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Results for “Functional Laterality”

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PubMed1995

A literature survey of a hundred years of anatomic and functional lateral pterygoid muscle research.

Controversial topics that influence the etiology and the treatment of temporomandibular disorders include anatomy and function of the lateral pterygoid muscle, and the nature of the disc-muscle connection. To explore whether an agreement has been reached among researchers, a literature survey focusing on the structure, performance, and disc-muscle interface of the lateral pterygoid muscle was performed. Eighty-nine original research articles were identified in the Index Medicus information system from 1879 to 1994 by applying the keyword phrase "lateral pterygoid muscle." A majority of references (65%) identified two separate parts of the lateral pterygoid muscle as well as insertions into the disc, the capsule, and the condyle. Seventy-five percent of the articles agreed on three major functions. This literature survey revealed a consensus regarding anatomy, function, and disc connection among the majority of the researchers. However, diverging opinions were persistent and could be identified.

Humans↗
PubMed1978

The development of the lateral functions and reading ability.

This study demonstrates a relationship between the development of two progressive processes: (1) language function in the brain, and (2) reading ability. The data suggest that different degrees of hemispheric asymmetry for speech appear to be advantageous as the various phases of reading are approached. The progression of laterality appears to be from little asymmetry between the right and left ears (ambilaterality) in the earliest learning-to-read stages (at 5, 6 and 7 years of age) when both sides of the brain are necessary for the vast amount of visual-spatial as well as linguistic information which must be processed, to a maximum asymmetry in the later, fluent reading stage (in those 8 years and older) when the language side of the brain, usually the left, appears to be specialized for this skill.

Aging↗
PubMed1995

Stimulation of later functions of the yeast meiotic protein kinase Ime2p by the IDS2 gene product.

Ime2p is a protein kinase that is expressed only during meiosis in Saccharomyces cerevisiae. Ime2p stimulates early, middle, and late meiotic gene expression and down-regulates expression of IME1, which specifies an activator of early meiotic genes that acts independently of Ime2p. We have identified a new gene, IDS2 (for IME2-dependent signaling), which has a functional relationship to Ime2p. An ids2 null mutation delays down-regulation of IME1 and expression of middle and late meiotic genes. In an ime1 null mutant that express IME2 from the GAL1 promoter (ime1 delta PGAL1-IME2 mutant), early meiotic gene expression depends only upon Ime2p. In such strains, Ids2p is dispensable for expression of the early genes HOP1 and SPO13 but is essential for expression of the middle and late genes SPS1, SPS2, and SPS100. Ids2p is also essential for the autoregulatory pathway through which Ime2p activates its own expression via the IME2 upstream activation sequences (UAS). An PGAL1-IME2 derivative that produces a truncated Ime2p (lacking its C-terminal 174 residues) permits IME2 UAS activation in the absence of Ids2p. This observation suggests that Ids2p acts upstream of Ime2p or that Ids2p and Ime2p act in independent, convergent pathways to stimulate IME2 UAS activity. Accumulation of epitope-tagged Ids2p derivatives is greatest in growing cells and declines during meiosis. We propose that Ids2p acts indirectly to modify Ime2p activity, thus permitting Ime2p to carry out later meiotic functions.

Amino Acid Sequence↗
PubMed1992

The effects of early experience on callosal development and functional lateralization in pigmented BALB/c mice.

A proportion of animals of the BALB/c inbred mouse strain have an unusually small (sometimes absent) midsagittal area of the corpus callosum (CC). In this study, we used a large sample of both males and females (total n = 198) from a pigmented congenic BALB/c line to investigate the relations among preweaning handling, area of CC, and direction and degree of lateralization as measured by Collins' paw preference task. Twenty litters were handled daily from the day after birth until day 25 (weaning) according to Denenberg's procedure and 18 litters were left undisturbed until weaning. All animals were tested for degree and direction of paw preference in a modification of Collins' apparatus at about 60 days and measures taken on CNS structures at 100 days of age. There were no handling or sex effects on degree or direction of paw preference or on the extent of CC defects, but for animals in the normal range (CC > or = 0.7 mm2), those which had been handled had significantly smaller callosa. No significant differences were detected between right and left hemisphere weights, and these measures did not appear to be related to the behavioural measures. There was no significant correlation between CC area and degree of paw preference nor was there any relationship between total agenesis and degree of handedness. This last result is particularly interesting in light of recent evidence that ILn/J mice, all acallosal, are exclusively ambilateral.

Animals↗
PubMed2002

Functional lateralization of the human premotor cortex during sequential movements.

A neurological truism is that each side of the brain controls movements on the opposite side of the body. Yet some left hemisphere brain lesions cause bilateral impairment of complex motor function and/or ideomotor apraxia. We report that the left dorsal premotor cortex of normal right-handed people plays a fundamental role in sequential movement of both right and left hands. Subjects performed sequential finger movements during functional magnetic resonance imaging of the motor cortices. In right-handed subjects, the volume of activated dorsal premotor cortex showed a left hemispheric predominance during hand movements. We suggest that the observed left premotor dominance contributes to the lateralization found in lesion studies.

Adult↗
PubMed2006

Larval lampreys possess a functional lateral line system.

Morphology of larval lampreys' neuromasts was found to be very similar to that of adults. Activity in the lateral line nerve, elicited by a vibrating ball, indicated a functional lateralis system. Analysis revealed at least two populations of afferents, responding to opposite directions of water flow, with adapting responses. The response magnitude increased monotonically with stimulus amplitude. Larval lampreys' neuromasts were less sensitive than those of teleosts. At low frequencies the response showed a phase lead of 200-220 degrees with respect to the maximum of the ball displacement and a gain that was approximately linearly proportional to frequency.

Afferent Pathways↗
PubMed1997

The effects of early environment on the development of functional laterality in Morris maze performance.

The current study examined the contribution of early postnatal experience to the functional lateralisation of spatial ability in the male rat. Litters were handled (H) or non-handled (NH) during the first 20 days of life, and three males from each litter were tested in the Morris water maze in adulthood. Two subjects from each litter were monocularly tested, one with the right eye patched and the other with the left eye patched. A third subject in each litter was tested with both eyes open. Handling interacted with Eye Patch for time and distance measures. Performance of Right- and Left-Patched rats was equivalent for the NH group, but the H subjects tested with the Right Patch outperformed H subjects with the Left Patch. These results confirm studies that found spatial navigation performance to be lateralised to the right hemisphere in male rats. The data indicate that functional asymmetry of spatial navigation behaviour in the adult male rat is sensitive to environmental influences during early development.

Journal Article↗
PubMedDate not supplied

[Sex differences of functional lateralization in the perception of verbal and emotional information in ontogeny].

Experimental data show certain differences between men and women in perception of verbal and emotional information. They are revealed in the ability of correct perception of definite kind of information, in the degree of brain functional asymmetry in perception of the given information, in prevalence of domination type. The character of sex differences in functional asymmetry changes little with the age; quantitative correlations of the coefficient of asymmetry diminish with the age.

Adolescent↗
PubMed1979

Intrahemispheric visual-motor information processing and cerebral functional lateralization.

A series of stimuli, words and faces, were presented tachistoscopically to 24 dextrals and 12 sinistrals. The stimuli were presented to one eye at a time and the subjects were instructed to respond to specific words or stimuli with a specific hand. The results indicate that (1) cerebral functional asymmetry is related to handedness; in the dextrals, the left hemisphere is more specialized in verbal recognition, while in the sinistrals, the right hemisphere is more specialized in recognizing non-verbal material. (2) An ipsilateral hand-and-eye combination is a valid method of measuring intrahemispheric information processing, provided that the tachistoscopically presented visual stimuli are capable of inciting specialized hemispheric function. The dominant relationship among the crossed and non-crossed visual pathways is discussed.

Adult↗
PubMed2000

A model of invariant object recognition in the visual system: learning rules, activation functions, lateral inhibition, and information-based performance measures.

VisNet2 is a model to investigate some aspects of invariant visual object recognition in the primate visual system. It is a four-layer feedforward network with convergence to each part of a layer from a small region of the preceding layer, with competition between the neurons within a layer and with a trace learning rule to help it learn transform invariance. The trace rule is a modified Hebbian rule, which modifies synaptic weights according to both the current firing rates and the firing rates to recently seen stimuli. This enables neurons to learn to respond similarly to the gradually transforming inputs it receives, which over the short term are likely to be about the same object, given the statistics of normal visual inputs. First, we introduce for VisNet2 both single-neuron and multiple-neuron information-theoretic measures of its ability to respond to transformed stimuli. Second, using these measures, we show that quantitatively resetting the trace between stimuli is not necessary for good performance. Third, it is shown that the sigmoid activation functions used in VisNet2, which allow the sparseness of the representation to be controlled, allow good performance when using sparse distributed representations. Fourth, it is shown that VisNet2 operates well with medium-range lateral inhibition with a radius in the same order of size as the region of the preceding layer from which neurons receive inputs. Fifth, in an investigation of different learning rules for learning transform invariance, it is shown that VisNet2 operates better with a trace rule that incorporates in the trace only activity from the preceding presentations of a given stimulus, with no contribution to the trace from the current presentation, and that this is related to temporal difference learning.

Algorithms↗
PubMedDate not supplied

Asian blepharoplasty with a short-pulsed contact Nd-Yag laser: limited-incision resectable laser double fold with internal medial and lateral functional epicanthoplasty.

The double-fold operation is the most common aesthetic procedure in Asia, but complications such as gross asymmetry, loss of folds, and scars on the medial canthal region and upper eyelid are relatively common. To prevent these complications, caused by displacement of fixation sutures secondary to excessive edema or hematoma, we use fine fiber-delivered contact surgical Nd-Yag (Japan SLT) laser for incision, excision, coagulation, dissection, ablation, and fusion of the soft tissue. Comparing this laser treatment to conventional electrocautery techniques or to CO2 laser blepharoplasty, this contact short-pulsed Nd-Yag laser gives us a tactile sensation, providing a more precise, controlled surgical procedure without lateral thermal damage, and it is possible to operate through a small incision. A long-term follow-up study shows that there was no gross asymmetry, loss of folds, or visible or hypertrophic scars on the upper eyelid and medial canthal regions.

Adolescent↗
PubMed1986

[Dilatation of the glottis in bilateral vocal cord paralysis. Review of various surgical procedures and a report of personal experience using a functional lateral fixation surgical technic].

For the treatment of bilateral vocal cord paralysis, the author's technique consists of preservation of the posterior crico-arytenoid ligament as a hinge as well as turning and tilting of the arytenoid cartilage laterally. It is held in this position with three permanent retention sutures, two of them armed with heavy knots. These knots will reinforce the lateral rotation of the arytenoid cartilage. These sutures run in the submucosa horizontally along the anterior surface of the arytenoid cartilage and are fixed through burr holes on the posterior margin of the thyroid cartilage. This method developed from the original "King Procedure" leaves the laryngeal mucosa maximally undisturbed so that in 80% of the cases preliminary tracheotomy became unnecessary. During a period of 27 years, 110 patients were operated; 27 of them had a previously created tracheostoma. Out of the remaining 83, 16 had tracheotomy directly before surgery. Of the remaining 67 patients, four required postoperative tracheotomy for a few days only, while 63 did not require this additional treatment. The average hospital stay was 11 days. In the majority of cases the operation could be performed under local anaesthesia which helped to establish proper voice function.

Adolescent↗
PubMed2004

Asymmetry and gender effect in functionally lateralized cortical regions: a proton MRS imaging study.

PURPOSE: to compare metabolite concentrations and ratios in gray matter regions known for their anatomical/functional asymmetry and evaluate gender effect. MATERIALS AND METHODS: Proton MRS imaging was performed at 1.5 T with TR/TE 2300/280 msec in 20 healthy right-handed subjects (mean age 29.6 +/- 5.3 years, 10 men). Concentrations of N-acetyl aspartate (NAA), choline (Cho), and creatine (Cr), and the peak area ratios NAA/Cho, NAA/Cr, and Cho/Cr were evaluated in hippocampal and parahippocampal gyri, thalamus, insula, Broca's and Wernicke's areas (and corresponding contralateral areas), primary and secondary visual areas, temporal, inferior parietal, cingulate, supplemental motor, dorsolateral prefrontal, and sensorimotor areas. Linear mixed-effects regression models were used for statistical analyses. RESULTS: NAA concentration and NAA/Cho were higher in the left thalamus by 21.9% and 20%, respectively (both P < 0.001). NAA concentration was 13% higher in the region contralateral to Wernicke's area (P < 0.02). No gender differences were found. CONCLUSION: Metabolite concentrations and ratios were symmetric and gender independent in most brain regions, however small hemispheric side differences in the thalamus and in Wernicke's area were found.

Adult↗
PubMed2006

Sleep disruptions mediate the relationship between early postoperative pain and later functioning following total knee replacement surgery.

Despite relatively standardized surgical procedures, patients undergoing total knee replacement (TKR) surgery differ dramatically in the speed of their recovery. Previous research has suggested a relationship between the experience of pain and sleep disruptions among patients with chronic pain or those undergoing surgery, such that more severe pain is associated with more frequent awakenings throughout the night. This study examined sleep disruptions 1 month following surgery as a mediator of the relationship between pain 1 month following surgery and functional limitations 3 months following surgery. A total of 110 patients scheduled to undergo unilateral TKR were examined at three time points: 2-3 weeks prior to surgery, 1 month following surgery, and 3 months following surgery. After controlling for presurgical levels of pain, sleep disruptions, and functional limitations, sleep disruptions 1 month following surgery partially mediated the relationship between pain 1 month following surgery and functional limitations 3 months following surgery. The present findings underscore the importance of adequate sleep during postsurgical recovery and suggest that interventions targeting sleep disruptions may improve the speed and quality of patients' recovery from TKR and other surgical procedures.

Aged↗
PubMed2003

Abnormal functional asymmetry in occipital areas may prevent frontotemporal regions from achieving functional laterality during the WCST performance in patients with schizophrenia.

There is much evidence of frontotemporal lateralized abnormalities in schizophrenia. However, the relationship has not yet been examined between performance on the Wisconsin Card Sorting Test, with supposed anterior left dominance and event-related potential (ERP) asymmetry. ERPs recorded at homologous bilateral sites were compared using statistical permutation methods. Patients had an unexpected abnormal lateralization over occipital regions, preceding slow anterior potentials. This indicates a defect in early stages of information processing, which may contribute to prevent further hemispheric lateralization during performance.

Adult↗
PubMed1993

Functional lateralization for auditory temporal processing in male and female rats.

In 3 studies adult male rats showed significantly better discrimination of tone sequences with the right ear than with the left ear. This result parallels similar findings of left-hemisphere specialization for auditory temporal processing in humans and nonhuman primates. Furthermore, because clinical evidence supports a link between specialization of the left hemisphere for auditory temporal processing and for speech processing, these results may reflect evolutionary precursors to left-hemisphere language specialization. Because male rats showed a stronger ear advantage than female rats, the findings may relate to evidence of a stronger right ear advantage in men than in women. Finally, results suggest that neonatal handling enhances lateralization for auditory temporal processing in both sexes. Combined results implicate neuroendocrine mechanisms as important factors in the development of lateralization for auditory temporal processing.

Animals↗