Stimulus response latency is the time period between the presentation of a stimulus and the occurrence of a change in the neural firing evoked by the stimulation. The response latency has been explored and estimation methods proposed mostly for excitatory stimuli, which means that the neuron reacts to the stimulus by an increase in the firing rate. We focus on the estimation of the response latency in the case of inhibitory stimuli. Models used in this paper represent two different descriptions of response latency. We consider either the latency to be constant across trials or to be a random variable. In the case of random latency, special attention is given to models with selective interaction. The aim is to propose methods for estimation of the latency or the parameters of its distribution. Parameters are estimated by four different methods: method of moments, maximum-likelihood method, a method comparing an empirical and a theoretical cumulative distribution function and a method based on the Laplace transform of a probability density function. All four methods are applied on simulated data and compared.

• MeSH
• Afferent Pathways physiology   MeSH
• Action Potentials physiology   MeSH
• Time Factors MeSH
• Physical Stimulation MeSH
• Humans MeSH
• Models, Neurological * MeSH
• Neural Inhibition physiology   MeSH
• Neurons physiology   MeSH
• Computer Simulation MeSH
• Reaction Time physiology   MeSH
• Models, Statistical MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Předkládaná práce uvádí rozbor literatury týkající se tuhosti a napětí kosterního svalu, spasticity, mechanoreceptorů v pohybovém aparátu, nervových reflexů spojených s řízením svalového napětí a topografické a směrové specifity mezi kůží a intenzitou napínacího a H-reflexu kosterních svalů. Cílem rešerše je získat vědecké podklady pro vyvození hypotéz pro dizertační práci, jejímž tématem je vliv stimulace kožních receptorů na svalové napětí ve vybraných svalech u zdravých jedinců a u pacientů se syndromem centrálního motoneuronu. Rozbor literatury ukázal, že napětí svalu má pasivní (EMG němou) a aktivní (EMG aktivní) složku. Pasivní složka je daná viskoelastickými vlastnostmi tkání ve svalu, tedy svalových vláken a vmezeřeného vaziva. Výzkumy dokazují, že vazivo obsahuje také kontraktilní buňky a že tedy dokáže aktivně kontrahovat. Aktivní složka je dána nervovými reflexy, které jsou vyvolány protažením svalu, a to napínacím reflexem segmentovým a reflexem transkortikálním. Tyto reflexy se uplatňují při zvýšené potřebě stabilizace kloubu. Spasticitu lze definovat jako poruchu senzomotorického systému charakterizovanou zvýšením svalového tonu v závislosti na rychlosti protažení. Spasticita je jednou ze složek syndromu centrálního motoneuronu společně s oslabením flexorových reflexů, svalovou slabostí a ztrátou zručnosti. Významnou roli přitom hrají změny v aktivaci napínacího reflexu v důsledku hyperexcitability alfa motoneuronů a snížení inhibice sestupnými motorickými drahami. Studie proprioreceptorů lze rozdělit na morfologické a na elektrofyziologické. Funkčně významné je hodnocení, podle kterého se v kloubu, ve svalu i v kůži rozlišují receptory s pomalou adaptací (statické), které registrují polohu kloubu, a receptory s rychlou adaptací (dynamické), registrující pohyb kloubu. Výsledky této studie nás opravňují k formulaci základních hypotéz pro naši práci: 1) můžeme očekávat, že dráždění kožních receptorů vyvolá statisticky významné změny v napětí ve vybraných svalech a 2) můžeme očekávat specifitu mezi směrem tahu kůže a facilitací či inhibicí svalového napětí. Rozbor literatury také významně přispěl k tvorbě homogenního experimentálního souboru zejména díky závěrům, ze kterých vyplývá, že do jedné skupiny nelze zařazovat současně pacienty s CMP a s transverzální lézí míšní, protože se z hlediska neurofyziologického nejedná o identické patologické stavy. Významné je rovněž zjištění, že zvýšení pasivní svalové tuhosti vazivovými kontrakturami či fibrózou svalu negativně ovlivňuje reflexní působení na kosterní svaly.

The work presented here offers an analysis of the literature dealing with the rigidity and tone of skeletal muscles, spasticity and mechanoreceptors in the locomotor apparatus, nerve reflexes associated with the muscle tone control and topographic and directional specificity between the skin and intensity of the stretching reflex and H-reflex of skeletal muscles. The purpose of the search for the literature is to provide a scientific basis for a derivation of hypotheses for dissertation theses, the scope of which is the effect of the skin receptor stimulation on the muscle tone in selected muscles in healthy individuals and in patients with central motoneuron syndrome. The analysis of the literature demonstrated that the muscle tone has its passive (EMG silent) and active (EMG active) components. The passive component is given by viscoelastic characteristics of muscle tissues, i.e. of muscle fibres and interstitial connective tissue. The research indicates that the connective tissue also contains contractile cells, thus being also capable of active contractions. The active component is given by nervous reflexes, which are induced by a muscle extension: by the stretching segmental reflex and transcortical reflex. These reflexes are active in enhanced requirements for the joint stabilization. The spasticity can be defined as a disorder of the sensomotor system characterized by an increase in the muscle tone depending on the rate of the extension. The spasticity is one of components of central motoneuron syndrome together with an attenuation of flexor reflexes, muscle weakness and loss of the skill. An important role in this process belongs to changes in the activation of the stretching reflex due to the hyperexcitability of alpha motoneurons and reduction in the inhibition by descendent motor ways. Studies of proprioreceptors can be divided into morphological and electrophysiological ones. In terms of the function, the evaluation is of importance, according to which it is possible to differentiate one from another receptors with slow adaptation (static) detecting the joint situation and receptors with a rapid adaptation (dynamic) detecting the joint movement. The results of this study justify the following formulation of principal hypotheses for our work: 1) we can expect that irritation of skin receptors induces statistically significant changes in the tension of selected muscles and 2) we can expect the specificity between directions of the skin tension and facilitation or inhibition of the muscle tone. The analysis of the literature also significantly contributed to the formation of a homogeneous experimental group, particularly due to conclusions indicating that one group cannot simultaneously include patients with CMP and transversal medullar lesion since in terms of neurophysiology, these are no identical pathological conditions. A finding is also of importance that an increase in the passive muscle rigidity by connective tissue contractures or muscle fibrosis negatively affects the reflex action on skeletal muscles.

• MeSH
• H-Reflex MeSH
• Humans MeSH
• Mechanoreceptors MeSH
• Reflex, Stretch MeSH
• Review Literature as Topic MeSH
• Elasticity MeSH
• Reflexotherapy utilization   MeSH
• Rehabilitation MeSH
• Muscle Relaxation MeSH
• Muscle Spasticity therapy   MeSH
• Muscle Tonus MeSH
• Check Tag
• Humans MeSH

In the nervous system, the representation of signals is based predominantly on the rate and timing of neuronal discharges. In most everyday tasks, the brain has to carry out a variety of mathematical operations on the discharge patterns. Recent findings show that even single neurons are capable of performing basic arithmetic on the sequences of spikes. However, the interaction of the two spike trains, and thus the resulting arithmetic operation may be influenced by the stochastic properties of the interacting spike trains. If we represent the individual discharges as events of a random point process, then an arithmetical operation is given by the interaction of two point processes. Employing a probabilistic model based on detection of coincidence of random events and complementary computer simulations, we show that the point process statistics control the arithmetical operation being performed and, particularly, that it is possible to switch from subtraction to division solely by changing the distribution of the inter-event intervals of the processes. Consequences of the model for evaluation of binaural information in the auditory brainstem are demonstrated. The results accentuate the importance of the stochastic properties of neuronal discharge patterns for information processing in the brain; further studies related to neuronal arithmetic should therefore consider the statistics of the interacting spike trains.

• MeSH
• Action Potentials physiology   MeSH
• Humans MeSH
• Models, Neurological MeSH
• Nerve Net physiology   MeSH
• Neural Inhibition physiology   MeSH
• Neurons physiology   MeSH
• Computer Simulation MeSH
• Stochastic Processes MeSH
• Probability Theory MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

• Keywords
• Ekonomie,
• MeSH
• Economics MeSH

• NML Fields
• ekonomie, ekonomika, ekonomika zdravotnictví

Background: People gain weight when assume more calories than their body can consume. Instead, they lose weight when they consume more than what they eat. Comparing the body to a closed system, we can call calorie balance the difference between the input and output calories. However, keep a balanced diet regime is never a rewarding activity and often people give up. Objectives: The goal is to help subjects with overweight problems: educate these people reduces the number of people that might migrate in the obese class. We propose an application to encourage healthier lifestyles, whose innovative feature is an automatic adaptive monitoring of the daily calorie balance. The system uses a familiar device and motivates the users to reach best result with the diet. Methods: The energy consumption is related to the oxygen consumption, obviously also if combined with physical activity. The heart rate is directly related to the supply of oxygen. Using this simple relation, the heartbeats are bound to the calorie consumption. Results: People achieve a greater awareness about food dosage and its calories weight. Moreover the application allows a more careful choice in food selection in order to not vanish the efforts made to change the lifestyles. Conclusions: We have obtained good result with off-theshelf hardware and user friendly software solutions. The users consider the system like a game where they have to keep higher the burned calories level. A motivational application has been found to be a winning card to promote healthier lifestyles, without intimidating the user.

• Keywords
• dietní chyby, chest belt,
• MeSH
• Algorithms MeSH
• Equipment Design MeSH
• Energy Metabolism MeSH
• Energy Intake MeSH
• Humans MeSH
• Mobile Applications * utilization   MeSH
• Cell Phone MeSH
• Motivation MeSH
• Overweight diet therapy   MeSH
• Software Design MeSH
• Health Promotion MeSH
• Motor Activity MeSH
• Weight Reduction Programs * MeSH
• Diet, Reducing MeSH
• Sedentary Behavior MeSH
• Oxygen Consumption MeSH
• Heart Rate physiology   MeSH
• Telemedicine * MeSH
• Models, Theoretical MeSH
• User-Computer Interface MeSH
• Health Behavior MeSH
• Check Tag
• Humans MeSH

• MeSH
• Cell Biology MeSH
• Molecular Biology MeSH
• Publication type
• Monograph MeSH

• Conspectus
• Biochemie. Molekulární biologie. Biofyzika
• NML Fields
• biologie
• cytologie, klinická cytologie

In hyperthermia, the general opinion is that pre-treatment optimization of treatment settings requires a patient-specific model. For deep pelvic hyperthermia treatment planning (HTP), tissue models comprising four tissue categories are currently discriminated. For head and neck HTP, we found that more tissues are required for increasing accuracy. In this work, we evaluated the impact of the number of segmented tissues on the predicted specific absorption rate (SAR) for the pelvic region. Highly detailed anatomical models of five healthy volunteers were selected from a virtual database. For each model, seven lists with varying levels of segmentation detail were defined and used as an input for a modeling study. SAR changes were quantified using the change in target-to-hotspot-quotient and maximum SAR relative differences, with respect to the most detailed patient model. The main finding of this study was that the inclusion of high water content tissues in the segmentation may result in a clinically relevant impact on the SAR distribution and on the predicted hyperthermia treatment quality when considering our pre-established thresholds. In general, our results underline the current clinical segmentation protocol and help to prioritize any improvements.

• Publication type
• Journal Article MeSH

This paper describes the design, construction, and testing of a multi-channel fetal electrocardiogram (fECG) signal generator based on LabVIEW. Special attention is paid to the fetal heart development in relation to the fetus' anatomy, physiology, and pathology. The non-invasive signal generator enables many parameters to be set, including fetal heart rate (FHR), maternal heart rate (MHR), gestational age (GA), fECG interferences (biological and technical artifacts), as well as other fECG signal characteristics. Furthermore, based on the change in the FHR and in the T wave-to-QRS complex ratio (T/QRS), the generator enables manifestations of hypoxic states (hypoxemia, hypoxia, and asphyxia) to be monitored while complying with clinical recommendations for classifications in cardiotocography (CTG) and fECG ST segment analysis (STAN). The generator can also produce synthetic signals with defined properties for 6 input leads (4 abdominal and 2 thoracic). Such signals are well suited to the testing of new and existing methods of fECG processing and are effective in suppressing maternal ECG while non-invasively monitoring abdominal fECG. They may also contribute to the development of a new diagnostic method, which may be referred to as non-invasive trans-abdominal CTG +  STAN. The functional prototype is based on virtual instrumentation using the LabVIEW developmental environment and its associated data acquisition measurement cards (DAQmx). The generator also makes it possible to create synthetic signals and measure actual fetal and maternal ECGs by means of bioelectrodes.

• MeSH
• Algorithms * MeSH
• Abdomen physiology   MeSH
• Electrocardiography methods   MeSH
• Gestational Age MeSH
• Cardiotocography MeSH
• Humans MeSH
• Fetal Monitoring methods   MeSH
• Nonlinear Dynamics MeSH
• Fetus physiology   MeSH
• Signal Processing, Computer-Assisted * MeSH
• Heart physiology   MeSH
• Heart Rate, Fetal physiology   MeSH
• Pregnancy MeSH
• Check Tag
• Humans MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Coniferous forests cover extensive areas of the boreal and temperate zones. Owing to their primary production and C storage, they have an important role in the global carbon balance. Forest disturbances such as forest fires, windthrows or insect pest outbreaks have a substantial effect on the functioning of these ecosystems. Recent decades have seen an increase in the areas affected by disturbances in both North America and Europe, with indications that this increase is due to both local human activity and global climate change. Here we examine the structural and functional response of the litter and soil microbial community in a Picea abies forest to tree dieback following an invasion of the bark beetle Ips typographus, with a specific focus on the fungal community. The insect-induced disturbance rapidly and profoundly changed vegetation and nutrient availability by killing spruce trees so that the readily available root exudates were replaced by more recalcitrant, polymeric plant biomass components. Owing to the dramatic decrease in photosynthesis, the rate of decomposition processes in the ecosystem decreased as soon as the one-time litter input had been processed. The fungal community showed profound changes, including a decrease in biomass (2.5-fold in the litter and 12-fold in the soil) together with the disappearance of fungi symbiotic with tree roots and a relative increase in saprotrophic taxa. Within the latter group, successive changes reflected the changing availability of needle litter and woody debris. Bacterial biomass appeared to be either unaffected or increased after the disturbance, resulting in a substantial increase in the bacterial/fungal biomass ratio.

• MeSH
• Biomass MeSH
• Coleoptera physiology   MeSH
• Fungi classification   isolation & purification   MeSH
• Forests * MeSH
• Soil Microbiology * MeSH
• Picea MeSH
• Trees MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

• MeSH
• Electrodiagnosis methods   MeSH
• Electromyography MeSH
• Spinal Cord Diseases diagnosis   MeSH
• Neural Conduction physiology   MeSH
• Synaptic Transmission physiology   MeSH
• Neuromuscular Diseases diagnosis   MeSH

• Conspectus
• Patologie. Klinická medicína
• NML Fields
• neurologie
• diagnostika
• NML Publication type
• kolektivní monografie