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10String-pulling in rodents (rats and mice) is a task in which animals make hand-over-hand 11 movements to spontaneously reel in a string with or without a food reward attached to its end. The task 12 elicits bilateral skilled hand movements for which rodents require little training. The task is suitable for 13 phenotyping physiology and pathophysiology of sensorimotor integration in rodent models of 14 neurological and motor disorders. Because a rodent stands in the same location and its movements are 15 repetitive, the task lends itself to quantification of topographical and kinematic parameters for on-line 16 tactile tracking of the string, skilled hand movements for grasping, and rhythmical bilateral forearm 17 movements to advance the string. Here we describe a Matlab® based software with a graphical user 18 interface to assist researchers in analyzing the video record of string pulling. The software allows global 19 characterization of position and motion using optical flow estimation, descriptive statistics, principal 20 component, and independent component analyses as well as temporal measures of Fano factor, entropy, 21 and Higuchi fractal dimension. Based on image segmentation and object tracking heuristic algorithms, the 22 software also allows independent tracking of the body, ears, nose, and forehands for estimation of 23 kinematic parameters such as body length, body angle, head roll, head yaw, head pitch, movement paths 24 and speed of hand movement. The utility of the task and that of the software is presented by describing 25 mouse strain characteristics in string-pulling behavior of two strains of mice, C57BL/6 and Swiss Webster. 26Postural and skilled hand kinematic differences that characterize the strains highlight the utility of the task 27 and assessment methods for phenotypic and neurological analysis of healthy and rodent models of diseases 28 such as Parkinson's , Huntington's, Alzheimer's and other neurological and motor disorders. 29Significance statement: 30 Mouse models are used to investigate the physiology and pathophysiology of motor deficits 31 observed in human neurological conditions, for testing substances for therapeutic drug development, and 32 to investigate the role of neural systems and their genetic basis in the expression of behavior. Behavioral 33 tasks involving unconditioned and natural behavior can provide rich insights into motor performance in 34 animal models and analyses can be aided by the automated processing of video data for reliable 35 quantification and high throughput. 36Swiss Webster, C57BL/6 Brooks 2018). The objective of the present paper is to describe a state-of-the-art method for analyzing 69 mouse string-pulling. 70 We present a Matlab based toolbox to facilitate the analyses of video data of different strains of 71 intact or neurologically compromised mice engaged in string pulling. The toolbox features a graphical 72 user interface for video data analysis and follows the analysis framework with two major components, a 73 global assessmen...