The pasta matrix reaching task: a simple test for measuring skilled reaching distance, direction, and dexterity in rats

Abstract

Skilled forelimb use has been used in many studies to examine motor system status, learning, and recovery from nervous system damage in rats. The dependent measures in many current skilled reaching models rely on endpoint measures, number of successful reaches, or qualitative measures, the movements used in performing a reach. The present study describes a new reaching task, which allows measurement of distance and direction of skilled forelimb movement while also permitting end point and qualitative measurements. Animals reached from a clear Plexiglas box through an aperture to retrieve pieces of straight, uncooked pasta from an array of 260 vertically oriented pieces of pasta arranged in rows distally and laterally away from the aperture (a matrix). By extending the range of a reach, more pasta is obtained. Limb movements, pieces of pasta removed, and the pattern of pasta removal are dependent measures. The usefulness of the test is demonstrated using control, dorsal column lesion, and unilateral dopamine depleted animals. The task uses a desired food, tests learning and skill, the range of limb movement, and the ability to reach for different distances and directions. The task can also be modified to investigate other features of limb use including skill adjustments, laterality, and force.