Category: physiology

The Eyes Have It—Mobile Eye Tracking

Eye tracking has been a consistent player in the physiological research field for a number of years, and more recently a “mobile” variation of this technology has become increasingly widespread. But just what is mobile eye tracking and how does it work? Unlike eye tracking studies tethered to a lab, where a participant visually follows an object on a computer screen, mobile eye tracking data can be acquired outside of the lab. All that is required, in fact, is a pair of glasses. Not just any glasses, but ETVision glasses, capable of recording not only multiple parameters of a participant’s “eye image” but also the scene the participant is gazing at and responding to. Let’s look briefly on how eye tracking glasses work. The lightweight ETVision glasses are equipped with two eye-facing cameras combined with a pair of LEDs for recording the various components of the “eye image,” such as pupil size/position, gaze path, fixation (when the participant’s eyes lock onto an area of interest), internal and external data markers, vergence angle (angle between the eyes), and corneal reflections (CRs). The cameras also look at the contrast between the pupil and the surrounding iris. This constant real-time feedback is recorded every 5.5 milliseconds and the eye images are rendered at 180 frames per second.

In addition to eye cameras, a built-in forward-facing 720p scene camera records the viewable area in front of the participant. This enables the landscape or scenery the participant is looking at to be combined and synchronized with the eye image data (say, if the participant is driving a car or riding a mountain bike).

Did I say riding a mountain bike? Yes. Full eye tracking data can be collected and stored in a 256 GB SD card and the logged data exported to a .*csv file, which in turn can be imported into AcqKnowledge software along with other logged physiological data. The glasses also have a coated visor for reducing glare. (Glare causes squinting and the eye tracking cameras do not perform as well on eyes that are squinting or closing due to excessive light or reflections.)

In addition, a small microphone built into the eyeglasses enables two-way audio between the investigator and the participant. Already wear glasses? No problem. Eye tracking glasses can be worn over corrective lenses without issue. However, contact lenses should be cleaned before wearing them under eye tracking glasses. The glasses are connected to a small controller via a standard HDMI cable, and the controller houses a 256 GB SD card. In addition to the SD card used for logging remote data, the controller can also be connected to a host computer via WiFi or LAN. The lithium-polymer battery will run the eye tracking glasses for 5.5 hours on a full charge.

Using the AcqKnowledge software’s Media feature, the eye tracking video data can be replayed with a tight correlation to other physiological data collected during the experiment by the BioNomadix Logger. (Other data acquisition hardware types, such as MP160 or MP36R, can be used within the lab.) The eye tracking video and graph data can be displayed side-by-side on the screen. Placing the I-beam cursor at any point in the AcqKnowledge graph takes you to the corresponding point in the eye-tracking video (say, during activities such as driving a car). Eye tracking data for vertical position, horizontal position, pupil diameter, and more can be imported as channels into the AcqKnowledge graph. This data will be synchronized with the eye tracking video, along with any added event markers.

Interested in more details about ETVision Eye Tracking Glasses and AcqKnowledge software? To see it all in action, we invite you to view our free on-demand Mobile Eye Tracking Webinar.

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.

Photo by Amanda Dalbjörn on Unsplash

Eye Tracking Insights

Try Not To Blink—This Won’t Hurt

What exactly, is eye tracking? Do I have to put on a helmet or stick something unpleasant into my eye? No, nothing so invasive, and not the least bit uncomfortable. Eye tracking is the process by which eye movements are recorded for the purpose of tracking where a subject is looking, what he/she is looking at, and the duration of the subject’s gaze on a given area. Eye tracking differs from electrooculogram (EOG) in that it records where and at what the subject is actually looking, whereas EOG primarily records the movements of the eye muscles. Rather than merely recording eye movement and position, eye tracking forges an invisible yet accurate connection between the subject and the objects within the subject’s field of vision. These “visual connections” of where the subject was looking during the study are clearly visible in the resulting data, as dramatic as tire tracks on an impressionable surface.

So how does eye tracking work? Using invisible near-infrared light combined with high-definition cameras, the eye tracking system projects invisible light onto the eye and records the direction from which it is reflected off the cornea. Eye tracking software is used to calculate the exact position and focal point of the eye. The sophisticated combination of eye tracking hardware and software allows for extremely accurate measuring and analyzing of visual behavior and fine eye movements. This makes it possible to create a detailed map of a subject’s field of vision and the specific visual elements honed in on by the subject. Eye tracking data is commonly acquired in tandem with other body signals for the purpose of determining the effects of what we are looking at has on our physiology. Common signals acquired during eye tracking studies are:

  • EEG (cognitive processes)
  • EDA (alertness)
  • ECG (anxiety)
  • EMG (muscle activity, conditioning)
  • EGG (pulse, respiration, temperature)

What are researchers looking for when conducting eye tracking studies? Eye tracking data is useful in a variety of different research fields including interface usability, reading analysis, psychological and emotional response, marketing research, training, clinical vision diagnosis, and more.

Eye tracking hardware mainly comes in two flavors. Screen based eye tracking involves having a subject sit in front of a computer monitor while being presented with various types of visual stimuli. A “bar type” eye tracker records the subject’s responses and interfaces with eye tracking software to present the stimulus and store the resulting data for analysis. BIOPAC’s AcqKnowledge software version 5.0.6 and higher, along with the BIOPAC MP160, MP36R, or Wireless Smart Center system, supports fully-integrated eye tracking functionality*. Rather than having to learn a second software program, the familiar AcqKnowledge interface has been extended to incorporate the EYE-TRACK-BAR and EYE-TRACK-BAR-XL remote screen eye tracking systems.

Mobile or “wearable” eye tracking systems utilize a pair of glasses with two types of built-in cameras. One camera faces the subject and tracks eye movements, gaze path, and other parameters, and a second camera (called a scene camera) records what the subject is looking at during the study. Mobile eye tracking allows the subject to engage in independent activities outside the lab, such as driving an automobile. Additional sensors record and log data from other body signals in real time, which can be loaded into the software for subsequent analysis.

For more information about eye tracking, we invite you to sign up for our free “Eye Tracking Fundamentals” webinar to be broadcast live on November 21, 2019 at 8:00 AM PST. Did you miss it or can’t attend? No problem. Follow the same link to watch it on demand.

*Eye Tracking Integration License for AcqKnowledge required.

Please also visit the following links for information about BIOPAC Eye Tracking products.

Eye Tracking Systems

Eye Tracking License

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.

Photo by Marina Vitale on Unsplash

Best Practices for Recording & Analyzing Data

Over the past several years, tools and techniques for recording and analyzing physiological data recording have seen steady and marked improvement. Modern life science data acquisition systems such as the MP160 System and powerful research-grade software suites such as AcqKnowledge bring high-end physiology tools within reach of the smallest lab. Even with continuing advances and reduced margin for error, it remains prudent to follow some fundamental guidelines for maximizing data quality and clarity.

Preparation is important. First, invest time exploring the system if it’s new or unfamiliar. An overview of the documentation, training videos, and available webinars, as well as some practice runs with the hardware and software will save time and effort when the time comes to conduct a study. This will also build proficiency at identifying the differences between good and poor data.

Next, familiarize yourself with the type of electrodes and/or transducers necessary for the physiological signals you will be acquiring, which includes proper electrode and skin site preparation. For example, gently abrading the skin prior to applying electrodes is normally recommended for most signal types, except for electrodermal activity (EDA), in which case it’s vital to NOT abrade the skin beforehand. It is also helpful to wait at least 5 minutes before starting a recording, which enables the electrode gel to be absorbed into the skin, helping reduce the impedance.

Performing an impedance check to ensure that the electrodes are making good contact with the skin is also highly recommended. This task is made easier by using an Electrode Impedance Checker (such as EL-CHECK), a simple device for quickly measuring the resistance between the skin and the electrode that provides an LED readout of the skin/electrode contact quality. If the resistance is too high (indicating poor contact) proper adjustments can be made before starting an experiment.

For certain signal types, excessive participant movement can introduce unwanted artifact into the signal, resulting in poor or skewed data. Make sure the participant remains as still as possible during studies involving these signals. Using tape to attach the electrode leads to the skin and keep them from moving excessively can also be helpful.

A thorough check of the system and all connections, cameras, and other hardware is important, so that any problems with equipment or setup can be addressed in advance, thus avoiding a show-stopping issue in the midst of an experiment. This would include performing a pilot study with trained personnel in order to head off any unforeseen issues with the data collection.

Creating a lab setup conducive to a relaxed environment for the participant and technician alike will yield better results. This means eliminating clutter, noise, and other distractions that can affect comfort and attention span. Some labs even avoid having their staff wear lab coats because this can heighten participant nervousness.

Keeping detailed notes on successful lab setups is also helpful and will streamline the preparation process for future experiments. Additionally, creating and saving graph templates for regularly-repeated experiments will save further time and effort.

For more about the fundamentals of recording great data, we invite you to view this free on-demand webinar Fundamentals of Physiology 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.

Photo by John Schnobrich on Unsplash

ECG – The Little Wave You Can’t Live Without

For millennia, ancient healers across the globe long recognized the human heart as immeasurably vital to human life. Other organs may take an occasional time out, but not the heart. This sinewy fist-sized pump contracts and relaxes an average 60 to 80 beats per minute and faithfully repeats this cycle some two and a half billion times over an average human lifespan, constantly driving and recirculating lifeblood through 100,000 miles of veins, arteries, and capillaries. It’s a monumental task that we take for granted, but if the process stops for more than a few minutes, so will this mysterious force we call life.

It’s intriguing to consider the wonder with which the ancients must have contemplated this organ that thumps so audibly. They knew it was of critical importance, and over the centuries learned its form and surface physiology, but what did they imagine animated it? What force kept the heart moving so steadily and faithfully, while remaining implacably divorced from the consciousness of its host? (Go ahead. Try to stop your heart. On second thought, don’t.)

The answer, in a word, is electricity. Although the stethoscope, invented in 1816 by French physician René Laennec, augmented audible heart sounds, it wasn’t until 1901 that Dutch physician Willem Einthoven developed a “string galvanometer,” capable of reliably recording the heart’s electrical activity. Einthoven’s work established a standard configuration for recording the electrocardiogram (ECG) and garnered him the Nobel Prize in 1924. Because the ECG reflects electrical activity, it is a useful “picture” of heart normality or abnormality through the observation and analysis of various distinct components of the cardiac cycle. If there are interruptions of the electrical signal generation or transmission, the ECG changes. These changes can be useful in diagnosing changes within the heart.

The methods for recording ECG have become increasingly sophisticated with the advent of digital technology and have put state-of-the art acquisition and analysis of ECG within reach of not only clinicians, but also researchers and educators. Wired in-lab systems such as the BIOPAC MP160 System with AcqKnowledge software are widely used for Research applications, while the MP36 System with Biopac Student Lab software are the industry standard for physiology education around the globe. Wireless systems such as BioNomadix or BioNomadix Smart Center can be used to collect ECG and other body signals in an untethered environment and the BioNomadix Logger is a great solution for acquiring ECG and other body signals over extended periods outside the lab.

We have come a long way since our forebears contemplated the mysteries of the vital mechanical wonder that beats in every chest, and we now have a myriad of accessible options for unlocking its secrets.

For further exploration of ECG, we invite you to enjoy the following comprehensive free ECG webinars:

Recording Great ECG

HRV & RSA – Fundamental ECG Analysis Techniques

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.

 

Exercise Physiology – Pulling Out All the Stops

Everyone has experienced showing up at the doctor’s office and being tasked with sitting very still while vital signs are taken. You sit almost trance-like, concentrating on slowing your heartbeat, willing your blood pressure down, avoiding any sudden movement that might affect the signals being monitored for posterity. It’s quite another matter when body signals are being monitored and measured from someone in full motion, particularly an elite athlete, all systems performing at maximum capacity. How are multiple facets of our physiology accurately captured when we are puffing and sweating at full exertion? Don’t these movements introduce artifact into the data and affect its quality? Won’t the result be an unusable mess? The truth is with proper setup and hardware, acquiring accurate signals from exercise physiology subjects has never been easier.

Signals typically and simultaneously acquired during exercise physiology studies are heartbeat (ECG), respiration (RSP), muscle activity (EMG), in addition to oxygen uptake, carbon dioxide production, blood pressure, core/surface temperature data, range of motion, and even GPS, if the participant is performing the activity outside the lab.

An important factor in exercise physiology studies is choosing the right electrodes, as well as their placement. We recommended using long-term electrodes, such as EL502, which can be worn up to 24 hours. If sweat is a problem, use stress electrodes which adhere better and are resistant to moisture. For even better adhesion to contoured parts of the body, use fabric electrodes. It is also important to prep the electrode site correctly, by first abrading the skin using an ELPAD, and making sure the electrode has sufficient conductive gel.

For measuring ECG signals, particularly Lead II, place the electrodes over bone such as a clavicle or rib to minimize movement artifact. For studies involving a lot of abdominal movement, a Lead I ECG configuration is recommended (left and right clavicle placement). This will help assure a good ECG signal during exercise.

If the participant is inside the lab (say, on a treadmill or exercise bike), a “wired” system, such as BIOPAC’s MP160 System with 100D-Series Smart Amplifiers is a good choice. Up to 16 channels of data can be acquired which can be extended to include 16 calculation channels of derived signals or online filters. For more freedom of movement, the MP160 System with BioNomadix wireless transmitters/receivers offer unrestrained comfort, including a BioShirt with built-in ECG fabric electrodes and RSP transducer. The wireless BioNomadix System has a range of 10 meters line-of-sight between transmitters and receivers. For long-term studies outside the lab, the BioNomadix Logger records and logs data for up to 24 hours while the subject goes about their protocol.

An additional wireless system commonly used for exercise studies is the Mobita System. Mobita is wireless, and like the aforementioned systems, works with the MP160 and AcqKnowledge software for recording and advanced analysis. Mobita is compact enough to fit in your hand and will record up to 32 channels of biopotential data.

No reason to keep still or be quiet any longer. With this many choices, acquiring high-quality exercise physiology data over a full range of body signals is within easy reach.

For more information about exercise physiology and how to maximize your results, we invite you to view our free webinar, Recording Great Data from Exercising and Mobile Subjects.

Why Smart Technology Is Smarter

Physiological research studies require a great deal of focused expertise, including an ability to properly set up all necessary equipment for the study at hand. This has long consisted of overseeing a host of manual hardware connections and software settings, and mistakes can be frustrating. The good news is most users become proficient at these detailed configurations, but wouldn’t it be a welcome change if these setups were easier? Think about how helpful it would be if the hardware and software were “smarter” and actively worked on your behalf. This is now a reality with the smart technology offered by BIOPAC’s newly-released line of 100D Smart Amplifiers.

What is smart technology and what makes Smart Amplifiers smarter? To begin with, these amplifiers are significantly smaller than standard amplifiers (only 4.6 mm in length) and have no buttons or switches. The convenient lightweight design is a powerful benefit, enabling these amplifiers to be attached closer to the participant’s body. Because the amp itself is positioned near the signal source(via a lightweight 3-meter cable), the resulting data is of superbly high quality, with less noise and artifact than conventional amplifiers. But let’s get to the smart part. The smart technology in Smart Amplifiers enables them to do the setup work for you. Each Smart Amplifier, regardless of signal type,  self-configures to the optimally recommended settings, negating the need for user-defined adjustments or monitoring of physical switch positions. Simply plug the amplifier into the new AMI100D Input Module now included with every BIOPAC MP160 System, launch the AcqKnowledge software, and begin recording data.

To minimize setup time and errors in the lab, Smart Amplifiers utilize auto-detection and auto-identification technology. Not only do they self-configure, they also alert you (via a software dialog) whether the amplifier is connected to the correct channel. So basically, using Smart Amplifiers right out of the box is a three step process. 1) connect the amplifiers, 2) select any desired calculation channels for derived signals, 3) click Record. That’s it.

Frequently-used calculation channels or transformations are pre-configured for all signals and can be enabled by simply checking a box in the amplifier’s software UI. (For example, the ECG100D Smart Amplifier offers options to add heart rate and/or R-R interval, and will automatically place these derived signals in a separate calculation channel in the AcqKnowledge graph.)

Smart Amplifiers are available for the following signals: ECG, EEG, EGG, EDA, RSP, PPG, ERS, EOG, SKT, EMG and new fEMG (facial and small muscle).

Significantly smaller footprint, simple setup, unparalleled user comfort, superlative data quality, compatible with previous-generation BIOPAC amplifiers (such as 100C and BioNomadix Series), portable and lightweight, Smart Amplifiers will be an epiphany for your research.

To see Smart Amplifiers in action, we invite you to watch our free on-demand webinar New Smart Technology for the Lab.

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.

Synchronize Participant Video with Physiological Data

AcqKnowledge software includes a Media feature that allows you to record and link participant video with physiological data. A common issue that crops up when analyzing physiological data with linked participant video is a lack of synchronization between the resulting video playback and onscreen data. This most often occurs when a USB webcam-type video camera is used. These types of cameras typically support a 30 frame-per-second rate whereas AcqKnowledge and the MP System can sample at rates up to 200,000 Hz. These factors can introduce an unwanted delay or misalignment between the video playback and data in the resulting AcqKnowledge graph.

So how do we synchronize these disparate signals to dovetail perfectly before recording our data and video? Fortunately, AcqKnowledge provides adjustment tools for addressing this common issue. This simple procedure requires the use of the AcqKnowledge software’s powerful Stimulator feature and a BIOPAC OUT103 LED Video Sync Cable.

Here is the sync method in a nutshell: With the OUT103 LED connected to the Analog Output of the MP160 unit’s HLT100C module, the AcqKnowledge software’s Stimulator is used to output a 5-volt square wave pulse into an AcqKnowledge graph, Using this setup, the LED illuminates when the 5-volt pulse is applied. The trick now is to use the AcqKnowledge Media feature and webcam to record a short video of the LED illuminating while the 5-volt pulse is being applied.

In the resulting graph, it’s easy to see in the Media playback screen when the light comes on by slowly advancing the AcqKnowledge software’s I-beam cursor through the graph data. Does the LED in the recorded video illuminate before the cursor reaches the 5-volt pulse? After? Or at the same time? Chances are, the recorded light will pop on slightly before or after the cursor reaches the pulse.

To compensate for this, the AcqKnowledge Delta-T measurement is used to determine the time interval between the pulse and when the recorded LED illuminates. For example, if the recorded LED lights up an indicated 185 ms before the onset of the pulse, then this discrepancy can be removed by setting a delay of 185 ms in the Media setup tools. If the LED lights up after the pulse onset, a negative delay must be set (ex. -185 ms). Once the playback delay is eradicated, the experiment can continue with confidence that all video and physiological data will be properly aligned.

It’s features such as this that enhance the usability AcqKnowledge Media feature, making it a powerful tool for recording and synchronizing participant video and audio during experiments. After a bit of practice, dialing in the playback video for linked Media acquisitions becomes second nature.

To see AcqKnowledge Media Synchronization in action, we invite you to view a free on-demand webinar covering this procedure in detail.

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.

How Stimulator Hardware and Software Work Together

In order to create an effective stimulation experiment, two main components are necessary – the stimulator software and and stimulator hardware module. Let’s briefly examine how they work together.

The Stimulator setup window in AcqKnowledge Software is an onscreen toolbox used for constructing  the stimulus waveform type, shape, duration, repetition, and displays a graphical representation of the stimulus type being presented. It also controls how often the stimulus starts and stops within the software. These controls extend to cleverly being able to output two different stimulus types simultaneously, such as a pulse in one channel and a tone in the other. It is bascially the canvas upon which the stimulation paradigm is created, and provides a blueprint for the output.

But without the stimulator hardware, these sophisticated setups are merely waveforms on a screen. In order to control the intensity or voltage level of the stimulation signal and output it to a participant, it’s necessary to incorporate simulator hardware, such as the STM100C stimulator module.

The STM100C, which connects directly to the BIOPAC MP160 System, has a number of controls for outputting and interacting with the stimulation signal generated by the software, the main one of which is the level control on the front panel. This enables you to increase or decrease the amplitude or intensity on the software stimulation waveform, and whereas the waveform shape will remain unaltered, the power of the pulse can be attenuated as desired. The STM100C can also interface with headphones (for audio stimulus), LEDs, and other devices. The STM100C module itself is not powerful enough to generate much voltage on its own, so to provide the desired voltage or current range for nerve conduction studies, an isolation adapter is required. Think of these adapters as small amplifiers that multiply the STM100C voltage or current output to the proper levels needed for the study. Isolation adapters plug directly into the STM100C unit, and the electrodes connected to the participant interface to the isolation adapters. Additionally, a monitoring cable can also be connected so the voltage or current output can be viewed onscreen in AcqKnowledge.

We also invite you to view a free webinar on various stimulation techniques using BIOPAC hardware and software.

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.

Understanding Stimulation Hardware

Physiology studies often involve the recording of responses from subjects who are reacting to a particular sensory input being presented, otherwise known as stimulation. The presented stimuli can take several forms, and are tightly controlled in lab environments for the comfort and safety of the subject. Different types of human and animal stimulation consist of:

  • Electrical
  • Haptic (touch)
  • Thermal (temperature)
  • Olfactory (scent)
  • Auditory (sound)
  • Visual (light, such as a strobe)

The following is an introduction to some stimulation hardware commonly used in the research market:

Stimulator Modules such as the BIOPAC STM100C is one of the building blocks for many types of stimulation protocols and create a variety of pulse and waveform outputs for nerve conduction, evoked response, audio stimulus-response, and somatosensory response studies. The STM100C interfaces with the BIOPAC MP150 or MP160 data acquisition system and a wide range of devices such as headphones, LEDs, piezo transducer for audio alarms, or haptic transducers. The device also provides technician control of the stimulus level, and works in concert with the AcqKnowledge software Stimulation setup window.

Stimulus Isolation Adapters: These adapters are added to the STM100C module and multiply the output of the STM100C by 5 or 10x to provide the desired range for nerve conduction, muscle twitch, or other studies requiring a stronger stimulus than what the STM100C can generate on its own.

The STM200 is a standalone device that interfaces with the Analog Outputs on the front panel of the Universal Interface (UIM100C) or High Level Transducer Interface (HLT100C) modules. This is a very powerful stimulator, capable of outputting up to 1 amp. It can be used for human and animal applications, including isolated tissue bath preparations.

Linear Isolated Stimulator: The STMISOLA Linear Isolated Stimulator is the most advanced and powerful stimulator offered by BIOPAC. This type of unit can handle almost any application and far exceeds most typical hardware devices in terms of flexibility and control. Typically, stimulators can only generate simple unipolar or bipolar pulses. The STMISOLA, however, can output unipolar or bipolar arbitrary waves such as pulse (single or train), square, sine, triangle, exponentially decaying, modulated envelopes, and fully user-specified types. STMISOLA can be used for Transcranial Direct Current Stimulation (tDCS) and High Definition Transcranial Direct Current Stimulation (HD-tDCS. These are forms of electrical stimulation to effect neuro-modulation in the brain.

Stroboscope: The TSD122 Stroboscope resembles a handheld flashlight and is used for visual evoked response applications and for synchronizing triggers. The unit has a range from zero to a maximum of 12,000 flashes per minute.

Haptic Stimulator: The TSD190 Haptic Stimulator incorporates an internal electromagnetically actuated plunger which can be used to mechanically stimulate a 1.5 mm diameter area of skin surface; both plunger force and travel can be infinitely adjusted between zero and a specified maximum value. This type of stimulator connects directly to the STM100C Stimulator Module and is used for tactile or somatosensory studies.

Thermal Stimulator: The STMTHERM* Thermal Stimulator is used for applying 5-second hot or cold temperature pulses to a  4 cm x 4 cm skin area. AcqKnowledge software controls the actual output from the MP160 data acquisition unit and the stimulator hardware multiplies the signal to achieve the desired voltage or current levels.

Auditory Stimulator: The OUT101 Tubephone is used to deliver aural stimulus in the form of clicks or tones for auditory evoked responses studies such as auditory brainstem response (ABR) and resembles a tube, which is worn in the ear. It connects directly to the STM100C Stimulator Module.

We hope the above thumbnail sketch serves as an introduction to various stimulator hardware and common stimulation protocols. Please visit the above linked content for more in-depth information.

We also invite you to view our free webinar, Stimulation Techniques for Researchers, available on-demand.

*STMTHERM Thermal Stimulator will be available soon! Stay tuned.

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.

Small and Smaller – Untethered and Unfettered

Advancements in the engineering of data acquisition components have closely paralleled the microchip revolution. Ever-smaller form factors available in wireless transmission formats have resulted in a boon for researchers wishing to collect high-quality physiological data from participants in unfettered environments undreamed of a few years ago.

One of the linchpins of these cutting-edge systems is BIOPAC’s BioNomadix Series of wireless life science transmitters and receivers. BioNomadix modular receiver/amplifiers connect to the mother ship of the acclaimed MP160 System while the bite-sized matched transmitters attach to the participant, or comfortably nestle in a garment such as the BioNomadix BIOSHIRT. Unobtrusive specially designed leads connect to skin electrodes affixed to the participant, and BioNomadix units relying on transducers (such as respiration and skin temperature) offer equal convenience.

An even more streamlined system, the BioNomadix Smart Center, is also available. This system combines BioNomadix transmitters with the Smart Center all-in-one receiver and data acquisition unit. The soap bar-sized Smart Center connects to a computer USB port and supports up to 9 channels of physiological data from up to three wireless BioNomadix transmitters. (All BioNomadix transmitters are supported but connection is limited to three at a time.)

BioNomadix transmitters are dual-channel or dual-signal, with the exception of the Accelerometer, which supports three channels (X, Y, and Z axes).

Acquired signals are of extremely high quality and clarity and are rendered in AcqKnowledge Research Software. BioNomadix systems are available for fourteen body signal types, including ECG, RSP, PPG, EDA, EOG, EEG, EMG, EGG, ACCL, SKT, Goniometer, Dynamometer with EMG, Cardiac Output, and Heel-Toe Strike.

What does all of this mean to the researcher? Nearly unlimited freedom of movement at distances up to 10 meters from the receiver units—opening up new avenues of research and even new vistas in artistic expression.

A stunning and eclectic example of the latter can be taken from this brief performance by Compagnie Linga, a contemporary dance company based in Lausanne, Switzerland. Dancers wore BioNomadix accelerometers to record transmit their movements in real time, which were then digitally rendered in sound. The result is a tableau of dance and self-generated musical accompaniment, an artscape created from the firings of human physiology.

For more information about BioNomadix, please see:

BioNomadix Wireless Amplifiers

BioNomadix Wireless EMG for Neuro-Controlled Prosthetic

Free On-Demand Webinar – Recording Great Data from Exercising and Mobile Subjects

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.

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