Technical Facilities

Magnetic resonance scanner Siemens MAGNETOM Skyra Connectom A

The super brain scanner

The super brain scanner

December 12, 2016
The MRI scanner CONNECTOM is one of three of its kind worldwide. Thanks to its unparalleled gradient strength, it will reveal information about the inner wiring of the living human brain. more
7T Magnetic Resonance Scanner MAGNETOM Terra

7T Magnetic Resonance Scanner MAGNETOM Terra

In March 2019, a new scanner was put into operation at the Institute, whose magnet produces a field of 7 Tesla—which is about 140,000 times stronger than the Earth's magnetic field. It replaces our first-generation 7T scanner, which has provided new insights into the structure and function of the human brain in numerous studies over 12 years of operation. The magnetic field is generated with a superconducting coil made of niobium-titanium alloy that is constantly cooled to a temperature of 4.2 degrees above absolute zero (–269 °C). The magnet is about 2.7 meters long, 2.9 meters wide and weighs (after installation) less than 25 tons. The opening of the patient tunnel has an inner diameter of 60 cm. The magnet is actively shielded, but was nevertheless installed in the existing iron cabin with dimensions of 10 × 5.7 × 5.7 meters and a weight of 362 tons, since dismantling it would be too costly. Overall, the stray magnetic field outside the shielding is reduced so efficiently that the 0.5 millitesla contour line passes entirely within the elliptical section of the building containing the facility.
The scanner has a powerful gradient unit for spatial encoding of the signals that can produce up to 80 millitesla per meter along any spatial axis within 0.4 milliseconds. The resonant frequency is 298 megahertz for experiments with hydrogen nuclei (“protons”). 64 parallel high-frequency channels are available on the receiving side. Up to 16 parallel channels, each with 2 kilowatts of power, are available for transmitting. In addition to hydrogen nuclei, all biologically significant atomic nuclei (e.g. C-13, Na-23, P-31) can be investigated.
3T Magnetic Resonance Scanner MAGNETOM Prismafit

3T Magnetic Resonance Scanner MAGNETOM Prismafit

This system was installed back in 2003—at that time as the first of its kind with a whole-body coil. In the 20 years it has been in operation, it has been continuously upgraded to the latest state of the art. The spatial information is encoded by a whole-body gradient system that generates gradients of up to 80 millitesla per meter along arbitrary directions within a minimum ramp time of 0.4 milliseconds. The resonant frequency for imaging experiments with hydrogen nuclei is 123.2 megahertz. Various special coils are used to study the human brain or spinal cord. In pulsed mode, the amplifier generates up to 35 kilowatts to drive the body coil. Up to 64 independent channels can be used simultaneously for signal reception.
Magnetic resonance scanner Siemens MAGNETOM Verio 3T

Magnetic resonance scanner Siemens MAGNETOM Verio 3T

Foto: © Hans - J. Krumnow, 2011
Magnetoencephalograph Vektorview

Magnetoencephalograph Vektorview

The MEG system was installed in November/December 2006 by Elekta Neuromag Oy, Helsinki, Finnland. It is a whole head system hosting 306 magnetic channels in total. The system is also equipped with an integrated 128 channel electroencephalography system and devices for auditory, visual and somatosensory stimulation. Currently, the maximum sampling rate is 5000 Hz for all channels. At this rate the device produces about 500 MByte of data per minute. This raw data usually passes extensive postprocessing before it allows conclusions about it's origin - the underlying brain activity. The magnetic sensors are operational only at a very low temperature below 10 K(elvin). The is achieved by placing them in a bath of liquid helium. While the liquid helium boils it stays at the temperature of the phase transition at 4.2 K. The liquid helium reservoir is much smaller compared to the one of MR scanners. It holds about 100 litres of liquid helium. It has to be refilled once per week.
Magstim Rapid2 TMS

Magstim Rapid2 TMS

Transcranial magnetic stimulation (TMS) is a method that relies on a short-lived magnetic field which is induced by a high current (approx. 5000 Amp) running through a well insulated cable wound into a coil. This field lasts for about half a millisecond and reaches peak amplitudes of 3 Tesla, which is comparable to the field strength used in MRI scanning. Neurons react to these extreme magnetic fluctuations (rising from 0 to 3 Tesla and back to 0 within less than a millisecond) by producing signaling impulses themselves. If the coil, being relatively small and lightweight, is placed to the head of the subject, the nerve cells just underneath the focus of the coil send impulses synchronous to the TMS pulse (normally up to once a second). Since this simultaneous firing of complete neural populations is without any functional content, information processing in this part of the brain is disturbed for fractions of a second. This allows us to induce "virtual lesions", i.e. simulate the failure of the brain region in question without jeopardizing the subject. By deliberately integrating TMS in a well elaborated experiment, one can prove the importance of the brain part in a given cognitive function because performance deficits can be expected. To optimize targeting during TMS experiments, previously obtained (functional) MR imaging data can be utilized for the so called neuro-navigation. A computer compares the brain scan with the subject's head and thus enables a very precise positioning of the coil on the head, just over the brain region of interest.
Magnetic field strength:
0,5 - 3,5 Tesla
Maximum repetition rate:
50 Hz bei 30% max. stimulator output
30 Hz bei 50%
18 Hz bei 80%
15 Hz bei 100%
In our experiments, we normally use stimulation frequencies of 1Hz, and sometimes short pulse series of 10Hz. Duration of a single impluse: 400µs.
Further technical facilities at the Institute:

Further technical facilities at the Institute:

  • EEG Laboratories with 64 bzw. 96 channels
  • 3-D Digitalisers for three-dimensional registration of scalp position of electrodes
  • Laboratories for reaction-time experiments, including one psychophysics and one pharmalogical lab
  • Psycho-acoustical lab with sound-isolated chamber
  • Language lab for the editing of language stimulus material for experimental-psychological tests
  • Analysis labs with three SGI-O2-Workstations
  • Parallel computer
  • Ethernet-LAN with GB-Ethernet-Backbone with components by Extreme Networks (Summit 48, Black Diamond)
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