Science homework help. NSCI100: Science News Assignment
Name _____________________ Date ______________________________
Read the article on the next 4 pages and answer the questions below in complete sentences about the scientific study in blue font in the reading.
- How many subjects were in the study? Do you think this is a representative sample? Why or why not?
- What was the independent variable in the study?
- Based on your answer to question 2, describe the experimental group. Also describe the control group.
- What was the dependent variable in the study?
- What type of measurement was done in collecting the results?
- What was the conclusion(s) from the study and how does it apply to people experiencing the Covid-19 pandemic?
How coronavirus stress may scramble our brains
Imaging studies show we should give ourselves a break
By Laura Sanders
Science News online: MAY 24, 2020 AT 6:00 AM
I’m on deadline, but instead of focusing, my mind buzzes with unrelated tidbits. My first-grader’s tablet needs an update before her online school session tomorrow. Heartbreaking deaths from COVID-19 in New York City make me tear up again. Was that a kid’s scream from upstairs? Do I need to run up there, or will my husband take care of it?
These hornets of thoughts drive out the clear thinking my job demands. Try as I might to conjure up a coherent story, the relevant wisps float away.
I’m scattered, worried and tired. And even though we’re all socially isolated, I’m not alone. The pandemic — and its social and economic upheavals — has left people around the world feeling like they can’t string two thoughts together. Stress has really done a number on us.
That’s no surprise to scientists who study stress. Our brains are not built to do complex thinking, planning and remembering in times of massive upheaval. Feeling impaired is “a natural biological response,” says Amy Arnsten, a neuroscientist at Yale School of Medicine. “This is how our brains are wired.”
Decades of research have chronicled the ways stress can disrupt business as usual in our brains. Recent studies have made even more clear how stress saps our ability to plan ahead and have pointed to one way that stress changes how certain brain cells operate.
Scientists recognize the pandemic as an opportunity for a massive, real-time experiment on stress. COVID-19 foisted on us a heavy mix of health, economic and social stressors. And the end date is nowhere in sight. Scientists have begun collecting data to answer a range of questions. But one thing is clear: This pandemic has thrown all of us into uncharted territory.
The human brain’s astonishing abilities rely on a web of nerve cell connections. One hub of activity is the prefrontal cortex, which is important for some of our fanciest forms of thinking. These “executive functions” include abstract thinking, planning, focusing, juggling multiple bits of information and even practicing patience. Stress can muffle that hub’s signals, studies of lab animals and humans have shown.
“Even relatively mild stress can impair the prefrontal cortex,” says Elizabeth Phelps, a psychologist and neuroscientist at Harvard University. “That’s one of the most robust effects of stress on the brain.”
That impairment has been described in lots of studies. One memorable example comes from 20 panicky medical students facing licensing exams. After a month of high-stress test prep, the students performed worse on an attention test than they did after exams were over. Functional MRI scans showed that under stress, the students’ prefrontal connections to other brain areas were diminished, scientists reported in Proceedings of the National Academy of Sciences in 2009.
Normally, an alert person’s brain has moderate amounts of chemical messengers that lead the prefrontal cortex to take charge and perform high-level thinking (left). But with stress, those chemical signals can flood the brain, activating amygdala-linked brain networks involved in sensing and responding to threats (right). A. Arnsten
When the prefrontal cortex goes quiet, more reactionary brain networks take over. Some of these “primitive” circuits, as Arnsten calls them, center on the amygdalae, two almond-shaped structures buried deep inside the brain that help us sense and respond to threats. Those fast, instinctual reactions “are helpful if you’re being faced with a snake,” Arnsten says, “but not helpful if you’re being faced with a complex medical decision.”
A more recent experiment, published online April 2 in Current Biology, illustrates how stress can shift people away from thoughtful planning. When people were threatened with electric shocks, their abilities to plan ahead flew out the window. Anthony Wagner, a cognitive neuroscientist at Stanford University, and colleagues asked 38 people to learn a familiar route through virtual towns. With practice, people learned these routes, as well as the locations of recognizable objects, such as a zebra, an apple, a stapler or Taylor Swift’s face, along the way.
“Our question was, ‘What are the effects of stress?’ ” Wagner says. To find out, the researchers used “moderately painful” electric zaps to induce stress in some participants, who returned to familiar virtual towns and were asked to find their way to the zebra, for instance. Subjects didn’t know when they would be shocked, and they couldn’t control any aspect of it.
After the training, the participants — some under stress from the expectation of further shocks and some not — were sent back into the virtual town and asked to find their way to a specific item.
But there was a trick: Participants could reach the stapler, for example, faster and more efficiently by taking a shortcut. The shortcut, however, required more planning, more initiative and a heavier reliance on previously learned relationships among streets.
Stressed people were less inclined to take the shortcut, the researchers found. People who were stressed by the possibility of a shock took the shortcut 31 percent of the time, compared with 47 percent for those who weren’t stressed. The stressed people still reached the object they were after, but in a roundabout way.
Drawing of map of virtual town used in experiment
In a virtual town, people devised a shortcut (left map, red dotted line) to reach a target object. But under the threat of a moderate electric shock, people were more likely to fall back on a familiar route (right map, green dotted line), even though it was longer.
T.I. BROWN, S.A. GAGNON AND A.D. WAGNER/CURRENT BIOLOGY 2020
Functional MRI brain scans hinted at what the added stress did to the volunteers’ thinking. The objects planted around town evoked recognizable patterns of brain activity when a person was seeing one of the previously seen objects, or even just thinking about it. By spotting these neural signposts, researchers could tell when people were thinking of a particular path — or of no path at all.
Participants were given eight seconds to plan their approach to reach the target object. Unstressed people generally had a plan; their brain activity contained patterns that signaled these volunteers were thinking about the objects along the shortcut route. Neural signals of a plan even showed up among those who chose to take the familiar route.
Those awaiting a shock appeared to use little foresight. “The stressed people didn’t seem to be thinking about the familiar route when they took it,” says study coauthor Thackery Brown, a cognitive neuroscientist at Georgia Tech in Atlanta. “They were on this fight-or-flight autopilot type behavior.”
What’s more, stress quieted the activity of brain areas needed to make a good plan, including a part of the prefrontal cortex and the hippocampus, a structure important for memory. Those findings suggest that under stress, we are less able to call up our previously learned knowledge and memories. We are working with a deficit.
“In some sense, we’re privileged when we’re not stressed, able to fully harness our cognitive machinery,” Wagner says. “That allows us to behave in more strategic, more efficient, more goal-directed ways.”
Brown sees parallels between these lab-based stressors and the complex and longer-lasting stresses of real life. The participants were attempting to do something complicated while worrying about something else. The stressor is “operating in the background while you’re trying to plan your daily life,” Brown says. “There’s a connection there with the type of thing people are experiencing right now in the context of the pandemic.”
—-The rest of the article can be found at the URL at the top for those who are interested.—