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Results for “spatial sequencing”

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PubMed2002

MRI of the coronary arteries: flip angle train optimization for 3D sequences.

Application of contrast agents in MRI of coronary arteries improves contrast-to-noise ratio (CNR), but widens the range of T1 relaxation times of the tissues to be imaged. The flip angle train, generated for the measurement of all phase-encoding steps in the 3rd spatial dimension of the navigator echo FLASH sequence used, is optimal only for one T1. Computer simulations show that it is not advisable to optimize the sequence on the basis of an extremely short T1 relaxation time (such as in the case of contrast-enhanced vessels) because the imaging of the surrounding tissue would be negatively influenced. A sequence optimization to a T1 of approximately 200 ms seems to allow a CNR improvement of > or = 50%.

Computer Simulation↗

PubMed2003

[Identification of Streptococcus species and Haemophilus influenzae by direct sequencing of PCR products from 16S-23S rRNA itergenic sacer regions].

To facilitate species level identification of bacteria without the requirement of presumptive identification, the paper describes a rapid identification method of bacteria by amplification and direct sequencing 16S-23S rDNA intergenic spacer regions (ISR) of the pathogens which cause the upper respiratory tract infective disease by Streptococcus and Haemophilus. Three pairs of primer targeting conserved sequences flanking the 3' end of 16S and the 5' end of 23S rRNA were used to amplify 16S~23S rRNA ISR of 7 streptococcus strains and 8 Haemophilus strains. The PCR products were separated by 1% agarose gel electrophoresis and the polymorphisms fragments were purified with the Wizard PCR Min-Prep Kit (Promega) and Protocol-SK131(Sangon). The nucleotide sequences of ISR inserts were determined by using the XEQTM DTCS Kitjj Terminator Cycle Sequencing and a CEQTM 2000XL DNA Analysis system (Backman Coulter) automatic DAN sequencer. Then those sequences were compared with known sequences on the GenBank. The alignment of nucleotide sequence, evolutionary distances and phylogenetic trees were analyzed by software DANMAN version 4.0. The PCR products were showed polymorphism patterns with agarose gel. One band was contained in streptococcus genus. The significant variation was found among the spacer sequences of different species in Streptococcus with the lengths of the spacer varying from 269 to 446 bp. All the ISR of the streptococcal species had a tRNA Ala gene in the spacer and the sequence identities varied from 78 to 88% within genera. It was found that some spacer sequence blocks were highly conserved between operons of a genome, whereas the presence of others was variable, three regions showed significant spatial variation. Most of the differences between the sequences came from several bases insertions/deletions and substitutions. There are two major bands in the Haemophilus biotypes (515 and 884 bp), the small ISR amplicon contained one tDNA coding for tRNA(Glu). In contrast to the large one contained two tRNA genes coding for tRAN(Ala) and tRNA(Ile). Two regions of repeating motifs with only A or T were present in higher copy numbers between tRAN(Ala) and tRNA(Ile). The phylogenetic trees varied from 97.5 to 98.8%. The PCR and direct sequencing of 16S-23S rRAN ISR were successful in the pathogen species identification.

English Abstract↗

PubMed1985

Mutual spatial orientation of hexons in the adenovirus capsid by electron microscopy and modelling.

On the basis of electron microscopic analysis of the virion and model experiments there are four hexon species in the adenovirus capsid which have different positional status and spatial orientation as compared to the six nearest neighbouring capsomers. The binding pattern of the polypeptide subunits according to their orientation is also different. The four hexon species are situated beside one another in the capsid and they form the capsid of 240 hexons besides the penton by repeating symmetrically 60 times, as a group of four hexons (GOF). Electron microscopic analysis and model experiments lead to the conclusion that the mutual spatial orientation of GOF hexons can be parallel (their longitudinal axes are parallel), or the direction of their longitudinal axes is different in one or two planes, thus they form different angles with the longitudinal axes of the neighbouring hexons. In the latter cases therefore, a bend and torsion of the bindings (connective elements) can be supposed as compared to the tendency-plane of parallel bindings. Based on the different combinations of the three kinds of rotational orientation of polypeptide subunits and of the different spatial orientation of hexons, six kinds of interhexonal bindings can be found in the adenovirus capsid. The distribution and characteristics of the 690 interhexonal bindings are the following; 240 bindings of "one-to-two" polypeptide orientation with parallel spatial orientation; 180 bindings of "one-to-two" polypeptide with spatial orientation divergent in two planes; 30 bindings of "one-to-one" polypeptide orientation with parallel spatial orientation; 60 bindings of "one-to-one" polypeptide orientation with spatial orientations divergent in one plane; 60 bindings of "one-to-one" polypeptide orientation with spatial orientation divergent in two planes; 120 bindings of "two-to-two" polypeptide orientation with spatial orientation divergent in two planes. The dissociational sequence of the capsid suggests that the firmest bindings are the ones having "one-to-two" polypeptide orientation and parallel spatial orientation. It may be supposed that any two hexons are able to connect to each other according to all three polypeptide orientations and the connections can tolerate the bends and torsions arising from the icosahedral structure. This suggests that only one kind of hexon is existing and the adenovirus capsid is formed by a homogeneous hexon population.

Adenoviridae↗

PubMed1999

Intranuclear anchoring of repetitive DNA sequences: centromeres, telomeres, and ribosomal DNA.

Centromeres, telomeres, and ribosomal gene clusters consist of repetitive DNA sequences. To assess their contributions to the spatial organization of the interphase genome, their interactions with the nucleoskeleton were examined in quiescent and activated human lymphocytes. The nucleoskeletons were prepared using "physiological" conditions. The resulting structures were probed for specific DNA sequences of centromeres, telomeres, and ribosomal genes by in situ hybridization; the electroeluted DNA fractions were examined by blot hybridization. In both nonstimulated and stimulated lymphocytes, centromeric alpha-satellite repeats were almost exclusively found in the eluted fraction, while telomeric sequences remained attached to the nucleoskeleton. Ribosomal genes showed a transcription-dependent attachment pattern: in unstimulated lymphocytes, transcriptionally inactive ribosomal genes located outside the nucleolus were eluted completely. When comparing transcription unit and intergenic spacer, significantly more of the intergenic spacer was removed. In activated lymphocytes, considerable but similar amounts of both rDNA fragments were eluted. The results demonstrate that: (a) the various repetitive DNA sequences differ significantly in their intranuclear anchoring, (b) telomeric rather than centromeric DNA sequences form stable attachments to the nucleoskeleton, and (c) different attachment mechanisms might be responsible for the interaction of ribosomal genes with the nucleoskeleton.

Cell Nucleus↗

PubMed1988

Developmental appearance of factors that bind specifically to cis-regulatory sequences of a gene expressed in the sea urchin embryo.

Previous gene-transfer experiments have identified a 2500-nucleotide 5' domain of the CyIIIa cytoskeletal actin gene, which contains cis-regulatory sequences that are necessary and sufficient for spatial and temporal control of CyIIIa gene expression during embryogenesis. This gene is activated in late cleavage, exclusively in aboral ectoderm cell lineages. In this study, we focus on interactions demonstrated in vitro between sequences of the regulatory domain and proteins present in crude extracts derived from sea urchin embryo nuclei and from unfertilized eggs. Quantitative gel-shift measurements are utilized to estimate minimum numbers of factor molecules per embryo at 24 hr postfertilization, when the CyIIIa gene is active, at 7 hr, when it is still silent, and in the unfertilized egg. We also estimate the binding affinity preferences (Kr) of the various factors for their respective sites, relative to their affinity for synthetic DNA competitors. At least 14 different specific interactions occur within the regulatory regions, some of which produce multiple DNA-protein complexes. Values of Kr range from approximately 2 x 10(4) to approximately 2 x 10(6) for these factors under the conditions applied. With one exception, the minimum factor prevalences that we measured in the 400-cell 24-hr embryo nuclear extracts fell within the range of 2 x 10(5) to 2 x 10(6) molecules per embryo, i.e., a few hundred to a few thousand molecules per nucleus. Three developmental patterns were observed with respect to factor prevalence: Factors reacting at one site were found in unfertilized egg cytoplasm at about the same level per egg or embryo as in 24-hr embryo nuclei; factors reacting with five other regions of the regulatory domain are not detectable in egg cytoplasm but in 7-hr mid-cleavage-stage embryo, nuclei are already at or close to their concentrations in the 24-hr embryo nuclei; and factors reacting with five additional regions are not detectable in egg cytoplasm and are low in 7-hr embryo nuclei, i.e., less than or equal to 10% per embryo of the level they attain in 24-hr embryo nuclei. The rise in concentration of factors of the latter class could provide the proximal cause for the temporal activation of the CyIIIa gene at the early blastula stage.

Animals↗

PubMed1995

[Dynamic 3D MR mammography using a rapid gradient-echo sequence].

Up to now, MR mammography is performed by two different methods: 2-D techniques with high temporal resolution and 3-D techniques with high spatial resolution. This article investigates whether a dynamic examination of the breast using a novel 3-D-gradient-echo sequence is feasible with sufficient spatial and temporal resolution. MR imaging was performed on a 1.0 Tesla imager using a gradient field strength of 15 mT/m. Phantom measurements were done to evaluate the correlation between signal intensity and contrast medium concentration for different sequences. Subsequently, 40 patients with 22 histologically verified lesions were examined using the double breast coil and a novel FLASH3D sequence (TR/TE/fa 9/3/50 degrees). Reading of the films in standardized documentation, multiplanar reconstruction (MPR), calculation and maximum intensity projection (MIP) of subtraction images as well as signal-to-time curve calculations in selected ROIs were performed for data evaluation. In the phantom measurements the FLASH3D-9/3/50 degrees sequence yielded the best correlation between signal intensity and Gd-DTPA concentration. The sequence provided good visualization even of small lesions. The 3-D postprocessing procedures facilitated the detection and localization of the lesions. Therefore, the new FLASH3D-9/3/50 degrees sequence enables a dynamic 3-D examination of the breast with a sufficient spatial and temporal resolution.

Adolescent↗

PubMed2026

Life in sediments fosters 'sexual' speciation in the Shewanella baltica complex.

Understanding how intra- and interspecific differentiation arises in natural microbial populations is central to explaining the processes that drive bacterial evolution. Motivated by the co-occurrence of multiple putative genospecies closely related to Shewanella baltica in Baltic Sea sediments, we investigated the genomic structure of this species complex across fine spatial scales. We analyzed 112 genome sequences from strains collected across several sediment cores and depths (0-6 cm) at Vaxön (Stockholm archipelago, Sweden) as well as earlier isolates from this site and allopatric strains from surrounding locations obtained from both sediments and the water column. Using a reverse-ecology population genomics approach, we found unprecedented genomic diversification among sediment-associated strains, which form a species complex resolving into three cohesive evolutionary groups (G1, G2, and G3) with distinct signatures of metabolic specialization including sulfite respiration. While G1 consists predominantly of a single species (S. baltica) with high gene turnover, G2 and G3 comprise an array of divergent putative genospecies and previously reported species consistently recovered from sediments. Patterns of homologous recombination indicate that diversification of the lineages within G2 and G3 is primarily recombination-driven ('sexual') and is associated with specialization in sulfite reduction and utilization of certain carbon sources. The extent of diversity uncovered here far exceeds that reported for S. baltica from other environments, suggesting that a sediment-associated lifestyle promotes the emergence of novel genotypes. These findings expand the known limits of sympatric speciation in prokaryotes beyond subspecific ecotypes, demonstrating that bacterial species can diverge and persist as distinct lineages in the absence of spatial segregation and at microgeographic scales. Furthermore, our results suggest that collective interactions and ecological differentiation can structure sediment-associated bacterial populations strongly enough to drive divergence at the species level.

Journal Article↗

PubMed2025

ConceptDrift: leveraging spatial, temporal and semantic evolution of biomedical concepts for hypothesis generation.

MOTIVATION: Hypothesis generation is a fundamental problem in biomedical text mining that aims to generate ideas that are new, interesting, and plausible by discovering unexplored links between biomedical concepts. Despite significant advances made by existing approaches, they do not fully leverage the evolutionary properties of biomedical concepts. This is limiting because scientific knowledge continually evolves over time, with new facts being added and old ones becoming obsolete. Thus, it is crucial to capture the evolutionary properties of biomedical concepts from multiple perspectives (e.g. spatial, temporal, and semantic) to generate hypotheses that reflect the up-to-date information landscape of the biomedical domain. RESULTS: We introduce a novel framework, ConceptDrift, that models the hypothesis generation task as a sequence of temporal graphlets and simultaneously encodes spatial, temporal, and semantic change. Unlike existing approaches that treat these dimensions independently, ConceptDrift is the first to provide a holistic understanding of concept evolution by integrating them into a unified framework. Grounded in the theories of the Distributional Hypothesis and Conceptual Change, our method adapts these principles to the unique challenges of large-scale biomedical literature. We conduct extensive experiments across multiple datasets and demonstrate that ConceptDrift consistently outperforms state-of-the-art baselines in generating accurate and meaningful hypotheses. Our framework shows immediate practical benefits for web-based literature mining tools in life sciences and biomedicine, offering more robust and predictive feature representations. AVAILABILITY AND IMPLEMENTATION: https://github.com/amir-hassan25/ConceptDrift (DOI: 10.6084/m9.figshare.29975476).

Semantics↗

PubMed1998

[Efficacy of multidirection MRCP].

Pancreatobiliary system has complex and thin structure except for gallbladder, thereby MRCP having lower spatial resolution gives sufficient information compared with the direct cholangiopancreatography. Multidirection MRCP using HASTE sequence obtains the data in plane to compensate the lower spatial resolution, thus high detectability of all over pancreatobiliary system is performed in a few minutes. This technique overcomes the demerits pointed by former investigators and gives sufficient information to diagnose the pancreatobiliary diseases.

Biliary Tract↗

PubMed1999

Mechanisms of mRNA surveillance in eukaryotes.

A conserved mRNA degradation system, referred to as mRNA surveillance, exists in eukaryotic cells to degrade aberrant mRNAs. A defining aspect of aberrant transcripts is that the spatial relationship between the termination codon and specific downstream sequence information has been altered. A key, yet unknown, feature of the mRNA surveillance system is how this spatial relationship is assessed in individual transcripts. Two views have emerged to describe how discrimination between proper and improper termination might occur. In the first view, a surveillance complex assembles onto the mRNA after translation termination, and scans the mRNA in a 3' to 5' direction for a limited distance. If specific downstream sequence information is encountered during this scanning, then the surveillance complex targets the transcript for rapid decay. An alternate view suggests that the downstream sequence information influences how translation termination occurs. This view encompasses several ideas including: (a) The architecture of the mRNP can alter the rate of key steps in translation termination; (b) the discrimination between a proper and improper termination occurs via an internal, Upf1-dependent, timing mechanism; and (c) proper termination results in the restructuring of the mRNP to a form that promotes mRNA stability. This proposed model for mRNA surveillance is similar to other systems of kinetic proofreading that monitor the accuracy of other biogenic processes such as translation and spliceosome assembly.

Animals↗

PubMed1998

Murine Hoxc-9 gene contains a structurally and functionally conserved enhancer.

Reporter gene analysis of the Hoxc-9 genomic region in transgenic mice allowed us to identify a positional enhancer in the Hoxc-9 intron that drives expression in the posterior neural tube of midgestation mouse embryos in a Hoxc-9-related manner. Sequence comparison to the chicken Choxc-9 intron revealed the existence of two highly conserved sequence elements (CSEs) in a similar spatial arrangement. These structural similarities in the mammalian and avian lineage are mirrored by conserved function of the chicken Choxc-9 intron in transgenic mice. Deletion analysis of the two introns suggests that full activity of both enhancers depends on cooperation between the two CSEs located close to the respective 5' and 3' splice sites. Following the paradigm of phylogenetically conserved developmental control mechanisms, the Hoxc-9 intragenic enhancer was tested in Drosophila. Our data show that the mouse Hoxc-9 enhancer acts in a conserved fashion in transgenic flies, conferring posteriorly restricted reporter gene expression to the developing central nervous system in third instar larvae. This finding indicates that the Hoxc-9 intragenic enhancer is involved in transcriptional regulatory circuits conserved between vertebrates and arthropods.

Animals↗

PubMed1988

Characterization of products derived from self-splicing of intron aI5 alpha which is located in the mitochondrial COX I gene of Saccharomyces cerevisiae.

We have characterized the in vitro self-splicing of intron aI5 alpha containing precursor RNA from the yeast mitochondrial gene coding for cytochrome oxidase subunit I. This intron follows the rules for group I self-splicing introns and all the characteristic products have been identified. In addition we have detected abnormal RNA products with features that indicate that the self-splicing behaviour of this intron is more complex. Two intron circles are formed by use of a major and minor intron-internal site for circle closure. A cryptic 5'-splice site located in the 3' exon results in guanosine nucleotide mediated opening at a position 30 nt downstream of the normal 3' splice site. The reactions can all be explained on the basis of the "splice guide" model proposed by Davies et al (1982 Nature 300 719-724). Although the sequence motifs at cyclization and splice sites occur more often in this intron, only some of them are allowed to interact with the internal guide sequence, suggesting that both primary structure and spatial folding of the RNA are involved in formation of productive reaction sites.

Base Sequence↗

PubMed1991

Temporal and spatial analysis of fields generated by eddy currents in superconducting magnets: optimization of corrections and quantitative characterization of magnet/gradient systems.

We propose methods for the spatial and temporal characterization of time-dependent magnetic fields generated by eddy currents after switching gradients. For an on-line determination of the temporal variations of the fields, we extract two terms from the unresolved signal of an extended sample, describing the time evolution of a frequency shift gamma delta Bz(t) and of a decay constant k(t). This procedure allows us to optimize interactively the multiexponential pre-emphasis as well as any spectral volume selection method with respect to eddy currents. Additionally, we suggest an imaging sequence which allows us to determine the spatial distribution of eddy current fields at a chosen time-point after any gradient sequence to be tested. Expansion of these eddy currents fields into spherical harmonic functions proves the existence of a higher order terms, which cannot be corrected by a standard pre-emphasis device, where time constants and amplitudes are adjusted on the X, Y, Z, and Z0 coils. The proposed numerical analysis gives a tool to characterize any magnet/gradient system quantitatively with respect to eddy current performance.

Magnetic Resonance Imaging↗

PubMed2005

Space-time super-resolution.

We propose a method for constructing a video sequence of high space-time resolution by combining information from multiple low-resolution video sequences of the same dynamic scene. Super-resolution is performed simultaneously in time and in space. By "temporal super-resolution," we mean recovering rapid dynamic events that occur faster than regular frame-rate. Such dynamic events are not visible (or else are observed incorrectly) in any of the input sequences, even if these are played in "slow-motion." The spatial and temporal dimensions are very different in nature, yet are interrelated. This leads to interesting visual trade-offs in time and space and to new video applications. These include: 1) treatment of spatial artifacts (e.g., motion-blur) by increasing the temporal resolution and 2) combination of input sequences of different space-time resolutions (e.g., NTSC, PAL, and even high quality still images) to generate a high quality video sequence. We further analyze and compare characteristics of temporal super-resolution to those of spatial super-resolution. These include: How many video cameras are needed to obtain increased resolution? What is the upper bound on resolution improvement via super-resolution? What is the temporal analogue to the spatial "ringing" effect?

Algorithms↗

PubMed1994

Silicone breast implant rupture: comparison between three-point Dixon and fast spin-echo MR imaging.

OBJECTIVE: This study was designed to compare the three-point Dixon technique with our present MR protocol incorporating T2-weighted fast spin echo and fast spin echo with water suppression to detect ruptured silicone breast implants. SUBJECTS AND METHODS: Eighty-two symptomatic women with silicone breast implants were examined with both the three-point Dixon technique and fast spin-echo MR sequences. Of these patients, 41 had surgery to remove their implants. Four radiologists reviewed the images from only those patients who had surgery and graded each for rupture by using a scale of 1-5. Receiver-operating-characteristic analysis was performed. RESULTS: Of 81 implants removed, 18 were ruptured. Silicone implant ruptures were identified more frequently on the fast spin-echo sequence than on the three-point Dixon sequence, with areas under the ROC curves of .95 and .84, respectively. Although the difference was not statistically significant, the sensitivity for detecting silicone implant rupture was 89% for the fast spin-echo sequence and 61% for the three-point Dixon sequence. The specificity was 97% for both sequences. CONCLUSION: Silicone implant ruptures were detected more frequently with fast spin-echo MR sequences than with the three-point Dixon technique, although the difference was not significant. The greater spatial resolution used for the fast spin-echo sequence partially accounts for the difference in detection of implant ruptures in this study.

Breast↗

PubMed1999

R-cadherin expression in the developing and adult zebrafish visual system.

Cell adhesion molecules in the cadherin family have been implicated in histogenesis and maintenance of cellular structure and function in several organs. Zebrafish have emerged as an important new developmental model, but only three zebrafish cadherin molecules have been identified to date (N-cadherin, paraxial protocadherin, and VN-cadherin). We began a systematic study to identify other zebrafish cadherins by screening zebrafish cDNA libraries using an antibody raised to the cytoplasmic domain of mouse E-cadherin. Here, we report a partial cDNA with extensive sequence homology to R-cadherin. Spatial and temporal expression of this putative zebrafish R-cadherin was examined in embryos and adults by Northern analysis, RNase protection, and in situ hybridization. R-cadherin message increased during embryogenesis up to 80 hours postfertilization (hpf) and persisted in adults. In the embryonic brain, R-cadherin was first expressed in groups of cells in the diencephalon and pretectum. In adult zebrafish brain, R-cadherin continued to be expressed in several specific regions including primary visual targets. In the retina, R-cadherin was first detected at about 33 hours postfertilization in the retinal ganglion cell layer and the inner part of the inner nuclear layer. Expression levels were highest during periods of axon outgrowth and synaptogenesis. Retrograde labeling of the optic nerve with 1,1'-dioctadecyl-3,3,3',3', tetramethylindocarbocyanine perchlorate (DiI) followed by in situ hybridization confirmed that a subset of retinal ganglion cells in the embryo expressed R-cadherin message. In the adult, R-cadherin expression continued in a subpopulation of retinal ganglion cells. These results suggest that R-cadherin-mediated adhesion plays a role in development and maintenance of neuronal connections in zebrafish visual system.

Age Factors↗

PubMed2002

Population structure of plaice (Pleuronectes platessa L.) in northern Europe: microsatellites revealed large-scale spatial and temporal homogeneity.

Philopatry to spawning grounds combined with well-known migratory patterns in the flatfish Pleuronectes platessa (plaice) has led to the hypothesis that regional populations may reflect relatively discrete, genetic stocks. Using six microsatellite loci we genotyped 240 adult individuals collected from locations in Norway, the Faeroe plateau, the Irish Sea, the Femer Baelt, Denmark, and the southern North Sea, and 240 0-class juveniles collected from five nursery-ground locations in Iceland, northwest Scotland, two sites in the Wadden Sea, and the Bay of Vilaine in Southern Brittany. The mean number of alleles/locus ranged from 5.3 to 20.4, with a mean of 13.9. Expected heterozygosity was uniformly high across all locations (multilocus H(exp)= 0.744 +/- 0.02). Pairwise comparisons of theta; among all 11 locations revealed significant differentiation between Iceland and all other locations (theta = 0.0290*** to 0.0456***), which is consistent with the deep-water barrier to dispersal in plaice. In contrast, no significant differentiation was found among any of the remaining continental-shelf sampling locations. This suggests that regional stocks are themselves composed of several genetic stocks under a model of panmixia which persists even to the spawning grounds. The presence of significant heterozygote deficiencies at all locations (not due to null alleles) suggests a temporal Wahlund effect yet the absence of significant population differentiation among continental shelf localities makes this explanation alone, difficult to reconcile. Sampling of eggs at the spawning grounds will be required to resolve this issue. Causes of the mismatch between genetic and geographical stocks is discussed in the context of high gene flow.

Alleles↗

PubMed2002

Non-invasive monitoring of functionally distinct muscle activations during swallowing.

OBJECTIVES: Dysphagia is an important consequence of many diseases. As some of the muscles of deglutition tend to be deep to the surface, needle electrodes are typically used, but this limits the number of muscles that can be simultaneously recorded. Since control of swallowing involves central pattern generators (CPGs) which distribute commands to several muscles, monitoring several muscles simultaneously is desirable. Here we describe a novel method, based on computing the independent components (ICs) of the simultaneous sEMG recordings (Muscle Nerve Suppl 9 (2000) 9) to detect the underlying functional muscle activations during swallowing using only surface EMG (sEMG) electrodes. METHODS: Seven normal subjects repeatedly swallowed liquids of varying consistency while sEMG was recorded from 15 electrodes from the face and throat. Active areas of EMG were excised from the recordings and the ICs of the sEMG were calculated. RESULTS: The ICs demonstrated less swallow-to-swallow variability than the raw sEMG. The ICs, each consisting of a unique temporal waveform and a spatial distribution, provided a means to segregate the complex sequence of muscle activation into rigorously defined separate functional units. The temporal profiles of the ICs and their spatial distribution were consistent with prior needle EMG studies of the cricopharyngeal, superior pharyngeal constrictor, submental and possibly arytenoid muscles. Other components appeared to correspond to EKG artifact contaminating the EMG recordings, laryngeal excursion, tongue movement and activation of the buccal and/or masseter musculature At least two of the components were affected by the consistency of the liquids swallowed. Re-testing one subject a week later demonstrated good intertrial reliability. CONCLUSIONS: We propose that the ICs of the sEMG provide a non-invasive means to assess the complex muscle sequence activation of deglutition.

Adult↗