The Martinos Imaging Center at MIT hosts a suite of tools and facilities for studying brain activity in humans and animals.
The center has two 3T Siemens Magnetom 60cm MRI scanners. One of these (referred to as 3T1) has been upgraded to Siemens’ Prisma Fit technology, which involves a retrofit of all computers, gradient coils and RF hardware. With double the gradient strength, the Prisma is ideally suited to measuring brain connectivity using diffusion imaging. The upgrade also increases the number of RF receivers from 32 to 64, allowing faster imaging and reduced scan times. Customized pulse sequences have been obtained from Siemens, from our collaborators at MGH, or written in-house.
The other scanner (referred to as 3T2) is a Magnetom Tim Trio. It is equipped with several interchangeable radiofrequency coils including custom coils that are sized for children. (Similar child-sized coils are being developed for the Prisma scanner.)
For both scanners, visual stimuli are projected through a wave guide and displayed on a rear projection screen (Da-Lite). Eye movements can be monitored with an in-bore, MRI compatible eyelink eyetracker. Audio stimuli are delivered via sensimetrics insert earphones. Behavioral responses can be monitored via a button response and trigger interface.
The center has a 9.4T Bruker Biospec 94_20 MRI scanner for high resolution scanning of small animals. The 20-cm bore is suitable for small animals including rodents, ferrets and squirrel monkeys. There is animal preparation room adjacent to scanner.
The center is equipped with a 128-channel Biosemi ActiveTwo electroencephalography (EEG) system. This system uses active electrode technology, which eliminates the need for scalp preparation during set-up while still providing excellent signal quality and improving the experience for research subjects. The EEG system is housed in a double-wall insulated, sound-attenuating, audiometric testing booth.
The MEG lab features an Elekta Triux scanner with 306 SQUID channels plus 128 channels for simultaneous EEG. The scanner is installed in a Vacuumschmelze 3-layer magnetically shielded room with active compensation coils. It is equipped with a high-fidelity projector and a 44" back-projection screen for visual stimuli, earphones for audio stimuli, a pair of electrical somatosensory stimulators, one-finger response pads, and a MEG-compatible eye tracking system.
A replica of the 3T MRI scanner is used to acclimatize subjects (especially children) to the scanning environment. The mock scanner includes an audiovisual system and touch-pad response device similar to those used in the real scanner. The mock scanner also simulates the noise and vibration of the real scanner. This allows subjects to become familiar with the procedures in a ‘kid-friendly’ environment prior to entering the real scanner, thereby allowing more efficient use of scan time and improving data quality.
Near-infrared spectroscopy (NIRS)
Our NIRS hub consists of a TechEn CW6 system with 16 sources and 16 detectors, as well as custom made headgear for infants and adults. The console computer can also be used for data analysis and anatomical registration with MGH's HOMER2 software package.
Technical Documentation and Software