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PubMed1999

Lateralization of cortical function in swallowing: a functional MR imaging study.

BACKGROUND AND PURPOSE: While functional MR imaging and other techniques have contributed to our knowledge of functional brain localization, these methods have not been extensively applied to the complex and incompletely understood task of swallowing. We used functional MR imaging to investigate motor cortex activity during swallowing in healthy human adults. METHODS: Eight subjects were imaged on a 1.5-T MR system using blood oxygen level-dependent contrast mechanisms. Subjects performed three swallowing tasks and a finger-tapping task. Areas of activation in the cortex and subcortical areas were tabulated, and a laterality index, defined as LI = [sigmas left - sigmas right]/[sigmas left + sigmas right] x 100, was computed for the three tasks. RESULTS: Activation was observed in the primary motor and sensory cortices, motor processing and association areas, and subcortical sites. This activity was dominant for one hemisphere with left hemispheric dominance more prevalent among the subjects. Right hemispheric dominance, however, showed stronger lateralization than the left hemisphere. CONCLUSION: Our data indicate that specific sites in the motor cortex and other cortical and subcortical areas are activated with swallowing tasks and that hemispheric dominance is a feature of swallowing under these conditions. In addition, we demonstrate the utility of functional MR imaging in the study of the cortical representation of swallowing and suggest a role for functional MR imaging in the diagnosis of dysphagia of cerebral origin.

Adult↗
PubMed2004

A functional screen identifies lateral transfer of beta-glucuronidase (gus) from bacteria to fungi.

Lateral gene transfer (LGT) from prokaryotes to microbial eukaryotes is usually detected by chance through genome-sequencing projects. Here, we explore a different, hypothesis-driven approach. We show that the fitness advantage associated with the transferred gene, typically invoked only in retrospect, can be used to design a functional screen capable of identifying postulated LGT cases. We hypothesized that beta-glucuronidase (gus) genes may be prone to LGT from bacteria to fungi (thought to lack gus) because this would enable fungi to utilize glucuronides in vertebrate urine as a carbon source. Using an enrichment procedure based on a glucose-releasing glucuronide analog (cellobiouronic acid), we isolated two gus(+) ascomycete fungi from soils (Penicillium canescens and Scopulariopsis sp.). A phylogenetic analysis suggested that their gus genes, as well as the gus genes identified in genomic sequences of the ascomycetes Aspergillus nidulans and Gibberella zeae, had been introgressed laterally from high-GC gram(+) bacteria. Two such bacteria (Arthrobacter spp.), isolated together with the gus(+) fungi, appeared to be the descendants of a bacterial donor organism from which gus had been transferred to fungi. This scenario was independently supported by similar substrate affinities of the encoded beta-glucuronidases, the absence of introns from fungal gus genes, and the similarity between the signal peptide-encoding 5' extensions of some fungal gus genes and the Arthrobacter sequences upstream of gus. Differences in the sequences of the fungal 5' extensions suggested at least two separate introgression events after the divergence of the two main Euascomycete classes. We suggest that deposition of glucuronides on soils as a result of the colonization of land by vertebrates may have favored LGT of gus from bacteria to fungi in soils.

Amino Acid Sequence↗
PubMed1994

Outcome of wheeze in childhood. Symptoms and pulmonary function 25 years later.

The outcome after 25 yr was studied for three groups of children classified in a random community survey in 1964 as having asthma (121 subjects), wheeze in the presence of infection (167 subjects), or no respiratory symptoms (167 comparison subjects). Approximately 80% of the subjects in each group, now aged 34 to 40 yr, were successfully traced. Current symptoms and smoking habit were recorded by questionnaire, and ventilatory function, peak flow variability, and bronchial reactivity to inhaled methacholine were measured. Subjects who had asthma in childhood were more likely to wheeze (odds ratio [OR] 14.4) or produce phlegm (OR 3.3) than comparison subjects. They also had significantly lower FEV1 values and greater bronchial reactivity than comparison subjects. Adult FEV1 correlated with childhood FEV1 (both expressed as % of predicted) (r = 0.44, p < 0.01). The prognosis for those children who were classed as having wheeze in the presence of infection in 1964 was better than for those who had asthma. Although they also were more likely to report wheeze (OR 3.8) or phlegm (OR 4.4) than comparison subjects, the wheezy symptoms were unlikely to interfere with activities and the ventilatory function and bronchial reactivity to methacholine did not differ from those of comparison subjects. Smokers were more likely to report wheeze (OR 2.0), cough (OR 7.2), and phlegm (OR 3.1) than never-smokers, and current smokers with current wheezy symptoms had significantly reduced FEV1 values, although smoking was not associated with increased methacholine reactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma↗
PubMed2001

Sympathetic sudomotor function and amyotrophic lateral sclerosis.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting motor neuron cells in the cerebral cortex, brain stem and spinal cord. Autonomic nervous system involvement is not a recognized feature of the disease; nonetheless, autonomic dysfunction has been reported in severely affected patients. The aim of this study was to evaluate sympathetic sudomotor function in ALS patients, employing the sweat imprint test. METHODS: Twenty-four ALS patients and 25 controls, matched for sex and age, were included. In total, 34 hands and 35 feet in controls, and 29 hands and 30 feet in the ALS population, were investigated. RESULTS: No inter-side difference was found in controls or in ALS patients. The mean number of sweat drops/cm2 was comparable in both populations. However, six ALS patients had a lower count on the hand than on the foot, which was never observed in controls. Furthermore, in the ALS population, five hands and three feet showed values below the lower limit of normal. The abnormalities were more frequent in very weak limbs, and could be ascribed to lack of use. CONCLUSION: Although significant sudomotor hypofunction does not occur in ALS, mild subclinical changes can be observed in weak limbs.

Adult↗
PubMed1978

Ovarian function, reproduction, and later operations following adnexal surgery.

Among 3102 patients who had major gynecologic operations, only 223 (7.18%) needed adnexal operations during which reproductive potential was preserved. Operations involved ovaries (156), tubes (55), and embryologic cysts (32). After recovery 53.69% of these patients had viable babies (64.46% of patients under age 30). Patients were examined up to 28 years after operations, an average 11.32 years. When last examined. most patients still retained physiologic evidence of ovarian hormonal function; 20 patients had passed through spontaneous menopause, at an average age of 49.4 years. Fifty-two patients needed subsequent pelvic operations, but only 7 for possibly related conditions (4 repeat tubal pregnancies and 3 cyst-adenomas). All but one twisted adnexal mass, with gangrene, originated as a paramesonephric duct cyst. Seventeen adnexal operations were associated with pregnancy: 15 mothers had healthy babies, and 2 aborted. Details concerning numbers and characteristics of specific lesions are included in the paper.

Adnexa Uteri↗
PubMed2006

Behavioral and neural lateralization of vision in courtship singing of the zebra finch.

Along with human speech and language processing, birdsong has been one of the best-characterized model systems for understanding the relationship of lateralization of brain function to behavior. Lateralization of song production has been extensively characterized, and lateralization of song perception has begun to be studied. Here we have begun to examine whether behavior and brain function are lateralized in relation to communicative aspects of singing, as well. In order to monitor central brain function, we assayed the levels of several activity dependent immediate early genes after directed courtship singing. Consistent with a lateralization of visual processing during communication, there were higher levels of expression of both egr-1 and c-fos in the left optic tectum after directed singing. Because input from the eyes to the brain is almost completely contralateral in birds, these results suggest that visual input from the right eye should be favored during normal singing to females. Consistent with this, we further found that males sang more when they could use only their right eye compared to when they could use only their left eye. Normal levels of singing, though, required free use of both eyes to view the female. These results suggest that there is a preference for visual processing by the right eye and left brain hemisphere during courtship singing. This may reflect a proposed specialization of the avian left hemisphere in sustaining attention on stimuli toward which a motor response is planned.

Animals↗
PubMed1992

Sex determination by discriminant function analysis of lateral cranial form.

To sex the cranium, morphological features of cranial specimens were quantified with a personal computer that automatically measures distance and gradient for 39 craniometric points in the lateral contour line of the skull, which were digitized by a tablet digitizer connected to the computer. Specimens used for discriminant analysis were 50 male and 50 female adult Japanese skulls. The lateral contour showed sex differences in the nasal bone, supraorbital ridge, forehead and vertex. The nasal bone and supraorbital ridge were more developed in male contour line, and the forehead was more rounded in female contour line. But compared with the supraorbital ridge and forehead, the vertex had a wide variety of contour lines in both sexes. The vertex seemed to be less reliable as the indicator of sex. The sex differences were better reflected by gradient than distance. From variables of the gradient and distance showing significant sex differences, the discriminant function was derived and tested in 21 other specimens (13 male and 8 female skulls). The mean ratio of correct sexing of the human skull by the discriminant function was 86%.

Adult↗
PubMed1993

Cortical function in amyotrophic lateral sclerosis. A positron emission tomography study.

Positron emission tomography was used to measure regional cerebral blood flow (rCBF) in 12 patients with amyotrophic lateral sclerosis (ALS) and six age-matched controls. Scans were performed at rest, and while subjects performed stereotyped and freely selected movements of a joystick with their right hand. Statistical parametric mapping was used to determine significant differences in rCBF between the two groups at rest and during activation. The ALS group showed no significant difference in global cerebral blood flow at rest compared with controls. However, rCBF at rest was significantly (P < 0.01) reduced in the ALS group in the primary sensorimotor cortex, the lateral premotor cortex, the supplementary motor area, the anterior cingulate cortex, the paracentral lobule and the superior and inferior parietal cortex. Comparison of the increase in rCBF caused by freely selected joystick movements over the resting state between the two groups of subjects showed significantly (P < 0.001) greater activation in ALS patients in the ventral third (face area) of the contralateral primary sensorimotor cortex and in the adjacent contralateral ventral premotor and parietal association cortices; significantly (P < 0.01) greater activation of the contralateral anterior insula and the ipsilateral anterior cingulate cortex (dorso-caudal area 24) was also present in ALS patients. When a comparison of the rCBF response to the free selection task with that to the stereotyped task was performed between the two groups of subjects, ALS patients showed significantly impaired (P < 0.01) activation of the rostral anterior cingulate cortex (area 32), medial prefrontal cortex (area 10), left parahippocampal gyrus and retrosplenial cortex. The pattern of reduced rCBF at rest in ALS patients probably reflects a combination of neuronal loss in all areas of cortex projecting through the pyramidal tract together with loss of projections from the sensorimotor cortex to the motor association areas. The expansion of the upper limb output zone of the sensorimotor cortex in ALS patients during contralateral upper limb movement may represent cortical reorganization in response to Betz cell loss or corticospinal tract disruption. Abnormal recruitment of non-primary motor areas may also represent functional adaptation to a corticospinal tract lesion. Focally impaired activation of the medial prefrontal cortex and parahippocampal gyrus in ALS patients during the process of internal generation of movement could underlie the frontal lobe cognitive deficits reported in previous neuropsychological studies of ALS.

Adult↗
PubMed1988

Retinal afferent arborization patterns, dendritic field orientations, and the segregation of function in the lateral geniculate nucleus of the monkey.

Optic tract fibers and cell bodies in the lateral geniculate nucleus of the monkey were studied intracellularly with micropipette electrodes containing the marker enzyme horseradish peroxidase. Single optic-tract fibers always projected to only one of the six geniculate layers. The majority of the axons innervating the four parvocellular laminae were red/green opponent color units; their terminations formed cylindrical columns that were perpendicular to the layers. In similar fashion, the geniculate cells in the parvocellular layers were mostly red/green units with narrow, bipolar dendritic fields oriented normal to the laminar borders. The majority of the retinal axons ending in parvocellular layers 6 and 5 were on-center units; nearly all geniculate cells in these two laminae were also on-center neurons. In layers 4 and 3 most terminating optic-tract fibers, as well as the geniculate cells themselves, were off-center units. All axons projecting to the magnocellular layers were broad-band units with spherical terminal arborizations. The magnocellular geniculate neurons, which were also broad band, had extensive spherical dendritic fields that often crossed laminar borders. Thus, the terminal patterns of each class of retinogeniculate axon closely resembled the dendritic orientations of the functionally related geniculate target cells.

Afferent Pathways↗
PubMed1976

Functional characteristics of lateral interactions between rods in the retina of the snapping turtle.

1. Intracellular recordings were made of the slow hyperpolarizing light responses of single rods in the retina of the snapping turtle. Physiological criteria used to identify rods were verified by intracellular injections of Procion Yellow. 2. The amplitudes of the responses elicited by fixed intensity flashes increased as the stimulus was enlarged to a diameter of 300 mum. Scattered light was found incapable of accounting for this effect, which must result from summative interaction of rods with neighbouring receptors. Effects of summative interaction were observed even at stimulus intensities that produced maximal responses. Enlarging the diameter of the higher intensity stimuli from 100 to 300 mum increased the peak response amplitude by almost 50%; it also produced a distinct initial peak of the response which we term overshoot. The amplitude of this overshoot was graded with stimulus size. 3. Complete intensity-response relationships were determined using stimulus diameters of 100 and 750 mum for each rod. With the smaller stimulus the intensity response range was 4-5 log units, and with the larger stimulus this was increased to 5-0 log units. For intensities below about 60 quanta/mum2 per flash (514 nm) the amplitudes elicited by the large stimulus followed a sigmoid-shaped curve. However, at higher intensities an additional lobe appeared on the intensity-response relationship. The appearance of this lobe correlated with the emergence of the overshoot on the response wave form. 4. Determinations of rod flash sensitivity (mV per quantum per mum2) showed that it increased with stimulus size up to a stimulus diameter of about 300 mum. With diameters between 50 and 150 mum, a linear relationship existed between the flash sensitivity and stimulus area. Absolute quantal sensitivities increased with stimulus area by a factor of 26, from a value of 28 muV per photoisomerization per rod with a stimulus 25 mum in diameter, to 720 muV per photoisomerization per rod with a stimulus 300 mum in diameter. 5. By comparison, red-sensitive cones showed increased sensitivity as a function of stimulus size only up to a stimulus diameter of 120 mum. Their over-all sensitivity was lower than that of rods and proved linear with stimulus diameter rather than with stimulus area. 6. Simultaneous recordings were made from rod-cone pairs to determine whether the overshoot, and hence the lobe on the amplitude-intensity function, could result from a cone input to the rod response. The time course of the cone response proved much too rapid to fit the overshoot of the rod response. 7. The spectral sensitivity of the dark-adapted rod response closely followed the difference spectrum of the rod photopigment for wave-lengths greater than 450 nm. This was true throughout the intensity range of the response, including low intensities where response averaging was necessary. 8. At low response amplitudes (approximately 1 mV), about 70% of the 40 rods tested showed responses to long wave-length stimuli consisting of two components...

Animals↗
PubMed1991

Factor analysis and the cerebral hemispheres: pilot study and parietal functions.

Although research on lateral differences has proliferated, attempts to specify fundamental dichotomies of hemispheric processing have yielded less than satisfactory results. The factor analysis of behavioral asymmetries can provide a different approach by helping to identify common functions underlying disparate tasks. It can also provide information on individual differences and interrelationships among functions. Here, the viability of the approach is demonstrated with a small pilot study (N = 29), and with two larger experiments (N = 70 and N = 60) that stress parietal lobe function. Seven lateralized functions were identified: auditory lexical, spatial attentive, spatial positional, spatial quantitative, tactile figural, visual emotional and visual lexical. A range of positive, negative and null correlations was found between functions, contrary to lateralization strength, hemisphericity, and independence models of individual differences in lateralization. However, a pattern of intercorrelations was observed among functions believed to be localized to the perisylvian region (Brodmann areas 22 and 39), which is consistent with the neurodevelopment theory of Geschwind and Galaburda (Cerebral Lateralization Biological Mechanisms, Associations and Pathology, The MIT Press, Cambridge, MA, 1987).

Adult↗
PubMed1990

[The relationship between severity of spastic diplegia and laterality of the cerebral function].

Seventeen children with clinical evidences of preterm birth and spastic diplegia (SD) were studied about the relationship between clinical severity and laterality of cerebral function. The result showed the patients with the left-handed SD were more serious than those with the right-handed in their intelligence and activity of daily living. As the severity increased, motor difficulty was also observed at upper limbs, and especially spasticity was detected at the right hand. The dichotic listening test showed the right ear dominance only in the patients with the right-handed SD. MRI examination was performed in 10 cases, and periventricular leukomalacia (PVL) was detected in all cases. There was few correlation between PVL and clinical laterality. We speculated that right-hand spasticity which was seen in severe cases was due to the fragility of periventricular structure in the left hemisphere.

Brain↗
PubMed1998

An objective analysis of the impact of lateral rhinotomy and medial maxillectomy on nasal airway function.

OBJECTIVE: The lateral rhinotomy and medial maxillectomy procedure, while known to interrupt nasal valve supports, has not previously been reported to adversely affect nasal airway function. The purpose of this study was to utilize state-of-the-art techniques to objectively analyze the impact of this procedure on nasal airway function. DESIGN: The study design was retrospective and subject controlled. METHODS: The study population was derived from an academic, tertiary-referral, otolaryngology-head and neck surgery department with an estimated catchment population of 4 million people. Subjects included 21 consecutive, long-term postoperative patients who had undergone lateral rhinotomy and medial maxillectomy for inverted papilloma. Objective measures included vestibular cephalometric measurements, airflow rhinomanometry, and acoustic rhinometry. RESULTS: Statistically significant results reveal that although lateral rhinotomy and medial maxillectomy are associated with alar collapse, both overall nasal airflow and valve areas are increased. CONCLUSION: Lateral rhinotomy and medial maxillectomy does not adversely affect nasal airway function. This appears to be the result of concomitant resection of the functionally dominant inferior turbinate. This suggests that lateral rhinotomy performed in conjunction with operations not requiring inferior turbinectomy, such as anterior craniofacial resection, may adversely affect nasal airway function.

Acoustics↗
PubMed1995

Oculomotor function in amyotrophic lateral sclerosis: evidence for frontal impairment.

Saccadic eye movements, fixation, and smooth pursuit were recorded in 17 subjects with amyotrophic lateral sclerosis (ALS) and 11 age-matched controls using a magnetic scleral search coil. Reflexive, remembered and antisaccades, and smooth pursuit at four target velocities were studied. Subjects with ALS showed significantly elevated error rates (distractibility) and latency in the antisaccade and remembered saccade paradigms but no abnormality of reflexive saccades. The frequency of small saccades that intruded on steady fixation (square-wave jerks) was also increased in ALS subjects. Peak velocity gain of smooth pursuit and performance on the Wisconsin Card Sort Test did not differ significantly between the two groups. These findings are consistent with prefrontal dysfunction in ALS and provide an independent source of support for the thesis that the pathology of this condition invades frontal cortex.

Adult↗
PubMed2006

Asymmetry of neuron numbers in the hippocampal formation of prenatally malnourished and normally nourished rats: a stereological investigation.

There is considerable evidence for lateralization of hippocampal function and hemispheric asymmetry in humans. In the rat, studies have reported asymmetries in the thicknesses of layers, the volumes of hippocampal subfields, and the density of cells at specific points along the septotemporal axis. To determine if there is an asymmetry of neuron numbers and whether prenatal malnutrition affects any asymmetries, 90-day old male Sprague-Dawley rats that were either normally nourished or malnourished prenatally were perfused with 4% paraformaldehyde and the brains cut into 30-micro m sections. One interrupted series of sections through the entire hippocampus was analyzed stereologically to estimate the total number of neurons in the hilus of the dentate gyrus, the CA3/CA2 stratum pyramidale (SP), the CA1 SP, and the SP of the prosubiculum/subiculum of both hemispheres. Significant asymmetries (P < 0.05) were found in the CA1 and CA3/CA2 subfields, with the right hemisphere containing 21 and 6% fewer neurons, respectively. Malnutrition reduced neuron numbers in the CA1 subfield by 12%, but did not alter the hemispheric asymmetry. Our findings agree with previous reports of left dominant asymmetries in the rat brain and suggest that this may result from differences in total numbers of neurons.

Analysis of Variance↗