Stimulus Delivery and Response Systems

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Stimulus / Response Equipment

                          *The stimulus should be set up prior to the subject’s arrival.

Visual Stimulus System

A. The Visual Stimulus Software includes:

•Stim Program – a DOS based software program which delivers visual stimuli.

•Presentation – a stimulus delivery and experimental control software system for neuroscience. Runs on Windows and uses standard PC hardware. Allows more precise timing for stimulus delivery and experimental control. Provides millisecond temporal precision and complete timing information for all stimulus and response events.

Features include:

- Images stored as bmp, jpg, or pcs (picture stimuli).

- Use any adapter display mode from 32 bit color to palletized display modes.

- Synchronizes stimulus appearance with monitor vertical scan (Picture Timing Control).

- Shows a new stimulus up to every vertical scan.

- AVI and MPEG video (video stimuli).

- Animations.

- Built-in programming language for custom control (PCL).

- Controls stimulus presentation in real-time.

- Adjusts stimuli based on responses or external inputs in real-time.

- Reports times for any event of interest (logfiles).

- Verifies all timing to detect operating system problems.

B. The Visual Interface includes the:

•DLP Visual Projector System which consists of:

-DLP Projector

-Screen

-Mirrors

-Remote Control

•Eye Tracker - which allows simultaneous visual stimulation and eye tracking for MEG applications consisting of:

-Eye Tracker

-Software

C. The Visual Projector System

The ProPixx DLP Back Projector system consists of a projector and a screen mounted to the gantry. Images are projected through a hole in the shielded room wall into a set of mirrors which projects the image onto the screen. The image size is up to 40 degrees visual field for eye-screen distance of 37.2 to 52.5 cm.

Features:

-a native resolution of 1920 x 1080 and can be driven with refresh rates up to 500Hz (RGB mode) or 1440 Hz (Greyscale mode) with deterministic timing.

-Uses high brightness LEDs as a light source, giving a larger color gamut

-The LEDs support high bit depth and high frequency full color stimulation.

-For stereo vision applications the high speed circular polarizer can project stereoscopic stimuli for passive polarizing glasses at up to 4000 Hz.

Equipped with:

-a stereo audio stimulator,

-a button box port for precise reaction-time measurement,

-triggers for electrophysiology and eye-tracking equipment, and

-a complete analog I/O subsystem that synchronizes subject I/Os to video refresh with microsecond precision.

Powering the Projector:

PROJECTOR STATUS - LEDs supply info on the:	Power Status	Energy Status
LEDS	ON	Blinking
BLUE LED	Awake Mode	LED Off mode
RED LED	Sleep Mode	Thermal Shutdown

•AWAKE MODE:	Press the POWER button and release, the projector will power ON. The LED will be a solid BLUE light.
•SLEEP MODE:	Press the POWER button for 3 secs, the POWER indicator/LEDs will be a solid RED and the projector will be in the sleep mode OR thermal shutdown.
•THERMAL SHUTDOWN:	Flashing RED LEDs indicates the lamp is shutting down. When flashing stops, the projector is in the SLEEP Mode (OFF) as indicated by the solid RED LEDs.

1. TO POWER ON - On the projector, press the POWER button once.

2. TO POWER OFF - press the POWER Button and hold for 3 seconds. The projector will enter the thermal shutdown mode and after a short delay the power will turn off / enter the sleep mode.

*The Projector has a 30-40 ms delay before it displays an image.

**In order to preserve the bulb life, turn the projector "OFF" after each use.

Positioning the Projector:

The projector position may be adjusted manually by shifting slightly to the:

• Left or Right and
• Up or Down.

Lens Adjustments:

Manual Adjustment

1. Images may be focused by turning the silver and black lens collar located on the projector.

2. The projector lens should be centered in the middle of the screen and should be perpendicular to the mirror; otherwise the image will be distorted, making viewing difficult.

Program Adjustment

This function can be used to adjust the focus, zoom, and keystone settings. *Generally only manual adjustments are necessary.

1. Press LENS to select mode. Each time LENS is pressed, the screen changes.

2. Press ENTER to display test pattern.

3. Press the arrow buttons to make adjustments.

4. Press LENS until normal screen appears.

5. To reset the KEYSTONE setting, press UNDO.

Mirror Adjustments

Wall Mirror Adjustments:

1. Project an image onto the mirror.

2. Adjust the wall mirrors:

a. Position the top mirror in front of the lens so that the image is reflected down to the bottom mirror.

b. Adjust the bottom mirror so that the image is projected centered onto the screen.

Ceiling Mirror Adjustments ( for Supine Recording):

1. Place the ancillary wall mirror on the 2nd set of wall brackets.

2. Project an image onto the mirror.

3. Adjust the mirror back or forward so that the image is projected down onto the screen.

Screen Adjustments:

1. Position the screen so that it is in the center of the subject's visual field. Then center the image so that it is projected centered onto the screen. If possible the screen should be perpendicular to the floor.

2. The screen distance can be increased or decreased by loosening the black knob located on the telescoping screen arm and adjusting the arm length. *Note: that adjusting this distance will change the visual angle. Always change the screen back to its original position when done.

3. If necessary, the screen can also be removed and flipped so that it is closer to the subject. Loosen the knob located on the telescoping screen arm. Pull the arm out, flip the screen and re-insert. Position the screen and tighten the knob. *Note: adjusting the distance will change the visual angle. Always change the screen back to its original position when done.

4. Use the black knob located on the Gantry Mounting Bar to raise and lower the screen.

Black Screen Function:

This function can be used to superimpose a black screen over the projected image. The Remote Control or theTouch Pad located under the projector can be used to activate this function.

1. Blacking out the Projected Image WITH On-Screen Display:

a. Press BLACK SCREEN. The screen turns black and “BLACK SCREEN” is displayed on the screen.

b. To return to the original projected image, press BLACK SCREEN again.

           *For remote control operation, slide the MOUSE/ADJUSTMENT switch to the MOUSE position.

Optical Sensor System

The optical sensor is positioned in front of the projector (inside the projector tube). It measures the light output of the projector and is used to determine accurate timing of visual stimulus onset times.

The system includes:

•Optical Sensor

•DLP Projector

•Illumination Sensor Box

Operation / Setup:

1. Place the Power Switch for the Illumination Sensor Box (which is located on the stand outside of the MSR) in the ON position.

2. Adjust the Optical Sensor located in the projector tube. *Sensor may be taped to the lower mirror for better accuracy.

3. Check the rack to ensure that the optical sensor output is plugged in. It is typically on ADC 16.

Eye Tracking / Video Presentation System

The SMI iView X Hi-Speed Drift-Free Eye Tracking System - is an eye tracking system that uses infrared illumination and computer based image processing. Images of the eye are analysed in real-time by detecting the pupil, calculating the center, and eliminating artifacts. Once a calibration is performed, the pupil locations is translated into gaze data. User's manual: http://twiki.cis.rit.edu/twiki/pub/MVRL/SmiTracker/iViewX_Manual.pdf

The SMI iView Eye Tracking System consists of:

•Dell Optiplex 7010 Computer iView X Workstation (located at the Stim Console on the floor) -

The workstation is the eye tracking computer system that runs the software and contains the hardware components that allow the system to capture eye movements. It controls all camera equipment and processes all eye and scene video signals from the experiment. Data and video files are collected there and additional data out is provided on the various IO interfaces of the workstation. The workstation is used to setup experiments, control the eye tracking camera system, and to trigger events, such as calibration, drift correction, start and stop recording.

•iView X Eye Tracker Remote Camera System (located in the MSR)

Software Operation:

1. Turn on the power to the iView X Workstation (Dell Optiplex 7010 Computer).

2. Double click on the iView icon to start the program.

3. Go to Setup -> Hardward and make sure the Eye Tracking Devise is set to RED (Remote Eyetracking Device) 250 (USB).

4. Now click on the advanced button and set tracking mode to 250Hz in the RED properties.

5. Click on the Communications tab in the Setup -> Hardward window to set the Remote Interface 1 to Ethernet and check the option Accept Remote Commands.

6. Go to Setup -> Hardware -> Communications-> Configure and verify that the Interface and Port numbers are the same.

7. Go to Setup -> Tracking. Make sure that the Input Filter has Binocular Data checked and check the Output in Video Pixels for Pupil Diameter. *In Binocular mode the data is collected for both eyes.

Camera Setup / Calibration:

Calibration is one of the crucial steps in eye tracking. It normally consists in looking at several marks on a screen in order to collect enough data to modify the parameters of an adjustable model.

1. Go to Setup-Calibration. The following options are recommended:

- enable Accept Points Automatically.

- enable Wait for Valid Data.

2. Start SMI Experiment Center or a stimulus program capable of running an automatic calibration.

3. In the stimulus program choose Calibration Background Color and Target Color so, that it is similar to the stimulus presentation (what you want to look at during recording).

4. Place your subject in a comfortable position in front of and centered to the screen and cameras.

5. If the eyes are tracked by the system, two white eye dots are visible in the RED Tracking Monitor screen.

6. If tracking is lost the white dots have disappeared from the RED Tracking Monitor.

7. Arrows indicate the optimum position for the test subject in front of the monitor:

-- If the test subject is too far away from the screen an up arrow ↑ indicates that the camera should be moved closer.

-- If the test subject is too close to the screen a down arrow ↓ indicates that the camera should be moved further away.

-- Other arrows direct the test subject to center his or her head in front of the monitor. The test subject is sitting correctly if all arrows have vanished. The correct distance should be between 60 and 80 cm.

8. Click in the Eye Control window to activate the eye tracker. The message in the System Log should read "Grab started". Then follow these steps:

a. Move the camera horizontally until the eyes are horizontally centered in the eye image control.

b. Adjust the vertical position of the camera (camera tilt) until the eyes are vertically centered in the eye image control.

c. Adjust the tilt of the mirror to remove possible reflections from the eye image, after which the vertical position/tilt of the camera probably needs to be readjusted.

d. Adjust the focus until the corneal reflection is as small as possible. This assures optimal focus on the eyeball.

e. Ask the test subject to look at a center target of the stimulus display. Click on the Auto Adjust button to automatically adjust the image regarding pupil threshold and image balancing.

f. The white cross-hair should be centered on the pupil and the black cross-hair on the corneal reflex (CR). If not, adjust them by moving the sliders.

g. As the test subject to look at the four corners of the screen.

h. Setup is complete if both cross-hairs follow the pupil and cornea reflex during these eye movements.

• If the image seems to be blurred, is too dark or too bright, click on the Image Adjust button to adjust brightness and contrast or you can also click on Auto Balance to let the eye tracker self-adjust its brightness and contrast.

• • The result of the measurement is an .idf file recorded and stored on the iView X computer. The resulting file can be laded into SMI BeGaze analysis software for visualization and further analysis.

Auditory Stimulus System

Auditory Software includes:

•SoundBlaster

The Sound Blaster software suite is a powerful audio platform equipped with cutting-edge audio technology. Provides premium audio quality, effects and features for ordinary PC systems equipped with only basic on board audio.

•Presentation

Presentation is a stimulus delivery and experiment control program for neuroscience. It runs on any Windows PC, and delivers auditory, visual and multimodal stimuli with sub-millisecond temporal precision. Presentation is powerful enough to handle almost any behavioral, psychological or physiological experiment using fMRI, ERP, MEG, psychophysics, eye movements, single neuron recording, reaction time measures, other performance measures. https://www.neurobs.com/menu_presentation/menu_features/features_overview

– Runs on Windows Vista/7/8/10

– Is built for precise stimulus delivery and accurate event logging

– Delivers 2D visual, 3D visual, and auditory stimuli separately or simultaneously

– Delivers compressed video with precise frame control

– Monitors responses on a variety of devices

– Interfaces with external hardware

– Is programmable

– Verifies time measurements for all events

– Is extensible

Auditory Stimulus Interface includes:

•Stereo amplifier.

•Binaural (stereo) auditory feed through a pair of low-distortion silicone tubes which have about a 10-11 msec delay and bandwidth of 5k Hertz.

•Foam ear inserts (in various sizes) to fit in the subject’s ears.

•Auditory tubing insert connecting nibs.

•A sound level meter to calibrate sound delivered to the subject.

Inserting the Auditory Tubes (Earphones) / Starting ACQ

1. Attach the short color coded Auditory Tubing Inserts onto the end of the Low Distortion Silicone Auditory Tubes which are hanging on each side of the Gantry mounting bar. Place Red on the right side and the Blue on the left.

2. Attach the Foam Ear Tip Insert into the Auditory Tubing Inserts. A connector (nib) is required to attach the insert.

3. Slowly roll (rather than squeeze) the Foam Ear Tip into as small a diameter as possible.

4. Quickly insert the compressed plug well into the ear canal.

5. Hold in the ear with finger tip until expansion is complete.

6. Repeat process for the remaining ear.

7. The tubing may be taped on the subject’s cheek to assure that the insert does not become dislodged during testing.

8. From the Stimulus Computer desktop, at the operator's console, click on SoundBlaster or Presentation software program.

a. Adjust the sound intensity level (db).

9. Set up Acq computer

a. Start acquisition - launch ACQ.

**Please Note: Insertion depth affects inter-aural attenuation. Be sure to select the correct size Foam Ear Tip to obtain the best fit in the ear canal. Insert as far as possible.

Somatosensory / EMG Stimulus

The Grass S88 Nerve / Muscle Stimulator is a dual output general purpose stimulator intended for nerve and muscle stimulation procedures. There are two output channels which can be operated independently or synchronized to produce complex paradigms. The outputs are non-isolated constant voltage positive pulses. Features include computer compatibility and flexibility of synchronization circuits: the synchronous inputs and outputs are TTL, 5 volts, PC compatible. A rear DB25S connector permits external analog control of the timing circuits. The Stimulus Isolation Unit (SIU) allows for applications requiring isolation and/or constant current. Grass S88 Electrical Nerve/Muscle Stimulator - Stimulation is triggered via TTL outputs from the S88 to the MEG Omega 3500 electronics.

The Grass S88 Nerve / Muscle Stimulator features include:

• Two output channels (S1 & S2) for separate nerve locations (with independent controls),

• Quartz crystal controlled digital timing circuitry,

• Variable pulse rates and durations,

• Variable train rates and durations,

• Variable delays, and

• Variable stimulus voltage.

One Channel Single Repetitive Nerve / Muscle Stimulation

*The Grass S88 has two stimulus channels: S1 Channel controls are silver; S2 Channel controls are black.

S88 Stimulator Settings - S1 Channel
DIAL	Setting	MULTIPLIER SWITCH	Setting
Volt	Variable	Volt Multiplier	10 SIU
Rate (pulse/sec)	Variable	Rate Multiplier	X1
Duration (ms)	Variable	Duration Multiplier	X1
Delay (ms)	*Optional	Delay Multiplier	*Optional

*Function Switch: Single

Grass Stimulator Setup:

1. Turn on the Power for the Grass S88. The switch is located at the bottom right corner of the unit.

a. The orange light should turn on.

2. Turn ON the S1 UNIT Press the ON Switch in the upward direction. The switch for the S1 (upper / silver) unit is located in the right upper corner flanked by the ON pilot lamp and the red Overload Lamp.

3. Set the S1 Volt Multiplier Switch to 10 SIU.

a. Set the S1 Volt Control Dial to 1 which is the lowest level. This will be equivalent to < 1 volt. (This is important because if the voltage is too high when the electrodes are plugged in, the subject might experience extreme discomfort).

4. Select the S1 Duration Multiplier Switch scale. (It is recommended that the multiplier is set on the X1 scale).

a. Select the S1 Duration using the dial (pulse length in ms).

5. Determine the S1 Delay using the dial (ms) if any.

6. Set the S1 Rate Multiplier Switch to X1.

a. Select the S1 Rate (pulses per sec) using the dial. *Usually better to set at a slow pulse rate in order to find/locate the correct muscle/nerve then increase to the correct testing rate.

7. Set the S1 Function Switch to Single.

8. Attach the SIU (Stimulus Isolation Unit) -

When the subject is seated outside of the MSR:

1. Plug the SIU into the S1 Stimulator OUT - ON THE FRONT OF THE GRASS S88 UNIT (unplug/unscrew the cable that is usually attached; re-attach original cable when done).

2. Plug a Bar Electrode into the SIU. *Check to make sure that the Volt dial is set to zero then gradually increase.

When the subject is seated inside the MSR:

1. Open the Access / Penetration Panel Cabinet Door. Find the S1 Cable.

2. Attach the SIU to the S1 Cable.

3. Plug the Bar Electrode into the SIU. *Make sure that the Volt Dial is at zero and gradually increase.

*The Stimulus Isolation Unit (SIU) / Constant Current Unit should be operated at all times with the                        
                                   stimulator VOLTS multiplier set to the X10(SIU).

Grass SIU7 (Stimulus Isolation Unit 7) Setup::

1. Plug the Bar Electrode into the appropriate positive and negative jacks.

2. Set CURRENT RANGE to: 1-15MA

3. Set the POLARITY to: NORM.

Note:

Delivering the Stimulus:

1. Clean off the subjects skin using Nuprep. Brush off any residual grit.

2. Apply electrolyte to the electrodes ends of the Stimulus Bar Electrode.

3. Place the Stimulus Bar Electrode on the nerve or muscle to be stimulated. Gradually increase the voltage until you can see a twitch in the appropriate nerve or muscle. Decrease to motor threshold (subject can feel the pulse but there is no muscle twitch/movement), if desired. Tape into place.

4. Place a ground electrode / bar / pad on the subject distal to the stimulation site.

    **Individual or ring electrode may be used as well. An electrolyte must be used with all electrodes.

Response Pads / Devices

We have are a range of fiber optic subject response devices designed specifically for use in the MEG environment including: handheld fiber optic response devices, response boxes, response pads, button boxes, and variable input devices like joysticks, trackballs, motion and force transducers.

•Lumitouch Response Pad

•Cedrus Lumina Response Pad

•FORP (Fibre Optic Response Pad)

•Optical Mouse

•Air Pressure Response Button

•Push Button Response Switch

•Optical Joystick (without a button)

•Motion Sensor

•Air Pressure Response Device

•Optical Microphone

•Two Button Split FORP

•One Button Split FORP

Lumitouch Response Pad

Lumitouch is a 5 key fiber optic response keypad. The system consists of metal free keypads connected via fiber optic cable to an opto-electronic controller unit. The cabling is fabricated from 100% plastic materials and therefore does not cause electromagnetic interference.

There are five response buttons which are arranged in a row so that all or a subset of fingers can be used in a natural order and comfortable positioning when responding to a visual and/or auditory stimuli. Designed for placing on the arm rest.

1. Instruct the subject in the use of the Lumitouch Response Pad.

Cedrus Lumina Response Pad

Lumina’s 5 key fiber optic response pad captures patients’ button presses and the triggers, time-stamps them with a millisecond accuracy, and converts them into simultaneous USB port and parallel outputs (time-stamped information is output only on the USB port). The response pads are built with 100% plastic and fiber optics.

1. Instruct the subject in the use of the Cedrus Lumina Response Pad.

Fiber Optic Response Pad (FORP)

The FORP is a fiber optic based response device which is completely non-metallic and non-electronic. It is intended for use in MEG, MRI or other environments where metal or electronics could hinder data acquisition, degrade image quality, or pose safety risks.

There are 4 colored buttons which are arranged in a diamond pattern. It is designed to be held or cupped in the hand while using the thumb to respond to the appropriate color, position, number or pattern of the buttons.

1. Instruct the subject in the use of the FORP Response Pad.

Optical Mouse

The optical mouse is a computer mouse which uses a light source, typically a light-emitting diode (LED), and a light detector, such as an array of photodiodes, to detect movement relative to a surface. It is an alternative to the mechanical mouse, which uses moving parts to sense motion.

1. Instruct the subject in the use of the FORP Response Pad.

Air Pressure Response Button

1. Instruct the subject in the use of the Air Pressure Response Button.

Push Button Response Switch

1. Instruct the subject in the use of the Push Button Response Switch.

Optical Joystick (with & without a button)

1. Instruct the subject in the use of the Optical Joystick.

Motion Sensor

1. Instruct the subject in the use of the Motion Sensor.

Air Pressure Response Device

1. Instruct the subject in the use of the Air Pressure Response Device.

Optical Microphone

1. Instruct the subject in the use of the Optical Microphone.