Structural complexity of motor patterns: A study on reaction times and movement times of handwritten letters

1984 ◽  
Vol 46 (1-2) ◽  
pp. 49-57 ◽  
Author(s):  
Gerard P. van Galen
Keyword(s):  
Reaction Times ◽  
Structural Complexity ◽  
Motor Patterns

scholarly journals Use-Dependent Plasticity Enhances Nociceptive and Non-Nociceptive Somatosensory Cortical Responses in Healthy Individuals

2020 ◽  
Author(s):  
A.M. Zamorano ◽  
B. Kleber ◽  
F. Arguissain ◽  
P. Vuust ◽  
H. Flor ◽  
...  
Keyword(s):  
Neural Plasticity ◽  
Musical Training ◽  
Reaction Times ◽  
Daily Practice ◽  
Healthy Individuals ◽  
Sensorimotor Training ◽  
Motor Patterns ◽  
Dependent Plasticity ◽  
Repetitive Movements ◽  
Neural Underpinnings

ABSTRACTRepetitive movements and multisensory integration promote use-dependent plasticity, which has been consistently demonstrated using musical training as a model. Prolonged and repeated execution of motor patterns is also a main risk factor for developing pain syndromes, yet the neural underpinnings that link repetitive movements and use-dependent plasticity to abnormal pain processing in humans are unknown. Employing nociceptive and non-nociceptive electrical stimulation to evoke brain responses, we demonstrate that healthy musicians compared to non-musicians show larger non-nociceptive N140 and nociceptive N200 responses, smaller non-nociceptive P200 responses, and faster reaction times (RTs) to both stimuli. Across participants, larger N140 and N200 amplitudes predicted the RTs, whereas amount of daily practice in musicians predicted RTs, non-nociceptive P200, and nociceptive P300 components. These novel findings indicate that the mechanisms by which repetitive sensorimotor training and multimodal integration promote neural plasticity in multisensory neural structures may also increase stimulus-selectivity to nociceptive cues in healthy individuals.

Conformation of eukaryotic ribosomal RNAs

1983 ◽  
Vol 41 ◽  
pp. 592-593
Author(s):  
M. Boublik ◽  
G. Thornton ◽  
G. Oostergetel ◽  
J.F. Hainfeld ◽  
J.S. Wall
Keyword(s):  
Molecular Weight ◽  
Mass Measurement ◽  
Carbon Film ◽  
Structural Complexity ◽  
Scanning Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Pure Nitrogen ◽  
Freeze Dried ◽  
Scanning Transmission ◽  
Partially Unfolded

Understanding the structural complexity of ribosomes and their role in protein synthesis requires knowledge of the conformation of their components - rRNAs and proteins. Application of dedicated scanning transmission electron microscope (STEM), electrical discharge of the support carbon film in an atmosphere of pure nitrogen, and determination of the molecular weight of individual rRNAs enabled us to obtain high resolution electron microscopic images of unstained freeze-dried rRNA molecules from BHK cells in a form suitable for evaluation of their 3-D structure. Preliminary values for the molecular weight of 28S RNA from the large and 18S RNA from the small ribosomal subunits as obtained by mass measurement were 1.84 x 106 and 0.97 x 106, respectively. Conformation of rRNAs consists, in general, of alternating segments of intramolecular hairpin stems and single stranded loops in a proportion which depends on their ionic environment, the Mg++ concentration in particular. Molecules of 28S RNA (Fig. 1) and 18S RNA (not shown) obtained by freeze-drying from a solution of 60 mM NH+4 acetate and 2 mM Mg++ acetate, pH 7, appear as partially unfolded coils with compact cores suggesting a high degree of ordered secondary structure.

Ultrastructural identification of three types of sensory setae on copepod antennae

1995 ◽  
Vol 53 ◽  
pp. 956-957
Author(s):  
T. M. Weatherby ◽  
P.H. Lenz
Keyword(s):  
Phase Locking ◽  
Membrane Surface ◽  
Reaction Times ◽  
High Sensitivity ◽  
Structural Features ◽  
Calanoid Copepods ◽  
Marine Food Webs ◽  
Dendritic Membrane ◽  
Ultrastructural Characterization

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.

Observations of Frozen-Hydrated Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 504-505
Author(s):  
D. Chrétien ◽  
D. Job ◽  
R.H. Wade
Keyword(s):  
Fourier Transforms ◽  
Structural Complexity ◽  
Image Contrast ◽  
Phase Behaviour ◽  
Experimental Conditions ◽  
Thin Sections ◽  
Surface Lattice ◽  
Cilia And Flagella ◽  
Outstanding Question

Microtubules are filamentary structures found in the cytoplasm of eukaryotic cells, where, together with actin and intermediate filaments, they form the components of the cytoskeleton. They have many functions and show various levels of structural complexity as witnessed by the singlet, doublet and triplet structures involved in the architecture of centrioles, basal bodies, cilia and flagella. The accepted microtubule model consists of a 25 nm diameter hollow tube with a wall made up of 13 paraxial protofilaments (pf). Each pf is a string of aligned tubulin dimers. Some results have suggested that the pfs follow a superhelix. To understand how microtubules function in the cell an accurate model of the surface lattice is one of the requirements. For example the 9x2 architecture of the axoneme will depend on the organisation of its component microtubules. We should also note that microtubules with different numbers of pfs have been observed in thin sections of cellular and of in-vitro material. An outstanding question is how does the surface lattice adjust to these different pf numbers?We have been using cryo-electron microscopy of frozen-hydrated samples to study in-vitro assembled microtubules. The experimental conditions are described in detail in this reference. The results obtained in conjunction with thin sections of similar specimens and with axoneme outer doublet fragments have already allowed us to characterise the image contrast of 13, 14 and 15 pf microtubules on the basis of the measured image widths, of the the image contrast symmetry and of the amplitude and phase behaviour along the equator in the computed Fourier transforms. The contrast variations along individual microtubule images can be interpreted in terms of the geometry of the microtubule surface lattice. We can extend these results and make some reasonable predictions about the probable surface lattices in the case of other pf numbers, see Table 1. Figure 1 shows observed images with which these predictions can be compared.

Structural Aspects of Phonological Development

1988 ◽  
Vol 19 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Karen E. Pollock ◽  
Richard G. Schwartz
Keyword(s):  
Clinical Management ◽  
Structural Complexity ◽  
Strong Preference ◽  
Phonological Development ◽  
Structural Position ◽  
Phonological Disorders ◽  
Syllabic Structure ◽  
The Relationship ◽  
Structural Aspects ◽  
Target Words

The relationship between syllabic structure and segmental development was examined longitudinally in a child with a severe phonological disorder. Six speech samples were collected over a 4-year period (3:5 to 7:3). Analyses revealed gradual increases in the complexity and diversity of the syllable structures produced, and positional preferences for sounds within these forms. With a strong preference for [d] and [n] at the beginning of syllables, other consonants appeared first at the end of syllables. Implications for clinical management of phonological disorders include the need to consider both structural position and structural complexity in assessing segmental skills and in choosing target words for intervention.

Factors Influencing Cognate Performance for Young Multilingual Children's Vocabulary: A Research Synthesis

2020 ◽  
Vol 29 (4) ◽  
pp. 2170-2188
Author(s):  
Lindsey R. Squires ◽  
Sara J. Ohlfest ◽  
Kristen E. Santoro ◽  
Jennifer L. Roberts
Keyword(s):  
Test Validity ◽  
Reaction Times ◽  
Bilingual Children ◽  
Second Grade ◽  
High Quality Research ◽  
Word Level ◽  
Research Questions ◽  
Word Characteristics ◽  
Study Inclusion ◽  
Task Level

Purpose The purpose of this systematic review was to determine evidence of a cognate effect for young multilingual children (ages 3;0–8;11 [years;months], preschool to second grade) in terms of task-level and child-level factors that may influence cognate performance. Cognates are pairs of vocabulary words that share meaning with similar phonology and/or orthography in more than one language, such as rose – rosa (English–Spanish) or carrot – carotte (English–French). Despite the cognate advantage noted with older bilingual children and bilingual adults, there has been no systematic examination of the cognate research in young multilingual children. Method We conducted searches of multiple electronic databases and hand-searched article bibliographies for studies that examined young multilingual children's performance with cognates based on study inclusion criteria aligned to the research questions. Results The review yielded 16 articles. The majority of the studies (12/16, 75%) demonstrated a positive cognate effect for young multilingual children (measured in higher accuracy, faster reaction times, and doublet translation equivalents on cognates as compared to noncognates). However, not all bilingual children demonstrated a cognate effect. Both task-level factors (cognate definition, type of cognate task, word characteristics) and child-level factors (level of bilingualism, age) appear to influence young bilingual children's performance on cognates. Conclusions Contrary to early 1990s research, current researchers suggest that even young multilingual children may demonstrate sensitivity to cognate vocabulary words. Given the limits in study quality, more high-quality research is needed, particularly to address test validity in cognate assessments, to develop appropriate cognate definitions for children, and to refine word-level features. Only one study included a brief instruction prior to assessment, warranting cognate treatment studies as an area of future need. Supplemental Material https://doi.org/10.23641/asha.12753179

The Effect of Symbol Background Color on the Speed of Locating Targets by Adults Without Disabilities: Implications for Augmentative and Alternative Communication Display Design

2019 ◽  
Vol 4 (6) ◽  
pp. 1482-1488
Author(s):  
Jennifer J. Thistle
Keyword(s):  
Augmentative And Alternative Communication ◽  
Reaction Times ◽  
The Other ◽  
Background Color ◽  
Alternative Communication ◽  
Display Design ◽  
Line Drawings ◽  
Research With Children ◽  
Study Participants ◽  
Perceptual Factors

Purpose Previous research with children with and without disabilities has demonstrated that visual–perceptual factors can influence the speech of locating a target on an array. Adults without disabilities often facilitate the learning and use of a child's augmentative and alternative communication system. The current research examined how the presence of symbol background color influenced the speed with which adults without disabilities located target line drawings in 2 studies. Method Both studies used a between-subjects design. In the 1st study, 30 adults (ages 18–29 years) located targets in a 16-symbol array. In the 2nd study, 30 adults (ages 18–34 years) located targets in a 60-symbol array. There were 3 conditions in each study: symbol background color, symbol background white with a black border, and symbol background white with a color border. Results In the 1st study, reaction times across groups were not significantly different. In the 2nd study, participants in the symbol background color condition were significantly faster than participants in the other conditions, and participants in the symbol background white with black border were significantly slower than participants in the other conditions. Conclusion Communication partners may benefit from the presence of background color, especially when supporting children using displays with many symbols.

Swallow Pattern Generator Reconfiguration of the Respiratory Neural Network

2009 ◽  
Vol 18 (1) ◽  
pp. 3-12
Author(s):  
Andrea Vovka ◽  
Paul W. Davenport ◽  
Karen Wheeler-Hegland ◽  
Kendall F. Morris ◽  
Christine M. Sapienza ◽  
...  
Keyword(s):  
Behavioral Control ◽  
Upper Airway ◽  
Pattern Generator ◽  
Breathing Patterns ◽  
Motor Patterns ◽  
Control Assembly ◽  
Pharyngeal Swallow ◽  
Laryngeal Vestibule ◽  
Lower Airways ◽  
Swallow Apnea

Abstract When the nasal and oral passages converge and a bolus enters the pharynx, it is critical that breathing and swallow motor patterns become integrated to allow safe passage of the bolus through the pharynx. Breathing patterns must be reconfigured to inhibit inspiration, and upper airway muscle activity must be recruited and reconfigured to close the glottis and laryngeal vestibule, invert the epiglottis, and ultimately protect the lower airways. Failure to close and protect the glottal opening to the lower airways, or loss of the integration and coordination of swallow and breathing, increases the risk of penetration or aspiration. A neural swallow central pattern generator (CPG) controls the pharyngeal swallow phase and is located in the medulla. We propose that this swallow CPG is functionally organized in a holarchical behavioral control assembly (BCA) and is recruited with pharyngeal swallow. The swallow BCA holon reconfigures the respiratory CPG to produce the stereotypical swallow breathing pattern, consisting of swallow apnea during swallowing followed by prolongation of expiration following swallow. The timing of swallow apnea and the duration of expiration is a function of the presence of the bolus in the pharynx, size of the bolus, bolus consistency, breath cycle, ventilatory state and disease.

Face and Word Recognition in Patients with Left and Right Hemispheric Lesions: Evidence from Reaction Times and ERPs

2002 ◽  
Vol 13 (1) ◽  
pp. 69-83 ◽  
Author(s):  
Stefan R. Schweinberger ◽  
Thomas Klos ◽  
Werner Sommer
Keyword(s):  
Slow Wave ◽  
Reaction Times ◽  
Memory Search ◽  
Event Related Potentials ◽  
Performance Deficits ◽  
Set Size ◽  
Left Brain ◽  
Related Potentials ◽  
Abstract Words ◽  
Left Brain Damage

Abstract: We recorded reaction times (RTs) and event-related potentials (ERPs) in patients with unilateral lesions during a memory search task. Participants memorized faces or abstract words, which were then recognized among new ones. The RT deficit found in patients with left brain damage (LBD) for words increased with memory set size, suggesting that their problem relates to memory search. In contrast, the RT deficit found in patients with RBD for faces was apparently related to perceptual encoding, a conclusion also supported by their reduced P100 ERP component. A late slow wave (720-1720 ms) was enhanced in patients, particularly to words in patients with LBD, and to faces in patients with RBD. Thus, the slow wave was largest in the conditions with most pronounced performance deficits, suggesting that it reflects deficit-related resource recruitment.

Retrieval from Memory or Procedural Strategies for Addition Problems

2011 ◽  
Vol 70 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Muriel Fanget ◽  
Catherine Thevenot ◽  
Caroline Castel ◽  
Michel Fayol
Keyword(s):  
Reaction Times ◽  
Long Term Memory ◽  
Verbal Reports ◽  
Term Memory ◽  
Simple Addition ◽  
Memory Traces ◽  
Addition Problem ◽  
Retrieval From Memory ◽  
Calculation Procedures

In this study, we used a paradigm recently developed ( Thevenot, Fanget, & Fayol, 2007 ) to determine whether 10-year-old children solve simple addition problems by retrieval of the answer from long-term memory or by calculation procedures. Our paradigm is unique in that it does not rely on reaction times or verbal reports, which are known to potentially bias the results, especially in children. Rather, it takes advantage of the fact that calculation procedures degrade the memory traces of the operands, so that it is more difficult to recognize them when they have been involved in the solution of an addition problem by calculation rather than by retrieval. The present study sharpens the current conclusions in the literature and shows that, when the sum of addition problems is up to 10, children mainly use retrieval, but when it is greater than 10, they mainly use calculation procedures.

Sign in / Sign up

Export Citation Format

Share Document