Mind and Machine: Exploring Brain-Computer Interfaces

In neuroscience, the frontier of brain-computer interfaces (BCI) holds the promise of bridging the gap between the human brain and external devices, offering revolutionary applications in fields ranging from robotics and prosthetics to communication and beyond. In the lab, scientists studying and developing new BCI technology leverage the human brain’s electrical and physiological signals.

Electroencephalography (EEG), functional near-infrared spectroscopy (fNIRS), and steady-state visually evoked potentials (SSVEP) are among the primary physiological and psychophysiological signals utilized in these investigations. Multimodal integration of two or more signal types allows researchers and engineers to take advantage of multiple data streams in their applications and studies.

EEG, which can measure electrical activity in the brain, is a cornerstone of BCI research. Researchers can decode various mental states and intentions by analyzing EEG patterns, enabling users to control external devices through mere thought. fNIRS complements EEG by measuring changes in blood oxygenation levels, offering insights into brain function with superior spatial resolution. SSVEP, on the other hand, capitalizes on the brain’s response to visual stimuli, providing a means for precise control in BCI applications.

The practical implications of BCI research extend far beyond the laboratory setting. In robotics, BCIs facilitate direct brain-to-machine communication, empowering users to manipulate robotic arms or navigate autonomous vehicles with their thoughts alone. A study published in the Journal of Information Science Engineering explored ways that an SSVEP-based BCI could be used to control assembly line robots via a headset measuring the operator’s EEG signals. The signals would communicate instructions to robots while operators identified defective parts, which the robots would pick out. During the experiment, EEG signals were obtained using a B-Alert X24 headset. The EEG-based BCI produced a 93.33% success rate in correctly identifying and removing defective parts from the assembly line process, allowing the operator to effectively “collaborate with the robot and communicate defective parts without manually operating the robot.”

Prosthetics benefit immensely from BCI advancements, enabling seamless integration with the user’s neural signals for intuitive control and enhanced functionality. A 2023 study by a team of researchers from the University of California Irvine explored the viability of creating low-cost cortical stimulators for bi-directional BCI (BD-BCI) research. BD-BCI takes brain-computer-interfaces to the next level with the brain not only providing motor commands to an artificial limb but also allowing it to receive sensory input from such a device. A BIOPAC data acquisition and analysis system was used to validate the charge balancing of subcortical electrocorticographic (ECoG) implants used in a stimulator. The charge balancing test was performed on phantom tissue designed to simulate real brain tissue. The resulting study successfully demonstrated “clinical validation of a fully-programmable electrical stimulator, integrated into an embedded BCI system.”

As researchers continue to refine BCI technologies, the possibilities for real-world applications are boundless. BIOPAC is among the companies on the cutting edge of BCI research, partnering with other innovators to provide the latest in multimodal BCI technologies such as Axon-R. For additional information on Axon-R, check out our recent webinar on the device.


Are you planning to explore the frontiers of BCI in the lab? Our regional customer reps have all the knowledge you need to integrate BIOPAC products into your BCI study.

Evoked Potentials: Low-amplitude Signals for High-value Data

Researchers studying the nervous system have a host of physiological signals at their disposal to provide critical data on neurological function. Various signals present advantages and disadvantages, depending on the demands of the research being conducted. Evoked potentials offer a particularly effective means of measuring the nervous system’s response to certain stimuli, notably visual and auditory cues.

Evoked potentials are employed in both research and clinical settings to measure electrical activity in the central nervous system. Stimulation of specific sensory neural pathways produces this electrical activity, allowing researchers to see the speed and thoroughness with which these signals reach the brain. Evoked potentials provide researchers with heightened precision when isolating and localizing a participant’s response to stimuli.

Because evoked potential amplitudes tend to be low, from less than one to just a few microvolts, these signals can be difficult to differentiate from other higher amplitude signals and background noise. This is resolved by using signal averaging to separate the low-amplitude signals from the noise. Multiple readings are taken with evoked potential signals time-locked to the stimulus. Averaging these measurements allows the evoked potential to be filtered from the random signal noise.

Along with providing useful data for research, evoked potential tests are commonly used in clinical settings to diagnose and explore treatments for a range of disorders such as multiple sclerosis (MS), epilepsy, glaucoma, neuropathies, Alzheimer’s, and others. In both research and clinical applications, evoked potential tests provide several advantages over using other approaches since they are noninvasive, painless, and provide results more quickly than other neurological scans, such as MRI. Types of evoked potentials can be categorized by the stimuli with which they are associated. Visual evoked potentials (VEP) are triggered by visual stimuli such as light flashes or by participants viewing certain patterns. Auditory evoked potentials (AEP) measure responses to sound stimuli such as clicks. Somatosensory evoked potentials (SEP) are triggered by electrical stimulation of peripheral nerves.

A 2022 study by researchers at the Autonomous University of Aguascalientes in Mexico evaluated the effectiveness of using VEP waveforms embedded in electroencephalographic (EEG) signals to determine the health of the optic nerve. The team employed an MP36 data acquisition system connected to an SS2LB lead set to record EEG signals from study participants. eyeThe signal data were used to create a database of VEPs that could be processed with analysis software for the early detection of glaucoma and other optic nerve-related illnesses.

A similar study combined the use of EEG signals with VEP to examine how participants recognize emotion in others. Researchers from two universities in China relied on a variation of VEP known as steady-state visual evoked potential (SSVEP), which exhibits distinctive frequency and phase properties. EEG signals were recorded via a BIOPAC data acquisition unit while participants were shown flickering images representing three emotional states—delight, sadness, and anger. The study found a positive correlation between SSVEP amplitude, alpha-frequency entrainment, and accurate identification of emotion.

These are just a few examples of how evoked potentials provide researchers with valuable insight into the central nervous system’s response to stimuli and its relationship to a wide range of physiological states. For additional information on how to use BIOPAC hardware and AcqKnowledge to stimulate a range of senses using electrical, auditory, visual, haptic, scent, and thermal stimuli and record evoked potentials, check out our webinar on Exogenous and Stimulus-related Evoked Potentials.


To learn more about how your study can benefit from using BIOPAC hardware and software to record and analyze evoked potential data, contact your local sales representative.

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