Data from Bremmer et al. (2017) Heading representations in primates are compressed by saccades. Nature Communications

Abstract

1. Electrophysiology

Experiments had previously been performed in three trained male macaque monkeys (C, H and R). Data, i.e. neural activity, come from the medial superior temporal area (area MST) in two hemispheres of monkeys R (Dataset #-1) and H (Dataset #-2) and from the ventral intraparietal area (area VIP) in two hemispheres of monkeys H (Dataset #-3) and C (Dataset #-4). Eye position was recorded at 500 Hz.

Optic flow stimuli consisted of large-field computer generated sequences that were back projected via a video projector (Electrohome) onto a tangent screen, 48 cm in front of the monkey. The size of the projection covered the central 90° x 90° of the visual field. Optic flow sequences (15s – 20s) simulated self-motion of a virtual observer over an extended horizontal plane covered with a texture pattern, located 37cm below eye–level. Trials simulated self–motion in one of three directions: 30° to the left, straight-ahead, and 30° to the right. Data come from 71 neurons with a significant tuning for heading.

In primates, self-motion stimuli induce reflexive, optokinetic like eye movements. For further data analysis, we determined periods of slow tracking and saccades. Tracking phases were temporally aligned to the onset of the preceding saccade (termed Trial in the following). Trial duration was 700 ms: from -200ms (i.e. 200 ms before the saccade) to 500 ms (i.e. 50 ms after the saccade. Eye-movement data are stored in the data files GrandAna1Data.mat (horizontal eye position) and GrandAna2Data.mat (vertical eye position). Neural activity in 20 ms bins was determined across these tracking phases for each trial for each of the three self-motion directions. Data come from single- or multi-electrode recordings. Activity from up to seven neurons could be recorded simultaneously. This data is stored in the data file PSTH.mat.

2. Psychophysics

Data on perisaccadic perception of heading.

Files:

main_exp.zip, main experiment in which all subjects performed a vertical saccade in the center of the screen (x=0°)

head_15.zip, control using the same vertical saccade as main_exp.zip but with head turned 15 degrees to the left (-15°)

eye_15.zip, control using the vertical saccade at a position 15 degrees to the left (-15°) while the head is directed straight ahead (0°)

Content of the files:

Each subject is represented by one .mat file. In each file two variables are stored:

Fix_Antwort: Control - heading perception during fixation. Column 1 presented heading, column 2 perceived heading

Sacc_Antwort: Cell array containing data on perisaccadic perception.

{1} presented heading = -30° (left)

{2} presented heading = -15°

{3} presented heading = 0°

{4} presented heading = 15°

{5} presented heading = 30° (right)

In each cell, each line represents one single trial:

Column 1: time of the onset of the heading stimulus relative to saccade onset (in ms)

Column 2: perceived heading