Search results for "hippocampu"

Segmentation automatique et analyse de forme d'hippocampes humains dans l'étude de la maladie d'Alzheimer

2011

The aim of this thesis is to investigate the shape change in hippocampus due to the atrophy in Alzheimer’s disease (AD). To this end, specific algorithms and methodologies were developed to segment the hippocampus from structural magnetic resonance (MR) images and model variations in its shape. We use a multi-atlas based segmentation propagation approach for the segmentation of hippocampus which has been shown to obtain accurate parcellation of brain structures. We developed a supervised method to build a population specific atlas database, by propagating the parcellations from a smaller generic atlas database. Well segmented images are inspected and added to the set of atlases, such that t…

Reservoir computing model of prefrontal cortex creates novel combinations of previous navigation sequences from hippocampal place-cell replay with sp…

2019

As rats learn to search for multiple sources of food or water in a complex environment, they generate increasingly efficient trajectories between reward sites. Such spatial navigation capacity involves the replay of hippocampal place-cells during awake states, generating small sequences of spatially related place-cell activity that we call “snippets”. These snippets occur primarily during sharp-wave-ripples (SWRs). Here we focus on the role of such replay events, as the animal is learning a traveling salesperson task (TSP) across multiple trials. We hypothesize that snippet replay generates synthetic data that can substantially expand and restructure the experience available and make learni…

Correction: Indomethacin blocks the increased conditioned rewarding effects of cocaine induced by repeated social defeat

2019

It is well established that repeated social defeat stress can induce negative long-term consequences such as increased anxiety-like behavior and enhances the reinforcing effect of psychostimulants in rodents. In the current study, we evaluated how the immune system may play a role in these long-term effects of stress. A total of 148 OF1 mice were divided into different experimental groups according to stress condition (exploration or social defeat) and pre-treatment (saline, 5 or 10 mg/kg of the anti-inflammatory indomethacin) before each social defeat or exploration episode. Three weeks after the last social defeat, anxiety was evaluated using an elevated plus maze paradigm. After this tes…

Vibrio harveyi causes disease in seahorse, Hippocampus sp.

2001

A mass mortality among cultured seahorses, Hippocampus kuda and Hippocampus sp., occurred in spring 1998 in Tenerife, Spain. Seahorses were held together with tropical shrimps, Stenopus hispidus, in glass aquaria supplied with 1000 L of sea water at 25 °C. The water supply was conducted between different tanks that contained various marine species, such as octopus, Octopus vulgaris, star®sh, Asterias rubens, sea-urchin, Paracentrotus lividu, greater weever, Trachinus draco, grouper, Epinephelus guaz and Canarian shrimp, Lismata amboiens. None of these species was affected, including the shrimps that shared aquaria with the seahorses. Mortalities of seahorses were very high (more than 90%), …

PB15. Neurophysiological biomarker for the clinical development of tuberous sclerosis

2018

Aim To investigate the neuronal networks in children with tuberous sclerosis complex (TS) undergoing treatment with Everolimus. Methods Sleep and wake electroencephalography (EEG) before and one year after the start of the treatment with Everolimus were investigated in 13 patients with TS. To investigate functional and effective connectivity within the network generating the delta and theta activity in the background sleep and wake EEG, the methods of dynamic imaging of coherent sources (DICS) and renormalized partial directed coherence (RPDC) were applied. Results Sources before the treatment . Independent of location of the tubera and severity of epilepsy, delta activity in the background…

Long-Term Potentiation in Slices from Human Hippocampus

1988

Long-term potentiation (LTP) has been observed in slices from human hippocampi removed for intractable epilepsy using extra- and intracellular recording in vitro. Furthermore the effects of several neuroactive substances with possible relevance for synaptic plasticity was investigated. Human hippocampal neurones in vitro display properties very similar to the respective rodent cells.

BDNF regulates spontaneous correlated activity at early developmental stages by increasing synaptogenesis and expression of the K+/Cl- co-transporter…

2003

Spontaneous neural activity is a basic property of the developing brain,which regulates key developmental processes, including migration, neural differentiation and formation and refinement of connections. The mechanisms regulating spontaneous activity are not known. By using transgenic embryos that overexpress BDNF under the control of the nestin promoter, we show here that BDNF controls the emergence and robustness of spontaneous activity in embryonic hippocampal slices. Further, BDNF dramatically increases spontaneous co-active network activity, which is believed to synchronize gene expression and synaptogenesis in vast numbers of neurons. In fact, BDNF raises the spontaneous activity of…

TRPV1 channels as putative targets in the cannabinoid-mediated synaptic activity of hippocampal neurons

Endocannabinoids (eCBs) play a critical part in pathophysiological conditions rooted on neuronal excitability such as epilepsy. eCBs seem to be involved in neuroprotection, putatively acting on the cannabinoid receptor type 1 (CB1r), but also on Transient Receptor Potential Vanilloid type 1 channels (TRPV1). Indeed, CB1r and TRPV1 are involved in the transduction of stimuli at synaptic level, though exact molecular mechanisms are far from being unveiled. Thus, we aimed to investigate the role of CB1r/TRPV1 interplay in the rat hippocampal neurotransmission by whole-cell patch clamp technique to evaluate excitatory bioelectric activity in the CA1. We pharmacologically manipulated this pathwa…

ROLE OF NITRIC OXIDE/cGMP PATHWAY IN CANNABINOID MODULATION OF PAROXYSMAL PHENOMENA

Activation of glycine receptors modulates spontaneous epileptiform activity in the immature rat hippocampus

2014

While the expression of glycine receptors in the immature hippocampus has been shown, no information about the role of glycine receptors in controlling the excitability in the immature CNS is available. Therefore, we examined the effect of glycinergic agonists and antagonists in the CA3 region of an intact corticohippocampal preparation of the immature (postnatal days 4-7) rat using field potential recordings. Bath application of 100 μM taurine or 10 μM glycine enhanced the occurrence of recurrent epileptiform activity induced by 20 μM 4-aminopyridine in low Mg(2+) solution. This proconvulsive effect was prevented by 3 μM strychnine or after incubation with the loop diuretic bumetanide (10 …