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.
Kuhn S.,Ghent University |
Kuhn S.,Charité - 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.
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.
Rankovic V.,Otto Von Guericke University of Magdeburg |
Ehling P.,University of Munster |
Coulon P.,University of Munster |
Landgraf P.,Leibniz Institute For Neurobiologie |
And 3 more authors.
European Journal of Neuroscience | Year: 2010
Neuronal Ca2+ channels are rapidly inactivated by a mechanism that is termed Ca2+-dependent inactivation (CDI). In this study we investigated the influence of intracellular Ca2+ release on CDI of high-voltage-activated Ca2+ channels in rat thalamocortical relay neurons by combining voltage-clamp, Ca2+ imaging and immunological techniques. Double-pulse protocols revealed CDI, which depended on the length of the conditioning pulses. Caffeine caused a concentration-dependent increase in CDI that was accompanied by an increase in the duration of Ca2+ transients. Inhibition of ryanodine receptors and endoplasmic Ca2+ pumps (by thapsigargin or cyclopiazonic acid) resulted in a reduction of CDI. In contrast, inhibition of inositol 1,4,5-tris-phosphate receptors by intracellular application of 2-aminoethoxy diphenyl borate or heparin did not influence CDI. The block of transient receptor potential channels by extracellular application of 2-aminoethoxy diphenyl borate, however, resulted in a significant reduction of CDI. The central role of L-type Ca2+ channels was emphasized by the near-complete block of CDI by nifedipine, an effect only surpassed when Ca2+ was replaced by Ba2+ and chelated by 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′,-tetraacetic acid (BAPTA). Trains of action potential-like stimuli induced a strong reduction in high-voltage-activated Ca2+ current amplitude, which was significantly reduced when intracellular Ca2+ stores were made inoperative by thapsigargin or Ba2+/BAPTA. Western blotting revealed expression of L-type Ca2+ channels in thalamic and hippocampal tissue but not liver tissue. In summary, these results suggest a cross-signalling between L-type Ca2+ channels and ryanodine receptors that controls the amount of Ca2+ influx during neuronal activity. © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.
Schreiber S.,Otto Von Guericke University of Magdeburg |
Bueche C.Z.,Otto Von Guericke University of Magdeburg |
Garz C.,Otto Von Guericke University of Magdeburg |
Kropf S.,Otto Von Guericke University of Magdeburg |
And 12 more authors.
Journal of Cerebral Blood Flow and Metabolism | Year: 2012
Cerebral small vessel disease (CSVD) is associated with vessel wall changes, microbleeds, blood-brain barrier (BBB) disturbances, and reduced cerebral blood flow (CBF). As spontaneously hypertensive stroke-prone rats (SHRSP) may be a valid model of some aspects of human CSVD, we aimed to identify whether those changes occur in definite temporal stages and whether there is an initial phenomenon beyond those common vascular alterations. Groups of 51 SHRSP were examined simultaneously by histologic (Hematoxylin-Eosin, IgG-Immunohistochemistry, vessel diameter measurement) and imaging methods (Magnetic Resonance Imaging, 201-Thallium-Diethyldithiocarbamate/99m-Technetium- HMPAO Single Photon Emission Computed Tomography conducted as pilot study) at different stages of age. Vascular pathology in SHRSP proceeds in definite stages, whereas an age-dependent accumulation of erythrocytes in capillaries and arterioles represents the homogeneous initial step of the disease. Erythrocyte accumulations are followed by BBB disturbances and microbleeds, both also increasing with age. Microthromboses, tissue infarctions with CBF reduction, and disturbed potassium uptake represent the final stage of vascular pathology in SHRSP. Erythrocyte accumulationswe parsimoniously interpreted as staseswithout cerebral tissue damage represent the first step of vascular pathology in SHRSP. If that initial phenomenon could be identified in patients, these erythrocyte accumulations might be a promising target for implementing prophylactic and therapeutic strategies in human CSVD. © 2012 ISCBFM All rights reserved.
Haroon F.,Otto Von Guericke University of Magdeburg |
Handel U.,Otto Von Guericke University of Magdeburg |
Angenstein F.,Leibniz Institute For Neurobiologie |
Goldschmidt J.,Leibniz Institute For Neurobiologie |
And 7 more authors.
PLoS ONE | Year: 2012
Upon infection with the obligate intracellular parasite Toxoplasma gondii, fast replicating tachyzoites infect a broad spectrum of host cells including neurons. Under the pressure of the immune response, tachyzoites convert into slow-replicating bradyzoites, which persist as cysts in neurons. Currently, it is unclear whether T. gondii alters the functional activity of neurons, which may contribute to altered behaviour of T. gondii-infected mice and men. In the present study we demonstrate that upon oral infection with T. gondii cysts, chronically infected BALB/c mice lost over time their natural fear against cat urine which was paralleled by the persistence of the parasite in brain regions affecting behaviour and odor perception. Detailed immunohistochemistry showed that in infected neurons not only parasitic cysts but also the host cell cytoplasm and some axons stained positive for Toxoplasma antigen suggesting that parasitic proteins might directly interfere with neuronal function. In fact, in vitro live cell calcium (Ca2+) imaging studies revealed that tachyzoites actively manipulated Ca2+ signalling upon glutamate stimulation leading either to hyper- or hypo-responsive neurons. Experiments with the endoplasmatic reticulum Ca2+ uptake inhibitor thapsigargin indicate that tachyzoites deplete Ca2+ stores in the endoplasmatic reticulum. Furthermore in vivo studies revealed that the activity-dependent uptake of the potassium analogue thallium was reduced in cyst harbouring neurons indicating their functional impairment. The percentage of non-functional neurons increased over time In conclusion, both bradyzoites and tachyzoites functionally silence infected neurons, which may significantly contribute to the altered behaviour of the host. © 2012 Haroon et al.
Noesselt T.,Otto Von Guericke University of Magdeburg |
Tyll S.,Otto Von Guericke University of Magdeburg |
Boehler C.N.,Otto Von Guericke University of Magdeburg |
Budinger E.,Otto Von Guericke University of Magdeburg |
And 4 more authors.
Journal of Neuroscience | Year: 2010
Combining information across modalities can affect sensory performance. We studied how co-occurring sounds modulate behavioral visual detection sensitivity (d′), and neural responses, for visual stimuli of higher or lower intensity. Co-occurrence of a sound enhanced human detection sensitivity for lower- but not higher-intensity visual targets. Functional magnetic resonance imaging (fMRI) linked this to boosts in activity-levels for sensory-specific visual and auditory cortex, plus multisensory superior temporal sulcus (STS), specifically for a lower-intensity visual event when paired with a sound. Thalamic structures in visual and auditory pathways, the lateral and medial geniculate bodies, respectively (LGB, MGB), showed a similar pattern. Subject-by-subject psychophysical benefits correlated with corresponding fMRI signals in visual, auditory, and multisensory regions. We also analyzed differential "coupling" patterns of LGB and MGB with other regions in the different experimental conditions. Effective-connectivity analyses showed enhanced coupling of sensory-specific thalamic bodies with the affected cortical sites during enhanced detection of lower-intensity visual events paired with sounds. Coupling strength between visual and auditory thalamus with cortical regions, including STS, covaried parametrically with the psychophysical benefit for this specific multisensory context. Our results indicate that multisensory enhancement of detection sensitivity for low-contrast visual stimuli by co-occurring sounds reflects a brain network involving not only established multisensory STS and sensoryspecific cortex but also visual and auditory thalamus. Copyright © 2010 the authors.
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.
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.
Brosch M.,Leibniz Institute For Neurobiologie |
Selezneva E.,Leibniz Institute For Neurobiologie |
Scheich H.,Leibniz Institute For Neurobiologie
European Journal of Neuroscience | Year: 2015
This study aimed at a deeper understanding of which cognitive and motivational aspects of tasks affect auditory cortical activity. To this end we trained two macaque monkeys to perform two different tasks on the same audiovisual stimulus and to do this with two different sizes of water rewards. The monkeys had to touch a bar after a tone had been turned on together with an LED, and to hold the bar until either the tone (auditory task) or the LED (visual task) was turned off. In 399 multiunits recorded from core fields of auditory cortex we confirmed that during task engagement neurons responded to auditory and non-auditory stimuli that were task-relevant, such as light and water. We also confirmed that firing rates slowly increased or decreased for several seconds during various phases of the tasks. Responses to non-auditory stimuli and slow firing changes were observed during both the auditory and the visual task, with some differences between them. There was also a weak task-dependent modulation of the responses to auditory stimuli. In contrast to these cognitive aspects, motivational aspects of the tasks were not reflected in the firing, except during delivery of the water reward. In conclusion, the present study supports our previous proposal that there are two response types in the auditory cortex that represent the timing and the type of auditory and non-auditory elements of a auditory tasks as well the association between elements. © 2015 Federation of European Neuroscience Societies and John Wiley and Sons Ltd.