A Buddhist saying states, “Pain is inevitable, but suffering is optional.” Pain’s dual nature has presented a conundrum for philosophy and the sciences. As a warning system, it protects us from harm, but it can also be the source of profound psychological and emotional damage. Pain is a complex and deeply subjective experience, yet it is one of the most critical areas of study in neuroscience.
Understanding pain involves not only exploring its physical origins but also decoding the neural circuits and physiological signals that contribute to its perception and regulation. Neuroscientific research into pain aims to answer fundamental questions about how pain is processed in the brain, how it varies from person to person, and how we can develop better treatments for chronic conditions.
This research uses various physiological signals to provide insights into pain mechanisms. Electroencephalography (EEG) captures brainwave activity, revealing how different regions of the brain respond to painful stimuli. Photoplethysmography (PPG) tracks blood flow changes, while electrocardiography (ECG) and skin conductance response (SCR) measure autonomic nervous system activity, offering clues about how the body reacts to stress and discomfort. Respiration patterns, too, are key indicators, as breathing can change in response to pain. Together, these signals help scientists map the body’s response to pain, shedding light on the underlying neural pathways and guiding the development of more effective pain management strategies. Understanding these physiological markers is a critical step toward personalized pain care and improving the quality of life for millions worldwide.
Pain research commonly focuses on the neurological mechanisms of pain to better understand its causes and how it can be treated. Researchers publishing their findings in the Journal of Biomedical and Health Informatics developed a device for studying pain perception biomarkers using thermal stimulation. Their device generates minutely controlled thermal stimuli using a computer-driven Peltier cell while simultaneously capturing EEG and PPG signals. Researchers identified the heat pain threshold (HPT) for each subject, defined as the maximum the subject can withstand when the Peltier cell gradually increases the temperature. The team used two-dimensional spectral entropy (SE) obtained from both the EEG and PPG signals to differentiate the condition of pain. EEG and PPG signals were fed to a BIOPAC MP36 data acquisition and analysis system running Biopac Student Lab (BSL) software. The study concluded that hemodynamics, brain dynamics, and their interactions can be used to discriminate thermal pain perception, which could have practical applications in monitoring pain perception. Possible applications include the study and treatment of “pathologies that affect the peripheral nervous system, such as small fiber neuropathies, fibromyalgia, or painful diabetic neuropathy.”
The pain mechanism associated specifically with fibromyalgia, one of the most common chronic pain disorders, was the focus of a study at the University of Jae´n in Spain. Despite its prevalence, much is still unknown about the underlying cause of this condition. Clinical and experimental studies of individuals diagnosed with fibromyalgia syndrome (FMS) have revealed autonomic nervous system (ANS) deficiencies. While both the parasympathetic and sympathetic components of the ANS have been studied, less is known about the sympathetic component as it relates to FMS. In this study, researchers used SCR as an indirect measure of the sweat response, which is controlled by the sympathetic mechanisms of the ANS. Researchers used a BIOPAC MP36 running AcqKnowledge to collect SCR data via an EDA lead set connected to participants’ fingers. The study found reduced skin conductance levels (SCL) and SCR in FMS patients compared to the non-FMS control group, indicating lower levels of sweating and reduced sympathetic activity in the skin. These factors provided the research team with a better understanding of the sympathetic nervous system’s role in FMS, with the potential for revealing new routes to better pain management and treatment.
For several decades, researchers and clinicians have studied the use of hypnosis to treat chronic pain. More recently, new technologies such as virtual
reality have been incorporated into these techniques. A team of researchers from the University of Strasbourg in France studied the application of virtual reality hypnosis (VRH) to regulate HPT in healthy adult participants. Researchers used several physiological signals to measure autonomic function during the experiment, including ECG, respiration, SCR, and EEG. ECG signals were recorded using the BIOPAC ECG amplifier, while respiration rate was measured by a thermistor transducer that determined the difference in temperature between inhaled and exhaled air. SCRs were measured from the index and middle fingers of the dominant hand with a BIOPAC skin conductance transducer. Physiological signals were fed into a BIOPAC data acquisition system for analysis. A computer-generated immersive environment was created in VR and combined with a hypnotic auditory script. As with classical hypnosis treatments, the VRH scheme in this study began with an “induction period” followed by a “dissociation” period (separation between the mental state and the environment), followed by suggestions of pain reduction as analgesia. The study results supported a positive correlation between VRH and an increase in the participants’ pain threshold with promising implications for new non-pharmacological approaches to pain management and treatment.
These are just some of the ways that BIOPAC equipment is being used to explore the frontier of pain research and help ease the suffering of millions who deal with chronic pain and its physical and psychological effects. See our webinars page for additional information on how physiological signals can be applied to your next study.
Are you planning a study on pain or any related neurological or physiological area of research? Our team of experts is ready to help you find the tools to ensure success.
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