The visual presentation is done with high luminance DLP Projector. The theoretical maximum refresh rate is 120 Hz, but to reduce the jettering, is better to use 60 Hz.
Be aware that there can be a considerable delay between the display command issued on your computer and the appearance of the stimulus on the screen (a latency of ms).
The projector is outside the Magnetically Shielded Room (MSR), but a periscope permit the projection of the image (50x38 cm) on the screen placed at 120 cm in front of the chair, see the marker on the floor.
The following section explains how to use the projector:
1.For powering up the Projector: Press the â€œIâ€ button (on the main unit or the remote control),
2. Select the input signal by pressing the input selector button to toggle though RGB2,
3. Make adjustments and selections (only if you needed)by pressing the button 'on the remote control. You might accomplish changes via the setuo screen (â€œLENS FOCUSâ€, â€œLENS ZOOMâ€ and â€œLENS SHIFTâ€),
4. Choose an item and adjust it using <- -> buttons.
5. Power off the projector pressing twice the POWER OFF button
(on the main unit or the remote control).
NOTE: Donâ€™t forget to power off the Projector before leaving the lab.
A photodiode is a type of photodetector capable of converting light into either current or voltage. Use the device if you like to check the delay between the stimulation computer and the projector, follow these steps.
1. Open the back door of the Electronics Cabinet.
2. Turn on the â€˜Light to Voltage Converterâ€™
3. Connect the Light to Voltage Converterâ€™ to the Channel 5 of the Stimulus Triggers Interface with a BNC cable.
The directional speakers (amplifier) create a highly focused and directional audio footprint that delivers sound to the intended target without disturbing the surrounding area.
Using a Stereo Audio Cable connect the Panphonics Sound Shower amplifier (in the stimulation cabinet) with the audio exit of the Stimulation PC.
We use a STIM2 system (Tip-300, Nicolet, Madison, WI, USA) via MEG-compatible tubal insert phones, which permit to present Sound Pressure Level for the maximal amplitude at approximately 65 dB.
The headphones are in-ear types. Use a new pair of ear-tips for each subject, and dispose of used tips immediately.
1. Plug in the Cables see the pic in the audio exit of the Stimulation PC,
2. Plug in the Tubal Insert Phones in Audio Stim. Out in the Left side of the MEG,
3. The headphones are in-ear types. Use a new pair of eartips for each subject, and dispose of used tips immediately (NB: Throwaway just the eartips, saving the transparent piece of plastic attached to the tubes),
4. Ask to the subject to inset the RED tube in the Left ear and the BLUE in the Right.
Note!! You can use the headphones to present white noise.
The PIEZO uses the principal of piezoelectricity that is the property of certain ceramics, notably crystals as PIEZO) to change their geometry when applying an electrical voltage. It is used generate skin indentations. Note, the piezo crystals receive a very low current but high voltage. Therefore, never open the casing of the stimulator and be aware that the stimulation might create magnetic artifacts. Ask MEG staff how you should design your stimuli in order to minimize disturbances of the MEG signal.
1. Connect the Stimulation PC with the Piezo stimulator using an USB Cable.
2. Connect Piezo to 8 OUTPUT in Stimulus Triggers Interface (in Stimulation cabinet) using a BNC Cable.
Pressurized air can be used for somatosensory stimulation of the skin. You can either apply an air puff directly to the skin or make use of the inflatable diaphragms available in the MEG lab. The diaphragms can be either taped to the skin or attached to the finger or mouth using a clip. Be aware that the pressure should be limited in order not to harm the subject or tot destroy the diaphragms. In particular you should be careful removing the plug closing the compressed air line. It might fly like a bullet directly into your subjectâ€™s face.
1. Open the Stimulation cabinet from the back door, take a black tube coming out from a blue box,
2. Connect it to the â€˜ARIA INDUSTRIALEâ€™ in the right side of the Stimulation cabinet and open the valve (see the figure),
3. Use a BNC cable to connect the Pneumatic box to the OUT9 in Stimulus Triggers Interface (in Stimulation cabinet).
NB: Use only the black tubes that come out from the blue box.
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