Somatosensory information is propagated from the periphery to the cerebral cortex by two parallel pathways through the ventral posterolateral (VPL) and ventral posteromedial (VPM) thalamus. VPL and VPM neurons receive somatosensory signals from the body and head, respectively. VPL and VPM neurons may also receive cell type-specific GABAergic input from the reticular nucleus of the thalamus. Although VPL and VPM neurons have distinct connectivity and physiological roles, differences in their functional properties remain unclear as they are often studied as one ventrobasal thalamus neuron population. Here, we directly compared synaptic and intrinsic properties of VPL and VPM neurons in C57Bl/6J mice of both sexes aged P25-P32. VPL neurons showed greater depolarization-induced spike firing and spike frequency adaptation than VPM neurons. VPL and VPM neurons fired similar numbers of spikes during hyperpolarization rebound bursts, but VPM neurons exhibited shorter burst latency compared with VPL neurons, which correlated with larger sag potential. VPM neurons had larger membrane capacitance and more complex dendritic arbors. Recordings of spontaneous and evoked synaptic transmission suggested that VPL neurons receive stronger excitatory synaptic input, whereas inhibitory synapse strength was stronger in VPM neurons. This work indicates that VPL and VPM thalamocortical neurons have distinct intrinsic and synaptic properties. The observed functional differences could have important implications for their specific physiological and pathophysiological roles within the somatosensory thalamocortical network.NEW & NOTEWORTHY This study revealed that somatosensory thalamocortical neurons in the VPL and VPM have substantial differences in excitatory synaptic input and intrinsic firing properties. The distinct properties suggest that VPL and VPM neurons could process somatosensory information differently and have selective vulnerability to disease. This work improves our understanding of nucleus-specific neuron function in the thalamus and demonstrates the critical importance of studying these parallel somatosensory pathways separately.

• MeSH
• mozková kůra MeSH
• myši MeSH
• nervový přenos fyziologie   MeSH
• neurony * fyziologie   MeSH
• somatosenzorické korové centrum fyziologie   MeSH
• synapse fyziologie   MeSH
• thalamus * fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Epilepsy presurgical investigation may include focal intracortical single-pulse electrical stimulations with depth electrodes, which induce cortico-cortical evoked potentials at distant sites because of white matter connectivity. Cortico-cortical evoked potentials provide a unique window on functional brain networks because they contain sufficient information to infer dynamical properties of large-scale brain connectivity, such as preferred directionality and propagation latencies. Here, we developed a biologically informed modelling approach to estimate the neural physiological parameters of brain functional networks from the cortico-cortical evoked potentials recorded in a large multicentric database. Specifically, we considered each cortico-cortical evoked potential as the output of a transient stimulus entering the stimulated region, which directly propagated to the recording region. Both regions were modelled as coupled neural mass models, the parameters of which were estimated from the first cortico-cortical evoked potential component, occurring before 80 ms, using dynamic causal modelling and Bayesian model inversion. This methodology was applied to the data of 780 patients with epilepsy from the F-TRACT database, providing a total of 34 354 bipolar stimulations and 774 445 cortico-cortical evoked potentials. The cortical mapping of the local excitatory and inhibitory synaptic time constants and of the axonal conduction delays between cortical regions was obtained at the population level using anatomy-based averaging procedures, based on the Lausanne2008 and the HCP-MMP1 parcellation schemes, containing 130 and 360 parcels, respectively. To rule out brain maturation effects, a separate analysis was performed for older (>15 years) and younger patients (<15 years). In the group of older subjects, we found that the cortico-cortical axonal conduction delays between parcels were globally short (median = 10.2 ms) and only 16% were larger than 20 ms. This was associated to a median velocity of 3.9 m/s. Although a general lengthening of these delays with the distance between the stimulating and recording contacts was observed across the cortex, some regions were less affected by this rule, such as the insula for which almost all efferent and afferent connections were faster than 10 ms. Synaptic time constants were found to be shorter in the sensorimotor, medial occipital and latero-temporal regions, than in other cortical areas. Finally, we found that axonal conduction delays were significantly larger in the group of subjects younger than 15 years, which corroborates that brain maturation increases the speed of brain dynamics. To our knowledge, this study is the first to provide a local estimation of axonal conduction delays and synaptic time constants across the whole human cortex in vivo, based on intracerebral electrophysiological recordings.

• MeSH
• Bayesova věta MeSH
• elektrická stimulace metody   MeSH
• epilepsie * MeSH
• evokované potenciály * fyziologie   MeSH
• lidé MeSH
• mapování mozku metody   MeSH
• mozek MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The effects of high-dose ethanol intoxication on cognitive flexibility processes are not well understood, and processes related to hangover after intoxication have remained even more elusive. Similarly, it is unknown in how far the complexity of cognitive flexibility processes is affected by intoxication and hangover effects. We performed a neurophysiological study applying high density electroencephalography (EEG) recording to analyze event-related potentials (ERPs) and perform source localization in a task switching paradigm which varied the complexity of task switching by means of memory demands. The results show that high-dose ethanol intoxication only affects task switching (i.e. cognitive flexibility processes) when memory processes are required to control task switching mechanisms, suggesting that even high doses of ethanol compromise cognitive processes when they are highly demanding. The EEG and source localization data show that these effects unfold by modulating response selection processes in the anterior cingulate cortex. Perceptual and attentional selection processes as well as working memory processes were only unspecifically modulated. In all subprocesses examined, there were no differences between the sober and hangover states, thus suggesting a fast recovery of cognitive flexibility after high-dose ethanol intoxication. We assume that the gamma-aminobutyric acid (GABAergic) system accounts for the observed effects, while they can hardly be explained by the dopaminergic system.

• MeSH
• cingulární gyrus fyziologie   patofyziologie   MeSH
• dechové testy MeSH
• dospělí MeSH
• elektroencefalografie MeSH
• evokované potenciály fyziologie   MeSH
• GABA MeSH
• kognice fyziologie   MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mozek fyziologie   patofyziologie   MeSH
• nervový přenos fyziologie   MeSH
• otrava alkoholem patofyziologie   psychologie   MeSH
• plnění a analýza úkolů MeSH
• pozornost MeSH
• reakční čas MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chondroitin sulfate proteoglycans (CSPGs) are the main active component of perineuronal nets (PNNs). Digestion of the glycosaminoglycan chains of CSPGs with chondroitinase ABC or transgenic attenuation of PNNs leads to prolongation of object recognition memory and activation of various forms of plasticity in the adult central nervous system. The inhibitory properties of the CSPGs depend on the pattern of sulfation of their glycosaminoglycans, with chondroitin 4-sulfate (C4S) being the most inhibitory form. In this study, we tested a number of candidates for functional blocking of C4S, leading to selection of an antibody, Cat316, which specifically recognizes C4S and blocks its inhibitory effects on axon growth. It also partly blocks binding of semaphorin 3A to PNNs and attenuates PNN formation. We asked whether injection of Cat316 into the perirhinal cortex would have the same effects on memory as chondroitinase ABC treatment. We found that masking C4S with the Cat316 antibody extended long-term object recognition memory in normal wild-type mice to 24 hours, similarly to chondroitinase or transgenic PNN attenuation. We then tested Cat316 for restoration of memory in a neurodegeneration model. Mice expressing tau with the P301S mutation showed profound loss of object recognition memory at 4 months of age. Injection of Cat316 into the perirhinal cortex normalized object recognition at 3 hours in P301S mice. These data indicate that Cat316 binding to C4S in the extracellular matrix can restore plasticity and memory in the same way as chondroitinase ABC digestion. Our results suggest that antibodies to C4S could be a useful therapeutic to restore memory function in neurodegenerative disorders.

• MeSH
• Alzheimerova nemoc farmakoterapie   etiologie   patofyziologie   psychologie   MeSH
• antigeny imunologie   metabolismus   fyziologie   MeSH
• cílená molekulární terapie MeSH
• extracelulární matrix metabolismus   MeSH
• kultivované buňky MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• neurodegenerativní nemoci farmakoterapie   etiologie   patofyziologie   psychologie   MeSH
• neuroplasticita MeSH
• neutralizující protilátky terapeutické užití   MeSH
• paměť fyziologie   MeSH
• potkani Sprague-Dawley MeSH
• proteoglykany imunologie   metabolismus   fyziologie   MeSH
• protilátky aplikace a dávkování   MeSH
• reakční čas MeSH
• tauopatie komplikace   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

U 51 nemocných s jednostranným postižením předního frontálního kortexu byl vyšetřen reakční čas pohybu ruky na somestetický podnět. Vlastní reakční čas (reakční čas po odečtu doby vstupu podnětu do mozku a doby výstupu z mozku do svalu) je nezávislý na místě, velikosti a tkáňové skladbě nádoru frontálního laloku velkého mozku. Rozsáhlé gliomy dorzolaterálního prefrontálního kortexu, orbitofrontálního kortexu, velké meningeomy konvexity a meningeomy parasagitální nezpůsobily významnou poruchu reakčního času. Vlastní reakční čas u jednostranných nádorů čelního laloku velkého mozku není stranově rozdílný. U 87 % vyšetřených měl hodnotu 110–260 ms. Vlastní reakční čas odpovídající době vypracování rozhodnutí k pohybu a výrobě pohybového vzorku je zajištěn neuronální soustavou odolnou vůči ložiskovému postižení předního frontálního kortexu. Toto zjištění je významným vodítkem při operacích v premotorické oblasti.

In 51 patients with unilateral involvement of the anterior frontal cortex, the reaction time of hand movement to a somesthetic stimulus was assessed. The actual reaction time (the reaction time left after subtracting the time taken for a stimulus to reach the brain and the time of brain output to muscle) is independent of the site, size, and tissue composition of a frontal lobe tumour of the cerebrum. Extensive gliomas of the dorsolateral prefrontal cortex and those of the orbitofrontal cortex, large convexity meningiomas, and parasagittal meningiomas failed to cause a significant disturbance in the reaction time. The actual reaction time in unilateral frontal lobe tumours of the cerebrum is not laterally different. In 87% of those investigated, it ranged from 110 to 260 ms. The actual reaction time, corresponding to the time taken to process a decision to move and to produce a movement pattern, is provided by the neuronal system resistant to focal involvement of the anterior frontal cortex. This finding is an important clue for surgeries in the premotor area.

• MeSH
• čelní lalok * patologie   MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádory mozku chirurgie   MeSH
• nervový přenos fyziologie   MeSH
• podněty MeSH
• pohyb fyziologie   MeSH
• reakční čas * MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• hodnotící studie MeSH

The kinetics of the phasic synchronous and delayed asynchronous release of acetylcholine quanta was studied at the neuromuscular junctions of aging rats from infant to mature animals at various frequencies of rhythmic stimulation of the motor nerve. We found that in infants 6 (P6) and 10 (P10) days after birth a strongly asynchronous phase of quantal release was observed, along with a reduced number of quanta compared to the synapses of adults. The rise time and decay of uni-quantal end-plate currents were significantly longer in infant synapses. The presynaptic immunostaining revealed that the area of the synapses in infants was significantly (up to six times) smaller than in mature junctions. The intensity of delayed asynchronous release in infants increased with the frequency of stimulation more than in adults. A blockade of the ryanodine receptors, which can contribute to the formation of delayed asynchronous release, had no effect on the kinetics of delayed secretion in the infants unlike synapses of adults. Therefore, high degree of asynchrony of quantal release in infants is not associated with the activity of ryanodine receptors and with the liberation of calcium ions from intracellular calcium stores.

• MeSH
• bungarotoxiny farmakokinetika   MeSH
• elektrická stimulace MeSH
• krysa rodu rattus MeSH
• kyselina gallová analogy a deriváty   farmakokinetika   MeSH
• nervosvalové spojení účinky léků   růst a vývoj   metabolismus   MeSH
• neurotransmiterové látky metabolismus   MeSH
• nikotinové receptory metabolismus   MeSH
• novorozená zvířata MeSH
• reakční čas fyziologie   MeSH
• ryanodin farmakokinetika   MeSH
• synaptické potenciály fyziologie   MeSH
• synaptofysin metabolismus   MeSH
• věkové faktory MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• elektrodiagnostika metody   MeSH
• elektromyografie MeSH
• nemoci míchy diagnóza   MeSH
• nervové vedení fyziologie   MeSH
• nervový přenos fyziologie   MeSH
• neuromuskulární nemoci diagnóza   MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• neurologie
• diagnostika
• NLK Publikační typ
• kolektivní monografie

Since recently, it is possible, using noninvasive cortical stimulation, such as the protocol of paired associative stimulation (PAS), to induce the plastic changes in the motor cortex, in humans that mimic Hebb's model of learning. Application of TMS conjugated with peripheral electrical stimulation at strictly coherent temporal manner lead to convergence of inputs in the sensory-motor cortex, with the consequent synaptic potentiation or weakening, if applied repetitively. However, when optimal interstimulus interval (ISI) for induction of LTP-like effects is applied as a single pair, Motor evoked potential (MEP) amplitude inhibition is observed, the paradigm known as short-latency afferent inhibition (SLAI). Aiming to resolve this paradox, PAS protocols were applied, with 200 repetitions of TMS pulses paired with median nerve electrical stimulation, at ISI equal to individual latencies of evoked response of somatosensory cortex (N(20)) (PAS(LTP)), and at ISI of N(20) shortened for 5 msec (PAS(LTD)) - protocols that mimic LTP-like changes in the human motor cortex. MEP amplitudes before, during and after interventions were measured as an indicator based on output signals originating from the motor system. Post-intervention MEP amplitudes following the TMS protocols of PAS(LTP) and PAS(LTD) were facilitated and depressed, respectively, contrary to MEP amplitudes during intervention. During PAS(LTP) MEP amplitudes were significantly decreased in case of PAS(LTP), while in the case of PAS(LTD) an upward trend was observed. In conclusions, a possible explanation for the seemingly paradoxical effect of PAS can be found in the mechanism of homeostatic modulation of plasticity. Those findings indicate the existence of complex relationships in the development of plasticity induced by stimulation, depending on the level of the previous motor cortex excitability.

• MeSH
• dospělí MeSH
• elektrická stimulace metody   přístrojové vybavení   MeSH
• elektromyografie metody   přístrojové vybavení   MeSH
• experimenty na lidech MeSH
• financování organizované MeSH
• homeostáza fyziologie   MeSH
• lidé MeSH
• motorické korové centrum fyziologie   MeSH
• nervus medianus fyziologie   MeSH
• neuroplasticita fyziologie   MeSH
• somatosenzorické evokované potenciály fyziologie   MeSH
• statistika jako téma MeSH
• transkraniální magnetická stimulace metody   využití   MeSH
• zápěstí fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH

Depresia je psychická porucha s rozmanitou klinickou manifestáciou, ktorá je často poddiagnostikovaná a neprimerane liečená. v súčasnosti najpoužívanejšie antidepresíva sú zvyčajne účinné len pomerne krátku dobu. Latencia dva až šesť týždňov do objavenia sa teraeutického účinku, chýbanie výrazného zlepšenia u značného počtu pacientov, reziduálna a rekurentná depresia, suicidáne riziko, pokles kognitívnych funkcií, nežiaduce účinky lieku a chýbanie výrazného zlepšenia pri závažných depresiách, to všetko je stále predmetom vážnej kUnickej dilemy. Posledné zistenia poukazujú na to, že selektívne inhibitory spätného vychytávania sérotonínu (SSRI) pôsobia pozitívne na oblasti mozgu, ktoré sú dôležité pre procesy myslenia, emócií a funkčnosť autonómneho nervového systému. Kontrolované Štúdie na ľuďoch aj experimentálne práce zamerané na psychosociálně a iné stresory poukázali na spojenie medzi veľkou depresívnou poruchou a morfologickými zmenami v mozgu, ktoré sú najpravdepodobnejšie dôsledkom stresom mediovanej hyperkortizolémie. Zvieracie experimenty aj klinické data potvrdili, že tianeptím, nekonvenčné antidepresívum, ktoré pôsobí zlepšením vychytávania sérotonínu v synapse, má rovnako efekt antidepresívny ako aj efekt neuroplastický. Práca sa venuje diskusii o úlohe neuroplasticity a jej klinickému významu.

Depression a disorder that presents with varied manifestations, tends to be unrecognized or inappropriately treated. Currently popular antidepressant drugs have been effective for short term use. Latency of two to six weeks before appearance of therapeutic benefits, absence of substantial improvement in a large segment of patients, residual and recurrent depression, suicide risk, cognitive decline. adverse effects of the drugs and absence of robust improvement in severe depressions continue to be serious clinical dilemma. Recent data suggest that selective serotonin reuptake inhibitors (SSRIs) rewire areas of the brain that are important for thinking, feeling, as well as operating the autonomie nervous system. Controlled studies on human subjects and animals subjected to psychosocial and other Stressors have revealed that major depressive illness is associated with morphological changes in the brain, attributable to stress mediated hypercortisolaemia. Animal experiments and clinical data reveal that tianeptine, an unconventional antidepressant drug that acts by enhancing synaptic serotonin reuptake, has proven antidepressant actions as well as proven neuroplastic effects. This presentation discusses the role neuroplasticity and its clinical relevance.

• Klíčová slova
• Risperdal Consta TM,
• MeSH
• antidepresiva farmakologie   škodlivé účinky   terapeutické užití   MeSH
• deprese etiologie   farmakoterapie   terapie   MeSH
• klinické zkoušky kontrolované jako téma MeSH
• lidé MeSH
• mozek fyziologie   metabolismus   MeSH
• neuropeptidy fyziologie   terapeutické užití   MeSH
• neuroplasticita fyziologie   účinky léků   MeSH
• neurotransmiterové látky farmakologie   terapeutické užití   MeSH
• psychický stres komplikace   psychologie   MeSH
• selektivní inhibitory zpětného vychytávání serotoninu farmakologie   terapeutické užití   MeSH
• thiazepiny farmakologie   terapeutické užití   MeSH
• Check Tag
• lidé MeSH

• MeSH
• Alzheimerova nemoc MeSH
• dospělí MeSH
• elektroencefalografie * MeSH
• epilepsie MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mozek fyziologie   MeSH
• mozková kůra * fyziologie   MeSH
• multiinfarktová demence MeSH
• nervový přenos MeSH
• neuropsychologické testy MeSH
• psychoakustika MeSH
• reakční čas MeSH
• senioři MeSH
• thalamus * fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH