Extraocular Muscle Force Transducers (MFTs)

The first and only way to chronically measure eye muscle forces in an alert behaving animal was developed in our laboratory. Extraocular Muscle Force Transducers (MFTs) have been implanted on lateral and medial rectus muscles (LRs & MRs). A properly implanted device can survive and deliver signals for many months.

Implantation Scheme for lateral rectus muscle. The fascial pocket is optional. it is more important to assure that a "U" of slack lead wire remains in the orbit, and that it does not cross itself (making an "" shape), which would quickly become fused by connective tissue.

Documentation

	Project Extraocular muscle force studies, and MFT development.
	MFT Fabrication Provided mostly for your amusement because, as you will see, the process is not one you would want to undertake yourself. We would be more than happy to receive your suggestions for improved procedures.
	Implantation Instruments, procedures, and cautionary notes for implantation in NHPs.
	Publications Journal articles that describe the properties of MFTs, and their applications to eye muscle force measurement.

Devices & Tools

MFTs are available from Eidactics, along with specialized tools needed for implantation.

MFTs sized for monkey EOMs are available in 2 orientations: left (MFT-2.10L), and right (MFT-2.10R), recommended for implantation on the left LR and right MR, and the right LR and left MR, respectively (ie, such that the lead wires course upwards as they depart from the MFT. We fabricate the devices in our laboratory (PDF 2.2MB).

MFTs are encapsulated in Paralyne C, 10 up to but not including the Teflon insulated lead wires. The devices must be held firmly during implantation, while protecting the Paryene coating from damage. Special MFT Forceps are used for this purpose. Implantation requires the initial 10 mm or so of the muscle be freed of its surrounding connective tissues. The muscle is not disinserted. Lead wires exit the orbit like those of the familiar eye coils. If both an eye coil and an MFT are implanted, it is best to do both together, to avoid the possibility that implantation of one will damage the lead wires of the other. See our implantation nores for more details (PDF 1.9MB).

You will also need appropriate solders and fluxes (for tinning SS lead wires, and then soldering the tinned leads to the skull-mounted connector pins.