MEG Online Magnetoencephalography MEG

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MEG OnlineMagnetoencephalography (MEG)

• Heinz Rongen
• Forschungszentrum Jülich GmbH
• Zentrallabor für Elektronik
• Tel. 02461 / 61 4512
• Fax. 02461 / 61 3990
• H.Rongen_at_fz-juelich.de
• www.fz-juelich.de/zel/zel_rongen

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Online Analysis of MEG Signals

• Joint project with the Institut für Medizin
  (IME), FZ-Jülich (Contact person IME is Mr.
  Prof. Peter Tass)
• 148 magnetic field Sensors (SQUIDs)Milestones
• 1) Hardware for 148 () signals, 2-4 KHz
  sampling rate, online dataacquisition,
  recording and Visualisation,
• 2) Synchronisation analysis (Phase
  synchronisation ..)
• 3) Rückrechnung (invers Bereich)
  Stromdichtevektoren (3D Bilder, ms Takt ..)

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What are the restrictions ?Why we want the
signals ONLINE ?

• Reconstruction of cerebral currents for all
  Voxelelements of the human brain to determine the
  effects of the stimulation by a electrode.
• Optimization of the stimulation parameters based
  on the tomographical methods.
• Only some hours between implantation of the
  electrode and the stimulator module.
• Therefore the tomographical reconstruction must
  be online, to obtain the optimized
  stimulationparameters.

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The 2500WH MEG at IME, FZ-Jülich

• At the IME we have an 2500WH MEG
• 148 MEG channels SQUID magnetometers
• 96 aux channels (EEG/ECG/EMG)
• 16 bit per channel A/D
• up to 8 kHz sampling rate

(http//www.4dneuroimaging.com/external_english/ht
ml/m25spec.html)
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The existing electronic
RCC Remote case Controller REI Remote
Interface Electronics Fiber optic Cypress
Hotlink, 250 Mbps
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The LWL splitter

• F.O CouplersDatasheet SINGLEMODE-COUPLERS
• Optical couplers are passive optical devices
  which allow the distribution and combination of
  optical signals. They are used in public and
  private fibre-optic networks as nodes in data
  transmission networks (telephone, cable TV etc.)
  further fields of application are in measurement
  set-ups, measuring instruments, and sensor
  technology.

(http//www.tedis.at)
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UniDAQuniversal DAQ board with DSP FPGA

• PCI and CPCI form factor
• 1 Gflop floating Point DSP
• 32 Mbyte Memory
• FPGA Xilinx Virtex XCV800
• loadable over PCI bus
• Dpiggy with 2 Hotlink fiber optic interfaces

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DSP D.Modul TMS320c6701
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National InstrumentsLabVIEW --gt FPGA
Develop on Host Computer
Implement code in hardware
Download
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Das LV-FPGA Modul
LabVIEW FPGA Functions Loop structures (while,
case, sequence) Arithmetic Boolean operators and
decision making Arrays, clusters Timing,
occurences I/O specific to the board used
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LabView FPGA sample code

• Pressing the RUN button
• Converts LabVIEW to VHDL
• Compiles to bit stream
• Stores bit stream information in the .vi file

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LabView for

• C code generation for Processors, DSPs
• VHDL code generation for FPGAs
• Download codes to the Target Platform(s)
• Host Application Programming

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Interested ?? Contact ??

• H. Rongen
• Forschungszentrum Jülich GmbH
• Zentrallabor für Elektronik
• Tel. 02461 / 61 4512
• Fax. 02461 / 61 3990
• H.Rongen_at_fz-juelich.de
• www.fz-juelich.de/zel/zel_rongen