Virtual Reality (VR) can be used for mice to investigate brain functions during decision making. The JetBall-Dome is a worldwide unique product with a Dome for mirror projection of a virtual environment and a spherical treadmill with optional operant devices. The JetBall, an air-cushioned spherical treadmill allows a restrained animal to navigate in a virtual environment. The animal can be examined with electrophysiological, imaging and optogenetic methods while it performs behavioural tasks employing navigation, cognition, learning and memory.
Examples of neural dynamics during navigation and decision making in, e.g., a Corridor or T-Maze:
“Our experiments provide, to the best of our knowledge, the first direct intracellular recordings of membrane potential in MEC neurons of navigating mice. By measuring subthreshold membrane potential, these recordings reveal how synaptic input interacts with the intrinsic properties of stellate cells to drive grid-like firing during spatial navigation.”
Schmidt-Hieber C. & Häuser M. 2013. Cellular mechanisms of spatial navigation in the medial entorhinal cortex. Nat Neurosci. 16, 3: 325-331
We thank Dr. Christoph Schmidt-Hieber for supporting the development of our dome sphere that is based on his original designs.
|Power input voltage||100-240 V AC|
|Power consumption||920 W (maximal)|
|JetBall Spherical Treadmill with Stand, 20cm for Mice|
|Ball Holder material||Aluminium|
|Ball diameter||20 cm|
|Ball material||Polyvinyl chloride|
|Flow meter||Range: 4-50 l/min, for experiments: 25 l/min|
|Pressure regulator||6.9 bar (maximal), for experiments: 2 bar|
|Sound pressure level||48-52 dBA (top of the ball, 1 cm distance from the ball, air flow 20 l/min)|
|Resolution||WXGA 1280 x 800|
|Light output||3000 or 3100 lumens|
|Contrast ratio||2000:1 or 3000:1|
|Max. speed||Up to 4.19 m/s|
|Liquid Reward System|
|Peristaltic pump, typical flow rate||0.45 ml/min|
|Lick sensor, material (outer cover)||Polyvinyl chloride|
|Height (without control monitor)||98.5 cm|
|Category||Option||Description||In Basic Package included|
|JetBall Basic Package||
120cm dome with stand, projector, spherical mirror, spherical treadmill with stand (Ball Holder, two balls), Dual XY-Motion Sensor, movable rack, computer (pre-installed: PhenoSoft Control, PhenoSoft Schedule, PhenoSoft VR, Virtual Corridor 2 m), control monitor, keyboard, computer mouse, power supply unit, pressure regulator system
Each maze is available with mode for free or linear run.
Basic package includes one Ball Holder.
|Extra Ball Holder||
Basic package includes two balls.
Retractable: position is adjustable, servo-driven.
Frontally directed tube; moved with retractable reward system.
Air flow when animal approaches virtual walls.
To stop the spherical treadmill, e.g., at the end of a virtual corridor or after a wrong decision in a Y-maze.
E.g. to use a sound as a landmark.
E.g. to combine an odour with a virtual landmark.
For optogenetics, imaging or electrophysiology.
Inside view of VR projection dome with JetBall and corridor maze.
Overview of the JetBall-Dome
Stand with a dome, projector, quarter-sphere mirror and the spherical treadmill (Ball Holder made from one solid block of aluminium with stand and polystyrene ball)
Navigating mouse in a virtual corridor.
Control Unit with movable rack
JetBall Spherical treadmill
Aluminium Ball Holder with polystyrene ball and the various operant modules (view from the top). The modules are highlighted in the following pictures.
Liquid Reward System
Mounted on the retractable operant device of the Ball Holder and lick sensor.
Air Puff System
Mounted on the retractable operant device of the Ball Holder. It consists of a metal tube connected by plastic tubing to a valve. The valve is connected to a flow meter, pressure regulator and the compressed air system.
Consisting of two lateral and a frontal servo-driven brake.
Consisting of two metal tubes mounted on articulated arms that are attached to the Ball Holder. Plastic tubing connects the tubes to the valves of the compressed air system.
Dual XY-Motion Sensor
There are two sensors measuring the movement of the polystyrene ball.
Ball Holder (view from the side) with head holder for fixing the mouse (on the right side).
PhenoSoft Control – Unser Interface
Basic software for all products by PhenoSys. Control of hardware components.
PheoSoft Control – Log File
The log file containing the experimental data is written in a CSV format and is automatically saved.
Experimental schedules are defined with the help of state diagrams by using predefined activities from PhenoSoft.