AnimalSQUID™ Family of Systems

The animalSQUID™ (pdf) is a set of research tools made to meet the specific requirements of research on mapping functional neurophysiology in animals or human neonates. Instruments are tailor made in size, shape, sensor geometry for detecting and mapping cortical sources. For basic research, animalSQUID™ provides an opportunity to make comparative cortical measurements with other modalities, such as EEG, and EcoG, sequentially, or even simultaneously. AnimalSQUID™ systems have been used to measure cortical sources in experimental animals such as rat, rabbit, pig, turtle, or monkey.

Some of the advantages of magnetic measurements are that they:

• Detect magnetic fields associated with cortical activity
• Are preferentially sensitive to sulcal sources
• Give sub-millisecond temporal resolution
• Offer better spatial localization than electrodes
• Are non-invasive (no need to attach electrodes)

The key to Tristan’s animalSQUID™ systems is our proprietary microSQUID™ technology. This brings the sensor coils very close to the subject. Because the sensitivity of biomagnetometers goes as the inverse square of the distance to the electrophysiological source, sub-cm spacing yields significant increases in signal/noise performance. Additionally, spatial resolution is greatly enhanced. Tristan is unique in its capacity to build thin “windows” between (cryogenic) sensors and (room temperature) source. The use of advanced window materials such as diamond and sapphire let us achieve very close spacing from sensors to cortex or scalp-in some cases smaller than 2 mm.

Tristan systems come with data acquisition hardware and software for data analysis ranging from basic LabVIEW™ drivers to sophisticated magnetic dipole and current dipole fits. Systems can be supplied with vector and tensor reference arrays for noise reduction. Dewar gantries can be supplied with up to five degrees of freedom. If needed, we can also supply magnetically shielded rooms.

A choice of coil diameters, array sizes, and dewar geometry is available to the user, along with reference channels to reduce ambient noise, so that the animalSQUID™ is optomized for specific animal measurements, in vitro studies, or neonatal studies. The combination of sensor array size, detector diameter, and channel count depends upon the area of coverage needed and the distance from cortical source to detector array. Our standard animal systems are comprised of 7, 19 and 37 detection channel systems.

The standard N-channel detection coil array is that of a Hexagonal Closed Packed (HCP) Array with N = 1, 4, 7, 19, 37, 61 …. or higher. The diameter of sensor coils is typically 3 mm, but can range from 1 mm to 10 mm. Normally, the gradiometer baseline is five times sensor coil diameter, but it can be a customer-defined value. The standard sensor geometry is that of a first order axial gradiometer, but other geometries (e.g., asymmetric or planar gradiometers, magnetometer, higher order gradiometers) are available along with vector coils (Bx, By). Most animalSQUID™ systems utilize flat tail dewars, but curved tail dewars and sensor arrays are available (e.g., monkeySQUID™).

Model 607A – Close-Spaced 7 Channel System

Features

• Seven detection coils in a hexagonally close packed (HCP) array
• 3-mm diameter 1st order gradiometer detection coils
• 3-mm coil-to-coil separation
• < 5 mm offset from room temperature outer dewar surface (dewar gap)
• Optional vector reference channels (dBz/dz, Bz, Bx, By)
• Optional dewar gantry and positioning aids
• Optional data acquisition hardware and software

Model 619A – Close-Spaced 19 Channel System

Features

• Similar to model 607A, but with 19 detection coils
• Four vector reference channels (dBz/dz, Bz, Bx, By) standard. 8-element tensor reference array optional
• Coil-in-vacuum dewar/probe optional
• Integrated subject platform/gantry and positioning aids optional

Model 637M monkeySQUID™

Features

• 37 detection coils with curved tail coil-in-vacuum dewar
• 8-element tensor reference array standard
• Integrated subject platform/gantry and positioning aids standard

Many of Tristan’s systems have been the result of a collaborative effort between us and our customers. We can vary virtually any aspect of the system to meet your requirements. Please contact Tristan to discuss your needs.

animalSQUID™, monkeySQUID™ and microSQUID™ are all trademarks of Tristan Technologies, Inc