ServoBall

The Virtual Reality ServoBall is based on an active, servo-driven spherical treadmill. It allows a video-tracked freely moving animal (e.g. mouse, rat) to navigate in virtual space. The ServoBall can be used for investigating navigation, cognition, learning and memory. A wide range of brain circuits can be stimulated through diverse operant protocols and multi-modal sensory stimulation. For unrestrained animals, even 24-hour experimentation is possible.

The ServoBall is made available in cooperation with Humboldt University, Berlin.

  • A servo-driven 60cm ball for freely moving animals
  • Infra-red camera for detecting movements of the animal
  • Octagonal 360° surround monitor (TFT)
  • Standard mazes or customized virtual reality scenes.

“A 60 cm diameter sphere rests on a multidirectional roller system. The walking-compensation mechanism is performed by two orthogonal feedback-controlled position servos. The current 2D-position of the freely moving animal walking on the spherical treadmill is sensed optically.

The deviation of the animal’s positional signal to the sphere’s top centre position is used to generate feedback signals which drive the motors to compensate displacement. Motor tachometers provide negative velocity feedback in X- and Y-directions for damping compensation. Free animal movement on the sphere is restrained by a plexiglass cylinder surrounding a 49 cm arena.

Visual stimuli and virtual reality are presented in the periphery beyond the cylinder wall on eight TFT-screens. Acoustic signals are presented by 4 loudspeakers above the cylinder. Extendable feeders integrated in the arena wall are the spatial targets of food search and spatial orientation behaviour. On arrival at a feeding location, treadmill compensation is suspended and the animal can use the feeder.”

Kaupert U, Thurley K, Frei K, Bagorda F, Schatz A, Tocker G, Rapoport S, Derdikman D, Winter Y. (2017)

“Spatial cognition in a virtual reality home-cage extension for freely moving rodents.” J Neurophysiol. doi: 10.1152/jn.00630.2016

 

  • Navigation of freely moving animals in a virtual reality environment
  • Operant conditioning, learning and memory processes
  • Pharmacology in any type of maze or operant environment
  • Cellular dynamics during active navigation.

“Rats learned to use the automatically driven experimental setup and the virtual reality in a few days.
They learned that a landmark indicated the entrance to the virtual reality goal arm and walked down such arms to collect rewards from a liquid reward feeder at the 1m or 2m end.
The ability of true, allothetic orientation of rats in this virtual reality paradigm is indicated by their ability to use the angle to a landmark to reach their goal.”

Kaupert U, Thurley K, Frei K, Bagorda F, Schatz A, Tocker G, Rapoport S, Derdikman D, Winter Y. (2017)

“Spatial cognition in a virtual reality home-cage extension for freely moving rodents.” J Neurophysiol. doi: 10.1152/jn.00630.2016

 

  • Eight retractable operant devices with positive (water) reinforcement
  • Fully automated by the ID-Sorter for connection to group home cage
  • Sound system
  • Olfactometer for fast-response odour generation.

Overview of a VR ServoBall.

Moving rat in a virtual corridor.