scholarly journals Response reversal during top-down modulation in cortical circuits with multiple interneuron types

2017 ◽  
Author(s):  
Luis Carlos Garcia del Molino ◽  
Guangyu Robert Yang ◽  
Jorge F. Mejias ◽  
Xiao-Jing Wang
Keyword(s):  
Complex Dynamics ◽  
Pyramidal Cells ◽  
Real Data ◽  
Neural Population ◽  
Cortical Circuits ◽  
Top Down ◽  
Thalamic Input ◽  
Response Reversal ◽  
Cell Type Specific ◽  
Cortical Circuit

AbstractPyramidal cells and interneurons expressing parvalbumin, somatostatin, or vasoactive intestinal peptide show cell type-specific connectivity patterns leading to a canonical microcircuit across cortex. Dissecting the dynamics of this microcircuit is essential to our understanding of the mammalian cortex. However, experiments recording from this circuit often report counterintuitive and seemingly contradictory findings. For example, the response of a V1 neural population to top-down behavioral modulation can reverse from positive to negative when the bottom-up thalamic input changes. We developed a theoretical framework to explain such response reversal, and we showed how this complex dynamics can emerge in circuits that possess two key features: the presence of multiple interneuron populations and a non-linear dependence between the input and output of the populations. Furthermore, we built a cortical circuit model and the comparison of our simulations with real data shows that our model reproduces the complex dynamics observed experimentally in mouse V1. Our explicit calculations allowed us to pinpoint the connections critical to response reversal, and to predict the existence of more types of complex dynamics that could be experimentally tested and the conditions to observe them.

scholarly journals Paradoxical response reversal of top-down modulation in cortical circuits with three interneuron types

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Luis Carlos Garcia del Molino ◽  
Guangyu Robert Yang ◽  
Jorge F Mejias ◽  
Xiao-Jing Wang
Keyword(s):  
Complex Dynamics ◽  
Pyramidal Cells ◽  
Cortical Circuits ◽  
Top Down ◽  
Paradoxical Response ◽  
Neural Populations ◽  
Connectivity Patterns ◽  
Response Reversal ◽  
Cell Type Specific ◽  
Cortical Circuit

Pyramidal cells and interneurons expressing parvalbumin (PV), somatostatin (SST), and vasoactive intestinal peptide (VIP) show cell-type-specific connectivity patterns leading to a canonical microcircuit across cortex. Experiments recording from this circuit often report counterintuitive and seemingly contradictory findings. For example, the response of SST cells in mouse V1 to top-down behavioral modulation can change its sign when the visual input changes, a phenomenon that we call response reversal. We developed a theoretical framework to explain these seemingly contradictory effects as emerging phenomena in circuits with two key features: interactions between multiple neural populations and a nonlinear neuronal input-output relationship. Furthermore, we built a cortical circuit model which reproduces counterintuitive dynamics observed in mouse V1. Our analytical calculations pinpoint connection properties critical to response reversal, and predict additional novel types of complex dynamics that could be tested in future experiments.

scholarly journals Author response: Paradoxical response reversal of top-down modulation in cortical circuits with three interneuron types

2017 ◽  
Author(s):  
Luis Carlos Garcia del Molino ◽  
Guangyu Robert Yang ◽  
Jorge F Mejias ◽  
Xiao-Jing Wang
Keyword(s):  
Author Response ◽  
Cortical Circuits ◽  
Top Down ◽  
Paradoxical Response ◽  
Response Reversal

scholarly journals Author response: Paradoxical response reversal of top-down modulation in cortical circuits with three interneuron types

2017 ◽  
Author(s):  
Luis Carlos Garcia del Molino ◽  
Guangyu Robert Yang ◽  
Jorge F Mejias ◽  
Xiao-Jing Wang
Keyword(s):  
Author Response ◽  
Cortical Circuits ◽  
Top Down ◽  
Paradoxical Response ◽  
Response Reversal

scholarly journals Correction: Paradoxical response reversal of top-down modulation in cortical circuits with three interneuron types

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Luis Carlos Garcia del Molino ◽  
Guangyu Robert Yang ◽  
Jorge F Mejias ◽  
Xiao-Jing Wang
Keyword(s):  
Cortical Circuits ◽  
Top Down ◽  
Paradoxical Response ◽  
Response Reversal

scholarly journals scSorter: assigning cells to known cell types according to marker genes

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hongyu Guo ◽  
Jun Li
Keyword(s):  
Real Data ◽  
Cell Types ◽  
Exact Expression ◽  
Marker Genes ◽  
Specific Marker ◽  
Sequencing Data ◽  
Reference Dataset ◽  
Over Expression ◽  
Higher Power ◽  
Cell Type Specific

AbstractOn single-cell RNA-sequencing data, we consider the problem of assigning cells to known cell types, assuming that the identities of cell-type-specific marker genes are given but their exact expression levels are unavailable, that is, without using a reference dataset. Based on an observation that the expected over-expression of marker genes is often absent in a nonnegligible proportion of cells, we develop a method called scSorter. scSorter allows marker genes to express at a low level and borrows information from the expression of non-marker genes. On both simulated and real data, scSorter shows much higher power compared to existing methods.

scholarly journals Functional selectivity and specific connectivity of inhibitory neurons in primary visual cortex

2018 ◽  
Author(s):  
Petr Znamenskiy ◽  
Mean-Hwan Kim ◽  
Dylan R. Muir ◽  
Maria Florencia Iacaruso ◽  
Sonja B. Hofer ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Pyramidal Cells ◽  
Fine Tuning ◽  
Inhibitory Neurons ◽  
Local Network ◽  
Cortical Circuits ◽  
Sensory Stimuli ◽  
Excitatory Neurons ◽  
Strong Excitation

In the cerebral cortex, the interaction of excitatory and inhibitory synaptic inputs shapes the responses of neurons to sensory stimuli, stabilizes network dynamics1 and improves the efficiency and robustness of the neural code2–4. Excitatory neurons receive inhibitory inputs that track excitation5–8. However, how this co-tuning of excitation and inhibition is achieved by cortical circuits is unclear, since inhibitory interneurons are thought to pool the inputs of nearby excitatory cells and provide them with non-specific inhibition proportional to the activity of the local network9–13. Here we show that although parvalbumin-expressing (PV) inhibitory cells in mouse primary visual cortex make connections with the majority of nearby pyramidal cells, the strength of their synaptic connections is structured according to the similarity of the cells’ responses. Individual PV cells strongly inhibit those pyramidal cells that provide them with strong excitation and share their visual selectivity. This fine-tuning of synaptic weights supports co-tuning of inhibitory and excitatory inputs onto individual pyramidal cells despite dense connectivity between inhibitory and excitatory neurons. Our results indicate that individual PV cells are preferentially integrated into subnetworks of inter-connected, co-tuned pyramidal cells, stabilising their recurrent dynamics. Conversely, weak but dense inhibitory connectivity between subnetworks is sufficient to support competition between them, de-correlating their output. We suggest that the history and structure of correlated firing adjusts the weights of both inhibitory and excitatory connections, supporting stable amplification and selective recruitment of cortical subnetworks.

scholarly journals Cell type-specific effects of isoflurane on two distinct afferent inputs to cortical layer 1

2020 ◽  
Author(s):  
Caitlin A. Murphy ◽  
Matthew I. Banks
Keyword(s):  
Ex Vivo ◽  
Brain Slices ◽  
Pyramidal Cells ◽  
Cellular Level ◽  
Cortical Layer ◽  
Cell Type ◽  
Specific Effects ◽  
Primary Mouse ◽  
Cell Type Specific ◽  
Synaptic Responses

ABSTRACTBackgroundWhile their behavioral effects are well-characterized, the mechanisms by which anaesthetics induce loss of consciousness are largely unknown. Anaesthetics may disrupt integration and propagation of information in corticothalamic networks. Recent studies have shown that isoflurane diminishes synaptic responses of thalamocortical (TC) and corticocortical (CC) afferents in a pathway-specific manner. However, whether the synaptic effects of isoflurane observed in extracellular recordings persist at the cellular level has yet to be explored.MethodsHere, we activate TC and CC layer 1 inputs in non-primary mouse neocortex in ex vivo brain slices and explore the degree to which isoflurane modulates synaptic responses in pyramidal cells and in two inhibitory cell populations, somatostatin-positive (SOM+) and parvalbumin-positive (PV+) interneurons.ResultsWe show that the effects of isoflurane on synaptic responses and intrinsic properties of these cells varies among cell type and by cortical layer. Layer 1 inputs to L4 pyramidal cells were suppressed by isoflurane at both TC and CC synapses, while those to L2/3 pyramidal cells and PV+ interneurons were not. TC inputs to SOM+ cells were rarely observed at all, while CC inputs to SOM+ interneurons were robustly suppressed by isoflurane.ConclusionsThese results suggest a mechanism by which isoflurane disrupts integration and propagation of thalamocortical and intracortical signals.

scholarly journals Cell-type specific innervation of cortical pyramidal cells at their apical dendrites

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Ali Karimi ◽  
Jan Odenthal ◽  
Florian Drawitsch ◽  
Kevin M Boergens ◽  
Moritz Helmstaedter
Keyword(s):  
Electron Microscopy ◽  
Pyramidal Cells ◽  
Inhibitory Input ◽  
Cell Type ◽  
Cell Type Specific ◽  
Cortical Regions ◽  
Apical Dendrites ◽  
Computational Properties

We investigated the synaptic innervation of apical dendrites of cortical pyramidal cells in a region between layers (L) 1 and 2 using 3-D electron microscopy applied to four cortical regions in mouse. We found the relative inhibitory input at the apical dendrite’s main bifurcation to be more than 2-fold larger for L2 than L3 and L5 thick-tufted pyramidal cells. Towards the distal tuft dendrites in upper L1, the relative inhibitory input was at least about 2-fold larger for L5 pyramidal cells than for all others. Only L3 pyramidal cells showed homogeneous inhibitory input fraction. The inhibitory-to-excitatory synaptic ratio is thus specific for the types of pyramidal cells. Inhibitory axons preferentially innervated either L2 or L3/5 apical dendrites, but not both. These findings describe connectomic principles for the control of pyramidal cells at their apical dendrites and support differential computational properties of L2, L3 and subtypes of L5 pyramidal cells in cortex.

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