Fig. 1: MEC neurons encode three Euler-angles of head position.
From: Mouse entorhinal cortex encodes a diverse repertoire of self-motion signals
a During open field exploration, head pitch (ai) and roll (aii) were measured with an accelerometer affixed to the headstage7,26,62; angular head velocity in the azimuthal (yaw) plane (aiii), azimuthal head direction, body position, and linear body speed (not pictured) were measured from two LEDs affixed to the headstage9,10. b Histograms show behavioral distributions in an example session. Plots on right show behavior in the recording arena. Boxplots show distributions observed in individual mice, averaged across sessions. Box, interquartile range; vertical line, median; whiskers extend from the 2.5th to 97.5th percentiles. Mean ± standard error of mean [sem] across mice; pitch: 2.5th percentile = −23.0 ± 4.5°, 25th percentile = −1.4 ± 4.1°, median = 11.5 ± 4.1°, 75th percentile = 25.8 ± 6.0°, 97.5th percentile = 55.6 ± 4.1° (n = 6 mice); roll: 2.5th percentile = −50.9 ± 3.6°, 25th percentile = −20.3 ± 7.0°, median = −0.8 ± 7.6°, 75th percentile = 19.3 ± 6.0°, 97.5th percentile = 43.6 ± 4.0° (n = 6 mice); azimuthal head velocity: 2.5th percentile = −389.9 ± 34.7°/s, 25th percentile = −37.7 ± 3.9°/s, median = −0.1 ± 0.3°/s, 75th percentile = 36.4 ± 3.8°/s, 97.5th percentile = 385.1 ± 34.7°/s (n = 25 mice from two datasets; Methods). c Bottom: Bar graph showing the percentage of cells significantly encoding each variable, with the cell count at top. Top: Bar graph showing the percentage of cells jointly encoding all combinations of two variables. B, body position; Bs, body speed; Ha, azimuth head direction; Hp, pitch; Hr, roll; \(\dot H_a\), azimuthal head velocity. d Pie chart illustrating tuning to multiple variables (n = 179 cells). Combinations observed in fewer than three cells are grouped together [“other”]. N.S., no significant tuning to any variable. Few cells encoded body speed, azimuthal head direction, pitch, roll, or azimuthal head velocity alone (% of MEC cells non-conjunctively encoding: body speed, 2%; azimuthal head direction, 5%; pitch, 1%; roll, 5%, azimuthal head velocity, 0%). In contrast, 15% of MEC cells encoded body position non-conjunctively.
