BIOPAC Blog

The Trouble with Fatigue

Fatigue is a troublemaker–it can have serious impacts on data quality, even when using gold standards of measurement.

Fatigue is a known troublemaker in athletics, but can also have negative effects in physiology research. Fatigue can become a confounding variable, giving researchers data that may be less accurate or reliable.

Men and women may respond to fatigue differently, which can make obtaining good data especially difficult. In one study on fatigue by Stern et al. (2012), the researchers attempted to monitor fatigue and show different effects between men and women. This study attempted to follow a central nervous system component, as well as the peripheral nervous system. Using the BIOPAC MP160 system with AcqKnowledge software to record and analyze EMG, researchers were able to continually monitor muscle and neuron activation during the exercise tests.

The results of the study found that females had a higher rate of reduced central neural drive of the quadriceps, coupled with knee extension torque preservation. These factors, when paired together, can create a higher percentage for the possibility of knee injury for women.

With coffee being such a staple in the home (and in the lab!), researchers Smirmaul et, al (2017) wanted to see if coffee had any effect on fatigue, duration of exercise, and the perception of effort. This study used seven adult male cyclists in moderate hypoxic states to obtain their results. The experiment used a double-blind procedure, with some participants receiving no coffee. The researchers wanted to see if the coffee participant group took a longer time to reach fatigue. EMG was obtained by using BIOPAC MP160 with EMG amplifiers. The results showed that coffee has no effect on fatigue, but coffee did improve the time it took until the athletes reached exhaustion in high endurance tasks. The researchers believe that coffee lowers the perceived effort of the athlete, leading them to think they can go further.

Fatigue can also have impacts on data, even when using gold standards of measurement. A separate study done on fatigue by Neyroud et al. (2016), attempted to show that muscle fatigue has an effect on the validity of the ITT (Interpolated Twitch Technique). The ITT is used to evaluate the capacity of the central nervous system in activating skeletal muscles. This study used BIOPAC’z MP research system with EMG amplifiers to monitor muscle and neuron activation. Electrical stimulus was given to both samples to create fatigue, and a separate stimulus was given to mimic the ITT. This study found that peripheral fatigue factors do have an effect on the outcome of the ITT.

BIOPAC offers a variety of equipment that can be used in studies similar to the ones presented. To find more information on solutions for recording and analyzing signals such as EEG, EMG, respiration, skin conductance using the MP160/MP150, MP36, and other platforms, you can visit the individual application pages on the BIOPAC website. If you are interested in reading other related studies, visit the publications page on the BIOPAC website.

Holiday Happiness Part 2: Sounds, Smells, and Self-Reflection

In a previous post, we discussed the stress-reducing benefits of loving interactions with close friends and family during the holiday season. In addition to family, there are many mood-shaping habits and activities that characterize the holidays: the smell of home-cooked meals, seasonal music, and reflection on the past year, to name a few. But do these have a real impact on happiness?

In a psychophysiology study, Matsunaga, et al., tested odor effects on autobiographical memory recall. The researchers introduced several odor stimuli to participants and measured their psychological and physiological reactions. Heart rate and skin conductance were recorded throughout the experiment with a BIOPAC data acquisition system. The odor stimuli resulted in decreased heart rate, increased skin conductance level, and an increase in positive mood states.

Another article tested the effects of meditation on emotional regulation. Participants completed emotional measures before and after a meditation intervention, and had their ECG, respiration, and blood pressure recorded using a BIOPAC MP unit. The meditation correlated with greater participant emotional regulation, as suggested by lower heart rate and respiration.

In addition to meditation and smell, Harmat and Eerola have found music to also be emotionally significant. Participants listened to a musical piece, and then responded to a questionnaire about their emotional state. In addition to measuring pulse rate and facial expressions, the BIOPAC Research System and EDA Amplifier were used to record skin conductance while participants listened to the stimulus. The results found that music samples evoked several emotions, including nostalgia and happiness.

This research suggests that we can affect happiness using subtle techniques that are part of everyday living. To read more studies about psychophysiology and stress reduction, visit the BIOPAC publication page.

BIOPAC offers a variety of equipment that can be used in studies similar to the ones presented. To find more information on solutions for recording and analyzing signals such as skin conductance, ECG, heart rate, respiration, and EDA using the MP160/MP150, and other platforms, you can visit the individual application pages on the BIOPAC website.

Holiday Happiness: Gratitude or Gifts?

Studies investigated the anxiety of gift-giving, the effects of social support in stressful situations, and what impact meditation has on heart rate, ECG, and blood pressure.

December has arrived, and for many the holidays bring a rush to check items off of a long shopping list for parents, siblings, friends, in-laws, and many more. Often we struggle to find that “perfect” gift, but are the physical goods we exchange the true source of the warmth and happiness that characterizes the season?

An article by Nomura investigated anxiety induced by gift-giving. To test this, EDA data was recorded with a BIOPAC data acquisition system and STP100 while participants responded to stimuli. The participants visualized a specific relative while being presented with potential gift options, and were asked how likely they were to purchase the potential gift for that relative. The data found that people who self-reported thinking of in-laws were the most stressed, while those who reported thinking of children or same-gender friends were least stressed.

A psychosomatic study by Inagaki and Eisenberger found that mental and physical well-being benefit from forms of social support. They tested this by administering mild shocks with the BIOPAC STMISOLA to male patients who held the hand of a female partner lying in an fMRI. The results suggest that this support (hand-holding) provided possible stress-reduction for both the male and female participants.

Another article on nonverbal communication and well being by Shaltout, et al. tested the effects of meditation and the subsequent ECG, blood pressure, and heart rate effects. The BIOPAC ambulatory BioHarness and NIBP Blood Pressure System gathered data while participants underwent several mediation episodes, during which they were instructed to focus on loving kindness towards a subject. The results found that participants had decreased heart rate.

Research suggests direct, loving interactions with those who are close to us have many stress-reducing benefits. So when you are shopping for gifts, remember that spending time is more important than spending money. To read more studies about love and stress reduction, visit the BIOPAC publication page.

BIOPAC offers a variety of equipment that can be used in studies similar to the ones presented. To find more information on solutions for recording and analyzing signals such as EEG, EMG, respiration, and EDA using the MP160/MP150, MP36, and other platforms, you can visit the individual application pages on the BIOPAC website.

BIOPAC Systems, Inc. provides life science researchers and educators with data acquisition and analysis systems that inspire people and enable greater discovery about life. Visit us at www.biopac.com.

The Physiology of Consumer Buying Habits

On “Black Friday” in the US, shoppers will come out in search of great deals, and researchers can measure the many physiological factors that motivate shoppers other than deals and price cuts.

Black Friday is one of the most exciting days for consumers in the United States. With the holidays right around the corner, significant deals and price cuts incentivize people to do bulk gift shopping. But is price the only factor influencing shoppers to dedicate hours waiting in line for a product?

In a neurophysiology study by Alexander et al., researchers found that participants who received a coupon while shopping online had a significant increase in oxytocin and a decrease in cortisol. A BIOPAC research system was used to gather ECG, respiration, and skin conductance data while the participants browsed a commerce website.

Another article by Ha-Brookshire and Bhaduri measured ECG response to stimuli that tested consumers’ perceived trust of businesses. The BIOPAC MP36R was used to record participants’ heart rates while they read negative reviews of an apparel business. The results found lower heart rate and less trust were correlated with the less favorable comments.

Conversely, a consumer research study by Langner et al. found that consumers’ love of brands is similar to their love of friends. Signals measured included EDA, EMG, ECG, and BPV, and were recorded by BIOPAC MP160/MP150 hardware to measure arousal levels while participants viewed different brand and interpersonal stimuli.

BIOPAC offers a variety of equipment that can be used in studies similar to the ones presented. To find more information on solutions for recording and analyzing signals such as EEG, EMG, respiration, skin conductance using the MP160/MP150, MP36, and other platforms, you can visit the individual application pages on the BIOPAC website. If you are interested in reading other related studies, visit the publications page on the BIOPAC website.

The Physiology of Election Decision-Making

The psychophysiological factors of stress, the behaviors of others, and of introception can play major roles in decision-making, and BIOPAC systems provide measurements of how physiological factors such as these influence decisions.

People experienced varying stress levels because of the 2016 US presidential election. There are a variety of factors that can impact voting behaviors and decision-making. Several recent studies using BIOPAC systems investigated the psychophysiological effects of stress, the behaviors of others, and introception on decision-making.

Stress has been shown to be very influential in decision-making. In their study, Yamakawa, Ohira, and Mastunga Isowa (2016) investigated effects of acute stress and risk taking in decision-making. Participants were asked to perform a decision-making choice where they either kept or bet the money they were given. Cardiodynamic activity was measured with ECG using a BIOPAC MP system. Results suggest that with an increase in cortisol, adrenaline, heart rate, and subjective stress, participants were likely to make fewer risky choices. So, high levels of stress may be key in helping make better decisions when selecting a future president.

Perhaps it’s not stress that will influence the choice of the next POTUS (President of the United States), but rather the behaviors of others. Work by Bault, Joffily, Rustichini, and Coricelli (2011) sought to compare private and social decision-making to discover the effect of social comparison on risky choices. The objective of the study was to understand more about how individuals evaluated the outcomes of their decisions in private as opposed to in a social context. Combining data from functional MRI (FMRI) and skin conductance recordings, subjects’ reactions were measured using a BIOPAC MP150 System. Researchers found that participants took significantly longer to make a decision in a social setting than in a private one.

In the end, many feel that it is important to listen to your heart when deciding who you find qualified to be the next president. A study by Dunn et al. (2010) examined whether introception moderates the coupling of bodily responses to emotional experience and intuitive decision-making. Bodily response and heart rate were recorded using a BIOPAC Research System and electrodes to measure introception through changes in heart rate. Researchers found that introception was not related to arousal, valence ratings, or heart rate response to images.

For more information on BIOPAC’s wide range of tools for recording, displaying, and analyzing physiological measurements from human and animal subjects including respiration, heart rate variability, ECG and EDA, visit BIOPAC’s psychophysiology page and view BIOPAC’s full line of electrodes, amplifiers, and wearable, wireless transmitters and loggers.

Think As Scientists Think—Empirical Research Skills

Learning to think as scientists think is empowering and drives this process and “Hard” and “soft” research skills combine well with Biopac Student Lab Lessons.

(Photo © 2016 Knowledge Growers, Inc.)

By Howard Iver Thorsheim, Ph.D., St. Olaf College

“Hard” and “soft” research skills combine well with Biopac Student Lab Lessons; for example:

Working as members of cooperative-learning teams;
Learning about basic psychophysiological measures;
Organizing supplies;
Following a protocol to greet a participant;
Explaining proposed procedure, and obtaining written informed consent using a form they draft;
Preparing participant, placing electrodes, and manipulating independent variables;
Debriefing participant;
Analyzing and graphing results;
Writing up research results in APA format.

Since the goal is learning skills for thinking, many of the usual requirements for rigorous research headed for publication can be relaxed for beginning students. This can motivate students for advanced student research honors projects or faculty/student research. Some examples of requirements that can be relaxed include naive participants (team members can serve as experimental participants in each other’s explorations—availability samples), sample sizes large enough to attain statistical power (instead two or three can be sufficient), and random assignment to conditions.

Learning to think as scientists think is empowering and drives this process, and some examples include students thinking about:

Articles of interest students find in data base searches that lead to their own research questions to explore;
Which psychophysiological measures they have practiced would provide information to help them learn more about their research question;
What they want their participants to do;
Key issues of experimental and statistical control, and
Any other equipment or supplies they might need to arrange for in addition to what is available within the limitations of available apparatus and facilities.

Before they may proceed, beginning students present their thinking on such issues to me as their consultant.

I provide a rubric with many tips, such as noting what they observed during the experiment that could have unintentionally influenced the results, describing strengths and limitations of their conclusions based on their findings, and answering the “So what?” question to extend their findings into their own life and think about the implications such findings might have for them.

See following for more ideas for teaching empirical research skills to help students think as scientists think, with research support:

Thorsheim, H. I. (2015). Experimental psychology. In D. S. Dunn (Ed.), The Oxford Handbook of Undergraduate Psychology Education. New York: Oxford University Press, 387-401. (Focus is.)

Learn more about BIOPAC’s education solutions, including complete teaching systems for psychophysiology and the life sciences. BIOPAC also provides a wide range of research systems for recording, displaying, classifying, and analyzing psychophysiological measurements.

Professor Thorsheim is a licensed Psychologist, educator, and author. He has published or presented over 125 papers, journal articles, books, book chapters or monographs, and received a patent in 1985 as a co-inventor for an educational book design with interactive elements. His work has been funded by marquee foundations across the globe. His most recent work is Doing Psychophysiology: Getting Started, available from Knowledge Growers, Inc., available as an iBook download in 51 countries.

Thinking As Scientists Think

By Howard Iver Thorsheim, Ph.D., St. Olaf College. Information literacy skills projects help students discover that they know that they know how to find information, which increases their sense of competency, and is self-reinforcing.

(Photo © 2016 Knowledge Growers, Inc.)

By Howard Iver Thorsheim, Ph.D., St. Olaf College

I have titled this blog “Thinking As Scientists Think.” A more accurate—but longer—description might be “Helping Students Learn Skills to Think As Scientists Think—Information Literacy Skills.” I have found it effective to help students learn two levels of skill development that will help them think as scientists think: (a) information literacy skills to learn about the skills, which is the focus of this blog, and (b) empirical research skills to do the skills they have learned about (discussed in this post, building on Biopac Student Lab lessons).

I partner with a librarian colleague to develop and provide an initial 45-minute information literacy skills session on how to use available databases to locate information. I provide a selected list of research skills to guide their search. Teams decide exactly what they read online about each listed skill, so information each team locates may be unique, though the skills searched are the same. They discover that they know that they know how to find information, which increases their sense of competency, and is self-reinforcing.

You can select your own list of research skills you wish students to learn about, to fit your own teaching/learning goals and schedule. The following are some examples from my skills list for introducing psychophysiology in courses:

strategy for using information literacy skills;
using a consultant (in this case it is me, their teacher);
forming research questions;
psychophysiology methods;
operationalization of variables;
psychophysiological measurement;
adhering to research ethics;
statistical analysis in psychophysiology (selecting methods appropriate from their course background ranging from descriptive to more sophisticated statistics);
writing following the format of the Publication Manual of the American Psychological Association, and
oral presentation skills (e.g., tips for presenting their summaries that will help them be excellent peer-mentors).

The genuine research skills students learn support your course goals and engage students in science, contribute to national STEM goals, and add to a student’s thinking toolkit. Students can annotate their team-based information-literacy searches and can include that in a cumulative personal skill inventory, useful for skill-based résumés for assistantships, jobs, and graduate applications.

Here are two helpful resources on the usefulness of helping students develop genuine research-oriented skills and begin using them:

Jenkins, A. & Healey, M. (2010). Undergraduate research and international initiatives to link teaching and research. Council on Undergraduate Research Quarterly, 30(3), 36-42.

Mervis, J. (2016). Genuine research keeps students in science. Science, 352(6291), 1266.
DOI: 10.1126/science.352.6291.1266

Respiration and ECG

By Alan Macy, BIOPAC Systems, Inc. The mechanical relationship between the diaphragm and heart and Respiratory Sinus Arrhythmia (RSA). are two influences of respiratory activity on the electrocardiogram (ECG).

By Alan Macy, BIOPAC Systems, Inc.

There are two influences of respiratory activity on the electrocardiogram (ECG). The first influence is characterized by the mechanical relationship between the diaphragm and heart. The second influence is a consequence of respiratory action on the vagus nerve and is known as Respiratory Sinus Arrhythmia (RSA).

The position and movement of the diaphragm determine the position of the heart because the pericardium is firmly attached to the central tendon of the diaphragm. With deep inspiration, the diaphragm contracts and becomes flatter and less dome-shaped. As it does, the heart descends, moves backward, and rotates to the right so that it becomes narrower and more vertical. The apex beat is lower and more medial. During deep expiration, the diaphragm relaxes, elevates, and becomes more dome-shaped, and movements of the heart are the converse of those that occur during deep inspiration. The degree of the directional movements of the heart during quiet breathing is similar, but reduced, compared to deep breathing and, in some persons, may be hardly noticeable. Diaphragmatic breathing cyclically affects the position of the heart, thus modifying the ECG.
Heart rate increases during inhalation and decreases during exhalation. Heart rate is normally controlled by centers in the medulla oblongata. One of these centers, the nucleus ambiguus, increases parasympathetic nervous system input to the heart via the vagus nerve. The vagus nerve decreases heart rate by decreasing the firing rate of the sinoatrial (SA) node. The SA node is the “pacemaker” of the heart. Upon expiration, the cells in the nucleus ambiguus are activated and heart rate slows down. In contrast, inspiration triggers inhibitory signals to the nucleus ambiguus and consequently the vagus nerve remains unstimulated. When recording the ECG, this phenomenon is experienced as subtle changes in the R-R interval that appears synchronized with respiration. This is the time period between two “R” waves on an electrocardiogram. The R-R interval associated with the ECG is shortened during inspiration and prolonged during expiration.

For more information on BIOPAC’s wide range of tools for recording, displaying, and analyzing ECG measurements from human and animal subjects including respiration, heart rate variability, and RSA, visit BIOPAC’s electrocardiography pages and view BIOPAC’s full line of electrodes, amplifiers, and wearable, wireless transmitters and loggers.

How to Promote Cooperative Thinking

By Howard Iver Thorsheim, Ph.D., St. Olaf College. How to promote cooperative thinking of team members doing psychophysiology, draw from their richly diverse interests and ideas, and in the process teach a “soft” skill that could transfer to later life.

By Howard Iver Thorsheim, Ph.D., St. Olaf College

Howard Iver Thorsheim is Professor of Psychology and Neuroscience at St. Olaf College, Northfield, Minnesota, USA. In these blogs he offers his first-person insights into effective teaching techniques gleaned from a combination of scholarly research and over 40 years in the classroom.

The Challenge:

The challenge was how to promote cooperative thinking of team members doing psychophysiology, drawing from their richly diverse interests and ideas, and in the process to learn a “soft” skill that could transfer to later life.

The Solution:

I adapted a tried-and-true group process to help team members doing psychophysiology research identify diverse ideas and think about their group project in a cooperative way. (The technique can be scaled up to engage many teams simultaneously). The technique is called the Nominal Group Technique, first developed by DelBecq and Van de Ven (1975).* The reason for the word nominal is evident in Step 1.

Step 1. Each student in a team was given a stack of 25 or so Post-it® notes. Because each student is working alone at this point, they are a group in name only (i.e., nominally a group). Their homework assignment was to think independently about ideas and interests that came to mind for them, and jot down a few words identifying their idea or interest on each of the Post-it notes. Interaction comes in step 2.

Step 2. The next class, the team members gathered together near a whiteboard. In a round-robin interactive fashion, one at a time, the students placed their Post-it notes on the board: One person started by placing the top Post-it from their stack on the board; the second person placing their first Post-it note close or further away from the first person’s Post-it note, depending upon their sense of closeness of the ideas. So it goes with the other students, with the round robin continuing until all Post-it notes are placed on the wall. Step 3 is the convergence!

Step 3. Again in a round-robin fashion, students take turns with a non-permanent marker drawing dashed lines around clusters they observe, and jotting down their idea for a name for each cluster. The result from the large group of individual ideas or interests becomes a smaller cluster of related ideas. The result is more coherence of ideas, engagement, social cohesion, and team focus. It works every time in any team or group!

See how the Center for Disease Control adapts the technique in this Nominal Group Technique (NGT) Evaluation Brief.

*Delbecq, A. L., Van de Ven, A. H., & Gustafson, D. H. (1975). Group techniques for program planners: a guide to nominal group and Delphi processes. Glenville, Illinois: Scott Foresman.

Start the First Class with EDA and Emotional Responses!

By Howard Iver Thorsheim, Ph.D., St. Olaf College. I wanted to start the first day of my class with an activity that would engage students’ curiosity and enthusiasm, to set the stage for introducing the course and going over the syllabus!

By Howard Iver Thorsheim, Ph.D., St. Olaf College

I find Electrodermal Activity (EDA) to be a great way to demonstrate psychophysiology measurement at the beginning of a course: students easily understand it. It takes little time to set up and record because it only involves two sensors on the finger tip pads. It works every time as a “window” to emotions with clear responses to a variety of stimuli (e.g., visual, auditory, gustatory, olfactory).

I show students a picture of a rock climber climbing a cliff, then ask them to jot down some notes of what they might feel when climbing like the woman pictured, and then buzz with a person sitting next to them about what they wrote. I ask for a show of hands of who has mentioned the bag hanging from the climber’s belt. Depending on the amount of time I choose to devote to the activity, I lead the entire class through a number of probing questions; for example:

“Who knows what the bag is for?” (Chalk for fingers.)

“Why does the climber use chalk?” (Reduce slipperiness from sweat.)

“Why do fingers get slippery?” (Emotion.)

“What other people encounter emotion daily?”

I then set the stage for EDA: changes in skin conductivity are due to the amount of sweat in sweat glands of the skin, which are produced by the sympathetic branch of the autonomic nervous system responding to emotion.

I explain to the class that I will be the first volunteer, and guarantee that no shock is involved using BIOPAC equipment. I connect electrodes on the volar pads of my index and middle fingers, and take a deep breath, which will generate EDA. Then I tell the class I will think of emotion-producing situations, and ask them if they can see any EDA detected by the equipment. There will be a few good chuckles because in anticipation of doing so, my response will already appear. Two of several easy classroom measurements of EDA include latency (about 1 to 3 seconds between a stimulus and beginning of the electrodermal response), and peak amplitude (the maximum size of the response). My eBook Doing Psychophysiology–Getting Started on the Apple iBooks Store has a graphic narrative and a one-minute video explanations about EDA, as well as other psychophysiology measures you can show your students. The Biopac Student Lab system also includes two lessons in which students can engage in interactive learning activities while measuring EDA; a lesson on the principles of biofeedback and one on the standard physiological measures of a polygraph.

An excellent summary of Electrodermal Activity is provided in the following chapter:

Dawson, M. E., Schell, A. M. & Fillion, D. L. (2007). The electrodermal system. In J. T. Cacioppo, L. G. Tassinary, & G. G. Berntson (Eds.). Handbook of psychophysiology (3^rd ed. pp. 159-181). New York: Cambridge University Press.