Nous sommes remercier les personnes suivantes pour leur soutien: des bourses du Commonwealth du Royaume-Uni Commission de financement (HP), l&#39;EPSRC (HP), le BBSRC (NPF) et l&#39;Union européenne Actions Marie Curie (NPF).

<ol>
	<li>O'Donnell, C., Nolan, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tuning+of+synaptic+responses:+an+organizing+principle+for+optimization+of+neural+circuits.">Tuning of synaptic responses: an organizing principle for optimization of neural circuits.</a> Trends Neurosci. 34, 51-60 (2011).</li><li>Garden, D. L. F., Dodson, P. D., O'Donnell, C., White, M. D., Nolan, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tuning+of+synaptic+integration+in+the+medial+entorhinal+cortex+to+the+organization+of+grid+cell+firing+fields.">Tuning of synaptic integration in the medial entorhinal cortex to the organization of grid cell firing fields.</a> Neuron. 60, 875-889 (2008).</li><li>Kuba, H., Yamada, R., Fukui, I., Ohmori, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tonotopic+specialization+of+auditory+coincidence+detection+in+nucleus+laminaris+of+the+chick.">Tonotopic specialization of auditory coincidence detection in nucleus laminaris of the chick.</a> Journal of Neuroscience. 25, 1924-1934 (2005).</li><li>Hafting, T., Fyhn, M., Molden, S., Moser, M. -. B., Moser, E. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microstructure+of+a+spatial+map+in+the+entorhinal+cortex.">Microstructure of a spatial map in the entorhinal cortex.</a> Nature. 436, 801-806 (2005).</li><li>Sargolini, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conjunctive+representation+of+position,+direction,+and+velocity+in+entorhinal+cortex.">Conjunctive representation of position, direction, and velocity in entorhinal cortex.</a> Science. 312, 758-762 (2006).</li><li>Fyhn, M., Hafting, T., Witter, M. P., Moser, E. I., Moser, M. -. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Grid+cells+in+mice.">Grid cells in mice.</a> Hippocampus. 18, 1230-1238 (2008).</li><li>Giocomo, L. M., Zilli, E. A., Frans&#233;n, E., Hasselmo, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+frequency+of+subthreshold+oscillations+scales+with+entorhinal+grid+cell+field+spacing.">Temporal frequency of subthreshold oscillations scales with entorhinal grid cell field spacing.</a> Science. 315, 1719-1722 (2007).</li><li>Giocomo, L. M., Hasselmo, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Time+constants+of+h+current+in+layer+II+stellate+cells+differ+along+the+dorsal+to+ventral+axis+of+medial+entorhinal+cortex.">Time constants of h current in layer II stellate cells differ along the dorsal to ventral axis of medial entorhinal cortex.</a> Journal of Neuroscience. 28, 9414-9425 (2008).</li><li>Burgalossi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microcircuits+of+functionally+identified+neurons+in+the+rat+medial+entorhinal+cortex.">Microcircuits of functionally identified neurons in the rat medial entorhinal cortex.</a> Neuron. 70, 773-786 (2011).</li><li>Dodson, P. D., Pastoll, H., Nolan, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dorsal-ventral+organization+of+theta-like+activity+intrinsic+to+entorhinal+stellate+neurons+is+mediated+by+differences+in+stochastic+current+fluctuations.">Dorsal-ventral organization of theta-like activity intrinsic to entorhinal stellate neurons is mediated by differences in stochastic current fluctuations.</a> J. Physiol. (Lond). 589, 2993-3008 (2011).</li><li>Nolan, M., Dudman, J., Dodson, P., Santoro, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HCN1+channels+control+resting+and+active+integrative+properties+of+stellate+cells+from+layer+II+of+the+entorhinal+cortex.">HCN1 channels control resting and active integrative properties of stellate cells from layer II of the entorhinal cortex.</a> Journal of Neuroscience. 27, (2007).</li><li>Boehlen, A., Heinemann, U., Erchova, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+range+of+intrinsic+frequencies+represented+by+medial+entorhinal+cortex+stellate+cells+extends+with+age.">The range of intrinsic frequencies represented by medial entorhinal cortex stellate cells extends with age.</a> Journal of Neuroscience. 30, 4585-4589 (2010).</li><li>Klink, R., Alonso, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphological+characteristics+of+layer+II+projection+neurons+in+the+rat+medial+entorhinal+cortex.">Morphological characteristics of layer II projection neurons in the rat medial entorhinal cortex.</a> Hippocampus. 7, 571-583 (1997).</li><li>van Groen, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Entorhinal+cortex+of+the+mouse:+cytoarchitectonical+organization.">Entorhinal cortex of the mouse: cytoarchitectonical organization.</a> Hippocampus. 11, 397-407 (2001).</li><li>Dolorfo, C. L., Amaral, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Entorhinal+cortex+of+the+rat:+organization+of+intrinsic+connections.">Entorhinal cortex of the rat: organization of intrinsic connections.</a> The Journal of Comparative Neurology. 398, 49-82 (1998).</li></ol>

Rien de divulguer.

Pour faciliter les enquêtes sur les propriétés du circuit de MEC qui suivent une organisation dorso-ventrale, nous avons décrit ici en détail une procédure pour la production d&#39;une préparation de tranches parasagittale qui préserve la mesure dorso-ventrale de la MEC. Les étapes critiques Retrait du cerveau de l&#39;animal. Prenez un soin particulier pour éviter d&#39;exercer des pressions sur le cerveau. Ceci est plus important que le ...

<table border="1"><tbody><tr><td></td><td> Coupe ACSF (mM) </td><td> Norme ACSF (mM) </td><td> Solution interne (mM) </td><td> CASNumber </td><td> Numéro de catalogue fournisseur </td></tr><tr><td> NaCl </td><td> 86 </td><td> 124 </td><td></td><td> 7647-14-5 </td><td> Sigma S9888 </td></tr><tr><td> NaH 2 PO 4 </td><td> 1.2 </td><td> 1.2 </td><td></td><td> 13472-35-0 </td><td> Sigma 71505 </td></tr><tr><td> KCl </td><td> 2.5 </td><td> 2.5 </td><td> 10 </td><td> 7447-40-7 </td><td> Sigma P3911 </td></tr><tr><td> NaHCO 3 </td><td> 25 </td><td> 25 </td><td></td><td> 144-55-8 </td><td> Fischer S/4240 </td></tr><tr><td> Glucose </td><td> 25 </td><td> 20 </td><td></td><td> 50-99-7 </td><td> Sigma G5767 </td></tr><tr><td> Saccharose </td><td> 75 </td><td></td><td></td><td> 57-50-1 </td><td> Sigma S5016 </td></tr><tr><td> CalifornieCl 2 </td><td> 0.5 </td><td> 2 </td><td></td><td> 10043-52-4 </td><td> VWR 190464K </td></tr><tr><td> MgCl 2 </td><td> 7 </td><td> 1 </td><td> 2 </td><td> 7786-30-3 </td><td> Sigma 63020 </td></tr><tr><td> K gluconate </td><td></td><td></td><td> 130 </td><td> 299-27-4 </td><td> Sigma G4500 </td></tr><tr><td> HEPES </td><td></td><td></td><td> 10 </td><td> 7365-45-9 </td><td> Sigma H3375 </td></tr><tr><td> EGTA </td><td></td><td></td><td> 0.1 </td><td> 67-42-5 </td><td> Sigma E4378 </td></tr><tr><td> Na 2 ATP </td><td></td><td></td><td> 2 </td><td> 34369-07-8 </td><td> Sigma A7699 </td></tr><tr><td> Na 2 GTP </td><td></td><td></td><td> 0.3 </td><td> 36051-31-7 </td><td> Sigma G8877 </td></tr><tr><td> NaPhospho-Créatine </td><td></td><td></td><td> 10 </td><td> 19333-65-4 </td><td> Sigma P7936 </td></tr><tr><td> Biocytine (facultatif) </td><td></td><td></td><td> 2.7 </td><td> 576-19-2 </td><td&gt; Sigma B4261 </td></tr></tbody></table> Tableau 1. Coupe ACSF, standard ACSF et K-gluconate recettes solution interne.

preparation of parasagittal slices for the investigation of dorsal-ventral organization of the rodent medial entorhinal cortex

Calcul dans le cerveau repose sur les neurones en répondant correctement à leurs entrées synaptiques. Les neurones se différencient par leur complément et la distribution des canaux ioniques membranaires qui déterminent la façon dont ils réagissent aux entrées synaptiques. Cependant, la relation entre ces propriétés cellulaires et la fonction neuronale à se comporter animaux n&#39;est pas bien comprise. Une approche de ce problème est d&#39;étudier la topographie des circuits neuronaux organisés dans lequel la position des cartes de neurones individuels sur les informations qu&#39;ils codent ou calculs qu&#39;ils effectuent 1. Des expériences utilisant cette approche suggèrent des principes pour le réglage des réponses synaptiques qui sous-tendent codage de l&#39;information dans les circuits sensoriels et cognitifs 2,3. L&#39;organisation topographique des représentations spatiales le long de l&#39;axe dorso-ventral de l&#39;médial cortex entorhinal (MEC) fournit une occasion d&#39;établir des relations entre les mécanismes cellulaires et des calculs important pour la cognition spatiale. Les neurones de la couche II de la MEC rongeurs coder emplacement à l&#39;aide en forme de grille de cuisson champs 4-6. Pour les neurones à des positions trouvées dans la MEC dorsale de la distance entre les champs de tir individuels qui forment une grille est de l&#39;ordre de 30 cm, tandis que pour les neurones à des positions progressivement plus ventrales cette distance augmente à plus de 1 m. Plusieurs études ont révélé des propriétés cellulaires de neurones dans la couche II de la MEC qui, comme l&#39;espacement entre les champs de la grille de cuisson, diffèrent également en fonction de leur position de dorso-ventral, ce qui suggère que ces propriétés cellulaires sont importantes pour le calcul spatiale 2,7-10. Nous décrivons ici les procédures de préparation et d&#39;enregistrement électrophysiologique de tranches de cerveau qui maintiennent la mesure dorso-ventral de l&#39;enquête de MEC permettant de l&#39;organisation topographique des propriétés biophysiques et anatomique des neurones de MEC. La position dorso-ventral de n identifiéeurons par rapport à des repères anatomiques est difficile d&#39;établir avec précision les protocoles qui utilisent des tranches horizontales de MEC 7,8,11,12, car il est difficile d&#39;établir des points de référence pour l&#39;exacte dorso-ventral emplacement de la tranche. Les procédures que nous décrivons permettent une mesure précise et cohérente de la localisation des cellules enregistrées le long de l&#39;axe dorso-ventral de la MEC ainsi que la visualisation des gradients moléculaires 2,10. Les procédures ont été élaborées pour une utilisation avec des souris adultes (&gt; 28 jours) et ont été employées avec succès sur des souris jusqu&#39;à 1,5 ans. Avec les ajustements qu&#39;ils pourraient être utilisés avec de jeunes souris ou d&#39;autres espèces de rongeurs. Un système normalisé de préparation et de mesure aidera investigation systématique des propriétés cellulaires et microcircuit de cette région.

Watch this Scientific Journal Video about Preparation of Parasagittal Slices for the Investigation of Dorsal-ventral Organization of the Rodent Medial Entorhinal Cortex at JoVE.com

Preparation of Parasagittal Slices for the Investigation of Dorsal-ventral Organization of the Rodent Medial Entorhinal Cortex

Nous décrivons les procédures de préparation et d&#39;enregistrement électrophysiologique de tranches de cerveau qui maintiennent l&#39;axe dorso-ventral de l&#39;médial cortex entorhinal (MEC). Parce que le codage neuronal de l&#39;emplacement suit une organisation dorso-ventrale au sein de la MEC, ces procédures de faciliter les enquêtes des mécanismes cellulaires importants pour la navigation et de la mémoire.

Préparation des tranches de parasagittales d&#39;enquête sur les dorso-ventrale de l&#39;Organisation des rongeurs cortex entorhinal médian

Computation in the brain relies on neurons responding appropriately to their synaptic inputs. Neurons differ in their complement and distribution of ...

preparation-parasagittal-slices-for-investigation-dorsal-ventral

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Neuroscience

15.5K vues.  University of Edinburgh. Nous décrivons les procédures de préparation et d'enregistrement électrophysiologique de tranches de cerveau qui maintiennent l'axe dorso-ventral de l'médial cortex entorhinal (MEC). Parce que le codage neuronal de l'emplacement suit une organisation dorso-ventrale au sein de la MEC, ces procédures de faciliter les enquêtes des mécanismes cellulaires importants pour la navigation et de la mémoire.

Vidéo: Preparation of Parasagittal Slices for the Investigation of Dorsal-ventral Organization of the Rodent Medial Entorhinal Cortex

Brain Imaging Investigation of the Neural Correlates of Emotion Regulation

The ability to control/regulate emotions is an important coping mechanism in the face of emotionally stressful situations. Although significant progress has been made in understanding conscious/deliberate emotion regulation (ER), less is known about non-conscious/automatic ER and the associated neural correlates. This is in part due to the problems inherent in the unitary concepts of automatic and conscious processing1. Here, we present a protocol that allows investigation of the neural correlates of both deliberate and automatic ER using functional magnetic resonance imaging (fMRI). This protocol allows new avenues of inquiry into various aspects of ER. For instance, the experimental design allows manipulation of the goal to regulate emotion (conscious vs. non-conscious), as well as the intensity of the emotional challenge (high vs. low). Moreover, it allows investigation of both immediate (emotion perception) and long-term effects (emotional memory) of ER strategies on emotion processing. Therefore, this protocol may contribute to better understanding of the neural mechanisms of emotion regulation in healthy behaviour, and to gaining insight into possible causes of deficits in depression and anxiety disorders in which emotion dysregulation is often among the core debilitating features.

We present a protocol that allows investigation of the neural correlates of deliberate and automatic emotion regulation, using functional magnetic resonance imaging. This protocol can be used in healthy participants, both young and older, as well as in clinical patients.

Investigation d&#39;imagerie cérébrale de les corrélats neuraux de régulation des émotions

The ability to control/regulate emotions is an important coping mechanism in the face of emotionally stressful situations. Although significant progress ...

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Neurosciences

Brain Imaging Investigation of the Memory-Enhancing Effect of Emotion

Emotional events tend to be better remembered than non-emotional events1,2. One goal of cognitive and affective neuroscientists is 
to understand the neural mechanisms underlying this enhancing effect of emotion on memory. A method that has proven particularly influential in the 
investigation of the memory-enhancing effect of emotion is the so-called subsequent memory paradigm (SMP). This method was originally used to investigate the 
neural correlates of non-emotional memories3, and more recently we and others also applied it successfully to studies of emotional memory (reviewed in4, 5-7). 
Here, we describe a protocol that allows investigation of the neural correlates of the memory-enhancing effect of emotion using the SMP in conjunction with 
event-related functional magnetic resonance imaging (fMRI). An important feature of the SMP is that it allows separation of brain activity specifically 
associated with memory from more general activity associated with perception. Moreover, in the context of investigating the impact of emotional stimuli, 
SMP allows identification of brain regions whose activity is susceptible to emotional modulation of both general/perceptual and memory-specific processing. 
This protocol can be used in healthy subjects8-15, as well as in clinical patients where there are alterations in the neural correlates of emotion perception 
and biases in remembering emotional events, such as those suffering from depression and post-traumatic stress disorder (PTSD)16, 17.

We present a protocol that uses functional magnetic resonance imaging to investigate the neural correlates of the memory-enhancing effect of emotion. This protocol allows identification of brain activity specifically linked to memory-related processing, contrary to more general perceptual processing, and can be used with healthy and clinical populations.

Investigation d&#39;imagerie cérébrale de l&#39;effet de mémoire-Amélioration de l&#39;émotion

Emotional events tend to be better remembered than non-emotional events1,2. One goal of cognitive and affective neuroscientists is 
to understand the ...

Simultaneous Electroencephalography, Real-time Measurement of Lactate Concentration and Optogenetic Manipulation of Neuronal Activity in the Rodent Cerebral Cortex

Although the brain represents less than 5% of the body by mass, it utilizes approximately one quarter of the glucose used by the body at rest1. The function of non rapid eye movement sleep (NREMS), the largest portion of sleep by time, is uncertain. However, one salient feature of NREMS is a significant reduction in the rate of cerebral glucose utilization relative to wakefulness2-4. This and other findings have led to the widely held belief that sleep serves a function related to cerebral metabolism. Yet, the mechanisms underlying the reduction in cerebral glucose metabolism during NREMS remain to be elucidated.
	One phenomenon associated with NREMS that might impact cerebral metabolic rate is the occurrence of slow waves, oscillations at frequencies less than 4 Hz, in the electroencephalogram5,6. These slow waves detected at the level of the skull or cerebral cortical surface reflect the oscillations of underlying neurons between a depolarized/up state and a hyperpolarized/down state7. During the down state, cells do not undergo action potentials for intervals of up to several hundred milliseconds. Restoration of ionic concentration gradients subsequent to action potentials represents a significant metabolic load on the cell8; absence of action potentials during down states associated with NREMS may contribute to reduced metabolism relative to wake.
	Two technical challenges had to be addressed in order for this hypothetical relationship to be tested. First, it was necessary to measure cerebral glycolytic metabolism with a temporal resolution reflective of the dynamics of the cerebral EEG (that is, over seconds rather than minutes). To do so, we measured the concentration of lactate, the product of aerobic glycolysis, and therefore a readout of the rate of glucose metabolism in the brains of mice. Lactate was measured using a lactate oxidase based real time sensor embedded in the frontal cortex. The sensing mechanism consists of a platinum-iridium electrode surrounded by a layer of lactate oxidase molecules. Metabolism of lactate by lactate oxidase produces hydrogen peroxide, which produces a current in the platinum-iridium electrode. So a ramping up of cerebral glycolysis provides an increase in the concentration of substrate for lactate oxidase, which then is reflected in increased current at the sensing electrode. It was additionally necessary to measure these variables while manipulating the excitability of the cerebral cortex, in order to isolate this variable from other facets of NREMS.
	We devised an experimental system for simultaneous measurement of neuronal activity via the elecetroencephalogram, measurement of glycolytic flux via a lactate biosensor, and manipulation of cerebral cortical neuronal activity via optogenetic activation of pyramidal neurons. We have utilized this system to document the relationship between sleep-related electroencephalographic waveforms and the moment-to-moment dynamics of lactate concentration in the cerebral cortex. The protocol may be useful for any individual interested in studying, in freely behaving rodents, the relationship between neuronal activity measured at the electroencephalographic level and cellular energetics within the brain.

A procedure is described for manipulating the activity of cerebral cortical pyramidal neurons optogenetically while the electroencephalogram, electromyogram, and cerebral lactate concentration are monitored. Experimental recordings are performed on cable-tethered mice while they undergo spontaneous sleep/wake cycles. Optogenetic equipment is assembled in our laboratory; recording equipment is commercially available.

Électroencéphalographie simultanée, en temps réel Mesure de la concentration de lactate et manipulation optogenetic de l&#39;activité neuronale dans le cortex cérébral des rongeurs

Although the brain represents less than 5% of the body  by mass, it utilizes approximately one quarter of the glucose used by the body  at rest1. The ...

A Comprehensive Protocol for Manual Segmentation of the Medial Temporal Lobe Structures

The present paper describes a comprehensive protocol for manual tracing of the set of brain regions comprising the medial temporal lobe (MTL): amygdala, hippocampus, and the associated parahippocampal regions (perirhinal, entorhinal,&#160;and parahippocampal proper). Unlike most other tracing protocols available, typically focusing on certain MTL areas (e.g., amygdala and/or hippocampus), the integrative perspective adopted by the present tracing guidelines allows for clear localization of all MTL subregions. By integrating information from a variety of sources, including extant tracing protocols separately targeting various MTL structures, histological reports, and brain atlases, and with the complement of illustrative visual materials, the present protocol provides an accurate, intuitive, and convenient guide for understanding the MTL anatomy. The need for such tracing guidelines is also emphasized by illustrating possible differences between automatic and manual segmentation protocols. This knowledge can be applied toward research involving not only structural MRI investigations but also structural-functional colocalization and fMRI signal extraction from anatomically defined ROIs, in healthy and clinical groups alike.

The present work provides a comprehensive set of guidelines for manually tracing the medial temporal lobe (MTL) structures. This protocol can be applied to research involving structural and/or combined structural-functional magnetic resonance imaging (MRI) investigations of the MTL, in both healthy and clinical groups.

Un protocole complet pour la segmentation manuelle des structures du lobe temporal médial

The present paper describes a comprehensive protocol for manual tracing of the set of brain regions comprising the medial temporal lobe (MTL): amygdala, ...

Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method

This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation.

Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method

This protocol demonstrates the implementation of an optimized N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. A single media formulation is used to reliably obtain healthy brain slices from animals of any age and for diverse experimental applications.

Préparation de tranches de cerveau aiguë en utilisant un optimisé N-méthyl-D-glucamine méthode de recouvrement protecteur

This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have ...

The Preparation of Oblique Spinal Cord Slices for Ventral Root Stimulation

Electrophysiological recordings from spinal cord slices have proven to be a valuable technique to investigate a wide range of questions, from cellular to network properties. We show how to prepare viable oblique slices of the spinal cord of young mice (P2 - P11). In this preparation, the motoneurons retain&#160;their axons coming out from the ventral roots of the&#160;spinal cord. Stimulation of these axons elicits back-propagating action potentials invading the motoneuron&#160;somas and exciting the motoneuron&#160;collaterals within the spinal cord. Recording of antidromic action potentials is an immediate, definitive and elegant way to characterize motoneuron identity, which surpasses&#160;other identification methods. Furthermore, stimulating the motoneuron collaterals is a simple and reliable way to excite the collateral targets of the motoneurons within the spinal cord, such as other motoneurons or Renshaw cells. In this protocol, we present antidromic recordings from the motoneuron somas as well as Renshaw cell excitation, resulting from ventral root stimulation.

We show how to prepare oblique slices of the spinal cord in young mice. This preparation allows for the stimulation of the ventral roots.

La Préparation de la moelle épinière Oblique tranches pour ventral Racine Stimulation

Electrophysiological recordings from spinal cord slices have proven to be a valuable technique to investigate a wide range of questions, from cellular to ...

Effects of Transcranial Alternating Current Stimulation on the Primary Motor Cortex by Online Combined Approach with Transcranial Magnetic Stimulation

Transcranial Alternating Current Stimulation (tACS) is a neuromodulatory technique able to act through sinusoidal electrical waveforms in a specific frequency and in turn modulate ongoing cortical oscillatory activity. This neurotool allows the establishment of a causal link between endogenous oscillatory activity and behavior. Most of the tACS studies have shown online effects of tACS. However, little is known about the underlying action mechanisms of this technique because of the AC-induced artifacts on Electroencephalography (EEG) signals. Here we show a unique approach to investigate online physiological frequency-specific effects of tACS of the primary motor cortex (M1) by using single pulse Transcranial Magnetic Stimulation (TMS) to probe cortical excitability changes. In our setup, the TMS coil is placed over the tACS electrode while Motor Evoked Potentials (MEPs) are collected to test the effects of the ongoing M1-tACS. So far, this approach has mainly been used to study the visual and motor systems. However, the current tACS-TMS setup can pave the way for future investigations of cognitive functions. Therefore, we provide a step-by-step manual and video guidelines for the procedure.

Transcranial Alternating Current Stimulation (tACS) allows the modulation of cortical excitability in a frequency-specific fashion. Here we show a unique approach which combines online tACS with single pulse Transcranial Magnetic Stimulation (TMS) in order to "probe" cortical excitability by means of Motor Evoked Potentials.

Effets de la Stimulation transcrânienne courant alternatif sur le Cortex moteur primaire par en ligne approche combinée avec la Stimulation magnétique transcrânienne

Transcranial Alternating Current Stimulation (tACS) is a neuromodulatory technique able to act through sinusoidal electrical waveforms in a specific ...

Evaluation of Synapse Density in Hippocampal Rodent Brain Slices

In the brain, synapses are specialized junctions between neurons, determining the strength and spread of neuronal signaling. The number of synapses is tightly regulated during development and neuronal maturation. Importantly, deficits in synapse number can lead to cognitive dysfunction. Therefore, the evaluation of synapse number is an integral part of neurobiology. However, as synapses are small and highly compact in the intact brain, the assessment of absolute number is challenging. This protocol describes a method to easily identify and evaluate synapses in hippocampal rodent slices using immunofluorescence microscopy. It includes a three-step procedure to evaluate synapses in high-quality confocal microscopy images by analyzing the co-localization of pre- and postsynaptic proteins in hippocampal slices. It also explains how the analysis is performed and gives representative examples from both excitatory and inhibitory synapses. This protocol provides a solid foundation for the analysis of synapses and can be applied to any research investigating the structure and function of the brain.

A protocol for accurately identifying and analyzing synapses in hippocampal slices using immunofluorescence is outlined in this article.

Évaluation de la densité de la Synapse dans des tranches de cerveau de rongeurs hippocampe

In the brain, synapses are specialized junctions between neurons, determining the strength and spread of neuronal signaling. The number of synapses is ...

Combined Transcranial Magnetic Stimulation and Electroencephalography of the Dorsolateral Prefrontal Cortex

Transcranial magnetic stimulation (TMS) is a non-invasive method that produces neural excitation in the cortex by means of brief, time-varying magnetic field pulses. The initiation of cortical activation or its modulation depends on the background activation of the neurons of the cortical region activated, the characteristics of the coil, its position and its orientation with respect to the head. TMS combined with simultaneous electrocephalography (EEG) and neuronavigation (nTMS-EEG) allows for the assessment of cortico-cortical excitability and connectivity in almost all cortical areas in a reproducible manner. This advance makes nTMS-EEG a powerful tool that can accurately assess brain dynamics and neurophysiology in test-retest paradigms that are required for clinical trials. Limitations of this method include artifacts that cover the initial brain reactivity to stimulation. Thus, the process of removing artifacts may also extract valuable information. Moreover, the optimal parameters for dorsolateral prefrontal (DLPFC) stimulation are not fully known and current protocols utilize variations from the motor cortex (M1) stimulation paradigms. However, evolving nTMS-EEG designs hope to address these issues. The protocol presented here introduces some standard practices for assessing neurophysiological functioning from stimulation to the DLPFC that can be applied in patients with treatment resistant psychiatric disorders that receive treatment such as transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), magnetic seizure therapy (MST) or electroconvulsive therapy (ECT).

The protocol presented here is for TMS-EEG studies utilizing intracortical excitability test-retest design paradigms. The intent of the protocol is to produce reliable and reproducible cortical excitability measures for assessing neurophysiological functioning related to therapeutic interventions in the treatment of neuropsychiatric diseases such as major depression.

La Stimulation magnétique transcrânienne combinée et électroencéphalographie du Cortex préfrontal dorsolatéral

Transcranial magnetic stimulation (TMS) is a non-invasive method that produces neural excitation in the cortex by means of brief, time-varying magnetic ...

Preparation of Rhythmically-active In Vitro Neonatal Rodent Brainstem-spinal Cord and Thin Slice

Mammalian inspiratory rhythm is generated from a neuronal network in a region of the medulla called the preB&#246;tzinger complex (pBC), which produces a signal driving the rhythmic contraction of inspiratory muscles. Rhythmic neural activity generated in the pBC and carried to other neuronal pools to drive the musculature of breathing may be studied using various approaches, including en bloc nerve recordings and transverse slice recordings. However, previously published methods have not extensively described the brainstem-spinal cord dissection process in a transparent and reproducible manner for future studies. Here, we present a comprehensive overview of a method used to reproducibly cut rhythmically-active brainstem slices containing the necessary and sufficient neuronal circuitry for generating and transmitting inspiratory drive. This work builds upon previous brainstem-spinal cord electrophysiology protocols to enhance the likelihood of reliably obtaining viable and rhythmically-active slices for recording neuronal output from the pBC, hypoglossal premotor neurons (XII pMN), and hypoglossal motor neurons (XII MN). The work presented expands upon previous published methods by providing detailed, step-by-step illustrations of the dissection, from whole rat pup, to in vitro slice containing the XII rootlets.

This protocol both visually communicates the brainstem-spinal cord preparation and clarifies the preparation of brainstem transverse slices in a comprehensive step-by-step manner. It was designed to increase reproducibility and enhance the likelihood of obtaining viable, long lasting, rhythmically-active slices for recording neural output from the respiratory regions of the brainstem.

Préparation de rythmiquement actifs In Vitro néonatale rongeurs tronc cérébral-moelle épinière et fine tranche

Mammalian inspiratory rhythm is generated from a neuronal network in a region of the medulla called the preB&#246;tzinger complex (pBC), which produces a ...