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Differential tuning of excitation and inhibition shapes direction selectivity in ferret V1
To encode specific sensory inputs, cortical neurons must generate selective responses for distinct stimulus features. In principle, a variety of factors contribute to a cortical neuron’s response selectivity: the tuning and strength of excitatory(1–3) and inhibitory synaptic inputs(4–6), dendritic n...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
2018
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946183/ https://www.ncbi.nlm.nih.gov/pubmed/30046106 http://dx.doi.org/10.1038/s41586-018-0354-1 |
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author | Wilson, Daniel E. Scholl, Benjamin Fitzpatrick, David |
author_facet | Wilson, Daniel E. Scholl, Benjamin Fitzpatrick, David |
author_sort | Wilson, Daniel E. |
collection | PubMed |
description | To encode specific sensory inputs, cortical neurons must generate selective responses for distinct stimulus features. In principle, a variety of factors contribute to a cortical neuron’s response selectivity: the tuning and strength of excitatory(1–3) and inhibitory synaptic inputs(4–6), dendritic nonlinearities(7–9), and spike threshold(10,11). Here we employ a combination of techniques including in vivo whole-cell recording, synaptic and cellular resolution in vivo two photon calcium imaging, and GABAergic-selective optogenetic manipulation to dissect the factors contributing to direction selective responses of layer 2/3 neurons in ferret visual cortex (V1). Two-photon calcium imaging of dendritic spines(12,13) revealed that each neuron receives a mixture of excitatory synaptic inputs selective for the somatic preferred or null direction of motion. The relative number of preferred- and null-tuned excitatory inputs predicted a neuron’s somatic direction preference, but failed to account for the degree of direction selectivity. In contrast, in vivo whole-cell patch clamp recordings revealed a striking degree of direction selectivity in subthreshold responses that was significantly correlated with spiking direction selectivity. Subthreshold direction selectivity was predicted by the magnitude and variance of the response to the null direction of motion, and several lines of evidence including conductance measurements demonstrate that differential tuning of excitation and inhibition suppresses responses to the null direction of motion. Consistent with this idea, optogenetic inactivation of GABAergic neurons in layer 2/3 reduced direction selectivity by enhancing responses to the null direction. Furthermore, using a new technique to optogenetically map connections of inhibitory neurons in layer 2/3 in vivo, we find that layer 2/3 inhibitory neurons make long-range, intercolumnar projections to excitatory neurons that prefer the opposite direction of motion. We conclude that intracortical inhibition exerts a major influence on the degree of direction selectivity in layer 2/3 of ferret V1 by suppressing responses to the null direction of motion. |
format | Online Article Text |
id | pubmed-6946183 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
record_format | MEDLINE/PubMed |
spelling | pubmed-69461832020-01-07 Differential tuning of excitation and inhibition shapes direction selectivity in ferret V1 Wilson, Daniel E. Scholl, Benjamin Fitzpatrick, David Nature Article To encode specific sensory inputs, cortical neurons must generate selective responses for distinct stimulus features. In principle, a variety of factors contribute to a cortical neuron’s response selectivity: the tuning and strength of excitatory(1–3) and inhibitory synaptic inputs(4–6), dendritic nonlinearities(7–9), and spike threshold(10,11). Here we employ a combination of techniques including in vivo whole-cell recording, synaptic and cellular resolution in vivo two photon calcium imaging, and GABAergic-selective optogenetic manipulation to dissect the factors contributing to direction selective responses of layer 2/3 neurons in ferret visual cortex (V1). Two-photon calcium imaging of dendritic spines(12,13) revealed that each neuron receives a mixture of excitatory synaptic inputs selective for the somatic preferred or null direction of motion. The relative number of preferred- and null-tuned excitatory inputs predicted a neuron’s somatic direction preference, but failed to account for the degree of direction selectivity. In contrast, in vivo whole-cell patch clamp recordings revealed a striking degree of direction selectivity in subthreshold responses that was significantly correlated with spiking direction selectivity. Subthreshold direction selectivity was predicted by the magnitude and variance of the response to the null direction of motion, and several lines of evidence including conductance measurements demonstrate that differential tuning of excitation and inhibition suppresses responses to the null direction of motion. Consistent with this idea, optogenetic inactivation of GABAergic neurons in layer 2/3 reduced direction selectivity by enhancing responses to the null direction. Furthermore, using a new technique to optogenetically map connections of inhibitory neurons in layer 2/3 in vivo, we find that layer 2/3 inhibitory neurons make long-range, intercolumnar projections to excitatory neurons that prefer the opposite direction of motion. We conclude that intracortical inhibition exerts a major influence on the degree of direction selectivity in layer 2/3 of ferret V1 by suppressing responses to the null direction of motion. 2018-07-25 2018-08 /pmc/articles/PMC6946183/ /pubmed/30046106 http://dx.doi.org/10.1038/s41586-018-0354-1 Text en Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms |
spellingShingle | Article Wilson, Daniel E. Scholl, Benjamin Fitzpatrick, David Differential tuning of excitation and inhibition shapes direction selectivity in ferret V1 |
title | Differential tuning of excitation and inhibition shapes direction selectivity in ferret V1 |
title_full | Differential tuning of excitation and inhibition shapes direction selectivity in ferret V1 |
title_fullStr | Differential tuning of excitation and inhibition shapes direction selectivity in ferret V1 |
title_full_unstemmed | Differential tuning of excitation and inhibition shapes direction selectivity in ferret V1 |
title_short | Differential tuning of excitation and inhibition shapes direction selectivity in ferret V1 |
title_sort | differential tuning of excitation and inhibition shapes direction selectivity in ferret v1 |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946183/ https://www.ncbi.nlm.nih.gov/pubmed/30046106 http://dx.doi.org/10.1038/s41586-018-0354-1 |
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