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Synthesis of a comprehensive population code for contextual features in the awake sensory cortex
- Source :
- eLife, eLife, Vol 10 (2021)
- Publication Year :
- 2021
- Publisher :
- eLife Sciences Publications, Ltd, 2021.
-
Abstract
- How cortical circuits build representations of complex objects is poorly understood. Individual neurons must integrate broadly over space, yet simultaneously obtain sharp tuning to specific global stimulus features. Groups of neurons identifying different global features must then assemble into a population that forms a comprehensive code for these global stimulus properties. Although the logic for how single neurons summate over their spatial inputs has been well explored in anesthetized animals, how large groups of neurons compose a flexible population code of higher-order features in awake animals is not known. To address this question, we probed the integration and population coding of higher-order stimuli in the somatosensory and visual cortices of awake mice using two-photon calcium imaging across cortical layers. We developed a novel tactile stimulator that allowed the precise measurement of spatial summation even in actively whisking mice. Using this system, we found a sparse but comprehensive population code for higher-order tactile features that depends on a heterogeneous and neuron-specific logic of spatial summation beyond the receptive field. Different somatosensory cortical neurons summed specific combinations of sensory inputs supra-linearly, but integrated other inputs sub-linearly, leading to selective responses to higher-order features. Visual cortical populations employed a nearly identical scheme to generate a comprehensive population code for contextual stimuli. These results suggest that a heterogeneous logic of input-specific supra-linear summation may represent a widespread cortical mechanism for the synthesis of sparse higher-order feature codes in neural populations. This may explain how the brain exploits the thalamocortical expansion of dimensionality to encode arbitrary complex features of sensory stimuli.
- Subjects :
- Male
Mouse
QH301-705.5
Computer science
Science
Population
receptive field
neural coding
Sensory system
Summation
General Biochemistry, Genetics and Molecular Biology
Mice
Physical Stimulation
sparse codes
medicine
Animals
Sensory cortex
Biology (General)
visual cortex
Wakefulness
education
education.field_of_study
General Immunology and Microbiology
General Neuroscience
Whisking in animals
Somatosensory Cortex
General Medicine
Visual cortex
medicine.anatomical_structure
Touch
Receptive field
two photon calcium imaging
Medicine
barrel cortex
Female
Neural coding
Neuroscience
Research Article
Subjects
Details
- ISSN :
- 2050084X
- Volume :
- 10
- Database :
- OpenAIRE
- Journal :
- eLife
- Accession number :
- edsair.doi.dedup.....4e573029851facdfeb586c9f8e4bdfb8