Tools in Neuroscience Research (Exam 3) Flashcards
1
Q
what are event-related potentials? what do they show us?
A
- used to study brain activity in response to specific stimuli or tasks
- ERPs involve recording electrical activity from the brain using electrodes placed on the scalp (EEG)
- by averaging the brain’s electrical signals across repetitions, random noise cancels out, and consistent patterns related to the task become clearer
- with enough repetitions, the resulting averaged signal shows “waves” that correspond to the timing of neural processes involved
- ERP waves are associated with different aspects of cognition and behavior
- ex. certain waves might reflect attention, decision-making, or memory processes
2
Q
what is transcranial magnetic stimulation (TMS)?
A
- use magnetic fields to change electricity in the brain
- can target parts of the cortex and turn them off (virtual lesions)
- not able to interfere with deeper brain areas
3
Q
what are the benefits of TMS?
A
- a way to induce a loss of function without any actual damage
- potential therapeutic effects for depression and anxiety that can’t be treated with medication
- good at targeting higher cognitive functions that are usually harder to get at
4
Q
why are non-human animal models valuable in research?
A
- provide tools to observe behavior (behavioral assays)
- cannot directly ask animals questions, so their behavior demonstrates responses
- model human behavior effectively (make the same gambling mistakes)
- mammalian brains share similar regions and structures
- differences include prefrontal cortex structure/organization
- animal cognition is sophisticated (rats can learn to drive a car in order to get reward)
5
Q
what are some tasks that show the benefit of animal models in neuroscience research?
A
- morris water maze: tool for learning spatial navigation
- 5-choice serial reaction time task: tool to observe attention and motor impulsivity
- t-maze tasks
6
Q
what is the Morris Water Maze and what does it measure?
A
- tool for learning spatial navigation
- rats swim in an opaque pool with a hidden platform
- measure: time it takes for the rat to find the platform
- over trials, rats learn and reach the platform faster
- task depends on hippocampal function
- rats with impaired hippocampi struggle to find the platform
- can use a maze like this to observe induced or reduced function related to spatial navigation
7
Q
how does the 5-Choice Serial Reaction Time Task measure attention?
A
- operant chamber with 5 lit-up holes
- rats must identify which hole lit up to receive a reward (sugar)
- measure: accuracy of finding the correct hole
- attention is operationalized as accuracy
8
Q
how does the 5-Choice Serial Reaction Time Task measure motor impulsivity?
A
- rats must wait for the light before acting
- early response = 5-second time-out.
- psychostimulants increase impulsivity but also improve accuracy
- task can be modified to offer harder or easier trials for varying rewards
9
Q
what is the difference between classical and operant conditioning?
A
- classical: learning through association
- operant: learning through rewards and punishments
10
Q
what is the T-maze and how is it used in research?
A
- rats choose between two options in a T-shaped maze
- their behavior indicates their response to a question or task
11
Q
what does the Forced Swim Test measure, and what are its limitations?
A
- meant to measure depression-like behavior and antidepressant efficacy in rodents
- animals are placed in a pool they cannot escape from
- idea was that depressive-like rats give up swimming sooner
- this was used to justify that medication works
limitations: - learned behavior: rats that repeat the task know they’ll be rescued if they stop swimming
12
Q
what are the limitations of animal models?
A
- quality of the model depends on the behavioral assay
- poor assays lead to unreliable interpretations
13
Q
what are potential routes for administering drugs to animals? what are their pros and cons?
A
- intramuscular (IM): injected into muscle
- pro: reaches brain quickly because muscle is close to blood flow
- con: causes soreness due to pH difference with muscle - intravenous (IV): catheter in vein
- pro: rapid effect
- con: unsuitable for some drugs (that aren’t usually put in veins), catheter can fall out - subcutaneous (SC): injected into fat
- pro: painless when injected in neck scruff
- con: slower drug effect - intraperitoneal (IP): injected into abdominal cavity
- pro: quick entry into bloodstream, painless
- most common route - intraventricular: injected into brain ventricles (with catheter)
- good for drugs that don’t cross the blood-brain barrier
14
Q
why is using multiple doses in drug challenges important?
A
- start with a saline injection (no drug) to establish a baseline response
- gradually increase drug doses: low, medium, and high
- helps researchers create a drug response curve:
- shows how different doses affect behavior or physiology
- higher doses may produce stronger effects, but not always linearly (some drugs have a threshold or maximum effect)
- this approach provides a clear picture of how the drug works across dose levels
- giving multiple doses is difficult in humans due to ethical concerns or practical limitations
15
Q
what are within-subject designs, and why are they useful?
A
- each animal is exposed to all experimental conditions (saline, low, medium, and high doses)
- allows researchers to compare how the same animal reacts under different conditions
benefits: reduces variability caused by individual differences, requires fewer animals
16
Q
what are the invasive electrical recording methods?
A
- intracellular unit recording: measures activity inside a single neuron
- extracellular unit recording: measures activity near (outside) a single neuron
- multiple-unit recording: records activity from multiple neurons at once using extracellular electrodes
- invasive EEG recording: done directly on or within brain tissue, reduces noise from the scalp
17
Q
how is invasive eeg recording combined with intracellular recording?
A
- there has been a study done with invasive EEG and intracellular recording
- combining them is challenging because the electrode must stay in the cell as the animal moves
- one study moved the environment around the rat to keep the electrode in place
18
Q
what is stereotaxic surgery used for? how is it done?
A
- precise surgical procedure used to target specific areas of the brain for experimental or therapeutic purposes (lesions, optogenetics, electrodes, etc.)
- requires a stereotaxic atlas of the rat brain (accurate to 0.1 mm) and precise instruments
- allows accurate placement of lesions, probes, electrodes, etc.
- the reference point is bregma, where the skull bones fuse
19
Q
what are the different lesion methods?
A
- chemical lesions: chemical spreads and destroys a spherical area in the brain by causing too much glutamate activity (excitotoxic)
- selective chemical lesions: target specific neurons using chemicals
ex: 6-OHDA kills dopamine neurons, 5,7-DHT kills serotonin neurons - reversible lesions (inactivations): temporarily turn off a brain region using a cannula and drugs like baclofen + muscimol (GABA agonists)
20
Q
what are the benefits to using reversible lesions?
A
- allow temporary inactivation of a brain region without permanent damage
- help avoid recovery or compensatory effects seen in permanent lesions
- use of cannulae allows us to inject drug directly into brain region
- enable within-subject designs, allowing the same animal to be tested in both the active and inactivated conditions
- provide more reliable data by reducing variability between subjects
21
Q
what are the challenges of lesion methods?
A
- researchers must kill the rat post-experiment to confirm the lesion area
- finding the right post-surgery testing window is difficult:
- testing too early risks confounding variables (tenderness)
- testing too late risks brain recovery from lesions - complexity of interpreting lesion study results and designing experiments to address specific research questions (lesions can be unilateral, bilateral, or contralateral)
22
Q
what are contralateral lesions used for?
A
- contralateral lesion - damaging one brain region on one side of the brain and a different region on the opposite side
- test if two brain areas work together in a circuit
- example: when studying decision making, found that the amygdala and cingulate cortex work together
- if two areas form a circuit, disrupting either will affect behavior
