Search results for "long-term"
showing 10 items of 436 documents
Motor cortical plasticity induced by motor learning through mental practice
2015
Several investigations suggest that actual and mental actions trigger similar neural substrates. Motor learning via physical practice results in long-term potentiation (LTP)-like plasticity processes, namely potentiation of M1 and a temporary occlusion of additional LTP-like plasticity. However, whether this neuroplasticity process contributes to improve motor performance through mental practice remains to be determined. Here, we tested skill learning-dependent changes in primary motor cortex (M1) excitability and plasticity by means of transcranial magnetic stimulation in subjects trained to physically execute or mentally perform a sequence of finger opposition movements. Before and after …
2019
Post-activation potentiation (PAP) is a well-described phenomenon with a short half-life (~28 s) that enhances muscle force production at submaximal levels of calcium saturation (i.e., submaximal levels of muscle activation). It has been largely explained by an increased myosin light chain phosphorylation occurring in type II muscle fibers, and its effects have been quantified in humans by measuring muscle twitch force responses to a bout of muscular activity. However, enhancements in (sometimes maximal) voluntary force production detected several minutes after high-intensity muscle contractions are also observed, which are also most prominent in muscles with a high proportion of type II fi…
Reduced presynaptic efficiency of excitatory synaptic transmission impairs LTP in the visual cortex of BDNF-heterozygous mice
2006
The neurotrophin brain-derived neurotrophic factor (BDNF) plays an important role in neuronal survival, axonal and dendritic growth and synapse formation. BDNF has also been reported to mediate visual cortex plasticity. Here we studied the cellular mechanisms of BDNF-mediated changes in synaptic plasticity, excitatory synaptic transmission and long-term potentiation (LTP) in the visual cortex of heterozygous BDNF-knockout mice (BDNF(+/-)). Patch-clamp recordings in slices showed an approximately 50% reduction in the frequency of miniature excitatory postsynaptic currents (mEPSCs) compared to wild-type animals, in the absence of changes in mEPSC amplitudes. A presynaptic impairment of excita…
Disruption of Slc4a10 augments neuronal excitability and modulates synaptic short-term plasticity
2015
Slc4a10 is a Na(+)-coupled Cl(-)-HCO3 (-) exchanger, which is expressed in principal and inhibitory neurons as well as in choroid plexus epithelial cells of the brain. Slc4a10 knockout (KO) mice have collapsed brain ventricles and display an increased seizure threshold, while heterozygous deletions in man have been associated with idiopathic epilepsy and other neurological symptoms. To further characterize the role of Slc4a10 for network excitability, we compared input-output relations as well as short and long term changes of evoked field potentials in Slc4a10 KO and wildtype (WT) mice. While responses of CA1 pyramidal neurons to stimulation of Schaffer collaterals were increased in Slc4a1…
A model for long-term potentiation and depression
1995
A computational model of long-term potentiation (LTP) and long-term depression (LTD) in the hippocampus is presented. The model assumes the existence of retrograde signals, is in good agreement with several experimental data on LTP, LTD, and their pharmacological manipulations, and shows how a simple kinetic scheme can capture the essential characteristics of the processes involved in LTP and LTD. We propose that LTP and LTD could be two different but conceptually similar processes, induced by the same class of retrograde signals, and maintained by two distinct mechanisms. An interpretation of a number of experiments in terms of the molecular processes involved in LTP and LTD induction and …
NG2 cells: Properties, progeny and origin
2010
The NG2 proteoglycan is a type 1-transmembrane protein expressed by a range of cell types within and outside the mammalian nervous system. NG2-expressing (NG2) cells are found in grey and white matter tracts of the developing and adult CNS and have previously been assumed to represent oligodendrocyte precursor cells: new work using transgenic mice has shown that NG2 cells generate oligodendrocytes, protoplasmic astrocytes and in some instances neurons in vivo. NG2 cells express GABAA receptors and the AMPA subtype of glutamate receptors. They make intimate contact to neurons prior to myelinating axons and also form electron-dense synaptic specialisations with axons in the cerebellum, cortex…
The role of N-methyl-D-asparate receptors in neurogenesis.
2006
The dentate gyrus continues to incorporate granule neurons during adulthood. Among the factors that we know modulate adult neurogenesis in the dentate gyrus, one of the first studied was the influence of excitatory amino-acids. These neurotransmitters, acting through NMDA receptors, are able to modulate both the proliferation of progenitor cells as well as the rate of neurogenesis in the adult dentate gyrus. However, the mechanisms by which these processes are influenced are not clearly known. Although there is no anatomical evidence of NMDA receptor expression in adult hippocampal progenitor cells or differentiating granule neurons, electrophysiological data and in vitro studies suggest th…
Experiences faced by next of kin during their older family members’ transition into long-term care in a Norwegian nursing home
2013
Aims and objectives To describe and explore experiences of next of kin during the older persons’ transition into long-term care. Background Moving into long-term care is a challenge for both resident and next of kin. Next of kin experience transitions at the same time as they play significant parts in their family members’ transition into long-term care placement. Design Constructivist hermeneutical design. Methods Ten next of kin to newly admitted eight residents were recruited by purposeful sampling and interviewed. Periodic participant observation periods following new residents on arrival day and the first week after admission and some written documentation were the backdrops to the int…
A mass balance evaluation of the ecological significance of historical nitrogen fluxes in Lake Kinneret
2010
Long-term outcomes in stage IIIB breast cancer patients who achieved less than a pathological complete response (pCR) after primary chemotherapy.
2009
Abstract Learning Objectives After completing this course, the reader will be able to: Summarize the main risk factors for relapse in patients with T4 breast cancer after neoadjuvant chemotherapy.Evaluate the role of hormone receptors and HER-2 as determinants of risk of relapse after neoadjuvant treatment.Compare the difference in outcomes between patients who achieve less than pCR in relation to receptor status. This article is available for continuing medical education credit at CME.TheOncologist.com. Purpose. Pathological complete response (pCR) to primary chemotherapy is the main determinant for improved disease-free survival (DFS) and overall survival (OS). The primary endpoints of ou…