Prediction of primary somatosensory neuron activity during active tactile exploration

  1. Dario Campagner
  2. Mathew Hywel Evans
  3. Michael Ross Bale
  4. Andrew Erskine
  5. Rasmus Strange Petersen  Is a corresponding author
  1. The University of Manchester, United Kingdom
  2. University of Sussex, United Kingdom
  3. The Francis Crick Institute, United Kingdom
5 figures and 1 video

Figures

Figure 1 with 2 supplements
Electrophysiological recording from single primary whisker units in awake, head-fixed mice and simultaneous measurement of whisker kinematics/mechanics. 

(A) Schematic of the preparation, showing a tungsten microelectrode array implanted into the trigeminal ganglion of a head-fixed mouse, whilst a metal pole is presented in one of a range of …

https://doi.org/10.7554/eLife.10696.003
Figure 1—figure supplement 1
Electrophysiological recording from trigeminal primary neurons of awake, head-fixed mice. 

Extracellular potential recorded from the same single unit during both anaesthetized and awake epochs. Spikes belonging to the cluster of the target unit are shown by black triangles. Inset shows …

https://doi.org/10.7554/eLife.10696.004
Figure 1—figure supplement 2
Computation of axial and lateral contact forces. 

Axial (Fax) and lateral (Flat) force components at the whisker base were calculated, in each video frame where there were whisker-pole contacts, as follows (Pammer et al., 2013). First, the point of …

https://doi.org/10.7554/eLife.10696.005
Figure 2 with 3 supplements
Primary whisker neurons encode whisker curvature, not whisker angle, during active sensation. 

(A) Schematic of the Generalized Linear Model (GLM). (B) For an example unit, whisker angle (top panel), whisker curvature change (middle panel) and simultaneously recorded spike train (bottom …

https://doi.org/10.7554/eLife.10696.007
Figure 2—figure supplement 1
Effect on GLM performance of quadratic input terms, simulated repeated trials and minimal stimulus filters. 

(A) Angle GLM prediction performance is robust to addition of quadratic stimulus-dependence. Prediction accuracy (PCC) for standard angle GLM (same data as Figure 2D of main text) in comparison to …

https://doi.org/10.7554/eLife.10696.008
Figure 2—figure supplement 2
Moment is near-perfectly correlated with axial/lateral contact force components during pole exploration. 

(A) Two example time series for simultaneously measured whisker angle, bending moment, lateral force and axial force (see Materials and methods). Red bars indicate episodes of whisker-pole contact. (…

https://doi.org/10.7554/eLife.10696.009
Figure 2—figure supplement 3
Example filters for curvature-based GLMs. 

Stimulus filter, history filter and bias term of curvature-based GLMs for two units (A, B), fitted as described in Materials and methods. Both units had negative history filters (in the 2 ms …

https://doi.org/10.7554/eLife.10696.010
Figure 3 with 1 supplement
Primary whisker neurons encode whisker angular acceleration during free whisking. 

(A) Mean response of an example whisking-sensitive unit to whisking amplitude, computed during non-contact episodes (dark green, shaded area shows SEM) with regression line (black). Inset shows …

https://doi.org/10.7554/eLife.10696.011
Figure 3—figure supplement 1
Whisking-sensitive units exhibit heterogeneous selectivity to angular acceleration. 

For each whisker-sensitive unit, an acceleration tuning curve was estimated (Figure 3B). Tuning to positive (negative) acceleration was quantified by the slope of a regression line fitted to the …

https://doi.org/10.7554/eLife.10696.012
Figure 4 with 2 supplements
Whisker angle and whisker curvature change are highly correlated during passive whisker deflection, but decoupled during active touch. 

(A) Whisker angle (top) and whisker curvature change (bottom) time series, due to passive, trapezoidal stimulation of C2 whisker in an anaesthetized mouse, estimated as mean over 10 repetitions. …

https://doi.org/10.7554/eLife.10696.013
Figure 4—figure supplement 1
Correlations between angle and curvature change during passive whisker stimulation can make curvature-tuned units appear angle-tuned. 

The data of Figure 4 show a strong correlation between whisker angle and whisker curvature during passive stimulation of the whisker. To test whether this correlation might make curvature-tuned …

https://doi.org/10.7554/eLife.10696.014
Figure 4—figure supplement 2
Measurement of whisker bending during passive whisker deflection.

(A). Four video frames taken during trapezoidal, passive whisker stimulation with whisker tracker solutions overlaid (coloured lines). (B) Curvature change (left) and corresponding tracker solutions …

https://doi.org/10.7554/eLife.10696.015

Videos

Video 1
Video of an awake mouse, exploring a pole with its whiskers with simultaneous electrophysiological recording of a primary whisker neuron.

At the start of the video, the pole is out of range of the whiskers. The whisker tracker solution for the principal whisker of the recorded unit is overlaid in red. White dots represent spikes; …

https://doi.org/10.7554/eLife.10696.006

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