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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

Tuning to ipsilateral and contralateral wall distance.(a) Example spike raster of regular spiking unit in open-loop trials when the wall is contralateral (top) or ipsilateral to the recording site (bottom). Only epochs with running speed over 3 m/s are represented. This neuron was activated by interactions with the wall. (b) Corresponding tuning curves recorded during locomotion (running speed over 3 m/s). (c,d) Same as a, b for a suppressed regular spiking unit. (e) Scatter plot of range of spiking of ipsilateral vs. contralateral tuning curves. The range of spiking is the difference between the maximum and minimum of the tuning curve. (f) Histogram of laterality modulation index, which is the difference in contralateral range and ipsilateral range divided by the sum of the contralateral range and ipsilateral range. Units that respond only to the contralateral wall have modulation 1, units that respond only to the ipsilateral wall have modulation −1, and units that respond to both the contralateral and ipsilateral wall have a modulation near 0.DOI:http://dx.doi.org/10.7554/eLife.12559.012
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fig4s5: Tuning to ipsilateral and contralateral wall distance.(a) Example spike raster of regular spiking unit in open-loop trials when the wall is contralateral (top) or ipsilateral to the recording site (bottom). Only epochs with running speed over 3 m/s are represented. This neuron was activated by interactions with the wall. (b) Corresponding tuning curves recorded during locomotion (running speed over 3 m/s). (c,d) Same as a, b for a suppressed regular spiking unit. (e) Scatter plot of range of spiking of ipsilateral vs. contralateral tuning curves. The range of spiking is the difference between the maximum and minimum of the tuning curve. (f) Histogram of laterality modulation index, which is the difference in contralateral range and ipsilateral range divided by the sum of the contralateral range and ipsilateral range. Units that respond only to the contralateral wall have modulation 1, units that respond only to the ipsilateral wall have modulation −1, and units that respond to both the contralateral and ipsilateral wall have a modulation near 0.DOI:http://dx.doi.org/10.7554/eLife.12559.012

Mentions: When running in a narrow corridor, whiskers can interact with both walls simultaneously. Information from the whiskers projects directly to the contralateral barrel cortex from subcortical structures; however, a small callosal projection also carries information from one side of the barrel cortex to the other (Czeiger and White, 1993). For a subset of mice (3 mice; 29 regular spiking units) we recorded activity in response to open-loop movements of the ipsilateral wall. Compared to interactions with the contralateral wall, very few units were strongly modulated by interactions with the ipsilateral wall (Figure 4—figure supplement 5a,b,c,d). Spike rate changes in response to interactions with the contralateral wall were consistently greater than to the ipsilateral wall (27/29; 93% contra vs ipsi modulation > 0) (Figure 4—figure supplement 5e,f). This finding is consistent with the results of the unilateral activation experiment, which suggest the hemisphere contralateral to the wall is predominantly involved in wall-tracking.


Neural coding in barrel cortex during whisker-guided locomotion.

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

Tuning to ipsilateral and contralateral wall distance.(a) Example spike raster of regular spiking unit in open-loop trials when the wall is contralateral (top) or ipsilateral to the recording site (bottom). Only epochs with running speed over 3 m/s are represented. This neuron was activated by interactions with the wall. (b) Corresponding tuning curves recorded during locomotion (running speed over 3 m/s). (c,d) Same as a, b for a suppressed regular spiking unit. (e) Scatter plot of range of spiking of ipsilateral vs. contralateral tuning curves. The range of spiking is the difference between the maximum and minimum of the tuning curve. (f) Histogram of laterality modulation index, which is the difference in contralateral range and ipsilateral range divided by the sum of the contralateral range and ipsilateral range. Units that respond only to the contralateral wall have modulation 1, units that respond only to the ipsilateral wall have modulation −1, and units that respond to both the contralateral and ipsilateral wall have a modulation near 0.DOI:http://dx.doi.org/10.7554/eLife.12559.012
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4764557&req=5

fig4s5: Tuning to ipsilateral and contralateral wall distance.(a) Example spike raster of regular spiking unit in open-loop trials when the wall is contralateral (top) or ipsilateral to the recording site (bottom). Only epochs with running speed over 3 m/s are represented. This neuron was activated by interactions with the wall. (b) Corresponding tuning curves recorded during locomotion (running speed over 3 m/s). (c,d) Same as a, b for a suppressed regular spiking unit. (e) Scatter plot of range of spiking of ipsilateral vs. contralateral tuning curves. The range of spiking is the difference between the maximum and minimum of the tuning curve. (f) Histogram of laterality modulation index, which is the difference in contralateral range and ipsilateral range divided by the sum of the contralateral range and ipsilateral range. Units that respond only to the contralateral wall have modulation 1, units that respond only to the ipsilateral wall have modulation −1, and units that respond to both the contralateral and ipsilateral wall have a modulation near 0.DOI:http://dx.doi.org/10.7554/eLife.12559.012
Mentions: When running in a narrow corridor, whiskers can interact with both walls simultaneously. Information from the whiskers projects directly to the contralateral barrel cortex from subcortical structures; however, a small callosal projection also carries information from one side of the barrel cortex to the other (Czeiger and White, 1993). For a subset of mice (3 mice; 29 regular spiking units) we recorded activity in response to open-loop movements of the ipsilateral wall. Compared to interactions with the contralateral wall, very few units were strongly modulated by interactions with the ipsilateral wall (Figure 4—figure supplement 5a,b,c,d). Spike rate changes in response to interactions with the contralateral wall were consistently greater than to the ipsilateral wall (27/29; 93% contra vs ipsi modulation > 0) (Figure 4—figure supplement 5e,f). This finding is consistent with the results of the unilateral activation experiment, which suggest the hemisphere contralateral to the wall is predominantly involved in wall-tracking.

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