = SPEED OF LIGHT

Summarize the main features of a black hole. Develop a sense of scale for black holes by calculating the Schwarzschild radius and/or mass of a black hole. Describe the effect that massive objects have on time (gravitational time dilation) qualitatively and quantitively.

A small area of space so massive that it's gravity is so strong nothing can escape it. Kayaker Analogy: if water was traveling faster than you can paddle, you can't help but go over edge. Since you can't travel faster than the speed of light, you will get sucked into black hole. To make a black hole: start with any amount of mass M, squeeze the mass into a ball with radius (use Schwarzchild Radius equation).

Massive objects slow passage of time. Time essentialy stops within the black hole because the black hole is so so massive.

We still don't know what is in the center of the black hole.

Explain what it means that the Universe is expanding. Interpret actual and hypothetical Hubble data, and determine what such data can tell us about the evolution of the Universe.

Hubble data shows that things farther from the earth are moving away from the earth at proportionally faster velocities. Shows that the universe is still expanding and has been since the Big Bang.

Describe what happens when the following objects pass through a wall with two-slits: a) pellets; b) water waves; c) electrons. Provide the interpretation of these results discussed in lecture.

(a) shows up behind the slits

(b) shows up in a wave pattern

(c) shows up in a wave pattern too! turns out it is a PROBABILITY WAVE (look same as (b))

Explain the role that probability plays in Quantum Mechanics.

The waves created when electrons go through slots are probability waves. We can never know where an electron is, just where it is more or less likely to be.

Discuss the Heisenberg Uncertainty Principle and the way in which it fundamentally limits the precision of concurrent measurements of position and momentum/speed of an object.

If you know position within a small confidence interval, you know momentum/speed less well. Can't ever know both when near the spread of light.

Max Born

wave is a PROBABILITY WAVE--radical idea at core of quantum mechanics

Schrodinger's Cat

electron in box with cat

if electron is on left side of box, poison will be released and kill cat and vice versa

If electron is fuzzy probability, then is cat alive or dead? By opening box, you change the disposition of cat from funny mix of alive and dead--how can our action of opening the box change that?

When do all observers agree on the speed of things?

When it is at the speed of light, because that is not relative. For everything slower than the speed of light, observers will disagree unless have the same constant speed and direction)