Kindermann H, Reuter M, Javor A, 2016, Playing counter-strike versus running: The impact of leisure time activities and cortisol on intermediate-term memory in male students, Cognitive Systems Research, 40, 1-7.
Hypotheses: Counter Strike evokes physical and psychological stress as a first-person shooter game. This combined stress raises cortisol levels. Therefore, playing CS after class or studying for a test hinders the ability to remember school-related topics. Physical activity such as running also raises cortisol levels because of physical stress. Since there is no immediate threat with running, the ability to remember school-related information is not hindered, and is in fact heightened.
Test Groups: Experienced CS players, runners, people who spent time outside after studying (1 hour for each)
Results: Cortisol levels increased in all groups while they were learning the information. During the experimental period, the control group and the CS group's cortisol decreased, while the runners' increased.
Discussion: Parts of the hypotheses were correct--running improved memory consolidation, and playing Counter Strike hindered it. But, given the decrease in cortisol from the CS players, they were not entirely correct. Yet, memory consolidation was diminished by playing the shooting game, so the study was still valid. The stress of playing CS, simulating a stressful environment where virtual death is an option and must be escaped, is what the researchers believe to be caused that group's memory consolidation to be hindered.
Experimental Paper #3
CREB is a transcription factor that has been linked to competition between neurons, and is looked at in this paper. This neuronal competition is not a bad thing, though--it may lead to adult brain plasticity. The specific kind of plasticity examined in this paper is located in the Lateral Amygdala (LA), and it is necessary for conditioned-fear memories. About 70% of LA neurons receive the required amount of sensory information for these memories, only 25% LA neurons have auditory conditioned-fear induced plasticity. A similar ratio was found within the LA neurons, if they had active CREB after the fear conditioning. This similarity indicated that CREB may impact which neurons are used for the fear memory trace. The researchers injected CREB-deficient mice with CREB, and then put it through fear conditioning, and assessed the mice's memory. The infusion of CREB barely even effected 20% of the LA neurons, but they had instant revival. 5 minutes after the fear memory test, the brain was removed, and researchers searched for Arc, which signifies when a neuron was recently active. In this situation, Arc would only mark the neurons that were active during the memory test. Increasing the function of CREB in the mice brains also increased their memory function. The researchers then hypothesized that if they decreased the amount of CREB in the mice, their memories would be poorer--they decreased it, and the mice could remember at the same rate as a typical mouse. Neuronal competition is important for memory formation, and for filtering and concentrating neural circuits during development.
Animal Behavior Reading
For reference, Oxford writes that a behavioral assay is "a technique used to determine an animal's response to a stimulus and its sensory powers."
-Behavior is the only way we can look into how an animal's mind works (emotions, cognitions, perceptions)
-A behavioral neuroscient's goal is to characterize an animal's behavior, identify & describe the genetic, biochemical, & cellular correlations of the behavior
-Behavioral neuroscience combines many different techniques & systems
-When choosing an animal model, researchers must consider the natural ethological capabilities of the animal, and the utility of the animal for other experiments
-Ethology means the organism's natural capabilities to perform specific behaviors
-Ex. worms are good models for interactions with their environment, like sensory transduction, motor control, and searching for food.
-As the organism gets more complicated (worm -> fly -> mouse/rat -> primate) the behaviors and cognitive processes also get more intricate
-Depending on what the study is looking at, larger organisms (rats rather than worms) may be necessary
-Ethical & moral issues must be taken into account
-Neuroethology: The study of the neural basis of an animal's natural behaviors
-Using animal models has helped us learn a lot about human functioning
-Institutional Animal Care and Use COmmittee (IACUC) must approve research to ensure it is ethical and will maintain the animals' welfare (minimize stress, maximize benefit to humans)
-Replacement: If research can be done w/o animals, it should be
-Reduction: Use as few animals as possible
-Refinement: Minimize distress & pain; promote amimal well-being
Springer: "Behavioral paradigms are sustematically arranged model situations that mirror the same critical contingencies as hte situations they are supposed to model"
-Assay must be quantifiable & measure discrete, easily observable variables
-Data often recorded as scatter plots/bar graphs
-Scientists must remember the animal may act in ways they don't expect
-Must consider other explanations for why experimental groups differ
-Must ensure animal is not sick
-Variable things to consider in the individual animals: genetic background, environmental things like diet, social interactions, seasonal differences, housing individually or with other animals
-Sex bias w female rodents having changing hormone levels
-If something could potentially be used on humans after the animal, sex differences must be discovered before testing on humans
-Face Validity: If the model's behavior/phenotype is similar to the human phenotype/behavior
-Construct Validity: State in which animal & human models have the same underlying genetic/cellular mechanism that may result in a certain behavior
-Predictive Validity: If treatments used in humans have the same effect on the animal model
-Possible to be one type of valid but not all
-The more types of validity the animal model is, the more useful it will be for humans
-Validity can't really be measured