EEG amplifiers Highlight - The main features of Brain Products EEG Amplifier 08 16 20 32 64 96 128 160 256 channels:
The work of an EEG amplifier is quite simple to understand and can be summarized in just a few steps:
First, the system considers the incoming signal as the difference in electrical potential (µV) between two electrodes (i.e., differential recording principle), whereby the ground electrode (GND) is normally used as primary reference. However, to avoid the influence of non-physiological electrical noise coming from the internal ground circuitry of the amplifier, another electrode is usually chosen as baseline for all channels (i.e., the online reference channel or REF). The actual incoming signal is therefore the difference in electrical potential between each EEG channel and the online REF.
The signal then passes through one if not two hardware filters within the amplifier to avoid potential conversion issues. The measured signal may in fact contain very high frequencies that the Analog-to-Digital Converter (ADC) is not able to process, thus it is important to exclude them beforehand with a low pass (or high cutoff) filter. Additionally, some amplifiers may have a second high pass (or low cutoff) filter to remove very low frequencies; if not, all frequencies down to 0 Hz (DC) are passed on to the ADC.
The filtered signal is then amplified and converted from analog (i.e., continuous in time) to digital (i.e., discrete in time) by the ADC.
The digital signal is then transmitted to the recording computer for further processing and is eventually saved.
EEG Amplifier LiveAmp and actiCHamp PLUS
EEG Amplifier actiCHamp PLUS
EEG Amplifier actiCHamp PLUS Synbox
EEG Amplifier ABR Auditory Brainstem Responses
Wireless EEG Amplifier LiveAmp
Wireless EEG Amplifier LiveAmp Sensor Trigger Extension
EEG Amplifier 32, 64, 96 and 128 channels BrainAmp for MRI
Neuroscience EEG Amplifier for Hyperscanner
Wireless EEG Amplifier BrainAmp EEG MOVE Wireless
FALAN Latin American map of neuroscience Research
LATBrain A brain with science and Latin American consciousness
BrainSupport Solution for Neuroscience Researchers – Neuroscience to improve Latin American Identity. Scientific questions and experimental designs for the development of culture, behavior, perception and Latin American consciousness.
Neuroscience EEG Applications
If you plan to run regular cognitive neuroscience studies, then our recommendation for you is the actiCHamp Plus for its advanced technical features, scalability of channel count, and versatility in terms of compatible electrode technologies.
However, there may be applications for which other solutions could be a better fit or are even required, for example:
For this advanced application, the BrainAmp MR or BrainAmp MR plus are the necessary solutions for you. Both are MR Conditional (i.e., usable inside the scanner under specific recording conditions) but they will also work perfectly outside of the scanner for more regular investigations. In particular, the BrainAmp MR plus could be the perfect choice if EEG-fMRI recordings and lab-based measurements are planned, because it allows you to change resolution, measurement range and cut off frequencies based on your recording environment.
Compatibility with Magnetoencephalography (MEG) depends on the amplifiers’ electromagnetic emissions, which are linked to the number of ADC card(s) of the system. The BrainAmp family amplifiers are equipped with only one ADC card and therefore almost silent in terms of electromagnetic emissions. In particular, the BrainAmp MR and BrainAmp MR plus are the recommended solutions for optimal compatibility with the MEG environment.
Emblem EEG-fNIRSFor such simultaneous recordings, we recommend the actiCHamp Plus for lab-based measurements, or the LiveAmp for mobile investigations.
Simultaneous EEG and Eye Tracking
Here our recommendation is the actiCHamp Plus for lab-based measurements or the LiveAmp for mobile investigations.
Emblem EEG-Brain Stimulation (TMS)
The BrainAmp DC and BrainAmp MR plus have been widely used for recording EEG whilst simultaneously applying Transcranial Magnetic Stimulation (TMS) thanks to their switchable internal features. Similarly, the BrainCap TMS is also highly appreciated for this application. Nevertheless, the actiCHamp Plus could now be a valid alternative for you thanks to its high sampling rates, the flexibility to combine it with active or passive gel-based electrode technologies, and the possibility of expanding your setup for real-time brain-state dependent stimulation.
Closed-loop and real-time applications
If you are interested in real-time brain-state dependent investigations (e.g., stimulation, neurofeedback, etc.) then the actiCHamp Plus together with our TurboLink is the right choice for you. All our amplifiers can in fact stream data from BrainVision Recorder to any third-party application either via RDA or LSL, but without the latency and accuracy required for advanced closed-loop investigations. The TurboLink accesses the data recorded by actiCHamp family amplifiers and transmits it reliably via Ethernet in less than 1.5 ms to any compatible online signal processor (e.g., the bossdevice RESEARCH by sync2brain).
Mobile experiments (MoBI and Sport Science)
Emblem mobile EEG
If you would like to investigate neural processes both inside and outside of the lab, maybe even during motion, then the LiveAmp is what you are looking for. Thanks to its wireless communication protocol, it gives freedom of movement whilst being able to stream the data to the recording computer. The internal memory card is an additional advantage: saving the data locally ensures no data point is lost due to unexpected communication issues. The combination of the LiveAmp with our actiCAP slim electrodes ensures high quality data even under strenuous conditions such as running or cycling.
If instead you are looking for high-coverage solutions, then the CGX Mobile systems are the right choice for you, available with 72 or 128 channels. Alternatively, if your measurements include minor movements (Marini et al., 2019), you can also consider the CGX Quick systems.
BCI and Neurofeedback
If you work in these fields and your application is less time-critical, you most likely look for a solution that is easy to handle and minimalistic, with the option to stream data to other online processing software. Even though all our amplifiers will work very nicely for you, the LiveAmp could be a very good candidate especially if coupled with electrode technologies that offer short preparation times (for example, our sponge-based R-Net caps or our active-dry actiCAP Xpress Twist). Accordingly, the CGX Quick systems could also be a good option for you thanks to their innovative design based on active dry electrodes. Both solutions will allow you to record data from many participants within a short period of time even in more realistic environment and situations.
Emblem Sleep EEGWhen measuring brain activity during sleep, you most likely aim to keep your setup as comfortable for your participants as possible. The LiveAmp is therefore a great option: being very small and wearable, it will ensure a more natural sleep, and by connecting it to an external power bank you will be able to reach even longer recording times.
Alternatively, if more than 64 channels or higher sampling rates are required, the actiCHamp Plus will give you more flexibility and technical power whilst keeping the setup as minimal as possible.
If you would like to record the neural activity of more than one participant simultaneously, you may choose from various options. The BrainAmp family will offer you the cleanest stationary setup: each participant is connected to dedicated amplifier unit(s) that transmit(s) to the BUA, which synchronizes the data and sends them to the recording computer with no need to further work on data re-alignment offline.
The CGX systems however are ideal for wireless hyperscanning: each amplifier will stream data to the dedicated recording computer, and synchronization can be obtained by sending the same triggers to each unit via the Wireless StimTrigger.
Alternatively, you may take advantage of the Mirror Mode of the trigger output ports of both actiCHamp Plus (stationary) and LiveAmp (mobile) to forward triggers across separate amplifier units, one for each participant. Furthermore, all our amplifiers allow for remote data access and can stream data to third-party applications like LSL, which allows the recording and synchronization of data streams from different amplifiers (read our article on this topic to learn how).