Author: Marketing Department

Keeping students engaged in the study of physiology can be a challenging exercise. Once the sole province of dusty textbooks and cumbersome lab manuals, the computer age ushered in quantum advances in the packaging of physiology curricula. Disadvantages were reflected in the cost of the systems, which often dictated that students crowd around a single computer, peering over shoulders with craned necks at confounding interfaces.

These early systems often left students feeling somewhat isolated because with only one student or instructor operating the computer, it was often difficult to engage all group members. Setting up the data collection was also a challenge and data quality itself was often poor. An unwelcome result was low student satisfaction and learning.

Gradually systems improved, becoming easier to use and more comprehensive. Current student physiology packages (such as Biopac Student Lab) divide various physiological disciplines into individual guided lessons (up to 65) and offer a high degree of interactive and multimedia content. Still, the challenge remains, how to keep students engaged and invested in the study of physiology? When considering a system, the following factors can help in this regard.

Choose a system that allows students to collect data on themselves. Engagement is higher when recording and analyzing one’s own data. Another key is to choose a system designed to offer all students a role. The student who isn’t the subject can be a recorder, director, or computer operator, and students can rotate to ensure everyone has a turn at being a subject. Everyone at every station has an integral role, rather than simply observing while an instructor operates complicated equipment. Simplicity of setup is also important. Systems such as Biopac Student Lab are compact and have standardized, modular “Simple Sensor” leads and transducers. The BSL systems come with all hardware, software, and support materials needed to begin collecting high-quality data within minutes.

The system should also support students’ ability to take their lessons home for further analysis. Biopac Student Lab can be augmented with a free downloadable analysis version of the software that can be used on any computer for analyzing data outside the lab. This enables students to remain more connected with their studies.

Lastly, interactive interfaces with clear onscreen instructions augmented by electronic and printed lab manual documentation are very helpful for beginning physiology students, and the system should be powerful enough to achieve clear, precise results while allowing for statistical comparisons be upper-level students.

This short list of key concepts encourages every student’s full participation, helps ensure all data is accurate, and allows students and instructors alike to obtain the most from the lab experience.

For more, click to watch a free BIOPAC webinar: Teaching Physiology: How to Engage Students in Lab Environments.

BIOPAC offers a wide array of wired and wireless equipment that can be used in your research. To find more information on solutions for recording and analyzing signals such as ECG, heart rate, respiration and more using any platforms mentioned in this blog post, you can visit the individual application pages on the BIOPAC website.

When setting up data acquisition parameters, one area of befuddlement often involves the use of filters. Which ones should I use, and how do I set them up? What are they really, and why do I need them? In a nutshell, filters are configurable controls for removing certain frequencies from a signal, while leaving others unaffected, and are  useful for removing noise and improving signal quality. Filters can be set up in the software as “online” (applied in real time during acquisition) or “offline” (applied post- acquisition). Some BIOPAC amplifiers, such as the 100C series, include a bank of filter switches relevant to the type of signal being acquired. As far as which filter to use, that is dependent on the type of physiological signal being acquired and BIOPAC amplifiers and software presets will help steer you toward the correct type of filter to use. Subsequent blog entries will delve more into specifics about which types are appropriate for which signals.

As in our earlier blog about frequencies, we’ll again be using the “cars” analogy to bring filtering concepts  into sharper focus. Say we want to look only at cars on a freeway that are traveling at or above the speed limit. To effectively do this, we’ll need to find a way to remove the slower vehicles from view. To isolate the “fastest” cars, we would apply a “High Pass” filter. By “High Pass,” we mean this filter eliminates all frequencies that fall below a specified cutoff point, and allows the higher frequencies to “pass through,” or remain present in the signal. Using the “cars/freeway” analogy, setting a High Pass filter to target cars traveling at 60 mph would eliminate all cars traveling at or below 60 mph and leave all faster cars unaffected.

Conversely, we can apply a “Low Pass” filter, which would eliminate all cars traveling faster than a specified speed and leave only the slower cars intact. Another “combination” filter that can be applied is a “Band Pass” filter, which eliminates the fastest and slowest moving “cars” and retains all cars that are traveling at a specified speed. Additional common filters are:

Band Stop isolates and removes a specific frequency or frequencies (all cars traveling at one particular speed, or range of speed, leaving all the others). This filter is most commonly used to eliminate 50 Hz or 60 Hz electrical noise frequencies from a signal.

Comb Band Stop is another powerful filter commonly used for removing electrical noise. The Comb Band Stop filter removes not only the 50 Hz or 60 Hz frequency, but also all overharmonics, or “echoes” of that frequency. For example, if you are in an area of the world that uses a 50 Hz line frequency, the Comb Band Stop filter will eliminate from the signal the 50 Hz frequency, plus 100 Hz, 150 Hz, 200 Hz, etc. If you live in the U.S. or other part of the world that uses a 60 Hz line frequency, this filter will remove 60 Hz, 120 Hz, 180 Hz, 240 Hz, etc. (A better analogy for this type of filter might be musical notes and their octaves rather than cars traveling at speed.)

All filters discussed above are supported in BIOPAC AcqKnowledge and BSL 4 software, as well 100C series  amplifiers, and can greatly enhance signal and data quality.

For further reading on filters, please see the following resources:

www.biopac.com/knowledge-base/high-pass-filters/

www.biopac.com/knowledge-base/band-pass-and-band-stop-filters/

For more information, please view our Fundamentals of Physiological Data Recording.

BIOPAC offers a wide array of wired and wireless equipment that can be used in your research. To find more information on solutions for recording and analyzing signals such as ECG, heart rate, respiration and more using any platforms mentioned in this blog post, you can visit the individual application pages on the BIOPAC website.

BIOPAC amplifiers used with the MP160 Data Acquisition System are equipped with configurable settings designed for optimizing the physiological signal being acquired, one of which is the gain setting. What is gain? Put simply, gain refers to the amplifier’s ability to adjust the power or amplitude of an incoming signal. If an incoming signal is very strong, and the gain level on the amplifier is set too high, the signal may appear onscreen as “clipped,” resulting in loss of data. This can happen when the strength of the signal exceeds the maximum input voltage range of -10 volts to +10 volts supported by the MP160 Data Acquisition System. (Think trying to fit 20 lbs of oranges into a 10 lb bag.)

This condition, also known as “railing,” means the amplifier gain level needs to be reduced in order for the signal to fall within the maximum 20 volt peak-to-peak range. Conversely, if an incoming signal is weak or of low amplitude, the gain level will need to be increased, lest the signal appear too small onscreen for proper analysis. (Akin to trying to fill up a 10 lb bag with one or two oranges.)

A good rule of thumb for setting proper gain levels is to remember that a lower amplitude signal requires a higher gain setting, while a higher amplitude signal can tolerate a lower gain setting.

BIOPAC 100C Series amplifiers generally have four gain settings (for example, 500, 1000, 2000 and 5000, in the case of the ECG100C amplifier). A gain setting of 5000 would result in a signal amplitude 10x greater than the same signal set to a gain of 500. Although the gain settings on BIOPAC 100C amplifiers cover a wide range, the included ranges are tailored for the signal the amplifier is designed for. This means even if the gain is not optimally set, the signal should still be within an acceptable range.

AcqKnowledge software also automatically scales the incoming signal so that it fits within the graph channel, but for the highest data quality possible, attention should be paid to the gain setting of the amplifier. The good news is that AcqKnowledge software Module Setup walks you through proper configuration of amplifiers and transducers, thereby minimizing error and maximizing data quality.

For more information, view Fundamentals of Physiological Data Recording.

BIOPAC offers a wide array of wired and wireless equipment that can be used in your research. To find more information on solutions for recording and analyzing signals such as ECG, heart rate, respiration and more using any platforms mentioned in this blog post, you can visit the individual application pages on the BIOPAC website.

The characteristics of a particular body signal are dictated by its amplitude and frequency. The frequency of a signal can help determine the ideal rate at which to sample a particular signal, thus ensuring the resulting waveform is of the highest quality. Basically, the higher the frequency of a signal, the faster the sample rate that should be used. As an analogy – if we liken the various signals to a freeway and assume all cars are traveling in the same direction, but at different speeds, we can then determine the signal’s frequency band by looking at the slowest cars and the fastest cars. For comparison, a “slow car” would be an electrogastrogram (EGG) signal (0-1 Hz) and a “fast car” would be an electromyogram (EMG) signal (10-2000 Hz). In order to acquire the information correctly, we need to ensure the sample rate is set high enough to sweep up in our dragnet the fastest cars along with the slower cars. In the case of the EMG signal, if the sample rate is set to only 100 Hz, many of the faster “cars” would not be captured, and the definition of the upper frequency ranges would be lost in the resulting waveform. Conversely, 100 Hz would be more than sufficient to capture all of the “cars” on the EGG signal freeway. (Other frequency range examples for particular signals are: ECG = .05-100 Hz, EEG = 1-100 Hz, EOG 01.-100 Hz.) The good news is that BIOPAC sets the acquisition sample rate to a default of 2000 Hz in our  MP160 or MP36 systems for AcqKnowledge or Biopac Student Lab software, more than sufficient for most applications. That said, it’s good practice to determine the maximum frequency response of a particular signal and multiply that maximum by four times to arrive at the sample rate that will capture all the cars moving down the freeway.

BIOPAC offers a wide array of wired and wireless equipment that can be used in your research. To find more information on solutions for recording and analyzing signals such as ECG, heart rate, respiration and more using any platforms mentioned in this blog post, you can visit the individual application pages on the BIOPAC website.

During the process of physiological data acquisition, the human body behaves much like a battery. Electricity flows from parts of the body that are negatively charged to parts of the body that are positively charged, and this occurs constantly throughout all living tissue.

Since each physiological signal has a distinctive electrical signature, we can place electrodes at the appropriate points on the body and accurately record the electrical activity of the desired signal. Modern data acquisition systems (such as the MP160 or MP36 systems) convert these analog signals into digital waveforms that can be displayed onscreen via life science software such as AcqKnowledge or Biopac Student Lab.

When acquiring physiological data, it’s important to understand the distinction between biopotential and transducer signals. Biopotential signals are electrical signals acquired directly from the body via electrodes, as previously referenced in the “human battery” analogy. Examples of biopotential signals are heartbeat (ECG), brain activity (EEG), muscle activity (EMG), eye movement (EOG),  and gastric system (EGG). Transducer signals differ from biopotential signals in that they are reliant on force, movement, or some other proportionate change, rather than electricity from the body. To measure these, the transducer itself provides a voltage signal which enables it to measure activity such as respiration/airflow, blood pressure, temperature, and grip strength. In all cases, the voltage signal produced by the transducer increases proportionately with the force, movement, or temperature exerted upon it. This affects the contour and appearance of the onscreen waveform.

Whether recording biopotential or transducer signals, both offer a glimpse into the varied and complex workings of the human body.

BIOPAC offers a wide array of wired and wireless equipment that can be used in your research. To find more information on solutions for recording and analyzing signals such as ECG, heart rate, respiration and more using any platforms mentioned in this blog post, you can visit the individual application pages on the BIOPAC website.