Time filter

Source Type

Burg bei Magdeburg, Germany

Bista P.,University of Munster | Meuth S.G.,University of Munster | Kanyshkova T.,University of Munster | Cerina M.,University of Munster | And 8 more authors.
Pflugers Archiv European Journal of Physiology | Year: 2012

Modulation of the standing outward current (I SO) by muscarinic acetylcholine (ACh) receptor (MAChR) stimulation is fundamental for the state-dependent change in activity mode of thalamocortical relay (TC) neurons. Here, we probe the contribution of MAChR subtypes, G proteins, phospholipase C (PLC), and two pore domain K + (K 2P) channels to this signaling cascade. By the use of spadin and A293 as specific blockers, we identify TWIK-related K + (TREK)-1 channel as new targets and confirm TWIK-related acid-sensitve K + (TASK)-1 channels as known effectors of muscarinic signaling in TC neurons. These findings were confirmed using a high affinity blocker of TASK-3 and TREK-1, namely, tetrahexylammonium chloride. It was found that the effect of muscarinic stimulation was inhibited by M 1AChR-(pirenzepine, MT-7) and M 3AChR-specific (4-DAMP) antagonists, phosphoinositide-specific PLCβ (PI-PLC) inhibitors (U73122, ET-18-OCH 3), but not the phosphatidylcholine-specific PLC (PC-PLC) blocker D609. By comparison, depleting guanosine-5′-triphosphate (GTP) in the intracellular milieu nearly completely abolished the effect of MAChR stimulation. The block of TASK and TREK channels was accompanied by a reduction of the muscarinic effect on I SO. Current-clamp recordings revealed a membrane depolarization following MAChR stimulation, which was sufficient to switch TC neurons from burst to tonic firing under control conditions but not during block of M 1AChR/M 3AChR and in the absence of intracellular GTP. These findings point to a critical role of G proteins and PLC as well as TASK and TREK channels in the muscarinic modulation of thalamic activity modes. © 2011 Springer-Verlag.

Kuhn S.,Ghent University | Kuhn S.,Charite - Medical University of Berlin | Kuhn S.,Max Planck Institute for Human Development | Schmiedek F.,Max Planck Institute for Human Development | And 8 more authors.
Social Cognitive and Affective Neuroscience | Year: 2013

Based on the philosophical notion that language embodies thought we investigated whether a habitual tendency for intrusive thought that younger and older participants report over a period of 100 sessions, spread out over about 6 months, is associated with brain regions related to language production. In favour of this hypothesis, we found that individual differences in habitual intrusive thoughts are correlated with activity in the left inferior frontal gyrus (IFG, Brocas area) as well as the cingulate cortex (CC) during a two-choice reaction-time task in fMRI. Participants who habitually tended to experience intrusive thoughts showed greater activity during task-free (baseline) compared to task periods in brain regions involved in language production. Task performance was unrelated to individual differences in intrusive thoughts. We conclude that intrusive thoughts may be represented in a language-like format and that individuals reporting a habitually higher tendency for intrusive thoughts may have stronger and more habitual inner speech processes. © The Author (2012). Published by Oxford University Press.

Viola H.,CONICET | Viola H.,University of Buenos Aires | Ballarini F.,CONICET | Martinez M.C.,CONICET | And 2 more authors.
Progress in Molecular Biology and Translational Science | Year: 2014

The synaptic tagging and capture theory (STC) was postulated by Frey and Morris in 1997 and provided a strong framework to explain how to achieve synaptic specificity and persistence of electrophysiological-induced plasticity changes. Ten years later, the same argument was applied on learning and memory models to explain the formation of long-term memories, resulting in the behavioral tagging hypothesis (BT). These hypotheses are able to explain how a weak event that induces transient changes in the brain can establish long-lasting phenomena through a tagging and capture process. In this framework, it was postulated that the weak event sets a tag that captures plasticity-related proteins/products (PRPs) synthesized by an independent strong event. The tagging and capture processes exhibit symmetry, and therefore, PRPs can be captured if they are synthesized either before or after the setting of the tag. In summary, the hypothesis provides a wide framework that gives a solid explanation of how lasting changes occur and how the interaction between different events leads to promotion, reinforcement, or impairment of such changes. In this chapter, we will summarize the postulates of STC hypothesis, the common features between synaptic plasticity and memory, as well as a detailed compilation of the findings supporting the existence of BT process. At the end, we pose some questions related to BT mechanism and LTM formation, which probably will be answered in the near future. © 2014 Elsevier Inc.

Nedelko V.,Kliniken Schmieder Allensbach | Hassa T.,Kliniken Schmieder Allensbach | Hamzei F.,Albert Ludwigs University of Freiburg | Weiller C.,Albert Ludwigs University of Freiburg | And 6 more authors.
Restorative Neurology and Neuroscience | Year: 2010

Purpose: Recent studies have found age-related BOLD signal changes in several areas of the human brain. We investigated whether such changes also occur in brain areas involved in the processing of motor action observation and imagery. Methods: Functional magnetic resonance imaging with an experimental paradigm in which motor acts had to be observed and/or imagined from a first person perspective was performed in twenty-six subjects. Results: In line with previous work action observation and imagery induced BOLD signal increases in similar areas, predominantly in the premotor and parietal cortex. In contrast to young subjects the elderly displayed a stronger activity in most activated brain areas indicative of compensatory activity for the age-related decline of neural structures. Importantly, activity in the ventrolateral premotor cortex and inferior parietal cortex, seminal areas of the mirror neuron system, did not exhibit activity changes as a function of age. Conclusion: These findings suggest that activity within the mirror neuron system is not age dependent and provide a neural basis for therapeutical interventions and novel rehabilitation treatments such as video therapy. © 2010 - IOS Press and the authors. All rights reserved.

Nedelko V.,Kliniken Schmieder Allensbach | Hassa T.,Kliniken Schmieder Allensbach | Hamzei F.,University Medical Center Jena | Schoenfeld M.A.,Kliniken Schmieder Allensbach | And 3 more authors.
Journal of Neurologic Physical Therapy | Year: 2012

BACKGROUND AND PURPOSE:: Both action observation (AO) and action imagery have been proposed as therapeutic options for stroke rehabilitation. Currently, it is not clear to what extent their underlying neuronal mechanisms differ from each other and whether one of these therapeutic options might be preferable for this purpose. METHODS:: Twenty-six neurologically healthy subjects were investigated using functional magnetic resonance imaging during AO alone and during AO with additional action imagery of video clips showing simple, object-related hand actions. RESULTS:: The blood oxygenation level dependent (BOLD) signal induced by AO increased in a bihemispheric, symmetrical network of areas including the occipital, superior, and inferior parietal cortex, dorsal and ventral premotor regions, and the prefrontal cortex. The addition of imagery to the AO elicited additional activation in both cerebellar hemispheres, caudate nucleus, ventral and dorsal premotor cortex, inferior parietal cortex, and the supplementary motor area. DISCUSSION AND CONCLUSION:: These data reveal more profound activations of the motor system during AO in conjunction with imagery than during AO alone. These results may have important implications for neurorehabilitation and motor learning. © 2012 Neurology Section, APTA.

Discover hidden collaborations