Search results for "Pyramid"
showing 10 items of 410 documents
Lateral habenula and hippocampus: A complex interaction raphe cells-mediated
1997
The study has shown an excitatory influence exerted by lateral habenula (LH) on hippocampal pyramidal cells. The modulatory influence is paradoxically serotonine-mediated; in fact all LH stimulation effects were abolished by intrahippocampal iontophoretic methysergide application. The data suggest the involvement of dorsal raphe nucleus. In fact, the dorsal raphe nucleus stimulation caused on hippocampus an expected inhibitory effect antagonized by intrahippocampal iontophoretic methysergide application. In the context of this neural structure we have highlighted a disinhibitory relation between two types of cells: slow serotonergic efferent neurones and fast GABAergic interneurones. The di…
PSA-NCAM expression in the rat medial prefrontal cortex
2005
The rat medial prefrontal cortex, an area considered homologous to the human prefrontal cortex, is a region in which neuronal structural plasticity has been described during adulthood. Some plastic processes such as neurite outgrowth and synaptogenesis are known to be regulated by the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). Since PSA-NCAM is present in regions of the adult CNS which are undergoing structural remodeling, such as the hypothalamus or the hippocampus, we have analyzed the expression of this molecule in the medial prefrontal cortex of adult rats using immunohistochemistry. PSA-NCAM immunoreactivity was found both in cell bodies and in the neuropil of…
Optical release of caged glutamate for stimulation of neurons in the in vitro slice preparation
2005
Optical stimulation techniques prove useful to map func- tional inputs in the in vitro brain slice preparation: Glutamate released by a focused beam of UV light induces action potentials, which can be detected in postsynaptic neurons. The direct activation effect is influenced by factors such as compound concentration, focus depth, light absorption in the tissue, and sensitivity of different neuronal do- mains. We analyze information derived from direct stimulation ex- periments in slices from rat barrel cortex and construct a computa- tional model of a layer V pyramidal neuron that reproduces the experimental findings. The model predictions concerning the influ- ence of focus depth on inpu…
Sporadic Parkinson disease and amyotrophic lateral sclerosis complex (Brait-Fahn-Schwartz disease).
2012
Clinical evidence for parkinsonism may accompany Amyotrophic Lateral Sclerosis with a frequency ranging from 5% to 17%. The concurrence of Amyotrophic Lateral Sclerosis and Parkinson's disease, outside the known Guam and Kii Peninsula foci, is instead rare, but this raises the possibility of a common pathogenesis. Clinically this complex presents with a levodopa-responsive parkinsonism and Amyotrophic Lateral Sclerosis and has been termed Brait-Fahn-Schwartz disease. Here we describe two patients with this uncommon neurodegenerative complex. Both presented with Parkinson disease and progressed to a full blown Amyotrophic Lateral Sclerosis. We further suggest that the association of Parkinso…
Stage-dependent and sector-specific neuronal loss in hippocampus during Alzheimer's disease
2000
Recent stereological studies documented a severe loss of hippocampal neurons in end-stage Alzheimer's disease. The development of the disease, however, is progressive and slow, over clinically inconspicuous decades. The Braak-staging system distinguishes six histopathological stages some of which are not accompanied by clinical symptoms. We analyzed hippocampal cell loss in correlation to Braak stages. Neuron numbers were determined with unbiased stereological principles in a defined subportion of the hippocampus of 28 subjects. There were no age-dependent neuronal losses in any of the hippocampal subdivisions examined. Compared to stage I, pyramidal cell loss in CA1 was reduced by 33% in s…
Clinical and neuroradiological findings in classic infantile and late-onset globoid-cell leukodystrophy (Krabbe disease)
1996
In the present study the clinical course and imaging of early and late-onset forms of Krabbe disease are analyzed. We report on 11 patients with a biochemical diagnosis of galactosyl ceramide β-galactoside deficiency. Two presented as the classic infantile form and died within the second year of life. In 9 children the first clinical signs, such as gait difficulties and visual failure, started after age 2 years. All these patients developed slow regression of motor and mental capacities, and most of them died within their first decade. In patients of both groups computed tomography (CT) and magnetic resonance imaging (MRI) were performed. In the late-onset form, hypodensities of the central…
Effects of caffeine on neuromuscular function in a non‐fatigued state and during fatiguing exercise
2020
New findings What is the central question of the study? What are the effects of caffeine on neuromuscular function in a non-fatigued state and during fatiguing exercise? What is the main finding and its importance? In a non-fatigued state, caffeine decreased the duration of the silent period evoked by transcranial magnetic stimulation. Caffeine-induced reduction of inhibitory mechanisms in the central nervous system before exercise was associated with an increased performance. Individuals who benefit from caffeine ingestion may experience lower perception of effort during exercise and an accelerated recovery of M-wave amplitude postfatigue. This study elucidates the mechanisms of action of …
Switching between persistent firing and depolarization block in individual rat CA1 pyramidal neurons
2018
The hippocampal formation plays a role in mnemonic tasks and epileptic discharges in vivo. In vitro, these functions and malfunctions may relate to persistent firing (PF) and depolarization block (DB), respectively. Pyramidal neurons of the CA1 field have previously been reported to engage in either PF or DB during cholinergic stimulation. However, it is unknown whether these cells constitute disparate populations of neurons. Furthermore, it is unclear which cell-specific peculiarities may mediate their diverse response properties. However, it has not been shown whether individual CA1 pyramidal neurons can switch between PF and DB states. Here, we used whole cell patch clamp in the current …
Intrinsically determined cell death of developing cortical interneurons.
2009
The cell death of inhibitory neurons, which originate far from the cortical areas to which they migrate during embryonic development, is determined autonomously rather than by competition for trophic signals from other cell types. It has long been known that apoptosis, a form of programmed cell death, eliminates young cells from developing tissues. In the field of neurobiology, it is widely believed that developmental neuronal-cell death results from cellular competition for environmentally derived survival signals that selects for an optimally sized and properly wired population of neurons. This study of developmental cell death in the mouse cortex in vivo, in vitro and after transplantati…