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Home » Products » Research & Scientific Instruments » fNIRS » MedelOpt-I

MedelOpt+ · Seenel Imaging / BIOPAC — Blood flow and brain waves — in one recording

A wearable headset that measures brain activity in two ways at once: with light (fNIRS — changes in blood oxygenation in the cortex) and with electrodes (EEG — electrical activity). You record it in BIOPAC AcqKnowledge together with heart rate, respiration or skin conductance — all on a common clock.

Request a quote How it works

fNIRS + EEGin one headset, simultaneously

±2.9 mmaverage sensor positioning accuracy

up to 8 hoursof continuous recording

from age 4to adults — one headset

Participant in a MedelOpt headset with fNIRS and EEG sensors looking at a monitor with recording settings

Signals from the headsetREC 00:04:12

fNIRS · EEG · physiology — one program, one clock · illustration

How fNIRS + EEG works

Two ways to see the working brain

When a part of the cerebral cortex is working, two things happen: neurons send tiny electrical impulses, and shortly afterwards more oxygenated blood flows to them. EEG measures the first, fNIRS — the second. MedelOpt+ has sensors of both types in one headset, so both signals are captured in the same recording.

Woman in a MedelOpt headset with a dense sensor grid on her head, against a meadow

fNIRS and EEG at onceLight from the emitter (E) returns to the detector (D), and the electrode collects neuronal impulses — at the same place and time.

The head cross-section on the photo is an illustration, not a device recording. Photo: Seenel Imaging.

Light through skin and boneThe emitters shine near-infrared light at wavelengths of 660 and 850 nm. Such light penetrates skin and skull bone, scatters in the cerebral cortex and partly returns to the surface of the head, where it is captured by a detector 2–5.5 cm away.
Blood reveals cortical activityHemoglobin with oxygen (HbO) and without oxygen (HbR) absorbs these two colors of light differently. From how much light reached the detector, the software calculates changes in their concentration. More HbO at a given cortical location means that area is working.
Electrodes capture impulsesEEG electrodes in the same headset record the electrical activity of neurons 512 times per second. EEG responds within milliseconds, fNIRS shows better where exactly something is happening — together they give a fuller picture.

fNIRS — where

Shows which cortical areas are working: it localizes activity more precisely than EEG and tolerates participant movement well.

~10 mmspatial resolution

EEG — when

Shows when the brain responds — with millisecond precision. It captures fast responses to a stimulus that blood flow cannot keep up with.

~1 mstemporal resolution

Together — coupling

Simultaneous recording lets you study how electrical activity translates into blood flow (neurovascular coupling) — e.g. in epilepsy research.

1 headsetone recording, common time base

HbOOxyhemoglobinchange in the amount of oxygenated blood under each channel

HbRDeoxyhemoglobinblood after releasing oxygen — usually changes in the opposite direction to HbO

EEGBrain potentials8 electrodes, 512 samples per second

short ch.Short channelsblood flow in the skin — to be subtracted from the cortical signal

eventsEvent markersstimuli, responses and tasks on the same timeline

Resolutions according to the comparison in the BIOPAC MedelOpt brochure; parameters: biopac.com (MedelOpt+ Brain-Body Platform), BIOPAC MedelOpt brochure.

Headset · an exoskeleton instead of a cap

The sensors land in the same place on every head

Most fNIRS systems mount the sensors in an elastic cap, which sits a little differently on every head. MedelOpt+ has a lightweight, adjustable frame with clipped-in sensors. According to BIOPAC, this gives an average positioning accuracy of ±2.9 mm — about five times better than with a cap — and repeatable measurements across participants and sessions.

MedelOpt headset on a mannequin: a frame with dozens of sensors, an adjustable strap with a scale and cables at the back of the head

1Sensors clipped into a rigid frame

fNIRS emitters and detectors and EEG electrodes are integrated into the headset. You design their layout — the montage — in the MeMoSoft program, and AcqKnowledge guides you to the positions during fitting.

2Skin access without removal

The design leaves access to the scalp: you move hair away from under a sensor without removing the headset. This shortens preparation and lets you improve contact during the session.

3One size — from age 4 to adults

An adjustable strap with a scale fits the frame to the head circumference. One headset serves children from age 4 and adults — no set of caps in different sizes.

4Add sensors as your research grows

The system is modular: you add more emitters and detectors to the headset to increase the number of channels, or move from a single modality to fNIRS + EEG. The same frame covers the cortex from frontal to cerebellum.

5Control unit: cable or Wi-Fi

The sensor cables converge in a small electronics unit (22 × 85 × 48 mm). In the Mobility variant, the headset transmits via Wi-Fi with no range limit, and if the live view drops, it keeps recording to its own memory — with no data loss. The Infinity and Tandem systems connect by cable; with the Mobility Pack (mini PC and battery) they also become mobile.

±2.9 mmaverage positioning accuracy, approx. 5× better than a cap

up to 8 hof continuous acquisition in one session

20–55 mmselectable source–detector distance

Manufacturer’s diagram: a long fNIRS channel reaches the cerebral cortex, a short channel covers only skin and bone

Short channels

Subtract what does not come from the brain

Part of the light passes only through the skin, where blood also circulates — with every heartbeat and breath. A short channel is a pair of sensors placed close together: it sees only the skin. Its signal is subtracted from the long channels so that only the cortical contribution remains. The number of short channels depends on the variant: from 1 in Mobility to 32 in Infinity 16-32.

Data: BIOPAC MedelOpt+ product sheet (11/2025); biopac.com — MedelOpt+ Brain-Body Platform. Photo and diagram: Seenel Imaging / BIOPAC.

Software · BIOPAC AcqKnowledge

One program from fitting the headset to analysis

MedelOpt+ works in AcqKnowledge — the same program in which BIOPAC records ECG, respiration or skin conductance. An AcqKnowledge license is always included and it is perpetual. Configuration, recording and analysis take place in one window, and one interface controls the headset and all connected BIOPAC amplifiers. You don’t need synchronization scripts or additional tools.

AcqKnowledge window with a MedelOpt+ recording: two EEG channels, HbO, HbR, PPG and EDA on a common timeline

What you see on the screen

A real MedelOpt+ recording with EEG and physiology. Select a signal:

EEG from the headset. Voltages from the electrodes in microvolts, sampled at 512 Hz. This is where you look for fast responses to a stimulus and brain rhythms.

HbO — oxyhemoglobin. Change in the amount of oxygenated blood under the selected fNIRS channel. It rises a few seconds after a cortical area starts working.

HbR — deoxyhemoglobin. Blood that has released its oxygen. In a typical brain response it falls when HbO rises — this pair of signals is the basis of fNIRS analysis.

Physiology from BIOPAC. The pulse wave (PPG) and skin conductance (EDA) from BIOPAC modules, saved in the same file. They help separate the brain response from changes in the whole body.

MedelOpt+ supported from AcqKnowledge 6.0.2

1 · Prepare

Montage and fitting

you design the sensor layout in MeMoSoft — EEG, fNIRS or hybrid
AcqKnowledge Setup guides you when fitting over regions of interest
calibration and signal quality check before starting

2 · Record

Everything with one button

live fNIRS channel monitor: sources, detectors, HbO, HbR
common start and stop of the headset and BIOPAC amplifiers
automatic event markers and stimulus presentation

3 · Analyze

Filters and automated analysis

filters during recording, transformations and automated analyses
instant playback of data from multiple modalities
SPA-fNIRS: modeling respiration, heart rate variability, EDA and movement to separate the brain contribution

4 · Export

Data for other tools

ACQ, MAT, EDF and SNIRF files — the standard format for fNIRS data
real-time access via Network Data Transfer (license)
multi-site studies with AcqKnowledge Cloud (license)

MeMoSoft

A Seenel Imaging application for montage design: “a few clicks” and the headset is configured for your study and your participants.

EEGfNIRShybrid

MedelOpt+ API

A library for real-time EEG and fNIRS streams in your own applications — neurofeedback and brain–computer interfaces (BCI). Purchased separately.

neurofeedbackBCIWindows

AcqKnowledge modules

Stimulus presentation, stimulator control, video and audio of the session, VR with eye tracking built into the headset — in the same program, on the same timeline.

stimulivideoeye trackingVR

Sources: biopac.com — MedelOpt+ Infinity product page (Details tab), Brain-Body Platform, AcqKnowledge — new features (6.0.2), MedelOpt+ API; seenel-imaging.com (MeMoSoft). Screenshot: BIOPAC.

Why MedelOpt+ from Interlab

Brain and physiology from one system — not a patchwork

A popular route to multimodal research is subscription platforms to which an fNIRS device from another manufacturer is connected. MedelOpt+ is a different approach: the headset, physiological amplifiers and BIOPAC software are designed to work together — and we deliver and set up the whole system.

MedelOpt+ from Interlab vs. a subscription platform with fNIRS hardware from another manufacturer
Feature	MedelOpt+ from Interlab	Subscription platform + fNIRS from another manufacturer
Synchronization with physiology	common clock and hardware triggers — no delays, drift or sampling rate mismatch	fNIRS data arrives as an LSL stream from the device manufacturer’s software
fNIRS analysis	configuration, recording and analysis in AcqKnowledge; live view of HbO and HbR	data export (CSV, SNIRF) for analysis in external tools
License	perpetual AcqKnowledge license included — one program for fNIRS, EEG, physiology and stimuli; only selected features are paid separately, e.g. Network Data Transfer	mandatory core module + separately paid modules with annual renewal; hardware not included in the price

Subscription platform: a popular multimodal platform with an fNIRS module; values based on its manufacturer’s website, as of 2026-10. MedelOpt+: biopac.com.

Two participants in MedelOpt headsets sitting opposite each other at a laptop

What you get from Interlab

An fNIRS + EEG lab set up together with you

We match the configuration to your research question, install the system and train your team.

Discuss your study with us

Multimodal laboratoryMedelOpt+, BIOPAC MP200 and wireless BioNomadix physiology from one supplier — configured to work together.
Methodological consultingWe help choose the montage, number of channels and protocol for your research question — before you buy anything.
Implementation and trainingWe set up the workstation and train your team in fitting the headset, recording and analysis in AcqKnowledge.
Grant supportTechnical descriptions and configurations for grant applications and tender specifications.
Online presentationWe show you the system and software in action before you make a decision.
Local support in PolandTechnical and methodological support after purchase — no intermediaries.

Multimodal research · Brain-Body Platform

What is happening in the brain — and in the whole body

Blood flow in the brain also depends on breathing, heart rate and arousal. That is why BIOPAC combines MedelOpt+ with the MP200 system into a “brain–body platform”: fNIRS, EEG, ECG, respiration, EDA, video and stimuli go into one file, on one timeline, hardware-synchronized. In the photo: a dual task — treadmill walking while counting backward.

Participant in a MedelOpt headset walking on a treadmill in the lab

One clock. Common timing and hardware triggers eliminate delays and sampling mismatch between devices.

In the MedelOpt+ headset

fNIRS: continuous wave 660/850 nm, detectors sampled at 128 Hz, sources up to 32 Hz
EEG: 512 Hz, shielding that reduces interference
short channels for removing the influence of skin blood flow

With the BIOPAC MP200 system

MP200: 16 analog channels, up to 100 kHz per channel, Ethernet-ready
signals: ECG and HRV, respiration, EDA, PPG, EMG, movement (accelerometers) — also wireless (BioNomadix)
physiology recorded at 2 kHz in one file with fNIRS and EEG

Stimuli, VR and eye tracking

stimulation controlled from AcqKnowledge: visual, auditory, electrical, tactile, olfactory and thermal
VR: scenario control from AcqKnowledge, event markers from VR and a biofeedback loop
eye tracking from sensors built into the VR headset, e.g. HTC VIVE Focus Vision

BIOPAC diagram: a computer running the experiment sends events via a Trigger Box to the headset unit, and a computer with AcqKnowledge combines the MP200 and MedelOpt+ in one recording

How it connects

The experiment program sends events via the MedelOpt+ Trigger Box (USB port) directly to AcqKnowledge, so fNIRS and EEG are synchronized with the stimuli. The MP200 and the headset run in one instance of the program thanks to the Linked Acquisition protocol — no extra integration steps.

Trigger Box USB · typically 1.3 mswireless MOBIL+ TRIG · typically 3.3 ms2 TTL inputs · 512 Hz

Trigger latencies: typical propagation delay according to the BIOPAC MedelOpt+ product sheet (11/2025). The signal waveforms on the photo are illustrative. Data: biopac.com — MedelOpt+ Brain-Body Platform, MedelOpt+ Infinity product page, MedelOpt+ for VR, AcqKnowledge — new features; BIOPAC MedelOpt brochure (gait protocol). Photo: BIOPAC.

The MedelOpt+ family

One technology, four kinds of research

All MedelOpt+ systems share the same exoskeleton, sensors and software. They differ in the number of sensors, mobility and the number of headsets. Choose what you want to study — we will point you to the right variant.

Whole-head map → Infinity. When you want to cover many cortical areas at once — from frontal to cerebellum — or build montages with different depths. We compare configurations and channel counts on the MedelOpt fNIRS Infinity Systems.

Participant in a MedelOpt headset with a dense sensor grid over the whole head

Infinity

The highest sensor density for laboratory research: whole-head mapping and advanced montages with different depths.

sensors: 16 sources, 16 or 32 detectors
EEG: in EEG models
models: INFIN+ 16-16, 16-16 EEG, 16-32 EEG

Choose an Infinity configuration →

Participant in a MedelOpt headset riding a bicycle across a meadow

Mobility

Wireless headset (Wi-Fi) with no range limit: research on the move — walking, running, sport, field work.

sensors: 8 sources, 8 or 16 detectors; up to 128 pairs
EEG: in EEG models
models: MOBIL+ 8-8, 8-8 EEG, 8-16 EEG

Ask about Mobility →

Two participants in MedelOpt headsets facing each other

Tandem

Two synchronized headsets: hyperscanning — the brains of two people in conversation, cooperation or competition.

sensors: 8 sources, 8 or 16 detectors per headset
headsets: 2, common recording
models: TAND+ 8-8, 8-16

Ask about Tandem →

Woman in VR goggles holding controllers; a MedelOpt headset under the goggles

VR

Headset combined with VR goggles: brain activity and physiology in response to a virtual environment.

sensors: 8 sources, 8 detectors
goggles: Meta Quest 3 included; also Quest 2, HTC VIVE Focus 3
models: VR+ 8-8, 8-8 EEG

Ask about VR →

Sources: biopac.com — MedelOpt+ Infinity, Mobility, Tandem and VR product pages (as of 2026-10).

Applications according to the manufacturer

Where MedelOpt+ makes a difference

A headset that tolerates movement and allows long recordings opens up research that is impossible in a scanner: walking, sport, a conversation between two people or a virtual environment.

Participant in a MedelOpt headset working at a computer

Cognitive neuroscience

Attention, memory, cognitive workload and stress — in computer tasks.

Manufacturer’s graphs: HbO and HbR waveforms from the channels of one source over the motor cortex in successive task blocks

Gait and dual tasks

Example protocol from the BIOPAC brochure: treadmill walking at 4 km/h while serially subtracting 7 — measures how the brain engages in gait control.

12 blocksbaseline rest 30 stask 30 sbreak 45 ± 15 s

Two people in MedelOpt headsets facing each other against a blue background

Social interaction

Hyperscanning: brain synchronization of two people in conversation and cooperation.

VR goggles fitted over a MedelOpt headset on a glass mannequin

Virtual reality

Brain responses to a simulated environment: attention, memory, decisions and emotions.

Participant in a MedelOpt headset in a meadow, outdoors

Sports science

Measurements on the move and outside the lab, with a participant who moves naturally.

Speech and hearing

Research on language and auditory perception — also in children from age 4, thanks to one adjustable headset.

Neurology and neuromodulation

Epilepsy research (EEG–hemodynamics coupling), deep brain stimulation (DBS) and vagus nerve stimulation (VNS), neurorehabilitation.

List of applications: BIOPAC MedelOpt brochure, seenel-imaging.com, biopac.com. Photos: Seenel Imaging / BIOPAC.

Specifications

MedelOpt+ in detail

According to BIOPAC and Seenel Imaging for the MedelOpt+ platform. Channel counts for individual Infinity configurations are compared on the MedelOpt fNIRS Infinity Systems.

MedelOpt+ technical specifications
Parameter	Value
fNIRS
Technique	near-infrared spectroscopy, continuous wave (CW); 660 and 850 nm
Sampling	4 / 8 / 16 / 32 Hz depending on the source duty cycledetectors sampled at 128 Hz, sources up to 32 Hz
Source–detector distance	20–55 mm, adjustable; choice of channel distance and depth
Detectors and converter	low-noise silicon photodiodes with preamplifier; 16-bit ADCsources: dual-wavelength LEDs; shielded NIRS cables, > 60 cm
Short channels	depending on the variant: Mobility 1, VR 2, Tandem 1 per headset, Infinity up to 16 (16-16) or up to 32 (16-32)
Signal quality	noise approx. 0.3% of the sensor’s dynamic range; SNR ≈ 151:16 hours of operation without drift according to MEDPHOT criteria
Light sources	LED, peak power up to 20 mW per sourceemitted light +53% and received light +48% compared with the previous generation
EEG
Channels and sampling	8 channels + reference electrode + active ground; 512 samples/sEEG optional — models marked EEG
Amplifier	24-bit ADC; gain 24 V/V; CMRR min. −110 dB; input impedance 500 MΩ ∥ 10 nF
Noise and range	input noise 1 µVpp typical (0.01–70 Hz); full scale 187.5 mVintegrated shielding reduces interference
Headset
Design	adjustable exoskeleton with integrated sensors; scalp access without removal
Positioning accuracy	±2.9 mm average — approx. 5× better than a cap (MeMoSoft + AcqKnowledge Setup)
Size	one headset: from age 4 to adults
Recording time	up to 8 hours
Measurement areas	from the prefrontal cortex to the cerebellum, parietal and lateral cortex
Variants
Infinity	16 sources / 16 or 32 detectors; INFIN+ 16-16, 16-16 EEG, 16-32 EEGlaboratory research; wireless connectivity optional
Mobility	8 sources / 8 or 16 detectors, up to 128 source–detector pairs; MOBIL+ 8-8, 8-8 EEG, 8-16 EEGWi-Fi with no range limit; recording to device memory if the live view drops
Tandem	2 headsets, 8 sources / 8 or 16 detectors each; TAND+ 8-8, 8-16wired; Trigger Box expandable with further systems
VR	8 sources / 8 detectors, 2 short channels; VR+ 8-8, 8-8 EEGincludes Meta Quest 3 with Elite Strap, control unit, Mobility Pack, mounting accessories; compatible with Quest 2 and HTC VIVE Focus 3
Software and data
Acquisition and analysis	BIOPAC AcqKnowledge included, perpetual license (MedelOpt+ supported from version 6.0.2); MeMoSoft — montage design
File formats	ACQ, MAT, EDF, SNIRF
Data access	real-time Network Data Transfer (license); AcqKnowledge Cloud (license); MedelOpt+ API (separate)
Integration
Physiology	BIOPAC MP200: ECG, HRV, respiration, EDA, PPG, EMG, accelerometry; physiology at 2 kHz
Synchronization	common clock and hardware triggers; with the MP200 via the Linked Acquisition protocol in AcqKnowledge
Triggers	TRIG BOX+ USB (Infinity, Tandem): latency typically 1.3 ms; wireless MOBIL+ TRIG (Mobility, VR): typically 3.3 ms2 TTL inputs sampled at 512 Hz; 5 kV rms optical isolation; additionally 4 auxiliary TTL inputs in the unit
Stimulation and other	visual, auditory, electrical, tactile, olfactory and thermal stimulation; video and audio; VR with eye tracking built into the headset
Electronics and standards
Electronics unit	22 × 85 × 48 mm; 5 V DC power (micro USB), max. 1 A
Safety	photobiological IEC 62471 — risk group 0; electrical IEC 60601-1; EMC IEC 60601-1-2; EEG IEC 80601-2-26; RoHS
Operating conditions	10–40 °C; humidity 0–70% non-condensing; up to 3000 m above sea level
Manufacturer	Seenel Imaging (France), technology protected by international patents; global distribution: BIOPAC Systems (since 2023)

Sources: BIOPAC MedelOpt+ product sheet (11/2025); biopac.com — MedelOpt+ Brain-Body Platform, MedelOpt+ Infinity, Mobility, Tandem and VR product pages, AcqKnowledge — new features, Seenel–BIOPAC partnership announcement (2023); as of 2026-10.

Frequently asked questions

How does fNIRS differ from EEG, and why use both at once?

EEG measures the electrical activity of neurons and shows when the brain responds — with millisecond precision. fNIRS measures changes in blood oxygenation in the cortex and shows better where this activity takes place. Recording both signals in one headset lets you study their relationship and gives a fuller picture of brain activity than either alone.

Can the participant move during the study?

Yes — this is one of the main features of MedelOpt+. The headset is lightweight, and the Mobility variant with the Mobility Pack (mini PC and battery) lets you study walking, running or cycling with no range limit. BIOPAC describes, among others, a dual-task protocol on a treadmill.

Does the headset fit a child’s head?

Yes. According to the manufacturer, one adjustable headset fits heads from age 4 to adults — no set of caps in different sizes.

What happens if the wireless connection drops?

In the Mobility variant, the headset also saves data to its own memory. If the live view is interrupted, recording continues without data loss — according to the BIOPAC product sheet.

How long can a recording last?

Up to 8 hours of continuous acquisition. BIOPAC also states 6 hours of fNIRS operation without drift according to MEDPHOT criteria.

Can I analyze the data in other programs?

Yes. AcqKnowledge saves data as ACQ, MAT (MATLAB), EDF and SNIRF — SNIRF is the common file format for fNIRS. Real-time data is available with the Network Data Transfer license, and the MedelOpt+ API lets you plug EEG and fNIRS streams into your own applications, e.g. for neurofeedback.

How does this page differ from MedelOpt fNIRS Infinity Systems?

Here we describe the MedelOpt+ platform — the technology, headset, software and the whole family of variants. On the MedelOpt fNIRS Infinity Systems page we compare specific Infinity configurations for whole-head mapping and help you choose a model.

Can I combine MedelOpt+ with VR and eye tracking?

Yes. The VR variant combines the headset with Meta Quest or HTC VIVE Focus 3 goggles, and AcqKnowledge controls the scenario and receives event markers from VR. Eye tracking then comes from sensors built into the goggles, e.g. HTC VIVE Focus Vision. Describe your study to us — we will select and configure the whole workstation.

Can I see the system before buying?

Yes — book an online presentation and talk to us about your protocol. Contact us.

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