Absence of a Prevalent Laminar Distribution of IPSPs in Association Cortical Neurons of Cat

1997 ◽  
Vol 78 (5) ◽  
pp. 2742-2753 ◽  
Author(s):  
Diego Contreras ◽  
Niklaus Dürmüller ◽  
Mircea Steriade
Keyword(s):  
Cortical Neurons ◽  
Feedback Inhibition ◽  
Anterior Part ◽  
Cortical Stimulation ◽  
Association Cortex ◽  
Postsynaptic Potentials ◽  
Thalamic Stimulation ◽  
Laminar Distribution ◽  
Deep Layers

Contreras, Diego, Niklaus Dürmüller, and Mircea Steriade. Absence of a prevalent laminar distribution of IPSPs in association cortical neurons of cat. J. Neurophysiol. 78: 2742–2753, 1997. The depth distribution of inhibitory postsynaptic potentials (IPSPs) was studied in cat suprasylvian (association) cortex in vivo. Single and dual simultaneous intracellular recordings from cortical neurons were performed in the anterior part of suprasylvian gyrus (area 5). Synaptic responses were obtained by stimulating the suprasylvian cortex, 2–3 mm anterior to the recording site, as well as the thalamic lateral posterior (LP) nucleus. Neurons were recorded from layers 2 to 6 and were classified as regular spiking (RS, n = 132), intrinsically bursting (IB, n = 24), and fast spiking (FS, n = 4). Most IB cells were located in deep layers (below 0.7 mm, n = 19), but we also found some IB cells more superficially (between 0.2 and 0.5 mm, n = 5). Deeply lying corticothalamic neurons were identified by their antidromic invasion on thalamic stimulation. Neurons responded with a combination of excitatory postsynaptic potentials (EPSPs) and IPSPs to both cortical and thalamic stimulation. No consistent relation was found between cell type or cell depth and the amplitude or duration of the IPSPs. In response to thalamic stimulation, RS cells had IPSPs of 7.9 ± 0.9 (SE) mV amplitude and 88.9 ± 6.4 ms duration. In IB cells, IPSPs elicited by thalamic stimulation had 7.4 ± 1.3 mV amplitude and 84.7 ± 14.3 ms duration. The differences between the two (RS and IB) groups were not statistically significant. Compared with thalamically elicited inhibitory responses, cortical stimulation evoked IPSPs with higher amplitude (12.3 ± 1.7 mV) and longer duration (117 ± 17.3 ms) at all depths. Both cortically and thalamically evoked IPSPs were predominantly monophasic. Injections of Cl− fully reversed thalamically as well as cortically evoked IPSPs and revealed additional late synaptic components in response to cortical stimulation. These data show that the amount of feed forward and feedback inhibition to cat's cortical association cells is not orderly distributed to distinct layers. Thus local cortical microcircuitry goes beyond the simplified structure determined by cortical layers.

Dynamics of the orientation tuning of postsynaptic potentials in the cat visual cortex

1995 ◽  
Vol 12 (4) ◽  
pp. 621-628 ◽  
Author(s):  
M. Volgushev ◽  
T.R. Vidyasagar ◽  
Xing Pei
Keyword(s):  
Cortical Neurons ◽  
Stimulus Presentation ◽  
Stimulus Onset ◽  
Temporal Coding ◽  
Orientation Tuning ◽  
Integration Time ◽  
Cortical Cells ◽  
Postsynaptic Potentials ◽  
Temporal Windows

AbstractWe evaluated the dynamic aspects of the orientation tuning of the input to cat visual cortical neurons by analyzing the postsynaptic potentials (PSPs) evoked by flashing bars of light. The PSPs were recorded using in vivo whole-cell technique, and we analyzed the orientation tuning during subsequent temporal windows after stimulus onset and offset. Our results show that the amplitudes of the postsynaptic potential are reliably tuned to orientation and matching that of the spike responses only during certain temporal windows. During the first 100 ms after stimulus presentation, orientation tuning of the membrane potential underwent regular changes. Within particular intervals, orientation tuning of the input was much sharper than that estimated according to the whole response. In most cells, optimal orientation was usually stable over the whole period. In several cells which had a second hump of EPSPs in the response, this second hump was tuned to the same orientation as the first one, but always showed sharper tuning. Estimation of the integration time revealed sufficient delay between the appearance of EPSPs and spikes, to let inhibition influence spike generation. These results show that orientation selectivity of the input to cortical cells is a dynamic function, and also indicate the possibility of temporal coding in the visual system.

scholarly journals Corticothalamic gating of population auditory thalamocortical transmission in mouse

2019 ◽  
Author(s):  
Baher A. Ibrahim ◽  
Caitlin Murphy ◽  
Guido Muscioni ◽  
Aynaz Taheri ◽  
Georgiy Yudintsev ◽  
...  
Keyword(s):  
Receptive Field ◽  
Auditory Cortex ◽  
Cortical Neurons ◽  
Feedback Inhibition ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Linear Filter ◽  
Sensory Stimuli

AbstractSince the discovery of the receptive field, scientists have tracked receptive field structure to gain insights about mechanisms of sensory processing. At the level of the thalamus and cortex, this linear filter approach has been challenged by findings that populations of cortical neurons respond in a stereotyped fashion to sensory stimuli. Here, we elucidate a possible mechanism by which gating of cortical representations occurs. All-or-none population responses (here called “ON” and “OFF” responses) were observed in vivo and in vitro in the mouse auditory cortex at near-threshold acoustic or electrical stimulation. ON-responses were associated with previously-described UP states in the auditory cortex. OFF-responses in the cortex were only eliminated by blocking GABAergic inhibition in the thalamus. Opto- and chemogenetic silencing of NTSR-positive corticothalamic layer 6 (CTL6) neurons as well as the pharmacological blocking of the thalamic reticular nucleus (TRN) retrieved the missing cortical responses, suggesting that the corticothalamic feedback inhibition via TRN controls the gating of thalamocortical activity. Moreover, the oscillation of the pre-stimulus activity of corticothalamic cells predicted the cortical ON vs. OFF responses, suggesting that underlying cortical oscillation controls thalamocortical gating. These data suggest that the thalamus may recruit cortical ensembles rather than linearly encoding ascending stimuli and that corticothalamic projections play a key role in selecting cortical ensembles for activation.

Intracellular Study of Excitability in the Seizure-Prone Neocortex In Vivo

1999 ◽  
Vol 82 (6) ◽  
pp. 3108-3122 ◽  
Author(s):  
Mircea Steriade ◽  
Florin Amzica
Keyword(s):  
Cortical Neurons ◽  
Control Period ◽  
Resting Membrane Potential ◽  
Postsynaptic Potentials ◽  
Inhibitory Postsynaptic Potentials ◽  
Neocortical Neurons ◽  
Slow Sleep ◽  
Intracellular Study ◽  
Spike Wave

The excitability of neocortical neurons from cat association areas 5–7 was investigated during spontaneously occurring seizures with spike-wave (SW) complexes at 2–3 Hz. We tested the antidromic and orthodromic responsiveness of neocortical neurons during the “spike” and “wave” components of SW complexes, and we placed emphasis on the dynamics of excitability changes from sleeplike patterns to seizures. At the resting membrane potential, an overwhelming majority of neurons displayed seizures over a depolarizing envelope. Cortical as well as thalamic stimuli triggered isolated paroxysmal depolarizing shifts (PDSs) that eventually developed into SW seizures. PDSs could also be elicited by cortical or thalamic volleys during the wave-related hyperpolarization of neurons, but not during the spike-related depolarization. The latencies of evoked excitatory postsynaptic potentials (EPSPs) progressively decreased, and their slope and depolarization surface increased, from the control period preceding the seizure to the climax of paroxysm. Before the occurrence of full-blown seizures, thalamic stimuli evoked PDSs arising from the postinhibitory rebound excitation, whereas cortical stimuli triggered PDSs immediately after the early EPSP. These data shed light on the differential excitability of cortical neurons during the spike and wave components of SW seizures, and on the differential effects of cortical and thalamic volleys leading to such paroxysms. We conclude that the wave-related hyperpolarization does not represent GABA-mediated inhibitory postsynaptic potentials (IPSPs), and we suggest that it is a mixture of disfacilitation and Ca2+-dependent K+ currents, similar to the prolonged hyperpolarization of the slow sleep oscillation.

scholarly journals Ex vivo and in vivo imaging of mouse parietal association cortex activity in episodes of cued fear memory formation and retrieval

2019 ◽  
Author(s):  
Olga I. Ivashkina ◽  
Anna M. Gruzdeva ◽  
Marina A. Roshchina ◽  
Ksenia A. Toropova ◽  
Konstantin V. Anokhin
Keyword(s):  
Parietal Cortex ◽  
Ex Vivo ◽  
Anterior Part ◽  
Fear Memory ◽  
Memory Formation ◽  
Movement Planning ◽  
Association Cortex ◽  
Memory Processing ◽  
Two Photon

AbstractThe parietal cortex in rodents has an integrative function and participates in sensory and spatial processing, movement planning and decision-making. However, much less is known about its functions in associative memory processing. Here using Fos immunohistochemical mapping of neuronal activity and two-photon imaging in Fos-eGFP mice we show an involvement of anterior part of the parietal cortex (PtA) in the formation and retrieval of recent fear memory in mice. Using ex vivo c-fos imaging we demonstrate the specific activation of the PtA during recent memory retrieval. In vivo two-photon c-fos imaging confirms these results as well as establishes the activation of the PtA neurons during fear memory formation. Additionally, we describe a design of Fos-Cre-GCaMP transgenic mice to investigate long-term changes of calcium dynamics in neurons captured with Fos-TRAP technique during fear conditioning training.

Electrophysiology of cat association cortical cells in vivo: intrinsic properties and synaptic responses

1993 ◽  
Vol 70 (1) ◽  
pp. 418-430 ◽  
Author(s):  
A. Nunez ◽  
F. Amzica ◽  
M. Steriade
Keyword(s):  
Action Potential ◽  
Cortical Neurons ◽  
Secondary Component ◽  
Intrinsic Properties ◽  
Postsynaptic Potentials ◽  
Current Pulses ◽  
Contralateral Cortex ◽  
Stimulation Of ◽  
Synaptic Responses

1. The intrinsic properties and synaptic responses of association cortical neurons (n = 179) recorded from cat's areas 5 and 7 were studied in vivo. Intracellular recordings were performed under urethane anesthesia. Resting membrane potential (Vm) was -71.7 +/- 1.2 (SE) mV, amplitude of action potential was 83.7 +/- 2.3 mV, and input resistance was 18.4 +/- 1.8 M omega. Cells were identified ortho- and antidromically from lateroposterior and centrolateral thalamic nuclei and from homotopic foci in the contralateral cortex. Physiologically identified neurons were intracellularly stained with Lucifer yellow (LY) and found to be pyramidal-shaped elements (n = 21). 2. We classified the neurons as regular-spiking and intrinsically bursting cells. Regular-spiking cells were further classified as slow- and fast-adapting according to the adaptation of spike frequency during long-lasting depolarizing current pulses. 3. Regular-spiking, slow-adapting neurons had a monophasic afterhyperpolarization (AHP) or a biphasic AHP with fast and medium components (FAHP, mAHP). Slow-adapting behavior was observed in 84% (n = 119) of the regular-spiking cells. 4. Regular-spiking, fast-adapting cells only fired a train of spikes at the beginning of the pulse. Thereafter, the Vm remained as a depolarizing plateau, occasionally triggering some spikes. These neurons had a monophasic AHP and represented 16% (n = 23) of the regular-spiking neurons. 5. Intrinsically bursting neurons (n = 37) were observed in 20% of neocortical cells at depolarized Vm. Their action potential was followed by a marked depolarizing afterpotential (DAP). Rhythmic (4-10 Hz) bursts occurred during long-lasting depolarizing current pulses. 6. Small (3-10 mV), fast (1.5-4 ms), all-or-none depolarizing potentials were triggered by depolarizing current pulses. They are tentatively regarded as dendritic spikes recorded from the soma because their rate of occurrence changed as a function of the Vm and they were eventually blocked by hyperpolarization. 7. Synaptic stimulation of either thalamic or homotopic contralateral cortical areas elicited a sequence of excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs). Two components of the EPSP were revealed. At a hyperpolarized Vm, the initial component of the EPSP increased in amplitude, whereas the secondary component was blocked. Repetitive (10 Hz) stimulation of the thalamus or contralateral cortex elicited incremental responses. The augmentation phenomenon was due to an increase in the secondary component of the EPSP. The cortically elicited augmenting responses survived extensive thalamic lesions. A short IPSP and a long-lasting IPSP were evoked by thalamic or cortical stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Synaptic potentials evoked in spiny neurons in rat neostriatal grafts by cortical and thalamic stimulation

1991 ◽  
Vol 65 (3) ◽  
pp. 477-493 ◽  
Author(s):  
Z. C. Xu ◽  
C. J. Wilson ◽  
P. C. Emson
Keyword(s):  
Membrane Conductance ◽  
Chloride Ions ◽  
Host Cells ◽  
Inward Rectification ◽  
Adult Rats ◽  
Postsynaptic Potentials ◽  
Thalamic Stimulation ◽  
Spiny Neurons ◽  
Synaptic Responses

1. Fetal rat striatal primordia were implanted into the neostriatum of adult rats 2 days after kainic acid lesion. Two to 6 mo after transplantation, in vivo intracellular recording and staining were performed to study the responses of spiny neurons in the grafts to the cortical and thalamic stimuli. The physiological characteristics and synaptic responses of 27 cells recorded in the grafts were compared with a sample of 23 neurons recorded from the surrounding host neostriatum in the same animals. Nineteen of the graft neurons and 19 of the host neurons were identified as spiny neurons by intracellular staining with biocytin. The responses of the remaining neurons were the same as those of identified spiny cells. 2. The spontaneous synaptically driven membrane potential shifts and long-lasting responses to afferent stimulation that are characteristic of neostriatal cells in normal animals were greatly reduced or absent in graft neurons. Presumably this reflects the reduction in synaptic input to the grafts and the lack of convergence of inputs from diverse sources. 3. Short-latency synaptic responses to cortical and thalamic stimulation were present and could consist of either excitatory postsynaptic potentials (EPSPs) or inhibitory postsynaptic potentials (IPSPs). The IPSPs were accompanied by a membrane conductance increase, and their reversal potentials could be altered by injection of chloride ions. Several minutes after impaling the cell, the IPSPs gradually disappeared, and the same stimuli could then evoke EPSPs. The disappearance of the IPSPs was independent of the presence of chloride in the electrodes. Most of the EPSP responses appeared to be monosynaptic but occurred at longer latencies than those seen in host neurons of the same type. 4. In cells not exhibiting IPSPs, or after the IPSP responses disappeared, cortical or thalamic stimulation could evoke slow depolarizing potentials and bursts of action potentials. These could not be evoked by current injection. They could be prevented or delayed by an exaggerated action potential after hyperpolarization that developed in neurons maintained in a depolarized state for several seconds, but could not be prevented by passage of hyperpolarizing current from the recording electrode. 5. The input resistance of graft spiny neurons was higher than that of the host cells, and time constants were longer. Both of these properties appeared to be due to the absence of the strong inward rectification that is usually present at resting membrane potentials in neostriatal neurons.

scholarly journals TRAF3 mediates neuronal apoptosis in early brain injury following subarachnoid hemorrhage via targeting TAK1-dependent MAPKs and NF-κB pathways

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yan Zhou ◽  
Tao Tao ◽  
Guangjie Liu ◽  
Xuan Gao ◽  
Yongyue Gao ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Brain Injury ◽  
Therapeutic Target ◽  
Cortical Neurons ◽  
Neuronal Apoptosis ◽  
Early Brain Injury ◽  
Neurological Deficits ◽  
Human Brain Tissue

AbstractNeuronal apoptosis has an important role in early brain injury (EBI) following subarachnoid hemorrhage (SAH). TRAF3 was reported as a promising therapeutic target for stroke management, which covered several neuronal apoptosis signaling cascades. Hence, the present study is aimed to determine whether downregulation of TRAF3 could be neuroprotective in SAH-induced EBI. An in vivo SAH model in mice was established by endovascular perforation. Meanwhile, primary cultured cortical neurons of mice treated with oxygen hemoglobin were applied to mimic SAH in vitro. Our results demonstrated that TRAF3 protein expression increased and expressed in neurons both in vivo and in vitro SAH models. TRAF3 siRNA reversed neuronal loss and improved neurological deficits in SAH mice, and reduced cell death in SAH primary neurons. Mechanistically, we found that TRAF3 directly binds to TAK1 and potentiates phosphorylation and activation of TAK1, which further enhances the activation of NF-κB and MAPKs pathways to induce neuronal apoptosis. Importantly, TRAF3 expression was elevated following SAH in human brain tissue and was mainly expressed in neurons. Taken together, our study demonstrates that TRAF3 is an upstream regulator of MAPKs and NF-κB pathways in SAH-induced EBI via its interaction with and activation of TAK1. Furthermore, the TRAF3 may serve as a novel therapeutic target in SAH-induced EBI.

scholarly journals Cortical neurons exhibit diverse myelination patterns that scale between mouse brain regions and regenerate after demyelination

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cody L. Call ◽  
Dwight E. Bergles
Keyword(s):  
Cortical Neurons ◽  
Regional Differences ◽  
Brain Regions ◽  
Axon Diameter ◽  
Neuronal Identity ◽  
Cortical Areas ◽  
Myelin Sheaths ◽  
Parvalbumin Interneurons ◽  
Selection Of

ABSTRACTAxons in the cerebral cortex show a broad range of myelin coverage. Oligodendrocytes establish this pattern by selecting a cohort of axons for myelination; however, the distribution of myelin on distinct neurons and extent of internode replacement after demyelination remain to be defined. Here we show that myelination patterns of seven distinct neuron subtypes in somatosensory cortex are influenced by both axon diameter and neuronal identity. Preference for myelination of parvalbumin interneurons was preserved between cortical areas with varying myelin density, suggesting that regional differences in myelin abundance arises through local control of oligodendrogenesis. By imaging loss and regeneration of myelin sheaths in vivo we show that myelin distribution on individual axons was altered but overall myelin content on distinct neuron subtypes was restored. Our findings suggest that local changes in myelination are tolerated, allowing regenerated oligodendrocytes to restore myelin content on distinct neurons through opportunistic selection of axons.

scholarly journals Machine learning-based classification of mitochondrial morphology in primary neurons and brain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Garrett M. Fogo ◽  
Anthony R. Anzell ◽  
Kathleen J. Maheras ◽  
Sarita Raghunayakula ◽  
Joseph M. Wider ◽  
...  
Keyword(s):  
Image Analysis ◽  
Cortical Neurons ◽  
Mitochondrial Dynamics ◽  
Automated Image Analysis ◽  
Mitochondrial Morphology ◽  
Analysis Pipeline ◽  
Genetic Ablation ◽  
Block Face

AbstractThe mitochondrial network continually undergoes events of fission and fusion. Under physiologic conditions, the network is in equilibrium and is characterized by the presence of both elongated and punctate mitochondria. However, this balanced, homeostatic mitochondrial profile can change morphologic distribution in response to various stressors. Therefore, it is imperative to develop a method that robustly measures mitochondrial morphology with high accuracy. Here, we developed a semi-automated image analysis pipeline for the quantitation of mitochondrial morphology for both in vitro and in vivo applications. The image analysis pipeline was generated and validated utilizing images of primary cortical neurons from transgenic mice, allowing genetic ablation of key components of mitochondrial dynamics. This analysis pipeline was further extended to evaluate mitochondrial morphology in vivo through immunolabeling of brain sections as well as serial block-face scanning electron microscopy. These data demonstrate a highly specific and sensitive method that accurately classifies distinct physiological and pathological mitochondrial morphologies. Furthermore, this workflow employs the use of readily available, free open-source software designed for high throughput image processing, segmentation, and analysis that is customizable to various biological models.

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