Skilled Pellet Reaching Task

The skilled pellet reaching task assesses fine motor dexterity and forelimb function by requiring rodents to reach through a narrow aperture, grasp a small food pellet from an external shelf, and retrieve it to the mouth. This paradigm is the gold standard for evaluating corticospinal tract integrity, as successful reaching demands precise digit coordination, wrist pronation and supination, and arpeggio-like grasp patterns that are uniquely dependent on the motor cortex and its descending projections.

Dependent variables include reaching success rate (pellets retrieved divided by total attempts), first-attempt success rate, qualitative reaching movement scores using the Whishaw rating scale (digits open, pronation, grasp, supination, release), pellet drop rate, and preferred paw laterality. High-speed video analysis can further decompose reach trajectories into kinematic components including reach endpoint accuracy, aperture, and digit closing velocity.

ConductMaze automates pellet delivery to the shelf via a precision stepper-driven dispenser, detects reach attempts and successful retrievals using shelf-mounted piezoelectric sensors and floor-level pellet detectors, and synchronizes high-speed video capture for post-hoc kinematic scoring. The system manages session structure including inter-trial intervals, pellet replenishment, and automatic termination after a configurable number of trials or elapsed time.