A low cost color visual stimulator for fMRI

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Imaging

Background:

• Developing effective visual stimuli for small animal research is crucial for neuroimaging studies.
• Existing visual stimulators may be costly or lack the flexibility required for diverse experimental designs.
• Software-driven solutions offer potential for greater control and adaptability in stimulus presentation.

Purpose of the Study:

• To develop and validate a low-cost, software-controlled visual stimulator for small animal imaging.
• To enable precise control over visual stimulus parameters such as flicker frequency, wavelength, intensity, and waveform.
• To facilitate visual stimulation during functional magnetic resonance imaging (fMRI) experiments.

Main Methods:

• A visual stimulator was engineered using a single tri-color LED per eye, controlled via a desktop computer's parallel port.
• Fiber optic cables transmitted light from LEDs in the control room to the MRI scanner room.
• The system's software allowed for dynamic control of light output (red, green, blue, or achromatic) and stimulus parameters.
• Light output linearity was calibrated using a radiometer.

Main Results:

• The visual stimulator demonstrated highly linear light output from zero to full intensity.
• The device was successfully employed for visual stimulation in fMRI studies on Sprague Dawley rats using an 11.7T magnet.
• Software control enabled easy modification and extension of stimulation protocols.

Conclusions:

• The developed low-cost visual stimulator is a flexible and effective tool for small animal neuroimaging.
• Its software-driven nature allows for straightforward adaptation to various research protocols and future functional enhancements.
• The system provides precise, calibrated visual stimuli essential for fMRI research.