scholarly journals Combinatorial neural inhibition for stimulus selection across space

2018 ◽  
Author(s):  
Nagaraj R. Mahajan ◽  
Shreesh P. Mysore
Keyword(s):  
Functional Module ◽  
Central Element ◽  
Visual Space ◽  
Inhibitory Neurons ◽  
Stimulus Selection ◽  
Neural Inhibition ◽  
Salient Stimulus ◽  
Spatial Locations ◽  
The Brain ◽  
High Firing

The ability to select the most salient stimulus among competing ones is essential for animal behavior and operates regardless of the spatial locations that stimuli occupy. Here, we reveal that the brain employs a combinatorially optimized strategy to solve such location-invariant stimulus selection. With experiments in a key inhibitory nucleus in the vertebrate midbrain selection network, called isthmi pars magnocellularis (Imc) in owls, we discovered that the central element is a ‘multilobe’ neuron, which encodes visual locations with multiple firing fields. This multilobed coding of space is necessitated by scarcity of Imc neurons. Although distributed seemingly randomly in space, the locations of these lobes are optimized across the high firing Imc neurons, allowing them to cooperatively suppress stimuli throughout 2D visual space while minimizing metabolic and circuit wiring costs. Our work suggests that combinatorial coding of space by sparse inhibitory neurons may be a general functional module for spatial selection.

scholarly journals Spatial Dependence of Stimulus Competition in the Avian Nucleus Isthmi Pars Magnocellularis

2019 ◽  
Vol 93 (2-3) ◽  
pp. 137-151 ◽  
Author(s):  
Hannah M. Schryver ◽  
Shreesh P. Mysore
Keyword(s):  
Functional Properties ◽  
Sensory Modality ◽  
Barn Owl ◽  
Inhibitory Neurons ◽  
Stimulus Selection ◽  
Nucleus Isthmi ◽  
Midbrain Tegmentum ◽  
The One ◽  
The Brain ◽  
Shed Light

The nucleus isthmi pars magnocellularis (Imc) is a group of specialized inhibitory neurons in the midbrain tegmentum, thought to be conserved across vertebrate classes. Past anatomical work in reptiles has suggested a role for it in stimulus selection, which has been supported by recent studies in avians. Additionally, focal inactivation of Imc neurons is known to abolish all competitive interactions in the optic tectum (OT; SC in mammals), a midbrain sensorimotor hub that is critical for the control of spatial attention, thereby revealing a key role for Imc in stimulus selection. However, the functional properties of Imc neurons are not well understood. Here, with electrophysiological experiments in the barn owl Imc, we show that Imc neurons themselves exhibit signatures of stimulus competition. Distant competing stimuli outside the spatial receptive field (RF) suppressed powerfully, and divisively, the responses of Imc neurons to stimuli inside the RF, and did so from all tested locations along the elevation as well as azimuth. Notably, this held true even for locations encoded by the opposite side of the brain from the one containing the recording site. This global divisive inhibition operated independently of the sensory modality of the competing stimulus. Thus, the Imc not only supplies inhibition to the OT to support competition there, but may itself be an active site of stimulus competition. These results from experiments in the barn owl shed light on the functional properties of a vital node in the vertebrate midbrain selection network.

scholarly journals The Spatial and Cell-Type Distribution of SARS-CoV-2 Receptor ACE2 in the Human and Mouse Brains

2021 ◽  
Vol 11 ◽  
Author(s):  
Rongrong Chen ◽  
Keer Wang ◽  
Jie Yu ◽  
Derek Howard ◽  
Leon French ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Spatial Distribution ◽  
Host Cells ◽  
Inhibitory Neurons ◽  
Middle Temporal Gyrus ◽  
Distribution Analysis ◽  
Cell Type ◽  
Type Distribution ◽  
The Brain ◽  
Human And Mouse

By engaging angiotensin-converting enzyme 2 (ACE2 or Ace2), the novel pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) invades host cells and affects many organs, including the brain. However, the distribution of ACE2 in the brain is still obscure. Here, we investigated the ACE2 expression in the brain by analyzing data from publicly available brain transcriptome databases. According to our spatial distribution analysis, ACE2 was relatively highly expressed in some brain locations, such as the choroid plexus and paraventricular nuclei of the thalamus. According to cell-type distribution analysis, nuclear expression of ACE2 was found in many neurons (both excitatory and inhibitory neurons) and some non-neuron cells (mainly astrocytes, oligodendrocytes, and endothelial cells) in the human middle temporal gyrus and posterior cingulate cortex. A few ACE2-expressing nuclei were found in a hippocampal dataset, and none were detected in the prefrontal cortex. Except for the additional high expression of Ace2 in the olfactory bulb areas for spatial distribution as well as in the pericytes and endothelial cells for cell-type distribution, the distribution of Ace2 in the mouse brain was similar to that in the human brain. Thus, our results reveal an outline of ACE2/Ace2 distribution in the human and mouse brains, which indicates that the brain infection of SARS-CoV-2 may be capable of inducing central nervous system symptoms in coronavirus disease 2019 (COVID-19) patients. Potential species differences should be considered when using mouse models to study the neurological effects of SARS-CoV-2 infection.

scholarly journals Confidence-Related Decision Making

2010 ◽  
Vol 104 (1) ◽  
pp. 539-547 ◽  
Author(s):  
Andrea Insabato ◽  
Mario Pannunzi ◽  
Edmund T. Rolls ◽  
Gustavo Deco
Keyword(s):  
Decision Making ◽  
Cognitive Functioning ◽  
Neuronal Activity ◽  
Emergent Property ◽  
Neuronal Responses ◽  
Attractor Network ◽  
Firing Rates ◽  
Integrate And Fire ◽  
The Brain ◽  
High Firing

Neurons have been recorded that reflect in their firing rates the confidence in a decision. Here we show how this could arise as an emergent property in an integrate-and-fire attractor network model of decision making. The attractor network has populations of neurons that respond to each of the possible choices, each biased by the evidence for that choice, and there is competition between the attractor states until one population wins the competition and finishes with high firing that represents the decision. Noise resulting from the random spiking times of individual neurons makes the decision making probabilistic. We also show that a second attractor network can make decisions based on the confidence in the first decision. This system is supported by and accounts for neuronal responses recorded during decision making and makes predictions about the neuronal activity that will be found when a decision is made about whether to stay with a first decision or to abort the trial and start again. The research shows how monitoring can be performed in the brain and this has many implications for understanding cognitive functioning.

scholarly journals Parallel updating and weighting of multiple spatial maps for visual stability during whole body motion

2015 ◽  
Vol 114 (6) ◽  
pp. 3211-3219 ◽  
Author(s):  
J. J. Tramper ◽  
W. P. Medendorp
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Spatial Information ◽  
Target Location ◽  
Visual Space ◽  
Body Motion ◽  
Whole Body ◽  
Spatial Representations ◽  
Integration Model ◽  
The Brain

It is known that the brain uses multiple reference frames to code spatial information, including eye-centered and body-centered frames. When we move our body in space, these internal representations are no longer in register with external space, unless they are actively updated. Whether the brain updates multiple spatial representations in parallel, or whether it restricts its updating mechanisms to a single reference frame from which other representations are constructed, remains an open question. We developed an optimal integration model to simulate the updating of visual space across body motion in multiple or single reference frames. To test this model, we designed an experiment in which participants had to remember the location of a briefly presented target while being translated sideways. The behavioral responses were in agreement with a model that uses a combination of eye- and body-centered representations, weighted according to the reliability in which the target location is stored and updated in each reference frame. Our findings suggest that the brain simultaneously updates multiple spatial representations across body motion. Because both representations are kept in sync, they can be optimally combined to provide a more precise estimate of visual locations in space than based on single-frame updating mechanisms.

Premotor Inhibitory Neurons Carry Signals Related to Saccade Adaptation in the Monkey

2008 ◽  
Vol 99 (1) ◽  
pp. 220-230 ◽  
Author(s):  
Yoshiko Kojima ◽  
Yoshiki Iwamoto ◽  
Farrel R. Robinson ◽  
Christopher T. Noto ◽  
Kaoru Yoshida
Keyword(s):  
Gradual Increase ◽  
Cerebellar Nuclei ◽  
Inhibitory Neurons ◽  
Voluntary Movements ◽  
Burst Neurons ◽  
Premotor Neurons ◽  
Saccade Size ◽  
Motoneuron Activity ◽  
Saccade Adaptation ◽  
The Brain

Cerebellar output changes during motor learning. How these changes cause alterations of motoneuron activity and movement remains an unresolved question for voluntary movements. To answer this question, we examined premotor neurons for saccadic eye movement. Previous studies indicate that cells in the fastigial oculomotor region (FOR) within the cerebellar nuclei on one side exhibit a gradual increase in their saccade-related discharge as the amplitude of ipsiversive saccades adaptively decreases. This change in FOR activity could cause the adaptive change in saccade amplitude because neurons in the FOR project directly to the brain stem region containing premotor burst neurons (BNs). To test this possibility, we recorded the activity of saccade-related burst neurons in the area that houses premotor inhibitory burst neurons (IBNs) and examined their discharge during amplitude-reducing adaptation elicited by intrasaccadic target steps. We specifically analyzed their activity for off-direction (contraversive) saccades, in which the IBN activity would increase to reduce saccade size. Before adaptation, 29 of 42 BNs examined discharged, at least occasionally, for contraversive saccades. As the amplitude of contraversive saccades decreased adaptively, half of BNs with off-direction spike activity showed an increase in the number of spikes (14/29) or an earlier occurrence of spikes (7/14). BNs that were silent during off-direction saccades before adaptation remained silent after adaptation. These results indicate that the changes in the off-direction activity of BNs are closely related to adaptive changes in saccade size and are appropriate to cause these changes.

Where Is Size in the Brain of the Beholder?

2015 ◽  
Vol 28 (3-4) ◽  
pp. 285-296 ◽  
Author(s):  
Dietrich Samuel Schwarzkopf
Keyword(s):  
Subjective Experience ◽  
Visual Space ◽  
Brain Regions ◽  
Future Research ◽  
The Brain

Despite advances in our understanding of how the brain represents visual space, it remains unresolved how the subjective experience of an object’s size arises. While responses in retinotopic cortex correlate with perceived size, this does not imply that those brain regions mediate perceived size differences. Here I describe how the percept of an object’s size could be generated in the brain and outline unanswered questions that future research should seek to address.

The Role of Brain Oscillations in the Temporal Limits of Attention

2014 ◽  
Author(s):  
Kimron Shapiro ◽  
Simon Hanslmayr
Keyword(s):  
Frequency Band ◽  
Visual Space ◽  
Visual Input ◽  
Brain Oscillations ◽  
Approaches To Studying ◽  
Alpha Frequency ◽  
Alpha Frequency Band ◽  
Long Time ◽  
The Brain

Attention is the ubiquitous construct referring to the ability of the brain to focus resources on a subset of perceptual input which it is trying to process for a response. Attention has for a long time been studied with reference to its distribution across space where, for example, visual input from an attentionally monitored location is given preference over non-monitored (i.e. attended) locations. More recently, attention has been studied for its ability to select targets from among rapidly, sequentially presented non-targets at a fixed location, e.g. in visual space. The present chapter explores this latter function of attention for its relevance to behaviour. In so doing, it highlights what is becoming one of the most popular approaches to studying communication across the brain—oscillations—at various frequency ranges. In particular the authors discuss the alpha frequency band (8–12 Hz), where recent evidence points to an important role in the switching between processing external vs. internal events.

scholarly journals Single circuit in V1 capable of switching contexts during movement using VIP population as a switch

2020 ◽  
Author(s):  
Doris Voina ◽  
Stefano Recanatesi ◽  
Brian Hu ◽  
Eric Shea-Brown ◽  
Stefan Mihalas
Keyword(s):  
Visual System ◽  
Visual Processing ◽  
Visual Space ◽  
Cell Types ◽  
Flexible Architecture ◽  
Multiple Cell ◽  
Context Dependent ◽  
Spatio Temporal ◽  
Context Integration ◽  
The Brain

AbstractAs animals adapt to their environments, their brains are tasked with processing stimuli in different sensory contexts. Whether these computations are context dependent or independent, they are all implemented in the same neural tissue. A crucial question is what neural architectures can respond flexibly to a range of stimulus conditions and switch between them. This is a particular case of flexible architecture that permits multiple related computations within a single circuit.Here, we address this question in the specific case of the visual system circuitry, focusing on context integration, defined as the integration of feedforward and surround information across visual space. We show that a biologically inspired microcircuit with multiple inhibitory cell types can switch between visual processing of the static context and the moving context. In our model, the VIP population acts as the switch and modulates the visual circuit through a disinhibitory motif. Moreover, the VIP population is efficient, requiring only a relatively small number of neurons to switch contexts. This circuit eliminates noise in videos by using appropriate lateral connections for contextual spatio-temporal surround modulation, having superior denoising performance compared to circuits where only one context is learned. Our findings shed light on a minimally complex architecture that is capable of switching between two naturalistic contexts using few switching units.Author SummaryThe brain processes information at all times and much of that information is context-dependent. The visual system presents an important example: processing is ongoing, but the context changes dramatically when an animal is still vs. running. How is context-dependent information processing achieved? We take inspiration from recent neurophysiology studies on the role of distinct cell types in primary visual cortex (V1).We find that relatively few “switching units” — akin to the VIP neuron type in V1 in that they turn on and off in the running vs. still context and have connections to and from the main population — is sufficient to drive context dependent image processing. We demonstrate this in a model of feature integration, and in a test of image denoising. The underlying circuit architecture illustrates a concrete computational role for the multiple cell types under increasing study across the brain, and may inspire more flexible neurally inspired computing architectures.

scholarly journals Preferential Pharmacological Inhibition of Nav1.6, but not Nav1.1, Abolishes Epileptiform Activity Induced by 4-AP in Mouse Cortical Slices

2020 ◽  
Author(s):  
Reesha R. Patel ◽  
Xingjie Ping ◽  
Shaun R. Patel ◽  
Jeff S. McDermott ◽  
Jeffrey L. Krajewski ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Epileptiform Activity ◽  
Inhibitory Neurons ◽  
Hek293 Cells ◽  
Functional Roles ◽  
Voltage Gated Sodium Channels ◽  
Whole Cell Patch Clamp ◽  
Epileptic Syndromes ◽  
The Brain ◽  
Cortical Slices

ABSTRACTBrain isoforms of voltage-gated sodium channels (VGSCs) have distinct cellular and subcellular expression patterns as well as functional roles that are critical for normal physiology as aberrations in their expression or activity lead to pathophysiological conditions. In this study, we asked how inhibition of select isoforms of VGSCs alters epileptiform activity to further parse out the roles of VGSCs in the brain. We first determined the relative selectivity of recently discovered small molecule, aryl sulfonamide, inhibitors (ICA-121431 and Compound 801) against Nav1.1, Nav1.2, and Nav1.6 activity using whole-cell patch clamp recordings obtained from HEK293 cells. To test the effects of these inhibitors on epileptiform activity, we obtained multielectrode array (MEA) recordings from mouse cortical slices in the presence of 4-aminopyridine (4-AP) to induce epileptiform activity. We found that the ICA-121431 and Compound 801 compounds are relatively selective for Nav1.1 and Nav1.6, respectively. From the MEA recordings, we found that inhibition of Nav1.6 and Nav1.2 with 500nM of the Compound 801 compound completely abolishes ictal local field potentials induced by 4-AP, whereas inhibition of Nav1.1 with 500nM of the ICA-121431 compound had minimal effect on epileptiform activity induced by 4-AP. Due to the prominent expression of Nav1.1 in inhibitory neurons, we asked whether inhibition of Nav1.1 alone alters activity. We found that, indeed, inhibition of Nav1.1 with the ICA-121431 compound increased basal activity in the absence of 4-AP. These findings expand our current understanding of the roles of VGSC isoforms in the brain and suggest that selective targeting of Nav1.6 may be a more efficacious treatment strategy for epileptic syndromes.

scholarly journals Sharp tuning of head direction by somatosensory fast-spiking interneurons

2020 ◽  
Author(s):  
Xiaoyang Long ◽  
Calvin K. Young ◽  
Sheng-Jia Zhang
Keyword(s):  
Cell Types ◽  
Inhibitory Neurons ◽  
Local Network ◽  
Head Direction ◽  
Layer 4 ◽  
Fast Spiking ◽  
External Stimuli ◽  
The Brain ◽  
Spatial Cell

AbstractHead direction (HD) information is intricately linked to spatial navigation and cognition. We recently reported the co-existence of all currently recognized spatial cell types can be found in the hindlimb primary somatosensory cortex (S1HL). In this study, we carried out an in-depth characterization of HD cells in S1HL. We show fast-spiking (FS), putative inhibitory neurons are over-represented in and sharply tuned to HD compared to regular-spiking (RS), putative excitatory neurons. These FS HD cells are non-conjunctive, rarely theta modulated, not locally connected and are enriched in layer 4/5a. Their co-existence with RS HD cells and angular head velocity (AHV) cells in a layer-specific fashion through the S1HL presents a previously unreported organization of spatial circuits. These findings challenge the notion that FS, putative inhibitory interneurons are weakly tuned to external stimuli in general and present a novel local network configuration not reported in other parts of the brain.

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