DOI: 10.5061/dryad.bk3j9kdd2
title: Data from: Twist and chew: three dimensional tongue kinematics during chewing in macaque primates

description: Three-dimensional (3D) tongue movements are central to performance of
 feeding functions by mammals and other tetrapods, but 3D tongue kinematics
 during feeding are poorly understood. Tongue kinematics were recorded
 during grape chewing by macaque primates using biplanar videoradiography.
 Complex shape changes in the tongue during chewing are dominated by a
 combination of flexion in the tongue’s sagittal planes and roll about its
 long axis. As hypothesized for humans, in macaques during tongue
 retraction the middle (molar region) of the tongue rolls to the chewing
 (working) side simultaneous with sagittal flexion, while the tongue tip
 flexes to the other (balancing) side. Twisting and flexion reach their
 maxima early in the fast close phase of chewing cycles, positioning the
 food bolus between the approaching teeth prior to the power stroke.
 Although 3D tongue kinematics undoubtedly vary with food type, the
 mechanical role of this movement—placing the food bolus on the post-canine
 teeth for breakdown—is likely to be a powerful constraint on tongue
 kinematics during this phase of the chewing cycle. The muscular drivers of
 these movements are likely to include a combination of intrinsic and
 extrinsic tongue muscles.
description: These data were collected using the University of Chicago XROMM
 Facility. All procedures were approved by the University of Chicago IACUC.
 Four adult rhesus macaques (<em>Macaca mulatta</em>) were
 observed in this study (Table 1). The animals were housed in an
 AAALAC-accredited animal facility, fed monkey biscuits and given daily
 enrichment. They were trained to feed while restrained in a radiolucent,
 acrylic primate chair. Monkeys C and H were trained to feed with their
 heads restrained, facilitating marker tracking, shortening recording
 durations, and reducing radiation exposure. The monkeys were fed red
 grapes (10-20 mm) and biplanar videoradiographic data were collected
 (technique: 90–100 kVp, 10–16 mA, 200 Hz, and with a 2–4 ms shutter
 speed). Data were processed using the XROMM workflow and custom R scripts.
 Analyses were conducted using custom R scripts, included here.
description: Please see the uploaded Readme.txt file. Data
 notes:<br> Four macaque monkeys were fed red grapes as described in
 the associated manuscript. Kinematics data were collected using the XROMM
 workflow, and transformed into mandibular and cranial coordinate systems
 following Orsbon et al. 2020. Note that while these data include cycles
 other than chews, the associated code files filter the data to only look
 at chews on the side of interest for a given individual. Descriptions of
 the variable names within the data files are given in
 Feeding_Codebook_for_Dryad.csv. Code usage:<br>
 This code was written in R (version 3.6.3) with dependencies on the
 following packages:<br> - circular (v. 0.4-93)<br> - cowplot
 (v. 1.0.0)<br> - tidyverse (v. 1.3.0) The data
 must be arranged in a directory structure as follows for the code to
 run:<br> Project Directory/<br> data/ = (contents of
 Feilich_etal_2021_rawdata.zip)<br> code/ = (contents of
 Feilich_etal_2021_code.zip) To run the analyses and
 generate figures, use the project directory as the working directory, and
 run the "FinalFigures.R". This script will source the other
 scripts in the code/ directory. The outputs of the data processing and
 analysis are generated as R objects entitled [animal name]_analysis, and
 [animal name]_summary in the R workspace. Circular statistics for each
 animal are output as [animal name]_stats.