L3: The Brain Flashcards
what are the five ethical guidelines and what do they mean. mention deception (what are some concerns of deception)
- informed consent
- given all the information of being a participant - right of withdrawal
- a lot of people actually do leave: attrition is the subject lost (very high rate) - protection of participants
- no unnecessary harm or distress - confidentiality
- participants data is kept anonymous - debriefing
- research is explained fully
- any deception has to be revealed and explained:
- placebo effect, nocebo effect and demand characteristics are concerns with deception
- Even though deception is often necessary, subjects should still be informed of potential harm
describe a study that didnt follow ethical guidelines
ie. Tuskegee Syphilis Study
- N = 600 people (399 with syphilis) of African-American descent observed over a 40-year period
- Participants not informed of the their condition or given proper medical care
- Tragedy which had lasting impact on trust
*didnt follow informed consent, protection of participants, or debriefing
what is the null and alternative hypothesis?
Null hypothesis (Ho): no difference between groups
Alternative hypothesis (Ha): there is a difference between groups
what is a treatment effect
If we reject the null hypothesis and accept the alternative hypothesis, we say that there is a treatment effect (or simply an effect)
what is the purpose of statistics
to quantify uncertainty in data. is it a real difference or is it due to random chance (ie. how likely is our result due to chance)
what are the two common statistical tests
t-test and ANOVA
what is the p value
p-value is the probability a result is due to chance
If p = 0.05, there is only a 5% probability could be due to chance
The lower the p value of a group comparison (0.05, 0.01, 0.001…), the more confident we can be that our group differences are not due to chance.
what are the p-value thresholds
- In advance, we decide what p values are acceptable (p threshold)
- p threshold of 0.05 is common
- We compare our p value to the threshold value
- If p value < threshold, the difference between the groups is statistically significant and can accept alternative hyp.
- the pvalue for studies vary - like for behaviour studies the p-value may be greater than form drug studies. depends on context
what is effect strength and how is it found
effect strength = demonstrates the magnitude of the treatment effect
we do statistical measures on datasets to find the effect size
for instance, aspirin and pain will have a weaker effect than opioids and pain.
ex. cohens d
what is effect size? how does it correspond with statistical differences? what is the difference between the two?
how do we apply effect sizes in context?
three conditions in an experimental condition may be statistically significant but may have diff effect sizes
small effect size = smallest difference between experimental group and control (even though it is statistically significant)
moderate effect size= moderate difference
large effect size = largest difference
–
* Strong effects could serve as first-line medical treatments and guide laws, regulations and policies
* Weak effects do not justify extreme action
* Statistical significance refer to the certainty that a difference exists whereas effect size refers to the strength of that difference
explain the correlation between sample size and effect size
- The larger the sample size (n), the more likely we are to reliably detect effect differences
- Strong effects can be found with small n (e.g. n ~ 10)
- ex. Opiate drugs and pain
- Weak effects generally require very large n (e.g. n ~ 50, 100, 500) to be considered reliable
- ex. Aspirin and pain
- low sample size is always a problem in psychology
what is the replication crisis
the crisis in which when studies were replicated, it was found that many do not replicate with the same findings
what caused the replication crisis? what is the outcome of studies that cannot replicate? how do we resolve this problem?
Many causes
* bad statistical procedures (e.g. p-hacking, low sample size)
* poor measurements
* inappropriate experimental designs
* publication bias (negative results not published)
- studies that do not replicate are not strong and should not dictate psychology. However many people still site them.
- Tough to resolve this situation, some fixes put forward
- Pre-registration and open science recommended
- register you samples and methods beforehand so you cannot change it afterwards
what are the two parts of the nervous system and what do they include generally
central nervous system (CNS)
- spine/spinal cord (encased by vertebrae) and brain (encased in skull)
peripheral nervous system (PNS)
- everything else
- uses the two types of neurons to send connections to the organs and gut
- includes two types of neurons:
– sensory nerves: receptors in the skin
– motor nerves: body muscles
what are the two main cell types in the brain
Two main cell types: neurons and glia (including astroglia, microglia and oligodendroglia).
Describe what happens when a neuron receives a transmitter aka neurotransmission (use diagram if needed)
dendrites receives input signals/transmitters.
the neuron integrates the signals. if it triggers the action potential it generates it own electrochemical signal. (excitable cells)
the electrochemical signal travels down the length of the neuron, on the myelin.
when it reaches the axon terminals it sends an output signal/releases a transmitter
identify parts of the neuron (look at diagram)
look at diagram
- dendrites
- axon
- myelin
- axon terminals
- cell body
what is a synapse
The places where neurons connect and communicate with each other
around 125 trillion synapses in the brain
explain the lock and key model of neurotransmitters and receptors. what happens when a transmitter binds to a receptor? how does this effect other cells?
a neurotransmitter can bind to a receptor on the cell membrane. when this happens, it can open an ion channel.
Transmitters released by one cell bind to receptors on another cell. Receptor activation can have many effects on the cell (excitation, inhibition and more)
what are some neurotransmitters and their receptors? what do the different receptors typically do?
serotonin, dopamine, acetylcholine, adrenaline.
serotonin has receptors -> 5-HT1, 5-HT2, 5-HT3, they all control different aspects of the transmitter
most transmitters do more than one thing
what are agonist and antagonists? what are competitive antagonists?
- Agonist: a compound that binds to a receptor and produces a response (e.g. glutamate is an agonist of glutamate receptors)
- Antagonist: A compound that binds to a receptor but does not produce a response
- Competitive antagonist: an agonist and antagonist can act at the same time and will cause no/less activation.
if you have a lot of antagonists enter, then agonists cannot react
explain the case study on opioid receptors and endorphin
- Your body has natural transmitters (e.g. ꞵ-endorphin) that act as ‘natural painkillers’
- Endorphins mediate pain responses by acting on targets in the nervous system, including μ- opioid receptors
- μ-opioid receptors are also highly responsive to opioid drugs (e.g. morphine)
