scholarly journals Cortical reliability amid noise and chaos

2018 ◽  
Author(s):  
Max Nolte ◽  
Michael W. Reimann ◽  
James G. King ◽  
Henry Markram ◽  
Eilif B. Muller
Keyword(s):  
Cortical Neurons ◽  
Biophysical Model ◽  
Spike Time ◽  
Cortical Circuits ◽  
Intrinsic Variability ◽  
Noise Sources ◽  
Sensory Stimuli ◽  
Simple Effect ◽  
Time Coding

Typical responses of cortical neurons to identical sensory stimuli are highly variable. It has thus been proposed that the cortex primarily uses a rate code. However, other studies have argued for spike-time coding under certain conditions. The potential role of spike-time coding is constrained by the intrinsic variability of cortical circuits, which remains largely unexplored. Here, we quantified this intrinsic variability using a biophysical model of rat neocortical microcircuitry with biologically realistic noise sources. We found that stochastic neurotransmitter release is a critical component of this variability, which, amplified by recurrent connectivity, causes rapid chaotic divergence with a time constant on the order of 10-20 milliseconds. Surprisingly, weak thalamocortical stimuli can transiently overcome the chaos, and induce reliable spike times with millisecond precision. We show that this effect relies on recurrent cortical connectivity, and is not a simple effect of feed-forward thalamocortical input. We conclude that recurrent cortical architecture supports millisecond spike-time reliability amid noise and chaotic network dynamics, resolving a long-standing debate.

scholarly journals Thalamic state influences timing precision in the thalamocortical circuit

2021 ◽  
Author(s):  
Clarissa J Whitmire ◽  
Yi J Liew ◽  
Garrett B. Stanley
Keyword(s):  
White Noise ◽  
Cortical Neurons ◽  
Spike Timing ◽  
Sensory Stimuli ◽  
Temporal Precision ◽  
Timing Precision ◽  
State Dependent ◽  
Sensory Encoding ◽  
The Impact

Sensory signals from the outside world are transduced at the periphery, passing through thalamus before reaching cortex, ultimately giving rise to the sensory representations that enable us to perceive the world. The thalamocortical circuit is particularly sensitive to the temporal precision of thalamic spiking due to highly convergent synaptic connectivity. Thalamic neurons can exhibit burst and tonic modes of firing that strongly influence timing within the thalamus. The impact of these changes in thalamic state on sensory encoding in the cortex, however, remains unclear. Here, we investigated the role of thalamic state on timing in the thalamocortical circuit of the vibrissa pathwayin the anesthetized rat. We optogenetically hyperpolarized thalamus while recording single unit activity in both thalamus and cortex. Tonic spike triggered analysis revealed temporally precise thalamic spiking that was locked to weak white-noise sensory stimuli, while thalamic burst spiking was associated with a loss in stimulus-locked temporal precision. These thalamic state dependent changes propagated to cortex such that the cortical timing precision was diminished during the hyperpolarized (burst biased) thalamic state. While still sensory driven, the cortical neurons became significantly less precisely locked to the weak white-noise stimulus. The results here suggests a state dependent differential regulation of spike timing precision in the thalamus that could gate what signals are ultimately propagated to cortex.

scholarly journals Developmental loss of ErbB4 in PV interneurons disrupts state-dependent cortical circuit dynamics

2020 ◽  
Author(s):  
Renata Batista-Brito ◽  
Antara Majumdar ◽  
Alejandro Nuno ◽  
Martin Vinck ◽  
Jessica A. Cardin
Keyword(s):  
Signaling Pathway ◽  
Cortical Neurons ◽  
Temporal Organization ◽  
Spine Density ◽  
Cortical Circuits ◽  
Neuregulin 1 ◽  
State Dependent ◽  
Sensory Responses ◽  
Early Developmental

AbstractGABAergic inhibition plays an important role in the establishment and maintenance of cortical circuits during development. Neuregulin 1 (Nrg1) and its interneuron-specific receptor ErbB4 are key elements of a signaling pathway critical for the maturation and proper synaptic connectivity of interneurons. Using conditional deletions of the ERBB4 gene in mice, we tested the role of this signaling pathway at two developmental timepoints in parvalbumin-expressing (PV) interneurons, the largest subpopulation of cortical GABAergic cells. Loss of ErbB4 in PV interneurons during embryonic, but not late postnatal, development leads to alterations in the activity of excitatory and inhibitory cortical neurons, along with severe disruption of cortical temporal organization. These impairments emerge by the end of the second postnatal week, prior to the complete maturation of the PV interneurons themselves. Early loss of ErbB4 in PV interneurons also results in profound dysregulation of excitatory pyramidal neuron dendritic architecture and a redistribution of spine density at the apical dendritic tuft. In association with these deficits, excitatory cortical neurons exhibit normal tuning for sensory inputs, but a loss of state-dependent modulation of the gain of sensory responses. Together these data support a key role for early developmental Nrg1/ErbB4 signaling in PV interneurons as powerful mechanism underlying the maturation of both the inhibitory and excitatory components of cortical circuits.

Rate Coding and Spike-Time Variability in Cortical Neurons With Two Types of Threshold Dynamics

2006 ◽  
Vol 95 (4) ◽  
pp. 2650-2663 ◽  
Author(s):  
T. Tateno ◽  
H.P.C. Robinson
Keyword(s):  
Cortical Neurons ◽  
Threshold Dynamics ◽  
Optimum Level ◽  
Spike Time ◽  
Spike Generation ◽  
Shunting Inhibition ◽  
Rate Coding

Neurons and dynamical models of spike generation display two different classes of threshold behavior: type 1 [firing frequency vs. current ( f– I) relationship is continuous at threshold] and type 2 (discontinuous f– I). With steady current or conductance stimulation, regular-spiking (RS) pyramidal neurons and fast-spiking (FS) inhibitory interneurons in layer 2/3 of somatosensory cortex exhibit type 1 and type 2 threshold behaviors, respectively. We compared the postsynaptic firing variability of type 1 RS and type 2 FS cells, during naturalistic, fluctuating conductance input. In RS neurons, increasing the level of independently random, shunting inhibition caused a monotonic increase in spike reliability, whereas in FS interneurons, there was an optimum level of shunting inhibition for achieving the most reliable spike generation and the most precise spike-time encoding. This was observed over a range of different degrees of synchrony, or correlation, in the input. RS cells displayed a progressive rise in spike jitter during natural-like transient burst inputs, whereas for FS cells, jitter was mostly kept low. Furthermore, RS cells showed encoding of the input level in the spike shape, whereas FS cells did not. These differences between the two cell types are consistent with a role of RS neurons as rate-coding integrators, and a role of FS neurons as resonators controlling the coherence of synchronous firing.

scholarly journals Activity-dependent modulation of NMDA receptors by endogenous zinc shapes dendritic function in cortical neurons.

2021 ◽  
Author(s):  
Annunziato Morabito ◽  
Yann Zerlaut ◽  
Benjamin Serraz ◽  
Romain Sala ◽  
Pierre Paoletti ◽  
...  
Keyword(s):  
Nmda Receptors ◽  
Cortical Neurons ◽  
Single Neuron ◽  
Pyramidal Neurons ◽  
Synaptic Activity ◽  
Cortical Circuits ◽  
New Perspective ◽  
Activity Dependent

Activation of NMDA receptors (NMDARs) has been proposed to be a key component of single neuron computations in vivo. However is unknown if specific mechanisms control the function of such receptors and modulate input-output transformations performed by cortical neurons under in vivo-like conditions. Here we found that in layer 2/3 pyramidal neurons (L2/3 PNs), repeated synaptic stimulation results in an activity-dependent decrease in NMDARs activity by vesicular zinc. Such a mechanism shifted the threshold for dendritic non-linearities and strongly reduced LTP induction. Modulation of NMDARs was cell- and pathway-specific, being present selectively in L2/3-L2/3 connections but absent in ascending bottom-up inputs originating from L4 neurons. Numerical simulations highlighted that activity-dependent modulation of NMDARs has an important influence in dendritic computations endowing L2/3 PN dendrites with the ability to sustain dendritic non-linear integrations constant across different regimes of synaptic activity like those found in vivo. The present results therefore provide a new perspective on the action of vesicular zinc in cortical circuits by highlighting the role of this endogenous ion in normalizing dendritic integration of PNs during a constantly changing synaptic input pattern.

Pulvino-cortical interaction: an integrative role in the control of attention

2019 ◽  
Author(s):  
Alexia Bourgeois ◽  
Carole Guedj ◽  
Emmanuel Carrera ◽  
Patrik Vuilleumier
Keyword(s):  
Executive Control ◽  
Sensory Information ◽  
Relevant Information ◽  
Cortical Circuits ◽  
Attention And Executive Control ◽  
Neural Communication ◽  
Subcortical Regions ◽  
Theoretical Proposal ◽  
Selection Of

Selective attention is a fundamental cognitive function that guides behavior by selecting and prioritizing salient or relevant sensory information of our environment. Despite early evidence and theoretical proposal pointing to an implication of thalamic control in attention, most studies in the past two decades focused on cortical substrates, largely ignoring the contribution of subcortical regions as well as cortico-subcortical interactions. Here, we suggest a key role of the pulvinar in the selection of salient and relevant information via its involvement in priority maps computation. Prioritization may be achieved through a pulvinar- mediated generation of alpha oscillations, which may then modulate neuronal gain in thalamo-cortical circuits. Such mechanism might orchestrate the synchrony of cortico-cortical interaction, by rendering neural communication more effective, precise and selective. We propose that this theoretical framework will support a timely shift from the prevailing cortico- centric view of cognition to a more integrative perspective of thalamic contributions to attention and executive control processes.

scholarly journals Cortical and Striatal Electroencephalograms and Apomorphine Effects in the FUS Mouse Model of Amyotrophic Lateral Sclerosis

2021 ◽  
pp. 1-15
Author(s):  
Vasily Vorobyov ◽  
Alexander Deev ◽  
Frank Sengpiel ◽  
Vladimir Nebogatikov ◽  
Aleksey A. Ustyugov
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Cortical Neurons ◽  
Primary Motor Cortex ◽  
Beta Activity ◽  
Systemic Injection ◽  
Eeg Spectra ◽  
Electroencephalogram Eeg ◽  
Lateral Sclerosis

Background: Amyotrophic lateral sclerosis (ALS) is characterized by degeneration of motor neurons resulting in muscle atrophy. In contrast to the lower motor neurons, the role of upper (cortical) neurons in ALS is yet unclear. Maturation of locomotor networks is supported by dopaminergic (DA) projections from substantia nigra to the spinal cord and striatum. Objective: To examine the contribution of DA mediation in the striatum-cortex networks in ALS progression. Methods: We studied electroencephalogram (EEG) from striatal putamen (Pt) and primary motor cortex (M1) in ΔFUS(1–359)-transgenic (Tg) mice, a model of ALS. EEG from M1 and Pt were recorded in freely moving young (2-month-old) and older (5-month-old) Tg and non-transgenic (nTg) mice. EEG spectra were analyzed for 30 min before and for 60 min after systemic injection of a DA mimetic, apomorphine (APO), and saline. Results: In young Tg versus nTg mice, baseline EEG spectra in M1 were comparable, whereas in Pt, beta activity in Tg mice was enhanced. In older Tg versus nTg mice, beta dominated in EEG from both M1 and Pt, whereas theta and delta 2 activities were reduced. In younger Tg versus nTg mice, APO increased theta and decreased beta 2 predominantly in M1. In older mice, APO effects in these frequency bands were inversed and accompanied by enhanced delta 2 and attenuated alpha in Tg versus nTg mice. Conclusion: We suggest that revealed EEG modifications in ΔFUS(1–359)-transgenic mice are associated with early alterations in the striatum-cortex interrelations and DA transmission followed by adaptive intracerebral transformations.

scholarly journals Subcortical circuits mediate communication between primary sensory cortical areas in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael Lohse ◽  
Johannes C. Dahmen ◽  
Victoria M. Bajo ◽  
Andrew J. King
Keyword(s):  
Cortical Neurons ◽  
Common Property ◽  
Primary Auditory Cortex ◽  
Facilitatory Effect ◽  
Thalamic Nuclei ◽  
Auditory Midbrain ◽  
Cortical Areas ◽  
Auditory Responses ◽  
Evoked Activity

AbstractIntegration of information across the senses is critical for perception and is a common property of neurons in the cerebral cortex, where it is thought to arise primarily from corticocortical connections. Much less is known about the role of subcortical circuits in shaping the multisensory properties of cortical neurons. We show that stimulation of the whiskers causes widespread suppression of sound-evoked activity in mouse primary auditory cortex (A1). This suppression depends on the primary somatosensory cortex (S1), and is implemented through a descending circuit that links S1, via the auditory midbrain, with thalamic neurons that project to A1. Furthermore, a direct pathway from S1 has a facilitatory effect on auditory responses in higher-order thalamic nuclei that project to other brain areas. Crossmodal corticofugal projections to the auditory midbrain and thalamus therefore play a pivotal role in integrating multisensory signals and in enabling communication between different sensory cortical areas.

scholarly journals Biofilm Lithography enables high-resolution cell patterning via optogenetic adhesin expression

2018 ◽  
Vol 115 (14) ◽  
pp. 3698-3703 ◽  
Author(s):  
Xiaofan Jin ◽  
Ingmar H. Riedel-Kruse
Keyword(s):  
Escherichia Coli ◽  
Cell Patterning ◽  
Biophysical Model ◽  
Microbial Consortia ◽  
Bacterial Biofilms ◽  
Surface Pretreatment ◽  
Resolution Cell ◽  
Stimulation Of

Bacterial biofilms represent a promising opportunity for engineering of microbial communities. However, our ability to control spatial structure in biofilms remains limited. Here we engineerEscherichia coliwith a light-activated transcriptional promoter (pDawn) to optically regulate expression of an adhesin gene (Ag43). When illuminated with patterned blue light, long-term viable biofilms with spatial resolution down to 25 μm can be formed on a variety of substrates and inside enclosed culture chambers without the need for surface pretreatment. A biophysical model suggests that the patterning mechanism involves stimulation of transiently surface-adsorbed cells, lending evidence to a previously proposed role of adhesin expression during natural biofilm maturation. Overall, this tool—termed “Biofilm Lithography”—has distinct advantages over existing cell-depositing/patterning methods and provides the ability to grow structured biofilms, with applications toward an improved understanding of natural biofilm communities, as well as the engineering of living biomaterials and bottom–up approaches to microbial consortia design.

scholarly journals Adaptive Integration in the Visual Cortex by Depressing Recurrent Cortical Circuits

2008 ◽  
Vol 20 (7) ◽  
pp. 1847-1872 ◽  
Author(s):  
Mark C. W. van Rossum ◽  
Matthijs A. A. van der Meer ◽  
Dengke Xiao ◽  
Mike W. Oram
Keyword(s):  
Visual Cortex ◽  
Physiological Data ◽  
High Contrast ◽  
Cortical Circuits ◽  
Response Latencies ◽  
Low Contrast ◽  
Visual Areas ◽  
Higher Visual Areas ◽  
Recurrent Connections

Neurons in the visual cortex receive a large amount of input from recurrent connections, yet the functional role of these connections remains unclear. Here we explore networks with strong recurrence in a computational model and show that short-term depression of the synapses in the recurrent loops implements an adaptive filter. This allows the visual system to respond reliably to deteriorated stimuli yet quickly to high-quality stimuli. For low-contrast stimuli, the model predicts long response latencies, whereas latencies are short for high-contrast stimuli. This is consistent with physiological data showing that in higher visual areas, latencies can increase more than 100 ms at low contrast compared to high contrast. Moreover, when presented with briefly flashed stimuli, the model predicts stereotypical responses that outlast the stimulus, again consistent with physiological findings. The adaptive properties of the model suggest that the abundant recurrent connections found in visual cortex serve to adapt the network's time constant in accordance with the stimulus and normalizes neuronal signals such that processing is as fast as possible while maintaining reliability.

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