DOI: 10.5061/dryad.mcvdnckbv
title: Data from: Fixational saccade inhibition and pupil dilation during self-paced limb movement preparation

description: Fixational saccades are modulated in anticipation of several kinds of
 stimuli and motor actions, suggesting that they can form an overt marker
 of preparatory state. However, no existing work has studied fixational
 saccades ahead of spontaneous limb movements in the absence of sensory
 stimuli, in order to isolate motor preparation from other anticipatory
 processes (e.g., those related to stimulus processing). Here we examined
 fixational saccades while participants made self-paced hand and foot
 movements. We observed that fixational saccade rate steadily dropped prior
 to either kind of motor action, and recovered immediately after. To
 examine the relation between this fixational saccade rate signal and other
 known signals that precede volitional action, we analyzed how this signal
 related to anticipatory pupil size changes in the same dataset.
 Replicating previous work, we found steady pupil dilation ahead of limb
 movements, followed by rapid re-constriction. The amplitude of this pupil
 signal covaried across individual limb movements with that of the
 fixational saccade rate signal. The pupil modulations, moreover, followed
 too shortly after the accompanying fixational saccade rate modulations to
 be caused by saccade-induced changes in visual input. Together, these
 observations suggest a joint neural factor influencing both fixational
 saccade rate and pupil size ahead of limb movements. We discuss possible
 interpretations of our findings, both specific ones that center on
 processes of motor planning or temporal expectation, and more general ones
 that are in terms effort.
description: # Data from: Fixational saccade inhibition and pupil dilation during
 self-paced limb movement preparation Dataset DOI:
 [10.5061/dryad.mcvdnckbv](10.5061/dryad.mcvdnckbv) ## Description of the
 data and file structure These are eye tracking and key press records from
 an experiment during which human participants engaged in spontaneous key
 presses (spacebar or foot pedal). ### Files and variables #### File:
 Archive.zip **Description:** The archive contains, for each of 120
 participants, 4 files for each of 2 experiment sessions. The file names
 are formatted like this: \[participant number]M[session number]_[kind of
 data].npy The [kind of data] string can be the following:
 derivative_cleaned: time series data of preprocessed temporal derivative
 of pupil size, in mm / s on a time axis defined in mm. foot: time stamps
 of foot presses, on the same mm time axis as derivative_cleaned. saccades:
 time stamps of saccades, on the same mm time axis as derivative_cleaned.
 space: time stamps of space bar presses, on the same mm time axis as
 derivative_cleaned. All files are numpy files that can be opened in python
 using its numpy package, on the same mm time axis as derivative_cleaned.
 ## Code/software Any unzip utility is needed to unpack the archive. After
 that, python and its numpy package (any recent version) are needed to open
 the files. Entering this code in python will provide access to the raw
 data: import numpy as np data = np.load("path/to/file.npy",
 allow_pickle=True) data ## Human subjects data We received explicit
 consent from our participants to publish the de-identified data in the
 public domain. The data contain no identifying features of the
 participants: just anonymized eye tracking and key press records.