Fiber-optic Rotary Joints consist of a lens system and high precision bearings which allow a rotation-insensitive optical power transfer between optical fibers. The fixed part of the rotary joint allows the connection to a light source and the rotating part releases the twisting of the optical fiber connected to the animal.
In neurosciences, freely-moving optogenetics experiments need a stable light input to the brain even if the animal ismoving in a confined space. Fiber-optic Rotary Joints avoid the damaging of the optical fibers while minimizing light fluctuations when rotating. The nomenclature used for our rotary joints is FRJ m X n where m and n represent the number of the fibers on the fixed and on the rotating side respectively.
Electrical Rotary Joints are used to transmit electrical signal from a moving sample to a fixed recording system (e.g. for in vivo electrophysiology experiments). Since it can be desirable to couple electrophysiological experiments with optogenetics stimulations, our Electrical Rotary Joints are designed with a central aperture (hollow bore) allowing the insertion (pass-through) of a fiber-optic patch cord. In this case, electrical and fiber-optic rotary joints (1x1 or 1x2) are used in tandem.
The electrical rotary joints have long been used for in vivo electrophysiology recordings. The arrival of optogenetics in neurosciences created the need of rotary joints allowing optical stimulations and electrophysiological recordings. This combination requires an opto-electrical hybridization in the connecting cables and the rotary joints.
To get better insights of the brain functions, it is desirable to combine different methods for deep brain manipulation of neuronal activity. In order to allow for the delivery of light and fluid simultaneously in freely-moving animals, the rotary joint needs to combine functions of the fiber-optic and liquid rotary joints within one instrument.