DOI: 10.5061/dryad.ffbg79d50
title: Eye saccades align optic flow with retinal specializations during object pursuit in freely moving ferrets

description: During prey pursuit, how eye-rotations, such as saccades, enable
 continuous tracking of erratically moving targets while simultaneously
 enabling an animal to navigate through the environment is unknown. To
 better understand this, we measured head and eye rotations in freely
 running ferrets during pursuit behavior. By also tracking the target and
 all environmental features we reconstructed the animal’s visual fields and
 their relationship to retinal structures. In the reconstructed visual
 fields, the target position clustered on and around the high acuity
 retinal area location, the area centralis, and surprisingly this cluster
 was not significantly shifted by digital removal of either eye saccades,
 exclusively elicited when the ferrets made turns, or head rotations which
 were tightly synchronized with the saccades. Here we show that, while the
 saccades did not fixate the moving target with the area centralis, they
 instead aligned the area centralis with the intended direction of travel.
 This also aligned the area centralis with features of the optic flow
 pattern, such as flow direction and focus of expansion, used for
 navigation by many species. While saccades initially rotated the eyes in
 the same direction as the head turn, saccades were followed by eye
 rotations countering the ongoing head rotation, which reduced image blur
 and limited information loss across the visual field during head-turns. As
 we measured the same head and eye rotational relationship in freely moving
 tree shrews, rats and mice, we suggest that these saccades and
 counter-rotations are a generalized mechanism enabling mammals to navigate
 complex environments during pursuit.
description: Simultaneous tracking of eye and head position of
 ferrets chasing a target. Analysis of gaze direction
 and reconstruction of visual fields
description: # Eye saccades in freely moving ferrets - open source data ## Summary The
 archives in this repository contain the data required to reproduce the
 results of the connected Current Biology manuscript "Eye saccades
 align optic flow with retinal specializations during object pursuit in
 freely moving ferrets". They allow reproduction of all major
 findings. We include kinetic data (positions and orientations) of head,
 eyes and environmental features for all experiments used in the
 publication. ## Description of data ### datasets\_config Contains csv
 files head, eyes and targets for all datasets (fXXX) and variants
 ("sacfrozen" for frozen eye position during saccades etc.). Data
 is organized in folders following the scheme *dataset_variant* ####
 Datasets *dataset*s used in the publication are named f005-f008 and f010.
 Datasets are named consecutively, including attempts that where
 interrupted early or had technical issues. Datasets f001-f004 and f009
 have been discarded for these reasons. #### Variants *variant*s denote
 various simulated variations of the raw data (without any
 "_*variant*"): * *sacfrozen* "freezes" the eye
 movements during saccades, replacing them with a linear interpolation with
 artificial noise. * *eyedelta_...* have the timing of the eye traces (and
 consequently saccades) shifted by minus (*_m0p05*) or plus (*_p0p05*) 50
 ms. * *SacAmpShift_...*  modifies the amplitude of the saccade by by scale
 factors of 0.5, 0.75, 1.25 or 1.5. This variant has been studied, but not
 included in the final main manuscript. See methods section of main
 publication for details on the changes. #### Files Each folder contains
 the following files: * *frametimes.csv* containing timing information with
 columns * *t*: time in seconds * *frn*: frame index of the tracking, i.e.
 data row in other csv files * *trajectory_[x].csv* containing kinetic
 information for object [x] with columns * *px*: x position of object *
 *py*: y position of object * *pz*: z position of object * *rx*: x
 quaternion coefficient of object * *ry*: y quaternion coefficient of
 object * *rz*: z quaternion coefficient of object * *rw*: w quaternion
 coefficient of object * *trajectory_[x].csv* containing kinetic
 information for object [x] with columns * *px*: x position of object *
 *py*: y position of object * *pz*: z position of object * *rx*: x
 quaternion coefficient of object * *ry*: y quaternion coefficient of
 object * *rz*: z quaternion coefficient of object * *rw*: w quaternion
 coefficient of object * *ball.[mtl,obj]* is the wavefront file of a ball
 in the size of a table tennis ball used for rendering the target in
 Multiview * *rectangles/rectangle_[nnn]_[mmm].csv* containing positions of
 rectangle objects of walls and boxes * *px*: x position of object * *py*:
 y position of object * *pz*: z position of object * *rx*: x quaternion
 coefficient of object * *ry*: y quaternion coefficient of object * *rz*: z
 quaternion coefficient of object * *rw*: w quaternion coefficient of
 object * *rectangles/rectangle_[nnn]_[mmm].obj* containing shape of
 rectangle objects of walls and boxes in wavefront format. ###
 multiview\_files Contains configuration files to rund datasets with
 Multiview software: ``` Multiview -s [config].multiview ``` Data is
 organized in the following naming scheme *dataset*_*variant*.multiview
 Each file contains proprietary scripting code for Multiview to perform the
 necessary action to generate flow data in OpenEXR format, where the first
 channel contains x flow, the second channel contains y flow and the third
 channel contains movement speed towards or away from the viewer. Note that
 folder paths may need to be adjusted in the script files to suit the local
 file system of the user. *export_frames.py* is a Python script called by
 Mutiview for saving the frames and does not need to be directly interacted
 with. ## Code/Software Multiview is required to generate optic flow
 fields. It can be obtained as open source at *
 [https://github.com/PaulStahr/Multiview](https://github.com/PaulStahr/Multiview) or * [https://zenodo.org/records/5493626](https://zenodo.org/records/5493626)