Motor Function
INFRAMOT (TSE SYSTEMS)
The InfraMot system is designed to register total activity of an animal by sensing a body-heat image, through use of infrared detection and its spatial displacement over time. The sensor assembly is mounted on top of the Opticages. The system is suited to short-term locomotor activity studies where total activity is a sufficient indicator of motor function or to long-term circadian studies.
ROTAROD TEST:
The purpose of the Rotarod test is to assess the mouse’s sensorimotor coordination and/or fatigue resistance. The test is sensitive to damage of the basal ganglia and cerebellum and to drugs that affect motor functions. Two slightly different variations of the Rotarod test can be performed: (i) using a fixed speed (~ 7 – 20 rpm) or (ii) a steady rate of acceleration (up to a set maximum speed of approximately 40 rpm). In both scenarios, the latency to which each individual mouse falls from the rod onto the sensing platform below is recorded automatically. If an animal does not fall off the rod then the test ends after a maximum allotted time (typically 2-5 min). Each of these procedures may be repeated 2-3 times (with a 5 – 60 min inter-trial interval) in order to assess motor learning in the mice or to provide a stable baseline performance level.
STRING AGILITY TEST:
This is a test of agility and grip capacity test and part of the neurological assessment battery. It provides measures of motor coordination/agility in mice. The apparatus is a wire stretched horizontally 40 cm above a table that is covered with soft padding material (i.e. 10-mm thick foam mat; mice do not appear to experience any discomfort from falling from that height). The mouse is placed onto the wire so that it can grip the wire with its forepaws and released. The latency to fall and the latency to catch the wire with hindpaws are recorded and the trial ends after 60 seconds or if the mouse falls.
BALANCE BEAM TEST:
This test is used to assess sensorimotor integration and balance. Mice are placed onto one end of a horizontal raised beam adjacent to a light source which serves to induce the mouse to ambulate along the beam to move away from the light. A dark shelter at the opposite end reinforces the movement of the mice along the balance beam. Animals are videotaped while on the beam and time to traverse, foot faults (slips) and falls are scored.
TREADMILL/GAIT TEST:
The use of a treadmill is a convenient and sensitive method to evaluate motor performance and motor coordination in mice. Combined with a sensitive video-tracking system, it also performs gait analysis. Mice are individually placed on a stationary treadmill (with clear treadmill belt), which then accelerates to a preset test speed (ranging from 15 to 100 cm/s). The video-tracking system identifies the stance and swing phases for all four limbs and measures the average values for stride length and stride frequency, as well as duration of stride, stance, and swing for each limb.
DIGIGAIT:
The DigiGaitTM system provides numerous spatial and temporal indices of posture and gait dynamics, including: Stride length, Stance width, Stance duration, Swing duration, Braking duration, Propulsion duration, Stride frequency, Paw Angle. DigiGaitTM allows imaging the ventral side of mice as they walk on a motorized transparent treadmill belt. One high-speed camera captures the dynamics of the paws and corresponding limbs as they approach the belt during the braking phase of stance, or move away from the belt during the propulsion phase of stance just before the swing phase. The DigiGaitTM system fully quantifies the stance and swing components of stride.
WHEEL RUNNING BEHAVIOR:
Circadian activity can be quantified conveniently and stress-free using a running-wheel paradigm where mice are housed in a light controlled environment in cages that contain, in addition to bedding, food, and water, a wheel. Importantly, the mouse has the “choice” not to run. Behavior is logged by a computer linked to the wheel sensors, and analyzed using MatLab software.
GRID WALKING:
The grid walking test assesses the ability of spinal cord injured mice to accurately place their limbs during locomotor tasks. The use of a grid walking test in the evaluation of spinal cord injured animals has been endorsed as a sensitive technique for behavioral testing and for providing an objective evaluation of neurological impairments. Animals are required to walk across a runway made of a wire grid. As the animals walk across the grid, the number of errors made and the amount of time they are actually walking will be video-recorded and measured to assess performance..
GRIP-STRENGTH TEST:
This test is part of the neurological assessment battery. It provides a measure of the force that is required to make a mouse release its grip (i.e. it measures muscle strength). The apparatus (i.e. grip-strength meter) consists of a grasping trapeze connected to a force transducer. The grip-strength meter will express the grip force in grams.
SWIM TEST:
This test is used to test the vestibular function of mice by analysing their swimming behavior. Mice with normal vestibular function are very competent swimmers, i.e. after being placed in the water, they stay on the water surface and move by “whipping” their tails and moving their legs. Mice with vestibular defects are known to have problems of movement or staying above the surface.