NatMEG Core Facility - our offer

The Swedish National Core Facility for Magnetoencephalography (NatMEG) is a national infrastructure, available for researchers from all across Sweden. It is the first and only core facility in Sweden for whole-head measurements of neuronal brain activity using magnetoencephalography (MEG).

The lab

The core system at NatMEG is a state-of-the-art 306-channel system for MEG measurements (Elekta Neuromag TRIUX) with an integrated 128-channel EEG system (Elekta), located inside a 2-layer magnetically shielded room (Vacuumschmelze GmbH), and related amplifiers and acquisition systems.

On top of the core system, NatMEG lab is uniquely equipped with wide array of best-available equipment stimulation (visual, auditory, somatosensory, olfactory and more), measurement of and registration of responses (psychophysiology, eye tracking, behaviour and more) all handpicked, modified, installed and verified for millisecond timing in the MEG environment.

Core MEG system

The core system at NatMEG is an Elekta Neuromag TRIUX 306-channel system (102 magnetometers, 204 planar gradiometers).

NatMEG has recently installed and integrated an internationally competitive whole-head on-scalp MEG system. The new osMEG system uses optically pumped magnetometer (OPM) sensors, a new type of quantum enhanced sensors that can measure closer to the scalp than conventional MEG sensors. Simulations have shown that by coming closer to the head (and the neural sources therein) osMEG can achieve higher sensitivty and spatial precision compared to conventional MEG.

The Elekta Neuromag TRIUX has an integrated MEG-compatible 128 channel EEG system. We currently use 128 channel caps, 74 channel caps and 128-slit custom montage caps from EasyCap.

The Elekta Neuromag TRIUX also has 12 integrated bipolar channels, for recording of electrooculgraphy (EOG), electrocardiography (ECG), and electromyography (EMG). We currently use the EL508 electrodes and LEAD108 and LEAD108a from BioPac for most biochannel measurements. We also use  the EL254RT for facial EMG.

 

A total of 32 digital channels and 24 analog channels are sampled in parallell and synchronized to the MEG, EEG and biochannels data.

All MEG/EEG recordings are done within a two-layer MSR, model Ak3B from Vacuumschmelze GmbH.

Peripheral Stimulus Equipment

  • For  visual stimulation, we use a FL35 LED DLP projector from Projection Design. The current installation runs at 32 bit color in 1920x1080 @120 fps. Maximum field of view for visual presentation is about  63 (horizontal) *41 (vertical) degrees
  • In standard settings (16:9 ratio, 1920x1080 resolution, 120 fps, 100 cm distance), the projector fills a 72 x 44 cm rectangle on the screen, ca 40 x 25 degrees of the visual field
  • Presenting a white picture on the screen gives 100 lumen on screen, 30 lumen at eye position
  • The visual stimulation is typically controlled via Neurobs Presentation, in which case the computer-to-eye delay is about 8 ms, with no frame drops or frame doubles

Technical specifications for the projector

  • For audio stimulation, we use either headphones or speakers
  • The headphones are binaural SoundTubes, model ADU1c, from KAR Audio

Technical specifications KAR Audio.

  • The stimulator-to-ear delay is about 10 msec
  • The  speakers are Sound Showers, model SSHP60X60W, from PanPhonics

Technical specifications on Sound Showers

  • The stimulator-to-ear delay is about 10 msec
  • The audio stimulation is typically controlled via the AudioFile stimulator from Cambridge Research Systems Limited, in which case  the sound onset jitter is below 1 ms.

AudioFile user guide

  • For electrical nerve stimulation, we use two DeMeTec SCG30 stimulators, either with felt tips for median nerve stimulation, or with ring electrodes for single phalange stimulation
  • The trigger to stimulation delay is about 3 msec

Technical specifications DeMeTec SCG30 stimulators

  • For olfactory stimulation, we use a  Monell 9-channel olfactometer
  • The trigger to stimulation delay is under evaluation
  • For tactile fingertip, toe and lip stimulation, we use a 4-channel Somatosensory Stimulus System from Biomagnetic Technologies
  • The trigger to stimulation delay is under evaluation

Somatosensory Stimulus System user guide

  • For proprioceptive  and/or tactile finger stimulation, we use a 5-channel custom-built PAM system from NatMEG Guest Professor Veikko Jousmäki
  • The trigger to stimulation delay is under evaluation
  • For pleasant touch stimulation, we use  custom-built 2-arm brush robot system from NatMEG Guest Professor Veikko Jousmäki
  • The trigger to stimulation delay is completely dependent on brush robot sequences. A combination of brush arm speedometer, accelerometer, load cell and brush touch onset optic sensors are used to assess the movements and stimulation periods
  • For mechanical pain stimulation, we use a custom-built pressure algometer from Somedic
  • The trigger to stimulation delay is under evaluation

Somedic APA software instruction manual

Peripheral response systems

  • For eye tracking we use an EyeLink 1000 binocular tracker from SR Research. The current installation runs at a maximum of 1000 Hz, tracking both eyes binocular
  • The eye tracker is typically controlled via Neurobs Presentation
  • Via Presentation you can access the eye tracker output in realtime. The X, Y and pupil diameter of each eye is also output into the MEG system analog channels and sampled side by side with the MEG data
  • The calibration space of the eyetracker is 1920x1080, with 0,0 in the top left corner
  • The eyetracker settings are aligned to the projector, so that the projector ini-file uses the pixel space (1920x1080), standard visual size (72x44 cm) and distance (100 cm) of the projector

EyeLink 1000 user manual

  • For psychophysiology measurements beyond ECG and EOG we use  an MP150 system from BioPac. In the current setup, we have modules for measurements of ECG, GSR, respiration and blood oxygenation
  • BioPac output is typically recorded via BioPac's AcqKnowledge software, but is also output into the MEG system analog channels and sampled side by side with the MEG data

Further information on BioPac systems

Rates

NatMEG not only provides access to the superbly equipped MEG lab, but also provides training and support to users in experimental design, piloting, measurements and analysis.

Currently, all normal support is completely free of charge, and MEG lab access is either completely free (during piloting) or subsidised (during main measurements).

Academic research and clinical routine

  • Qualifies for maximum subsidy of lab and service use 
  • Requires adherence to Vancouver guidelines regarding authorship

Services and access (2022)

  • Training in preparation and measurements
    • NatMEG support: 100% subsidized
  • Project conception and development
    • NatMEG support: 100% subsidized
  • Piloting recordings (maximum of 2 days of lab time; additional time counts as Measurements)
    • Lab time: 100% subsidized
    • NatMEG support: 100% subsidized
  • Main measurements
    • Lab time: 60% subsidized = 2500 SEK per hour (bookable in 1-hour slots)
    • NatMEG general support: 100% subsidized
    • Measurement support: If NatMEG staff presence is required during measurements (i.e., assistance beyond initial training): 500 SEK per hour
  • Qualifies for partial subsidy if lab and service use
  • Requires adherence to Vancouver guidelines regarding authorship (Appendix A)

Services and access (2022)

  • Training in preparation and measurements
    • NatMEG support: 100% subsidized
  • Main measurements
    • Lab time: 0% subsidized = 5000 SEK per hour (bookable in 1-hour slots)
    • NatMEG general support: 100% subsidized
    • Measurement support: If NatMEG staff presence is required during measurements (i.e., assistance beyond initial training): 500 SEK per hour