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Results for “Functional Laterality”

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PubMed2003

Experimental determination of adsorption energies, adsorption isotherms, probability density functions, and lateral molecular interactions on CXHY/CaO systems.

Reversed-flow gas chromatography (RF-GC) is extended to the measurements of the probability density function for the adsorption energies as well as the differential energies of adsorption due to lateral interactions of molecules adsorbed on different heterogeneous solid surfaces. All these calculations are based on a non-linear adsorption isotherm model as it is well accepted that the linear one is inadequate for substances such as these used in this work. Thus, some new important physicochemical parameters have been obtained for the characterization of the heterogeneous systems studied. The adsorbent used in this study was calcium oxide. The adsorption of many significant hydrocarbons was investigated. With these systematic experiments under conditions which are similar to the atmospheric ones, an extrapolation of the results obtained to "real" atmospheres with a high degree of confidence is possible.

Adsorption↗

PubMed1987

Sex differences in spatial task performance of patients with and without unilateral cerebral lesions.

Two visuospatial tasks, the WAIS Block Design and the Street Gestalt Completion Test, were administered to men and women with and without unilateral cerebral lesions. These two tasks represent different categories of visuospatial functions. The Street test is a visual-perceptual gestalt task, requiring the closure of fragmented pictures, whereas Block Design is an analytical, manipulospatial task requiring rotation of spatial coordinates. For the non-brain-damaged group, the men showed a nonsignificant trend toward better Block Design performance relative to the women, whereas there was no sex-related difference in Street performance. For the brain-damaged groups, patients with right hemisphere lesions performed significantly worse than patients with left hemisphere lesions on both the Street test and Block Design, indicating that both tasks were more sensitive to right hemisphere functioning. There was, however, a significant sex X side of lesion interaction on Block Design only, with the men showing a more asymmetrical pattern of scores. These results suggest that sex differences in functional lateralization may underlie sex differences in visuospatial ability, and that sex differences in functional lateralization may be present for only certain visuospatial processes.

Adult↗

PubMed1991

Prospective analysis of masticatory function following lateral mandibulotomy.

Based on clinical impressions and subjective reports by patients, it is generally accepted that a loss of mandibular continuity will result in decreased masticatory function while preserving continuity will result in maintenance of masticatory function. Surprisingly, there is a paucity of well controlled studies objectively evaluating masticatory function to support these statements. The purpose of this study was to objectively evaluate masticatory function in a patient who underwent surgical resection for cure of a tonsillar carcinoma where a lateral mandibulotomy was used. Masticatory performance and swallowing threshold were assessed using a 0.5 gm frito as the test food substance and a sieve analysis. The subject was evaluated pre and post surgery and post prosthetic rehabilitation. When compared with pre surgery function, masticatory function and swallowing threshold were maintained and enhanced with prosthetic treatment 1 year post surgery. Maintenance of mandibular continuity did have functional merit for the subject studied.

Denture, Complete, Upper↗

PubMed1983

Hypnosis and lateral cerebral function as assessed by dichotic listening.

In a replication of Frumkin et al. we investigated the hypothesis that hypnosis may facilitate a shift in brain hemispheric dominance, as assessed by right-ear dominance shifts in a dichotic listening paradigm. Eight low, 13 medium, and 8 high hypnotizables, as assessed by the Stanford Hypnotic Susceptibility Scale, Form C, were given the Berlin et al. dichotic tape during two waking conditions and following an alert hypnotic induction. Results contradicted Frumkin et al. In contrast, low hypnotizables showed a significant reduction in right-ear dominance, suggestive of greater participation of the right cerebral hemisphere following hypnotic induction. Highs and mediums did not change. Discussion centers around procedural differences between the two studies (particularly type of hypnotic induction and instructions to attend to one or both ears) and the possible influence of relaxation/anxiety levels upon lateral shifts in cerebral function.

Adult↗

PubMed1999

Expression of connexin 26 and Na,K-ATPase in the developing mouse cochlear lateral wall: functional implications.

The immunohistochemical localization of connexin 26 (a gap junction protein) and Na,K-ATPase in the mouse cochlear lateral wall was studied at different ages between 0 and 30 days after birth (DAB). Connexin 26-like immunoreactivity was sparsely distributed among the connective tissue cells just lateral to the future marginal cells of the stria vascularis on 0 DAB. In the mice of 3-6 DAB, connexin 26 was observed in the strial basal cell area, and was increased in its distribution density on 10 DAB. Connexin 26 was sparsely distributed among the fibrocytes in the spiral ligament and the suprastrial zone on 10 DAB, and its distribution density increased rapidly in the mouse on 12 DAB. The immunohistochemical distribution reached the adult pattern in the cochlear lateral wall on 15 DAB. Weak Na, K-ATPase-like immunoreactivity was observed in the epithelial cells, corresponding to the future strial marginal cells, on 0 DAB. Its staining intensity was enhanced with the increase of age, and reached the adult pattern on 10 DAB. In contrast, Na,K-ATPase-like immunoreactivity in the type II fibrocytes and suprastrial fibrocytes was first detected on 12 DAB, and reached the mature level on 15 DAB. It is well known that the endolymphatic potential (EP) reaches the adult level 2 weeks after birth. The expression patterns of connexin 26 and Na,K-ATPase in the fibrocytes of the spiral ligament and the suprastrial zone coincided with the rapid growth and maturation of EP. These findings may suggest a role for the gap junctional communications and Na,K-ATPase activity of the fibrocytes within the cochlear lateral wall in the generation and maturation of EP.

Age Factors↗

PubMed1998

Frontal, temporal and lateralized brain function in children with attention-deficit hyperactivity disorder: a psychophysiological and neuropsychological viewpoint on development.

This article considers deficits in the selective aspects of perception underlying symptoms of impaired attention and impulsivity in children with attention-deficit hyperactivity syndrome (ADHD) in terms of frontal and temporal lobe function and cerebral asymmetry. Tomographic studies suggest a disturbed fronto-striatal function, but have neglected limbic contributions under activating conditions and are equivocal on the nature of apparent lateralized differences. Neuropsychological and psychophysiological studies suggest that early and late stages of information processing are affected in both the frontal and temporal lobes and imply impaired intercortical dialog. Given the evidence for a normal specialization in global processing in the right and the processing of details in the left hemisphere, the lateralized impairment may progress from situational ADHD (impaired selective aspects of perception on the right) to pervasive ADHD (additional impairment in decision-making on the left). Accordingly some ADHD children may experience an early negative neurodevelopmental influence that only appears as the brain region matures while others show a delayed development of CNS function.

Attention Deficit Disorder with Hyperactivity↗

PubMed2006

Differential functions of lateral and medial rostral prefrontal cortex (area 10) revealed by brain-behavior associations.

We analyzed the behavioral data from 104 neuroimaging studies using positron emission tomography or functional magnetic resonance imaging that reported activation peaks in rostral prefrontal cortex (PFC), approximating Brodmann's area 10. The distribution of absolute x coordinates of activation peaks (i.e., x coordinate regardless of hemisphere) differed significantly from a unimodal normal distribution, reflecting distinct clusters of activation in lateral and medial subregions. These 2 clusters were associated with different patterns of behavioral data. Lateral activations were associated with contrasts between experimental and control conditions where response times (RTs) were slower in the experimental condition. Medial activations were associated with contrasts where RTs were, if anything, faster in experimental than control conditions. These findings place important constraints on theories of rostral PFC functions.

Adult↗

PubMed1988

Modest decrements in plasma glucose concentration cause early impairment in cognitive function and later activation of glucose counterregulation in the absence of hypoglycemic symptoms in normal man.

To establish the glycemic threshold for onset of neuroglycopenia (impaired cognitive function, measured by the latency of the P300 wave), activation of hormonal counterregulation and hypoglycemic symptoms, 12 normal subjects were studied either under conditions of insulin-induced, glucose-controlled plasma glucose decrements, or during maintenance of euglycemia. A decrement in plasma glucose concentration from 88 +/- 3 to 80 +/- 1 mg/dl for 150 min did not result in changes in the latency of the P300 wave nor in an activation of counterregulatory hormonal response. In contrast, a greater decrement in plasma glucose concentration from 87 +/- 3 to 72 +/- 1 mg/dl for 120 min caused an increase in the latency of the P300 wave (from 301 +/- 12 to 348 +/- 20 ms, P less than 0.01), a subsequent increase in all counterregulatory hormones but no hypoglycemic symptoms. Finally, when plasma glucose concentration was decreased in a stepwise manner from 88 +/- 2 to 50 +/- 1 mg/dl within 75 min, the increase in the latency of the P300 wave was correlated with the corresponding plasma glucose concentration (r = -0.76, P less than 0.001). The glycemic threshold for hypoglycemic symptoms was 49 +/- 2 mg/dl. Thus, in normal man the glycemic threshold for neuroglycopenia (72 +/- 1 mg/dl) is greater than currently thought; the hormonal counterregulation follows the onset of neuroglycopenia; the hypoglycemic symptoms are a late indicator of advanced neuroglycopenia.

3-Hydroxybutyric Acid↗

PubMed1999

Structural and functional brain asymmetries in human situs inversus totalis.

OBJECTIVE: To determine whether individuals with situs inversus totalis (SI), a condition in which there is a mirror-image reversal of asymmetric visceral organs, have alterations in brain asymmetries. BACKGROUND: The human brain is asymmetric in structure and function. Although correlations between anatomic asymmetries and functional lateralization in human brain have been demonstrated, it has been difficult to further analyze them. Characterization of asymmetries of brain structure and function in SI might advance the understanding of these relationships. METHODS: Using anatomic and functional MRI techniques, we analyzed asymmetries in the brains of three individuals with SI. RESULTS: Two major anatomic asymmetries of the cerebral hemispheres, the frontal and occipital petalia, were reversed in individuals with SI. In contrast, SI subjects had left cerebral hemisphere language dominance on functional MRI analysis as well as strong right-handedness. CONCLUSION: These observations suggest that the developmental factors determining anatomic asymmetry of the cerebral petalia and viscera are distinct from those producing the functional lateralization of language.

Adult↗

PubMed1989

Crossed aphasia in a dextral.

A case of crossed aphasia in a monolingual dextral with detailed clinical, neuropsychological and language assessment is described. The presence of Gerstmann-syndrome suggested cross-over of even dominant parietal lobe functions. Lateralization and localization of various language functions in relation to crossed aphasia are discussed.

Adult↗

PubMed1998

Noninvasive determination of language lateralization by functional transcranial Doppler sonography: a comparison with the Wada test.

BACKGROUND AND PURPOSE: Functional transcranial Doppler ultrasonography (fTCD) can assess event-related changes in cerebral blood flow velocities and, by comparison between sides, can provide a measure of hemispheric perfusional lateralization. It is easily applicable, insensitive to movement artifacts, and can be used in patients with less than perfect cooperation. In the present study we investigated the validity of fTCD in determining the hemispheric dominance for language by direct comparison of fTCD with intracarotid amobarbital anesthesia (Wada test). METHODS: fTCD and the Wada test were performed in 19 patients evaluated for epilepsy surgery. By the Wada test, 13 patients were classified as left-hemisphere dominant and 6 as right-hemisphere dominant for language. fTCD was based on the continuous bilateral measurements of blood flow velocities in the middle cerebral arteries and event-related averaging during a cued word generation task previously shown to activate lateralized language areas in normal adults. RESULTS: In 4 patients fTCD assessment was not possible because of lack of an acoustic temporal bone window. In the remaining 15 candidates, determination of language dominance was concordant with the Wada test in every case. Moreover, the correlation of the lateralization measures from both procedures was highly significant (r=.92, P<.0001). CONCLUSIONS: This strong correlation validates fTCD as a noninvasive and practical tool for the determination of language lateralization that can be applied for clinical and investigative purposes.

Adolescent↗

PubMed2001

Neuropeptide Y Y1 receptor-mediated anxiolysis in the dorsocaudal lateral septum: functional antagonism of corticotropin-releasing hormone-induced anxiety.

Neuropeptide Y and corticotropin-releasing hormone are involved in the regulation of various physiological functions including the expression of anxiety and fear. The anxiogenic effects of corticotropin-releasing hormone can be modulated by neuropeptide Y, yet the brain regions involved in this interaction are only partly understood. By utilizing antibodies raised against neuropeptide Y and the Y1 receptor protein we identified a densely labeled cell group in the dorsal zone of caudal part of the rat lateral septum. Bilateral microinjections of neuropeptide Y into the dorsocaudal lateral septum but not into the intramedial septum dose-dependently decreased anxiety in the social interaction test of rats, whereas the effects of corticotropin-releasing hormone were opposite. The anxiogenic-like effect of corticotropin-releasing hormone was reversed by neuropeptide Y pretreatment. Local microinjection of the neuropeptide Y receptor selective antagonists revealed that neither Y1 receptor nor Y2 receptor selective antagonists had effects on experimental anxiety on their own suggesting that neuropeptide Y-induced anxiolysis is not tonic. The Y1 receptor antagonist blocked the anxiolytic-like effect of neuropeptide Y, while the Y2 receptor antagonist was ineffective.We conclude that neuropeptide Y in the dorsocaudal lateral septum may act as an endogenous anxiolytic and antagonize corticotropin-releasing hormone (stress)-induced anxiety. This functional antagonism probably shapes behavior under aversive conditions, as neuropeptide Y-induced anxiolysis is not tonic in nature. An imbalance between these two neuropeptide systems in the septum may lead to a maladaptive expression of anxiety after stress exposure.

Animals↗

PubMed1981

Assessing VP function: the lateral still technique vs. cinefluorography.

Thirty consecutive patients with clinical manifestations of velopharyngeal insufficiency were evaluated by the radiographic techniques of 70 mm lateral stills and lateral cinefluorography. The purpose of this study was to make retrospective comparisons between the actual decisions on velopharyngeal competency or incompetency which were originally made on the basis of cinefluorographic findings with those which we believe would have been made from that information obtained from lateral stills alone had the lateral stills been the only radiographic information available. The results of the comparison between the two techniques suggests that one is apt to misdiagnose the presence or absence of velopharyngeal insufficiency on the order of 30% of th time when relying on the lateral still X-ray technique alone. We attribute this potential error rate to the very limited speech sample that can be employed with the lateral still technique. With the increasing number of secondary procedures available for treating VP dysfunction it is our opinion that cine- or videofluoroscopy allows the clinician to examine additional aspects of the patient's palatal function that are as important in the final management decision as simply the identification of closure or the lack of closure of the velopharyngeal sphincter.

Adolescent↗

PubMed1985

Cerebral hemisphere function and laterality of migraine.

We report preliminary findings of a study exploring the hypothesis that migraine is the experience of a protective cerebrovascular mechanism arising in response to unilateral cerebral information overload. The necessary population to be studied, namely those with exclusive one-sided migraine, proved to be rare. The measures of cerebral hemisphere function were the verbal and non-verbal scales of Wechsler's Adult Intelligence Scale. Preliminary results suggest that it is worthwhile continuing to explore the notion using additional and more sophisticated measures.

Adult↗

PubMed2001

Morphology of the temporomandibular joint in skeletal class iii symmetrical and asymmetrical cases: a study by cephalometric laminography.

The aetiology of asymmetric growth in the mandible is not well understood. Previous studies have indicated that the functional lateral shift of the mandible in the period of prepubertal growth may translate to a true skeletal asymmetry, exclusively in skeletal Class III malocclusion. This asymmetry develops more characteristic features during the pubertal and post-pubertal growth periods. Early correction of a functional lateral shift of the mandible is recommended. The purpose of this study was to examine the relationship between the morphology of the temporomandibular joints and asymmetry in skeletal Class III malocclusion in adult female patients. Cephalometric and laminographic findings in 36 asymmetric skeletal Class III patients with a lateral shift of mandible (group 3) were compared to those of 25 symmetric skeletal Class I patients (group 1) and the same number of symmetric skeletal Class III malocclusions (group 2). All the patients had received no orthodontic treatment. The results showed that the TMJ of the side to which the mandible shifted showed a significantly narrower and shorter shape of the condyle head, smaller superior condylar space, and steeper eminence than those of the unshifted side.

Adolescent↗

PubMed2003

Lateral cerebellum: functional localization within crus I and correspondence to cortical zones.

The present study investigates the functional connections of different parts of the medial-most folium of crus I in the cat cerebellar hemisphere. Three areas were identified physiologically by recording on the cerebellar surface climbing fibre (CF) field potentials evoked by electrical stimulation of different body sites. From medial to lateral in relation to the long axis of the folium, area 1 receives convergent input from all body sites tested (optic chiasm, ipsilateral periorbital region, ipsilateral and contralateral forelimbs), area 2 receives input mainly from the ipsilateral periorbital region, while area 3 receives input mainly from the optic chiasm. These physiological differences were used to guide injections of bi-directional tracer material into individual cortical areas. The inferior olive and cerebellar nuclei were then mapped, revealing a precise topography within the olivo-cerebellar and cortico-nuclear projections for each area. On the basis of their anatomical and physiological characteristics areas 1, 2 and 3 correspond to zones C2, C3 and D1, respectively. CF inputs arise from the rostral medial accessory olive (C2), the interface between the rostral dorsal accessory olive and ventral lamella of the principal olive (vlPO, C3), and from vlPO (D1). The corresponding cortico-nuclear projections are nucleus interpositus posterior (C2), the transitional region between the dentate nucleus and nucleus interpositus anterior (C3), and the dentate nucleus (D1). Overall, the results provide a comprehensive description of the functional localization of different zones within crus I (folium 1), and suggest that a potent source of CF input to the C2 and D1 zones within this region of cortex arises from visual pathways.

Animals↗

PubMed2000

Interhemispheric cooperation during word processing: evidence for callosal transfer dysfunction in schizophrenic patients.

Functional lateralization and interhemispheric interaction during word processing were investigated in schizophrenic patients (n=12) and matched healthy controls (n=18). Words and phonologically regular pseudowords were presented tachistoscopically either in the left or right visual field (unilateral conditions), or simultaneously in both visual hemifields (bilateral condition). Consistent with earlier findings, healthy controls showed a right visual field advantage (RVFA), indicating left-hemispheric dominance for language. The patients showed a RVFA similar to that of controls, consistent with normal left-hemispheric language dominance. Importantly, controls performed much better on words presented in the bilateral condition, when two copies of the same word appeared twice, compared to stimulation in only one of the visual hemifields. This bilateral advantage, which has been interpreted as evidence for cooperation between the hemispheres, was absent in schizophrenics. These data show that schizophrenic patients can exhibit similar lateralization patterns as healthy controls. Their specific functional deficit may be a lack of cooperation between the hemispheres.

Adult↗

PubMed1994

[Assessment of viable myocardium after infarction with transesophageal echocardiography and myocardial echocontrastography].

Left ventricular recovery of dysfunctioning but viable myocardium can occur only in tissue in which both myocardial contractile reserve and microvascular integrity are preserved. Recent studies have demonstrated that both inotropic stimulating echo tests and myocardial contrast echocardiography can be used to assess myocardial viability in post-myocardial infarction patients. Therefore we performed a transesophageal and myocardial contrast echocardiographic evaluation of post-myocardial infarction patients to assess: the respective accuracy of post-extrasystolic potentiation and low-dose dobutamine (5 and 10 mcg) during transesophageal echocardiography in eliciting contractile reserve, and the potential of myocardial contrast echocardiography in predicting later functional recovery. Results of our studies showed comparable effects of low-dose dobutamine (5 mcg) and post-extrasystolic potentiation in increasing myocardial thickening while low-dose dobutamine (10 mcg) had a greater potential in eliciting residual contractility. Lastly, myocardial contrast echocardiography provided a clear spectrum of intramyocardial perfusion patterns in dysfunctioning areas but did not accurately correlate with later functional recovery as better predicted by low-dose dobutamine in the same segments. In conclusion, these methods represent the preferred choice of studying the perfusion-contraction match in viable myocardium thus playing an important role in prognostic and therapeutic strategies in myocardial infarction patients.

Echocardiography↗