fMRI-GLM
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The fMRI compatible grip-lift manipulandum is a device designed to study the motor control of the precision grip in humans. The motor control of the precision grip relies on the coordination of the grip force (i.e. the force applied by between the thumb and index fingers on an object) and the load force (i.e. the apparent weight of the object) when manipulating an object in space. The instrumented object manipulated by the subject is called the manipulandum or grip-lift manipulandum (fMRI-GLM). The experimental setup is designed to be used in MRI scanners, although it can be used in a conventional environment as well. The experimental setup is composed of the grip-lift manipulandum, a signal conditioner and peripheral devices controlled all together by the data acquisition system.
The table below is a subset of the main features and specifications of the fMRI-grip-lift manipulandum system.
| Model name | fMRI-GLM |
|---|---|
| material | TA6V (Titanium alloy grade5) |
| basic mass | ~250g |
| structure | Two half shells and a center weight |
| dimensions | 106x56x36 mm (height,width,depth) |
| grip distance | 30 mm |
| force transducers | Strain gauges (Vishay Measurements, N2A-xx-S124N-10x) |
| Additional weight | The fMRI-GLM includes two center weights: - The light weight made of titanium that is part of the basic fMRI-GLM mass (~250g) - The Heavy weight is identical in shape and appearance to the light weight but is filled with lead to bring the total mass of the fMRI-GLM to ~500g |
| Amplifier | included (3 channels LF, Gfright, GFleft, 4 stages amplification x1,x2,x4,x8) |
| Measuring range Fx, Fy, Fz | up to xx kN |
| Sensitivity LF,GFr,GFl | xx – xx – xx – xx mV/N |
| Noise rejection Fx,Fy,Fz | Low pass filter: Bessel 4th order filter with Fc = 150 Hz |
| Resonance frequency | > xxx Hz |
| Power supply | 240 V, 50 Hz. Fuse: 250 mA.] |
| data acquisition system | USB-DAQ 6221 (National Instruments, USA) |
| Peripherals | up to 5 extra analog inputs and 4 digital inputs can be configured and acquired in parallel with the load and grip forces |
| software | requires windows XP. All basic functions are implemented in the dedicated software: Setup, Calibration, Acquisition, signals display, ASCII files saving |
Applications
Classical applications are:
- Hand function experiments in different environments including functional magnetic resonance imaging
- Clinical hand evaluation
- Motor control research