Electrophysiological and morphological diversity of neurons from the rat subicular complex in vitro

Prida, Liset Menéndez de la; Suárez, Francisco; Pozo, M.A.

doi:10.1002/hipo.10123

Cited by 72 publications

(82 citation statements)

References 56 publications

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“…They were blocked by AMPA receptor antagonists, reversed at depolarized potentials and were preceded by discharges in a subset of pyramidal cells near their initiation site 40 . Presumably recurrent excitatory synapses between subicular pyramidal cells are responsible 41 . The existence of distinct groups of initiating cells may explain both the contemporaneous generation of PID and IID and the weak temporal interactions between them (Suppl.…”

Section: Discussionmentioning

confidence: 99%

Glutamatergic pre-ictal discharges emerge at the transition to seizure in human epilepsy

et al. 2011

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Mechanisms involved in the transition to an epileptic seizure remain unclear. We studied this question in tissue slices from human subjects with mesial temporal lobe epilepsies. Ictal-like discharges were induced in the subiculum by increasing excitability together with an alkalinization or low Mg 2+ . During the transition, distinct pre-ictal discharges emerged concurrently with interictal events. Intracranial recordings from the mesial temporal cortex of epileptic subjects revealed similar discharges before seizures were restricted to seizure onset sites. In vitro, pre-ictal events spread faster, have a larger amplitude and a distinct initiation site than interictal discharges. They depend on glutamatergic mechanisms and are preceded by pyramidal cell firing, while interneuron firing precedes interictal events which depend on both glutamatergic and depolarizing GABAergic transmission. Once established, recurrence of these pre-ictal discharges triggers seizures. Thus the subiculum supports seizure generation and the transition to seizure involves a novel, emergent glutamatergic population activity.3

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Section: Discussionmentioning

confidence: 99%

Glutamatergic pre-ictal discharges emerge at the transition to seizure in human epilepsy

et al. 2011

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“…Bursting cells firing only one burst in response to several suprathreshold current pulses were classified as IBϪ cells, whereas those firing more than one burst were classified as IBϩ. Previous studies have shown that bursting and RS neurons are projection glutamatergic cells, whereas the FS type corresponds to inhibitory interneurons Menendez de la Prida, 2003;Menendez de la Prida et al, 2003).…”

Section: Methodsmentioning

confidence: 99%

Synaptic Contributions to Focal and Widespread Spatiotemporal Dynamics in the Isolated Rat SubiculumIn Vitro

Prida¹,

Gal²

2004

J. Neurosci.

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The subiculum, which has a strategic position in controlling hippocampal activity, is receiving significant attention in epilepsy research. However, the functional organization of subicular circuits remains unknown. Here, we combined different recording and analytical methods to study focal and widespread population activity in the isolated subiculum in zero Mg 2ϩ media. Patch and field recordings were combined to examine the contribution of different cell types to population activity. The properties of cells leading field activity were examined. Predictive factors for a cell to behave as leader included exhibiting the bursting phenotype, displaying a low firing threshold, and having more distal apical dendrites. A subset of bursting cells constituted the first glutamatergic type that led a recruitment process that subsequently activated additional excitatory as well as inhibitory cells. This defined a sequence of synaptic excitation and inhibition that was studied by measuring the associated conductance changes and the evolution of the composite reversal potential. It is shown that inhibition was time-locked to excitation, which shunted excitatory inputs and suppressed firing during focal activity. This was recorded extracellularly as a multi-unit ensemble of active cells, the spatial boundaries of which were controlled by inhibition in contrast to widespread epileptiform activity. Focal activity was not dependent on the preparation or the developmental state because it was also recorded under 5 mM [K ϩ ] o and in adult tissue. Our data indicate that the subicular networks can be spontaneously organized as leader-follower local circuits in which excitation is mainly driven by a subset of bursting cells and inhibition controls spatiotemporal firing.

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“…Pyramidal cell location within the subiculum was not related to their depolarizing or hyperpolarizing activity during population bursts. Deeper pyramidal cells of the internal pyramidal layer (n ϭ 14) had long apical dendrites spanning all layers, whereas more superficial cells of the external pyramidal layer (n ϭ 9) had shorter apical dendrites (Amaral and Insausti, 1990;Menendez de la Prida et al, 2003). The cells that were hyperpolarized during interictal-like events included five neurons in the internal pyramidal layer, six neurons in the external pyramidal layer, and two cells with apical dendrites that ramified near the soma.…”

Section: Cellular Behavior During Interictal-like Activitymentioning

confidence: 99%

Perturbed Chloride Homeostasis and GABAergic Signaling in Human Temporal Lobe Epilepsy

Huberfeld

Wittner²,

Clemenceau³

et al. 2007

J. Neurosci.

553

556

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Changes in chloride (Cl Ϫ) homeostasis may be involved in the generation of some epileptic activities. In this study, we asked whether Cl Ϫ homeostasis, and thus GABAergic signaling, is altered in tissue from patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis. Slices prepared from this human tissue generated a spontaneous interictal-like activity that was initiated in the subiculum. Records from a minority of subicular pyramidal cells revealed depolarizing GABA A receptor-mediated postsynaptic events, indicating a perturbed Cl Ϫ homeostasis. We assessed possible contributions of changes in expression of the potassium-chloride cotransporter KCC2. Double in situ hybridization showed that mRNA for KCC2 was absent from ϳ30% of CaMKII␣ (calcium/calmodulindependent protein kinase II␣)-positive subicular pyramidal cells. Combining intracellular recordings with biocytin-filled electrodes and KCC2 immunochemistry, we observed that all cells that were hyperpolarized during interictal events were immunopositive for KCC2, whereas the majority of depolarized cells were immunonegative. Bumetanide, at doses that selectively block the chloride-importing potassium-sodium-chloride cotransporter NKCC1, produced a hyperpolarizing shift in GABA A reversal potentials and suppressed interictal activity. Changes in Cl Ϫ transporter expression thus contribute to human epileptiform activity, and molecules acting on these transporters may be useful antiepileptic drugs.

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Electrophysiological and morphological diversity of neurons from the rat subicular complex in vitro

Cited by 72 publications

References 56 publications

Glutamatergic pre-ictal discharges emerge at the transition to seizure in human epilepsy

Glutamatergic pre-ictal discharges emerge at the transition to seizure in human epilepsy

Synaptic Contributions to Focal and Widespread Spatiotemporal Dynamics in the Isolated Rat SubiculumIn Vitro

Perturbed Chloride Homeostasis and GABAergic Signaling in Human Temporal Lobe Epilepsy

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