The syntactic organization of pasta-eating and the structure of reach movements in the head-fixed mouse

Ian Q Whishaw,Behroo Mirza Agha,Jamshid Faraji,Gerlinde A S Metz,Majid H Mohajerani,Jessica R Kuntz

doi:10.1038/s41598-017-10796-y

Ian Q Whishaw, Behroo Mirza Agha + Show 4 more

Open Access

https://doi.org/10.1038/s41598-017-10796-y

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Abstract

Mice are adept in the use of their hands for activities such as feeding, which has led to their use in investigations of the neural basis of skilled-movements. We describe the syntactic organization of pasta-eating and the structure of hand movements used for pasta manipulation by the head-fixed mouse. An ethogram of mice consuming pieces of spaghetti reveals that they eat in bite/chew bouts. A bout begins with pasta lifted to the mouth and then manipulated with hand movements into a preferred orientation for biting. Manipulation involves many hand release-reach movements, each with a similar structure. A hand is advanced from a digit closed and flexed (collect) position to a digit extended and open position (overgrasp) and then to a digit closed and flexed (grasp) position. Reach distance, hand shaping, and grasp patterns featuring precision grasps or whole hand grasps are related. To bite, mice display hand preference and asymmetric grasps; one hand (guide grasp) directs food into the mouth and the other stabilizes the pasta for biting. When chewing after biting, the hands hold the pasta in a symmetric resting position. Pasta-eating is organized and features structured hand movements and so lends itself to the neural investigation of skilled-movements.

Highlights

Skilled hand use by rodents, including the mouse, have been described in tasks of skilled reaching, in which an animal extends a hand to grasp a piece of food to place it in the mouth for eating[1,2,3,4]
Attention was directed to the overall pattern of hand use by using an ethogram of eating behavior with subsequent descriptions of the behaviors displayed in the ethogram, including details of reaching and grasp patterns of pasta manipulation
The analyses indicate that the behavior of pasta eating is organized and that the mice use a structured reach that is modified online as required for pasta manipulation

Summary

Introduction

Skilled hand use by rodents, including the mouse, have been described in tasks of skilled reaching, in which an animal extends a hand to grasp a piece of food to place it in the mouth for eating[1,2,3,4]. Food holding postures are different in different species of rodents[6] and the complexity of holding postures varies depending upon whether an animal is handling a prey item such as a cricket[7], nuts that require shell removal, or food items such as pasta of various types that require complex manipulation[8] These studies find that do animals vary their arm postures as a function of food type, they vary their hand preshape and grasp movements in relation to food size as food size becomes smaller as it is consumed[6, 9]. The analyses indicate that the behavior of pasta eating is organized and that the mice use a structured reach that is modified online as required for pasta manipulation

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