Data from Churan et al. Action-dependent processing of self-motion in parietal cortex of macaque monkeys

Animals

Two adult male monkeys (macaca mulatta) participated in the study. Single-unit recordings were done using standard tungsten microelectrodes (FHC, Bowdoin, USA) with an impedance of ~2 MΩ at 1 kHz that were positioned by an hydraulic micromanipulator (MO-95, Narishige, Tokyo, Japan). A stainless-steel guiding tube was used for transdural penetration and support of the electrode. The neuronal signal was processed using a commercial system (Alpha Omega, Nof HaGalil, Israel). It was band-pass filtered (cut-off frequencies at 500 Hz and 8000 Hz) and sampled at 44 kHz.

Apparatus

During recordings, the monkeys were sitting head-fixed in a primate chair in a dark room, and their eye-position was monitored at 1000 Hz using a video-based eye tracker (EyeLink 1000, SR Research, Ottawa, Canada). The chair was positioned at a distance of 97 cm from a semi-transparent screen (size 160 cm x 90 cm, subtending the central 79 deg x 50 deg of the visual field) on which the visual stimuli were back-projected using a PROPixx-projector (VPixx Technologies, St-Bruno de Montarville, Canada) running at a resolution of 1920 x 1080 pixels and at a frame rate of 100 Hz. A custom-made touch sensor (length 10 cm, diameter 1 cm) was integrated into the monkey chair in front of the monkey and its status was monitored online at a sampling rate of 1 kHz.

Data processing

Single units were isolated using a semi-manual spike sorter (Plexon Inc, Dallas, Texas). To this end we used a threshold on the electrode signal that was set manually to separate the action potentials from noise. The samples that exceeded the threshold were further analyzed using principal components as well as other features that were derived from the signal (like local maxima and minima). Then clusters of samples with similar properties were identified visually and each defined as representing a single unit. For a detailed description of the sorting process see the offline User Guide (Plexon, 2020).

Further description of the Methods, see: Churan et al. 2021, doi: 10.1152/jn.00049.2021

Data:

The file 'data_active_passive.mat' contains following variables:

monkey: code for the tested monkey (1=monkey S, 2=monkey O)

baseline: Mean and standard deviation of the activity in a time window of 150 ms to 20 ms before the press of the button.

reaction: Mean time between the switch of the color of the fixation point from red to green and the time of the button press.

anti_p: Significance of a one sided t-test between the baseline activity and activity 200 ms to 0 ms prior to the onset of stimulus motion.

p_win (a (1-3),b (1-3),c (1-3),n(1-110)): 4D matrix containing p-values of t-tests

a:

1: Was preparatory activity significantly higher in the passive relative to the active condition?

2: Was preparatory activity significantly lower in the passive relative to the active condition?

3: Was the tonic motion response (200 ms to 500 ms after motion onset) significantly different between the active and the passive conditions?

b:

1: Calculation was made based on all motion directions

2: Calculation was made based on the preferred motion direction

3: Calculation was made based on the flanking motion directions

c:

1: Calculation was made based on all presented delays

2: Calculation was made based on the shorter set of delays (500 ms to 700 ms)

3: Calculation was made based on the longer set of delays (701 ms to 1000 ms)

n: number of the investigated neuron

psth_alldir: cell array containing the PSTHs (obtained by convolving each spike with a Gaussian as described in the manuscript) in a time window between 1000 ms before and 800 ms after the onset of motion (in 1 ms steps). PSTHs were calculated based on data from all tested directions. Each cell array consists of 4 elements containing different conditions:

1: active condition

2: passive condition shorter set of delays (500 ms to 700 ms)

3: passive condition longer set of delays (701 ms to 1000 ms)

4: passive condition all delays

psth_bestdir: same as above - using only the preferred direction

psth_nbestdir: same as above - using only the flanking directions

d_alldir: cell array containing the continuous d-prime (as described in the manuscript) in a time window between 1000 ms before and 800 ms after the onset of motion (in 1 ms steps). d' were calculated based on data from all tested directions. Each cell array consists of 4 elements containing different conditions:

1: active condition

2: passive condition shorter set of delays (500 ms to 700 ms)

3: passive condition longer set of delays (701 ms to 1000 ms)

4: passive condition all delays

d_bestdir: same as above - using only the preferred direction

d_nbestdir: same as above - using only the flanking directions

The file 'timecourse_preparatory.mat' contains the cell array 'd_alldir_preparatory' that consists of 201 elements. Each of the elements contains PSTHs of 23 neurons that have exhibited significant preparatory activity in the passive condition in a time window 1000 ms to 0 ms before the motion onset. Each of the 201 elements describes a specific range of delays between button press and motion onset. This delay range is always a 100 ms wide sliding window, e.g. the element 1 represents delays between 500 and 600 ms, in element 2, the delays are between 501 and 601 ms and so on with the last element (201) representing delays between 700 and 800 ms.

Some example code that re-creates most of the figures from the manuscript and that may serve as a starting point for further exploration of the data is available on request from the corresponding author.