Search results for "hippocampal"
showing 10 items of 352 documents
The effect of adult-acquired hippocampal damage on memory retrieval: an fMRI study.
2005
Bilateral hippocampal pathology typically results in significant memory problems. Despite apparently similar structural damage, patients with such lesions can differ in the pattern of impairment and preservation of memory functions. Previously, an fMRI study of a developmental amnesic patient whose anoxic hippocampal damage was incurred perinatally revealed his residual hippocampal tissue to be active during memory retrieval. This hippocampal activity was apparent during the retrieval of personal and general facts relative to a control task. In this study, we used a similar fMRI paradigm to investigate whether residual hippocampal activation was present also in patient VC with adult-acquire…
Effects of low frequency electric fields on synaptic integration in hippocampal CA1 pyramidal neurons: implications for power line emissions
2014
The possible cognitive effects of low frequency external electric fields, such as those generated by power lines, are poorly understood. Their functional consequences for mechanisms at the single neuron level are very difficult to study and identify experimentally, especially in vivo. The major open problem is that experimental investigations on humans have given inconsistent or contradictory results, making it difficult to estimate the possible effects of external low frequency electric fields on cognitive functions. Here we investigate this issue with a realistic model of hippocampal CA1 pyramidal neurons. The model suggests how and why external electric fields, with environmentally obser…
WNK3 Maintains the GABAergic Inhibitory Tone, Synaptic Excitation and Neuronal Excitability via Regulation of KCC2 Cotransporter in Mature Neurons
2021
The activation of chloride (Cl-)permeable gamma (γ)-aminobutyric acid type A(GABAA) receptors induces synaptic inhibition in mature and excitation in immature neurons. This developmental "switch" in GABA function controlled by its polarity depends on the postnatal decrease in intraneuronal Cl- concentration mediated by KCC2, a member of cation-chloride cotransporters (CCCs). The serine-threonine kinase WNK3 (With No Lysine [K]), is a potent regulator of all CCCs and is expressed in neurons. Here, we characterized the functions of WNK3 and its role in GABAergic signaling in cultured embryonic day 18 (E18) hippocampal neurons. We observed a decrease in WNK3 expression as neurons mature. Knock…
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…
Hippocampal theta (3-8 Hz) activity during classical eyeblink conditioning in rabbits
2007
In 1978, Berry and Thompson showed that the amount of theta (3–8 Hz) activity in the spontaneous hippocampal EEG predicted learning rate in subsequent eyeblink conditioning in rabbits. More recently, the absence of theta activity during the training trial has been shown to have a detrimental effect on learning rate. Here, we aimed to further explore the relationship between theta activity and classical eyeblink conditioning by determining how the relative power of hippocampal theta activity [theta/(theta + delta) ratio] changes during both unpaired control and paired training phases. We found that animals with a higher hippocampal theta ratio immediately before conditioning learned faster a…
Differential vesicular targeting and time course of synaptic secretion of the mammalian neurotrophins.
2005
Neurotrophins are a family of secreted neuronal survival and plasticity factors comprising NGF, BDNF, neurotrophin-3 (NT-3), and NT-4. Whereas synaptic secretion of BDNF has been described, the routes of intracellular targeting and secretion of NGF, NT-3, and NT-4 in neurons are poorly understood.To allow for a direct comparison of intracellular targeting and release properties, all four mammalian neurotrophins were expressed as green fluorescent protein fusion proteins in cultured rat hippocampal neurons. We show that BDNF and NT-3 are targeted more efficiently to dendritic secretory granules of the regulated pathway of secretion (BDNF, in 98% of cells; NT-3, 85%) than NGF (46%) and NT-4 (…
Spatial learning and expression patterns of PP1 mRNA in mouse hippocampus.
2009
<i>Background:</i> Synaptic plasticity is believed to be the major cellular basis for learning and memory. Protein phosphorylation is a key process involved in changes in the efficacy of neurotransmission. In long-term changes synaptic plasticity is followed by structural plasticity and protein de novo synthesis. Such mechanisms are believed to build the basis of hippocampal learning and memory investigated in the Morris water maze (MWM) task. To examine the role of dephosphorylation during that model for spatial learning, we analyzed protein phosphatase 1 (PP1) expression in the hippocampus of mice at various stages of the task and in two groups with different learning abilitie…
Detection of Fibroblast Growth Factor Receptor 1 (FGFR1) Transactivation by Muscarinic Acetylcholine Receptors (mAChRs) in Primary Neuronal Hippocamp…
2018
In addition to their canonical intracellular signals involved in the regulation of neuronal plasticity, G-protein coupled receptors can also rapidly transactivate tyrosine kinase receptors and their downstream intracellular signaling in absence of specific ligands. Here we describe our protocol for dissociating and maintaining hippocampal primary neurons in high- and low-density culture, followed by a description of methods employed to evaluate neurite outgrowth and protein phosphorylation associated with fibroblast growth factor receptor 1 transactivation by muscarinic acetylcholine receptors. Our goal was to provide the reader with detailed protocols of the abovementioned techniques and t…
Early life stress programming of NG2+ glia transcriptome alters functional properties of voltage gated sodium (Nav) channels and cognitive performance
2020
AbstractThe precise mechanisms underlying the detrimental effects of early life stress (ELS) on adult mental health remain still elusive. To date, most studies have exclusively targeted neuronal populations and not considered neuron-glia crosstalk as a crucially important element for the integrity of stress-related brain function. Here, we have investigated the impact of ELS on a glial subpopulation with unique properties in brain homeostasis, the NG2+ cells. ELS shifted the NG2+ transcriptome towards more mature stages, and these transcriptional effects were dependent on stress-induced glucocorticoids. The functional relevance of one candidate gene, Scn7a, could be confirmed by an increase…