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PubMedDate not supplied

An instrumented object for evaluation of lateral hand grasp during functional tasks.

We developed an instrumented object for quantitative evaluation of functional tasks performed with lateral hand grasp. The device was instrumented with three force transducers based on metal foil strain gauges. The transducers allowed simultaneous monitoring of the grasp force, the perpendicular force at the tip, and the force in the long axis of the instrumented object. The device was used for evaluation of a simulated eating task performed by able-bodied subjects and a tetraplegic subject instrumented with an FES hand grasp system. Use of the instrumented object will allow us to gain a more thorough understanding of the application of forces on a tool during important functional tasks of daily living. This knowledge will be used to improve the control of a closed-loop FES hand grasp system incorporating natural sensory feedback.

Biomechanical Phenomena↗
PubMed1984

Functional precursors to language and its lateralization.

An adequate account of language evolution must reconcile the propositions that language is unique but has precursors. The paper of Bellman and Goldberg and that of Tzeng and Wang each neglects one of these propositions. We suggest that the uniqueness of language lies primarily in its dualistic structure which has a frame-content mode of organization: at the phonological level, consonant and vowel elements are inserted into syllabic frames; and at the morphological level, stem forms of content words are inserted into syntactic frames. We suggest that the morphological level evolved from the phonological level and that the frame-content mode of organization in phonology had a precursor in the form of bimanual coordination in which the nonpreferred (frame) hand holds an object operated on by the preferred hand (content). It is argued that lateralization of cortical function evolved first for bimanual coordination, then for language. Old World monkey hand preferences may be consistent with both the putative left-hemisphere specialization for bimanual coordination and the human right-hemisphere specialization for spatial functions.

Brain↗
PubMed2005

Single-breath test in lateral decubitus reflects function of single lungs grafted for emphysema.

The slope of alveolar plateau for nitrogen derived from the single-breath test is useful to assess the function of bilateral lung grafts, but this technique is not applicable to patients with single-lung grafts due to the confounding influence of the native lung. We tested the hypothesis that the nitrogen slope measured in lateral decubitus with the graft in nondependent position may primarily reflect the distribution of ventilation in this lung. Fifteen patients with single-lung transplantation for emphysema, 10 healthy controls, and 7 patients with advanced emphysema performed single-breath washouts in right and left lateral decubitus; nitrogen slope was measured between 75 and 100% of expired volume. In 10 transplant recipients, the volume of each lung was measured in the two postures by computerized tomography. Nitrogen slope was unaffected by posture in normal controls and emphysema patients. On the other hand, nitrogen slope in transplant recipients was invariably smaller, with the graft in nondependent vs. in dependent position. Values of nitrogen slope with the graft in nondependent position were similar to those obtained in normal controls but significantly smaller than those obtained in emphysema patients. Computerized tomography studies in this position indicated that the volume expired below functional residual capacity was exclusively contributed by the graft. We conclude that, in patients with single-lung transplantation for emphysema, 1) measuring nitrogen slope in lateral decubitus allows to distinguish between the graft and the native lung, and 2) nitrogen slope obtained with the graft in nondependent position reflects ventilation distribution in this lung.

Breath Tests↗
PubMed2000

Cognitive function in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder of unknown etiology. Although there was a widely held belief that ALS does not cause cognitive impairment, cognitive function in patients with ALS has received more attention recently. In this paper, we discuss the clinical, neuroanatomical and neuropathological basis for cognitive dysfunction in ALS.

Brain↗
PubMed1977

Functional organization of lateral cell groups of cat superior olivary complex.

1. Single-unit discharges to auditory stimuli were recorded extracellularly from superior olivary complex (SOC) units located lateral to the medial superior olive. Stimuli consisted of monaurally or binaurally presented tone bursts. The response measures obtained were effective ear, nature of effect, stimulus-frequency representation, maximum output, latency of response, and temporal pattern of tone burst-elicited discharges. Electrolytic marks were made at the unit studied or at the end of the electrode tract and in the medial superior olive. Following each experiment the locations of the units studied were determined histologically. An atlas of the laterally located SOC cell groups was developed to permit classification of units on the basis of localization within cell groups. Units were also classified according to the effects of stimulating the two ears. 2. All SOC units located lateral to the medial superior olive were excited by stimulation of the ipsilateral ear. Stimulation of the contralateral ear either excited, inhibited, had no effect, or had a potentiating effect on the discharges elicited by stimulating the ipsilateral ear. 3. Most lateral superior olivary (LSO) units were inhibited by contralateral stimulation, were narrowly tuned, produced low to high levels of maximum output, had short latencies, and produced regular discharge patterns characterized by chopper PST histograms with narrow initial peaks. 4. Most units within the caudal margins of the LSO (pLSO) were not affected or were inhibited by a contralateral stimulus; many were broadly tuned and exhibited intensity functions with large dynamic range and low slope. These units also had long latencies and produced chopper PST histograms with wide initial peaks. 5. Most units located dorsal to the LSO (DPO and DLPO) were not affected by the contralateral stimulus, were narrowly tuned, produced moderate levels of maximum discharge, had long latencies, and produced chopper PST histograms with wide initial peaks. 6. Units located ventral to the LSO appeared to have response characteristics related to unit location. Most units below the ventral hilum of the LSO (VLPO) were inhibited by the contralateral stimulus and many were broadly tuned VLPO units produced wide or poorly defined narrow-chopper discharge patterns and intensity functions with high maximum output. Most units located ventral to the lateral loop of the LSO (LNTB) were not affected by the contralateral stimulus and had response characteristics that may be related to the rostrocaudal location of the unit. 7. The cell groups located dorsal and ventral to the LSO were tonotopically organized with low-frequency-sensitive units located laterally and high-frequency-sensitive units located medially. The units located along the caudal margins of the LSO had a tonotopic organization similar to that of the LSO.

Acoustic Stimulation↗
PubMed2000

Cerebellar on-beam and lateral inhibition: two functionally distinct circuits.

Optical imaging of voltage-sensitive dyes in an isolated cerebellum preparation was used to study the spatiotemporal functional organization of the inhibitory systems in the cerebellar cortex. Responses to surface stimulation of the cortex reveal two physiologically distinct inhibitory systems, which we refer to as lateral and on-beam inhibition following classical terminology. Lateral inhibition occurs throughout the area responding to a stimulus, whereas on-beam inhibition is confined to the area directly excited by parallel fibers. The time course of the lateral inhibition is twice as long as that of the on-beam inhibition. Both inhibitory responses increase with stimulus intensity, but the lateral inhibition has a lower threshold, and it saturates at lower stimulus intensity. The amplitude of the on-beam inhibition is linearly related to the excitation at the same location, whereas that of the lateral inhibition is linearly related to the excitation at the center of the beam. Repetitive stimulation is required to activate on-beam inhibition, whereas the same stimulus paradigm reveals prolonged depression of the lateral inhibition. We conclude that lateral inhibition reflects the activation of molecular layer interneurons, and its major role is to increase the excitability of the activated area by disinhibition. The on-beam inhibition most likely reflects Golgi cell inhibition of granule cells. However, Purkinje cell collateral inhibition of Golgi cells cannot be excluded. Both possibilities suggest that the role of the on-beam inhibition is to efficiently modulate, in time and space, the mossy fiber input to the cerebellar cortex.

Animals↗
PubMed1991

Are lateral eye-movements a valid index of functional hemispheric asymmetries?

Lateral eye-movements (LEMs) to verbal and spatial questions are frequently used as an index of asymmetries in hemisphere activation and the concept of 'hemisphericity'. There have, however, been few attempts to validate LEMs using independent cognitive measures of hemisphere function. This study relates laterality indices of LEMs recorded in the dark using infrared recording techniques, and elicited by verbal and spatial questions, to other measures of left and right hemisphere functioning (verbal and non-verbal dichotic listening, block design, digit span) in 43 subjects. LEM laterality indices were unrelated to these validation measures. It is concluded that although appropriate question type-LEM relationships may reflect transient asymmetries in hemispheric activation, they are not a valid index of stable individual differences in hemisphere utilization.

Adolescent↗
PubMed2004

Retinotopic organization and functional subdivisions of the human lateral geniculate nucleus: a high-resolution functional magnetic resonance imaging study.

Functional magnetic resonance imaging (fMRI) has provided intriguing insights into the topography and functional organization of visual cortical areas in the human brain. However, little is known about the functional anatomy of subcortical nuclei. Here, we used high-resolution fMRI (1.5 x 1.5 x 2 mm3) at 3 tesla to investigate the retinotopic organization of the human lateral geniculate nucleus (LGN). The central 15 degrees of the visual field were mapped using periodic flickering checkerboard stimuli that evoked a traveling wave of activity. The contralateral visual hemifield was represented with the lower field in the medial-superior portion and the upper field in the lateral-inferior portion of each LGN. The horizontal meridian was significantly overrepresented relative to the vertical meridian. The fovea was represented in posterior and superior portions, with increasing eccentricities represented more anteriorly. The magnification of the fovea relative to the periphery was similar to that described for human primary visual cortex. The magnocellular regions of the LGN were distinguished based on their sensitivity to low stimulus contrast and tended to be located in its inferior and medial portions. Our results demonstrate striking similarities in the topographic organization of the macaque and human LGN and support accounts of a constant magnification from the retina through the cortex in both species.

Adult↗
PubMed1984

Lateral diffusion of an 80,000-dalton glycoprotein in the plasma membrane of murine fibroblasts: relationships to cell structure and function.

The lateral diffusion of an 80,000-dalton major cell surface glycoprotein of murine fibroblasts has been measured. This antigen, identified through the use of monoclonal antibodies, is an integral glycoprotein distributed through the plasma membrane as judged by immunofluorescence and immunoelectron microscopy (see preceding paper). Measurements of fluorescence recovery after photobleaching were performed on the antigen-antibody complex within the plasma membrane of C3H/10T1/2 and NIH/3T3 cells after labeling the monoclonal antibody with fluorescein. Measurements were performed as a function of temperature, for interphase, mitotic, and G0 C3H/10T1/2 cells. The mean lateral diffusion coefficients (D) for the antibody-protein complex in interphase cells were in the range of 0.7-3.5 X 10(-10) cm2/s between 9 degrees and 37 degrees C, while that for the lipid analog probe, dihexadecylindocarbocyanine was about two orders of magnitude greater. This comparison indicates that peripheral interactions other than bilayer fluidity limit the lateral mobility of the antigen. The mobile fraction of mitotic, G0, and interphase cells showed a monotonic increase with temperature with most of the antibody-antigen complexes being free to move about 25 degrees C. Semi-quantitative interpretations of both the slow glycoprotein diffusion and the immobile fraction are offered. Comparison of diffusion coefficients for cells in different phases of the cell cycle does not reveal striking differences. Mobile fractions for G0 cells at 25 degrees C or less are substantially lower than in interphase cells. In all cases, there was a remarkably broad range of the fluorescence recovery data between different cells, resulting in up to a 10-fold variation in diffusion coefficients, which is far greater than the precision limits of the experiment. Diffusion values and mobile fractions were generally well within a factor of two when measured at several arbitrary points on a single cell. The origins of this cellular heterogenity remain to be elucidated. Lateral mobility in cell fragments and specific regions of single cells was also examined. The glycoprotein was mobile in ventral surface cell fragments. Its mobility was not altered in regions of cell-cell underlapping. However, the diffusion coefficient was threefold higher near the leading edge of motile cells compared to the trailing region. This difference may reflect weaker coupling of the glycoprotein to the underlying cytoskeleton in the dynamic leading edge region.

Animals↗
PubMed1987

Sympathetic iris function in amyotrophic lateral sclerosis.

Autonomic fibres are generally regarded as being spared in amyotrophic lateral sclerosis. Anatomical studies have cast some doubt upon this hypothesis. The present study describes the pupillary responses to tyramine, a norepinephrine releaser, and to phenylephrine, a directly acting sympathomimetic, in 11 patients with ALS and matched controls. Patients and controls showed a similar sensitivity to sympathomimetic agents, and our results lend some support to the hypothesis that sympathetic functions are not involved in ALS.

Adult↗
PubMed2001

The effect of non-invasive positive pressure ventilation (NIPPV) on cognitive function in amyotrophic lateral sclerosis (ALS): a prospective study.

OBJECTIVES: Neuropsychological investigations have shown a degree of cognitive dysfunction in a proportion of non-demented patients with ALS. Respiratory muscle weakness in ALS can lead to nocturnal hypoventilation, resulting in sleep disturbance and daytime somnolence. Sleep deprivation of this type may cause impairments in cognitive function, but this has not been formally evaluated in ALS. METHODS: Cognitive functioning was evaluated in nine patients with ALS with sleep disturbance caused by nocturnal hypoventilation (NIPPV group), and in a comparison group of 10 similar patients without ventilation problems (control group). The NIPPV group then started non-invasive positive pressure ventilation (NIPPV) at night. After about 6 weeks, change in cognitive function was evaluated. RESULTS: Statistically significant improvement in scores on two of the seven cognitive tests was demonstrated in the NIPPV group postventilation, and a trend towards significant improvement was found for two further tests. Scores in the control group did not improve significantly for these four tests, although an improvement was found on one other test. CONCLUSIONS: Nocturnal hypoventilation and sleep disturbance may cause cognitive dysfunction in ALS. These deficits may be partially improved by NIPPV over a 6 week period. This has important implications for investigations of both cognitive dysfunction in non-demented patients with ALS, and the effect of ventilation on quality of life.

Aged↗
PubMed1977

The role of early left-brain injury in determining lateralization of cerebral speech functions.

Preparatory to craniotomy for the relief of medically refractory focal epilepsy, the lateralization of cerebral speech functions was determined by the Wada intracarotid Amytal test in 134 patients with clinical and radiologic evidence of an early left-hemisphere lesion. Their results were compared with those for 262 patients (140 right-handed, 122 left-handed), who were tested in a similar way. One-third of the patients with early lesions were still right-handed, and 81% of these right-handers were left-hemisphere dominant for speech. In the non-right-handers, speech was represented in the left cerebral hemisphere in nearly a third of the group, in the right hemisphere in half the group, and bilaterally in the remainder. Bilateral speech representation was demonstrated in 15% of the non-right-handers without early left-brain injury and in 19% of those with evidence of such early injury, whereas it was extremely rare in the right-handed groups. In addition, nearly half the patients with bilateral speech representation exhibited a complete or partial dissociation between errors of naming and errors in the repetition of verbal sequences after Amytal injection into left or right hemispheres. This points to the possibility of a functionally asymmetric participation of the two hemispheres in the language processes of some normal left-handers. The results of the Amytal speech tests in this series of patients point to locus of lesion as one of the critical determinants in the lateralization of cerebral speech processes after early left-brain injury. It is argued that in such cases the continuing dominance of the left hemisphere for speech in largely contingent upon the integrity of the frontal and parietal speech zones.

Adolescent↗
PubMed2004

Functions of the lateral pterygoid muscle.

The lateral pterygoid, a muscle of mastication has been implicated, with little evidence, in the aetiology of temporomandibular disorders. Three to five percent of the population in developed countries requires treatment for temporomandibular disorders. There is limited information about the normal function of the muscle, which is anatomically divided into a superior and an inferior head. The superior head is involved in clenching, contralateral, ipsilateral, protrusive, retrusive and open-close jaw movements and the inferior head in contralateral, protrusive and opening jaw movements. Recent electromyographic data suggest the muscle participates in fine control of horizontal movements and there are similarities in functional properties between the two heads.

Humans↗
PubMed1999

[A radioimmunologic assay of insulin in lateral pterygoid muscle after functional mandibular protrusion in rats].

OBJECTIVE: To investigate the effect of insulin on the lateral pterygoid muscle after functional mandibular protrusion in rats. METHODS: Radioimmunoassay was used to examine the level of insulin in lateral pterygoid muscle quantitatively after functional mandibular protrusion in young growing rats. RESULTS: The amount of insulin in lateral pterygoid muscle in young growing rats enhanced after functional mandibular protrusion. CONCLUSION: Insulin plays an important role in adaptive remodeling of lateral pterygoid muscle after functional mandibular protrusion.

Animals↗
PubMed2003

Respiratory function in amyotrophic lateral sclerosis.

The aim of this study was to examine the vital capacity (FVC) and forced expiratory volume in 1 s (FEV 1) in relation to the site of amyotrophic lateral sclerosis (ALS) onset and the duration of the disease. Respiratory involvement is the principal cause of death in ALS patients. The study was conducted at the Department of Neurology, University School of Medicine in Lublin. The study comprised 18 ALS patients. The average duration of ALS was 12 months. The patients were divided into two groups according to the site of ALS onset and into two groups according to the duration of the disease. FVC was significantly higher in the group of patients with a limb onset than in the group of patients with a bulbar onset of the disease. The study has shown respiratory function disturbances in ALS patients. FVC significantly depends on the site of ALS onset but not on the duration of the disease.

Adult↗