Standard spectral density mapping protocols, well suited for the analysis of (15)N relaxation rates, introduce significant systematic errors when applied to (13)C relaxation data, especially if the dynamics is dominated by motions with short correlation times (small molecules, dynamic residues of macromolecules). A possibility to improve the accuracy by employing cross-correlated relaxation rates and on measurements taken at several magnetic fields has been examined. A suite of protocols for analyzing such data has been developed and their performance tested. Applicability of the proposed protocols is documented in two case studies, spectral density mapping of a uniformly labeled RNA hairpin and of a selectively labeled disaccharide exhibiting highly anisotropic tumbling. Combination of auto- and cross-correlated relaxation data acquired at three magnetic fields was applied in the former case in order to separate effects of fast motions and conformational or chemical exchange. An approach using auto-correlated relaxation rates acquired at five magnetic fields, applicable to anisotropically moving molecules, was used in the latter case. The results were compared with a more advanced analysis of data obtained by interpolation of auto-correlated relaxation rates measured at seven magnetic fields, and with the spectral density mapping of cross-correlated relaxation rates. The results showed that sufficiently accurate values of auto- and cross-correlated spectral density functions at zero and (13)C frequencies can be obtained from data acquired at three magnetic fields for uniformly (13)C-labeled molecules with a moderate anisotropy of the rotational diffusion tensor. Analysis of auto-correlated relaxation rates at five magnetic fields represents an alternative for molecules undergoing highly anisotropic motions.

• MeSH
• algoritmy * MeSH
• interpretace statistických dat * MeSH
• magnetická rezonanční spektroskopie s uhlíkem 13C metody   MeSH
• magnetické pole MeSH
• malá interferující RNA analýza   chemie   MeSH
• počítačové zpracování signálu * MeSH
• reprodukovatelnost výsledků MeSH
• senzitivita a specificita MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND AND OBJECTIVE: Capturing the population variability of bone properties is of paramount importance to biomedical engineering. The aim of the present paper is to describe variability and correlations in bone mineral density with a spatial random field inferred from routine computed tomography data. METHODS: Random fields were simulated by transforming pairwise uncorrelated Gaussian random variables into correlated variables through the spectral decomposition of an age-detrended correlation matrix. The validity of the random field model was demonstrated in the spatiotemporal analysis of bone mineral density. The similarity between the computed tomography samples and those generated via random fields was analyzed with the energy distance metric. RESULTS: The random field of bone mineral density was found to be approximately Gaussian/slightly left-skewed/strongly right-skewed at various locations. However, average bone density could be simulated well with the proposed Gaussian random field for which the energy distance, i.e., a measure that quantifies discrepancies between two distribution functions, is convergent with respect to the number of correlation eigenpairs. CONCLUSIONS: The proposed random field model allows the enhancement of computational biomechanical models with variability in bone mineral density, which could increase the usability of the model and provides a step forward in in-silico medicine.

• MeSH
• kosti a kostní tkáň * MeSH
• kostní denzita * MeSH
• počítačová rentgenová tomografie MeSH
• Publikační typ
• časopisecké články MeSH

It has long been known that environmental conditions, particularly during development, affect morphological and functional properties of the brain including sensory systems; manipulating the environment thus represents a viable way to explore experience-dependent plasticity of the brain as well as of sensory systems. In this review, we summarize our experience with the effects of acoustically enriched environment (AEE) consisting of spectrally and temporally modulated complex sounds applied during first weeks of the postnatal development in rats and compare it with the related knowledge from the literature. Compared to controls, rats exposed to AEE showed in neurons of several parts of the auditory system differences in the dendritic length and in number of spines and spine density. The AEE exposure permanently influenced neuronal representation of the sound frequency and intensity resulting in lower excitatory thresholds, increased frequency selectivity and steeper rate-intensity functions. These changes were present both in the neurons of the inferior colliculus and the auditory cortex (AC). In addition, the AEE changed the responsiveness of AC neurons to frequency modulated, and also to a lesser extent, amplitude-modulated stimuli. Rearing rat pups in AEE leads to an increased reliability of acoustical responses of AC neurons, affecting both the rate and the temporal codes. At the level of individual spikes, the discharge patterns of individual neurons show a higher degree of similarity across stimulus repetitions. Behaviorally, rearing pups in AEE resulted in an improvement in the frequency resolution and gap detection ability under conditions with a worsened stimulus clarity. Altogether, the results of experiments show that the exposure to AEE during the critical developmental period influences the frequency and temporal processing in the auditory system, and these changes persist until adulthood. The results may serve for interpretation of the effects of the application of enriched acoustical environment in human neonatal medicine, especially in the case of care for preterm born children.

• MeSH
• akustická stimulace * MeSH
• akustika MeSH
• colliculus inferior růst a vývoj   fyziologie   MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• neurony fyziologie   MeSH
• neuroplasticita * fyziologie   MeSH
• novorozená zvířata MeSH
• sluchová dráha * růst a vývoj   fyziologie   MeSH
• sluchová percepce MeSH
• sluchové korové centrum * růst a vývoj   fyziologie   MeSH
• věkové faktory MeSH
• životní prostředí MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

• MeSH
• fyzikální jevy MeSH
• magnetická rezonanční tomografie MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• radiologie, nukleární medicína a zobrazovací metody
• NLK Publikační typ
• kolektivní monografie

• MeSH
• fyzika MeSH

• Konspekt
• Fyzika
• Učební osnovy. Vyučovací předměty. Učebnice
• NLK Obory
• fyzika, biofyzika
• NLK Publikační typ
• učebnice vysokých škol

• MeSH
• fyzika MeSH

• Konspekt
• Přírodní vědy. Matematické vědy
• NLK Obory
• přírodní vědy
• NLK Publikační typ
• učebnice vysokých škol

The structure of neurons in the central auditory system is vulnerable to various kinds of acoustic exposures during the critical postnatal developmental period. Here we explored long-term effects of exposure to an acoustically enriched environment (AEE) during the third and fourth weeks of the postnatal period in rat pups. AEE consisted of a spectrally and temporally modulated sound of moderate intensity, reinforced by a behavioral paradigm. At the age of 3-6 months, a Golgi-Cox staining was used to evaluate the morphology of neurons in the inferior colliculus (IC), the medial geniculate body (MGB), and the auditory cortex (AC). Compared to controls, rats exposed to AEE showed an increased mean dendritic length and volume and the soma surface in the external cortex and the central nucleus of the IC. The spine density increased in both the ventral and dorsal divisions of the MGB. In the AC, the total length and volume of the basal dendritic segments of pyramidal neurons and the number and density of spines on these dendrites increased significantly. No differences were found on apical dendrites. We also found an elevated number of spines and spine density in non-pyramidal neurons. These results show that exposure to AEE during the critical developmental period can induce permanent changes in the structure of neurons in the central auditory system. These changes represent morphological correlates of the functional plasticity, such as an improvement in frequency tuning and synchronization with temporal parameters of acoustical stimuli.

• MeSH
• akustická stimulace MeSH
• colliculus inferior cytologie   fyziologie   MeSH
• dendritické trny fyziologie   MeSH
• dendrity fyziologie   MeSH
• krysa rodu rattus MeSH
• metathalamus cytologie   fyziologie   MeSH
• neurony cytologie   fyziologie   MeSH
• neuroplasticita fyziologie   MeSH
• novorozená zvířata MeSH
• potkani Long-Evans MeSH
• sluchová dráha cytologie   fyziologie   MeSH
• sluchové korové centrum cytologie   fyziologie   MeSH
• tvar buňky fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Preictal, ictal, and postictal oscillations in the basal ganglia were analyzed. Five persons with temporal lobe epilepsy who were candidates for surgery had diagonal depth electrodes implanted in the basal ganglia: four of them in the putamen, and one in the pallidum and caudate. Time-frequency and power spectral analyses were used to analyze the EEG. Significant frequency components of 2-10 Hz were consistently observed in the basal ganglia. The frequency of this component slowed during seizures. There was a significant ictal increase in power spectral density in all frequency ranges. The changes in the basal ganglia were consistent while seizure activity spread over the cortex, and partially persisted after the clinical seizure ended. They were inconsistent in the period after seizure onset. Seizures originating in the mesiotemporal structures can affect physiological rhythms in the basal ganglia. The basal ganglia did not generate epileptiform EEG activity. An inhibitory role for the basal ganglia during temporal lobe seizures is suggested.

• MeSH
• analýza hlavních komponent MeSH
• audiovizuální záznam metody   MeSH
• bazální ganglia patofyziologie   MeSH
• biologické hodiny fyziologie   MeSH
• dospělí MeSH
• elektroencefalografie metody   MeSH
• epilepsie temporálního laloku patologie   MeSH
• lidé MeSH
• mapování mozku MeSH
• mladý dospělý MeSH
• mozkové vlny fyziologie   MeSH
• spektrální analýza MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Klíčová slova
• SPSS 6.1,

• Konspekt
• Lékařské vědy. Lékařství
• NLK Obory
• lékařská informatika