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Neural coding in barrel cortex during whisker-guided locomotion.

Sofroniew NJ, Vlasov YA, Andrew Hires S, Freeman J, Svoboda K - Elife (2015)

Bottom Line: We measured neural activity using two-photon calcium imaging and extracellular recordings.Neurons were tuned to the distance between the animal snout and the contralateral wall, with monotonic, unimodal, and multimodal tuning curves.This rich representation of object location in the barrel cortex could not be predicted based on simple stimulus-response relationships involving individual whiskers and likely emerges within cortical circuits.

View Article: PubMed Central - PubMed

Affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.

ABSTRACT
Animals seek out relevant information by moving through a dynamic world, but sensory systems are usually studied under highly constrained and passive conditions that may not probe important dimensions of the neural code. Here, we explored neural coding in the barrel cortex of head-fixed mice that tracked walls with their whiskers in tactile virtual reality. Optogenetic manipulations revealed that barrel cortex plays a role in wall-tracking. Closed-loop optogenetic control of layer 4 neurons can substitute for whisker-object contact to guide behavior resembling wall tracking. We measured neural activity using two-photon calcium imaging and extracellular recordings. Neurons were tuned to the distance between the animal snout and the contralateral wall, with monotonic, unimodal, and multimodal tuning curves. This rich representation of object location in the barrel cortex could not be predicted based on simple stimulus-response relationships involving individual whiskers and likely emerges within cortical circuits.

No MeSH data available.


Related in: MedlinePlus

Imaging activity of layer 2/3 neurons during whisker-guided locomotion.(a) Schematic of two-photon calcium imaging. (b) Overlay of a pixelwise regression map and mean intensity image. Each pixel in the regression map is colored according to its tuning to wall distance; brightness was adjusted according to the r2 value of the tuning. Three example ROIs are highlighted (corresponding to panel c). This imaging region is approximately centered on the C2 barrel (diameter, 300 μm) and contains parts of the neighboring D1 and C1 barrels. (c) Distance from the snout to the wall as a function of time (top) and ΔF/F for three example ROIs (same ROIs as in b). (d) Fraction of neurons in L2/3 that are inactive, tuned, and untuned to the wall distance. (e) Tuning curves to wall distance for example ROIs (mean ± SE over trials). (f) Heatmap of tuning curves normalized by maximum activity across all mice. (g) Histogram of the location of tuning curve peaks.DOI:http://dx.doi.org/10.7554/eLife.12559.006
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fig3: Imaging activity of layer 2/3 neurons during whisker-guided locomotion.(a) Schematic of two-photon calcium imaging. (b) Overlay of a pixelwise regression map and mean intensity image. Each pixel in the regression map is colored according to its tuning to wall distance; brightness was adjusted according to the r2 value of the tuning. Three example ROIs are highlighted (corresponding to panel c). This imaging region is approximately centered on the C2 barrel (diameter, 300 μm) and contains parts of the neighboring D1 and C1 barrels. (c) Distance from the snout to the wall as a function of time (top) and ΔF/F for three example ROIs (same ROIs as in b). (d) Fraction of neurons in L2/3 that are inactive, tuned, and untuned to the wall distance. (e) Tuning curves to wall distance for example ROIs (mean ± SE over trials). (f) Heatmap of tuning curves normalized by maximum activity across all mice. (g) Histogram of the location of tuning curve peaks.DOI:http://dx.doi.org/10.7554/eLife.12559.006

Mentions: To examine population encoding of wall distance, we recorded neuronal activity in layer 2/3 of barrel cortex using 2-photon microscopy and GCaMP6s (Chen et al., 2013) in a separate group of mice running through the winding corridor (6 mice). Mice were left with all their whiskers, so we could look at neural coding under their natural whisker configuration. Three 600 x 600 μm planes separated by 20 μm in depth were imaged at 7.1 Hz around the center of the C2 barrel column, found using intrinsic signal imaging (Peron et al., 2015). To measure repeated responses across a range of wall distances, we also included 'open-loop' trials in the winding corridor, in which the contralateral wall was moved to fixed distances away from the mouse independent of the animal’s locomotion (Figure 3a).10.7554/eLife.12559.006Figure 3.Imaging activity of layer 2/3 neurons during whisker-guided locomotion.


Neural coding in barrel cortex during whisker-guided locomotion.

Sofroniew NJ, Vlasov YA, Andrew Hires S, Freeman J, Svoboda K - Elife (2015)

Imaging activity of layer 2/3 neurons during whisker-guided locomotion.(a) Schematic of two-photon calcium imaging. (b) Overlay of a pixelwise regression map and mean intensity image. Each pixel in the regression map is colored according to its tuning to wall distance; brightness was adjusted according to the r2 value of the tuning. Three example ROIs are highlighted (corresponding to panel c). This imaging region is approximately centered on the C2 barrel (diameter, 300 μm) and contains parts of the neighboring D1 and C1 barrels. (c) Distance from the snout to the wall as a function of time (top) and ΔF/F for three example ROIs (same ROIs as in b). (d) Fraction of neurons in L2/3 that are inactive, tuned, and untuned to the wall distance. (e) Tuning curves to wall distance for example ROIs (mean ± SE over trials). (f) Heatmap of tuning curves normalized by maximum activity across all mice. (g) Histogram of the location of tuning curve peaks.DOI:http://dx.doi.org/10.7554/eLife.12559.006
© Copyright Policy
Related In: Results  -  Collection

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fig3: Imaging activity of layer 2/3 neurons during whisker-guided locomotion.(a) Schematic of two-photon calcium imaging. (b) Overlay of a pixelwise regression map and mean intensity image. Each pixel in the regression map is colored according to its tuning to wall distance; brightness was adjusted according to the r2 value of the tuning. Three example ROIs are highlighted (corresponding to panel c). This imaging region is approximately centered on the C2 barrel (diameter, 300 μm) and contains parts of the neighboring D1 and C1 barrels. (c) Distance from the snout to the wall as a function of time (top) and ΔF/F for three example ROIs (same ROIs as in b). (d) Fraction of neurons in L2/3 that are inactive, tuned, and untuned to the wall distance. (e) Tuning curves to wall distance for example ROIs (mean ± SE over trials). (f) Heatmap of tuning curves normalized by maximum activity across all mice. (g) Histogram of the location of tuning curve peaks.DOI:http://dx.doi.org/10.7554/eLife.12559.006
Mentions: To examine population encoding of wall distance, we recorded neuronal activity in layer 2/3 of barrel cortex using 2-photon microscopy and GCaMP6s (Chen et al., 2013) in a separate group of mice running through the winding corridor (6 mice). Mice were left with all their whiskers, so we could look at neural coding under their natural whisker configuration. Three 600 x 600 μm planes separated by 20 μm in depth were imaged at 7.1 Hz around the center of the C2 barrel column, found using intrinsic signal imaging (Peron et al., 2015). To measure repeated responses across a range of wall distances, we also included 'open-loop' trials in the winding corridor, in which the contralateral wall was moved to fixed distances away from the mouse independent of the animal’s locomotion (Figure 3a).10.7554/eLife.12559.006Figure 3.Imaging activity of layer 2/3 neurons during whisker-guided locomotion.

Bottom Line: We measured neural activity using two-photon calcium imaging and extracellular recordings.Neurons were tuned to the distance between the animal snout and the contralateral wall, with monotonic, unimodal, and multimodal tuning curves.This rich representation of object location in the barrel cortex could not be predicted based on simple stimulus-response relationships involving individual whiskers and likely emerges within cortical circuits.

View Article: PubMed Central - PubMed

Affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.

ABSTRACT
Animals seek out relevant information by moving through a dynamic world, but sensory systems are usually studied under highly constrained and passive conditions that may not probe important dimensions of the neural code. Here, we explored neural coding in the barrel cortex of head-fixed mice that tracked walls with their whiskers in tactile virtual reality. Optogenetic manipulations revealed that barrel cortex plays a role in wall-tracking. Closed-loop optogenetic control of layer 4 neurons can substitute for whisker-object contact to guide behavior resembling wall tracking. We measured neural activity using two-photon calcium imaging and extracellular recordings. Neurons were tuned to the distance between the animal snout and the contralateral wall, with monotonic, unimodal, and multimodal tuning curves. This rich representation of object location in the barrel cortex could not be predicted based on simple stimulus-response relationships involving individual whiskers and likely emerges within cortical circuits.

No MeSH data available.


Related in: MedlinePlus