Research methods final Flashcards
(6 cards)
You have been hired to serve as a consultant for a company that is hoping to develop an at-home biofeedback device that will allow their clients to measure their brain activity in real time. They hope it will have major implications for treating anxiety and depression. Your task is as follows: a) choose the brain imaging technique that you think would provide the most affordable solution, b) explain how that technique will allow for real-time biofeedback, and c) suggest a couple of possible obstacles the device might face.
EEG is the most affordable at home biofeedback device. EEG provides a temporal resolution of milliseconds, meaning that it can monitor brain activity in real time. Possible obstacles include it can’t record the activity of individual neurons and the spatial resolution is poor. Also, it misses deeper brain structures like the amygdala or the hippocampus, which are important for anxiety and depression. Also, since the intended use is at home, noise may be a disruption, EEG is very sensitive to muscle movement and environmental noise, making feedback less reliable.
You’re reading a paper about a novel technique to model Parkinson’s disease in rats. The technique involves the use of a new neurotoxin, DA-B-GON, into the substantia nigra of an adolescent rat. The rat develops Parkinsonian symptoms over the course of a week, starting to show slowness of movement, tremor, and stiffness. In humans, Parkinson’s usually develops over time late in life. One of the major advances of the DA-B-GON technique is that the rat’s symptoms actually improve with levodopa, the most effective Parkinson’s drug. Describe, with examples, the a) face, b) construct, and c) predictive validity of this model.
Face validity refers to how closely the model’s observable symptoms resemble human disease, so rats injected show symptoms of slowness of movement, tremor, and stiffness, which mirror the symptoms of parkinsons in humans. Construct validity refers to whether the model is based on the same underlying biological mechanisms as humans. So this model has strong construct validity because it targets the same brain structures and NT system as human parkinson’s disease. Predictive validity is if treatments used in human patients have the same effect on the animal model. In this model, symptoms improved with levodopa, just as they do in humans, this demonstrates high predictive validity.
You’ve just joined a lab as a new graduate student and your advisor has asked you to design a couple of new experiments. The focus of the lab is on the periaqueductal gray (PAG), a region of the brainstem that is a critical structure in regulating the perception of pain. You have been tasked with developing a) an experiment that uses observational neuroscientific techniques to measure neural activity during a pain-processing task and b) an experiment that directly manipulates the activity of the PAG during a pain-processing task. Make sure to carefully describe how you will do each of these experiments and select the experimental details with the location and size of the PAG in mind.
Using a mice model, I would use non ratiometric Ca2+ indicator dyes like GCaMP which glow brighter when neurons are active. After a few weeks after brain cells start making GCaMP, I would insert a fiber optic cable above the PAG, then give the mouse a mild pain task like the hot plate assay, and use fiber photometry to measure the changes in fluorescence. For an experiment that directly manipulates the activity of the PAG during a pain processing task is injecting the PAG with a virus that makes neurons light sensitive. Implant a fiber optic cable and during a pain test shine light through the fiber. The light turns neurons on or off in real time, showing how PAG activity affects pain behavior.
You are an expert in identifying key genes involved with novel phenotypes and you have the ability to work with C. elegans, Drosophila, and mice. You are collaborating with a research team that studies epilepsy and they have asked you to help find a novel genetic mutation that leads to seizures. a) What type of genetic screen would you use to start with and what animal model would you choose to run the screen? b) Once you’ve identified a novel gene, what sorts of experiments would you need to run in your chosen animal model to validate whether it has a reliable seizure-producing phenotype?
A forward genetic screen would allow me to start with a phenotype then work backwards to identify the specific gene. I would use Drosophila as my model organism because it is a complex, multicellular organism that is relatively easy to manipulate genes. Once the gene is identified, experiments like mechanically stimulating the flies and observing seizure-like behavior. Also, removing the mutation and seeing if the fly goes back to normal would confirm the gene is the cause.
A mad scientist created a time machine that forced you back to 2000–the only way they’ll help you return to your own time is to develop a transgenic mouse model for them. They want a knock-out (KO) of the TRPC4 gene, which is a nonselective cation channel heavily expressed in various reward and learning pathways. Since CRISPR-Cas9 systems have yet to be invented, you need to do things the old-fashioned way. a) Describe the steps that you will need to take to create this TRPC4 KO model and b) what techniques you will use to validate that it is no longer expressed in the mouse brain.
The first step is creating a target construct using recombinant DNA technology that will replace the gene of interest. Then injecting and selecting ES cells. To select ES cells that have successfully recombined the targeting construct at the correct location, you utilize the positive and negative selection genes in the targeting construct. After several positive ES cells are identified, they are injected into blastocyst. Once mice are born, it is necessary to determine which mice have incorporated the knockout construct. In order to validate that TRPC4 is no longer expressed in the mouse brain, I would use a southern blot, which is used to detect the presence of specific sequences of DNA from the genome. It confirms that the TRPC4 gene has been disrupted.
You love NSCI 010 so much that you decide to take it again next spring! However, Emmons won’t let you do the same mock grant proposal project… Come up with a new idea and describe a) your key research question and the gap that you’re trying to fill, b) your two specific aims and their associated hypotheses, and c) what significance you think this grant proposal will have for the field.
How do common anxiety medications affect brain development and stress responses in teenagers. While medications are often prescribed to teens to help with anxiety, there is a gap in literature about the impact they have on the developing brain, most studies focus on adults.
Aim 1: Test how anxiety medication affects adolescent anxiety behavior. I hypothesize that mice given this medication will show less anxiety in behavior tests (like open field tests with mice), but may have changes on how they respond to stress later.
Aim 2: Examine how anxiety medication impacts brain development. I hypothesize that the medication will alter brain activity in certain areas like the amygdala or prefrontal cortex, which correspond to emotion and stress.
This research could help us better understand the long term effects on anxiety medications have on teenagers. It might guide safer treatment plans.
