SEARCH · PubMed Health

Results for “Functional Laterality”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59Linked to original sources

PubMed1983

Brain laterality: differences in cognitive style or motor function?

Two studies were completed to evaluate the role of motor function in the observable brain laterality of normal, familial, dextral males. A right-brain advantage was demonstrated on a figure-matching task and on a sequential-spatial task when subjects responded with a manual key press. A left-brain advantage for the same two tasks was demonstrated when subjects responded by compressing a microswitch embedded in a mouthpiece. The data suggest that both hemispheres of the brain may be capable of processing visuospatial stimuli but do not share the same facility for effecting appropriate motor responses. The results were discussed in terms of lateralized cognitive styles in brain and lateralized control of effector systems.

Adult↗

PubMed2001

A method for standardizing jaw displacements in the horizontal plane while recording single motor unit activity in the human lateral pterygoid muscle.

The normal function of the lateral pterygoid muscle is not well understood although this muscle is thought to play an important role in the control of jaw and jaw-joint function and is implicated in temporomandibular disorders (TMD). The lack of a validated method for standardization of jaw movement in studies of lateral pterygoid function has contributed to the lack of understanding of the normal function of this muscle. An improved understanding of normal function will allow valid comparisons to be made with TMD patients in order to identify whether purported differences in activity actually exist. This paper describes a methodology for standardizing command jaw movements in the horizontal plane, together with reliable recordings of single-motor-unit (SMU) activity. In six human participants, jaw movements were standardized by having participants track a linear bank of light-emitting diodes (LEDs) aligned on a monitor displaying the mid-incisor point (MIPT). In all participants, the MIPT target (i.e. an illuminated LED) could be tracked, according to a pre-determined criterion, during single- and multiple-step displacements at different rates (1.3--6.5 mm/s at MIPT) and magnitudes (0.65--12 mm) of movement. SMU activity from the superior (SHLP) or inferior (IHLP) head of the lateral pterygoid muscle could be reliably discriminated during repeated trials of these defined tasks. This methodology establishes a reliable technique for characterizing the firing properties of SMUs within the lateral pterygoid, and has implications for analogous studies in other jaw muscles.

Adult↗

PubMed2000

Accessory nerve function after modified radical and lateral neck dissections.

OBJECTIVES: Evaluate preoperative and postoperative electrophysiological changes related to the accessory nerve with reference to dissection technique, modified radical neck dissection, and lateral neck dissection. STUDY DESIGN: Prospective electrophysiological analysis of accessory nerve function in a total of 20 laryngeal carcinoma patients after neck dissection, 12 being lateral neck dissection (4 bilateral) and 8 being modified radical neck dissection. METHODS: Distal latencies, compound muscle action potentials, and electromyography findings were investigated before surgery and, in early and late postoperative periods in 20 laryngeal carcinoma patients. Results were evaluated by Student t test and chi2 test for intragroup and intergroup differences. RESULTS: In the lateral neck dissection group, postoperative distal latencies were longer, without statistical significance, whereas in the modified radical neck dissection group postoperative latencies were statistically longer. Postoperative compound muscle action potentials were significantly lower in both groups. Electromyographic work-up showed deterioration in early postoperative periods and improvement in late postoperative periods. When intergroup differences were compared, both postoperative compound muscle action potential and electromyographic findings were worse in the lateral neck dissection group. CONCLUSIONS: The accessory nerve function after modified radical neck dissection is better than function after lateral neck dissection because of increased stress applied to the nerve during retraction of the sternocleidomastoid muscle for achievement of a better exposed surgical field in lateral neck dissection.

Accessory Nerve↗

PubMed2005

Left prefrontal repetitive transcranial magnetic stimulation impairs performance in affective go/no-go task.

Functional neuroimaging studies have associated affective go/no-go function with lateral prefrontal activation, but they have not established a causal role and have not determined whether one hemisphere is predominantly engaged. In the present study, 11 normal volunteers underwent slow repetitive transcranial magnetic stimulation of the left and right dorsolateral prefrontal cortex, and the occipital cortex prior to performance of a picture-based affective go/no-go task. We found an interfering effect of left prefrontal repetitive transcranial magnetic stimulation compared with both right prefrontal and occipital repetitive transcranial magnetic stimulation. This impairment concerned positive and negative task stimuli to a similar extent, and tended to be greater in shift compared with nonshift blocks. Our findings demonstrate a functionally relevant lateralization of the prefrontal contribution to affective go/no-go tasks.

Adult↗

PubMed1997

Differential rates of age of seizure onset between sexes and between hemispheres?

In a descriptive analysis of 158 patients with temporal lobe epilepsy, Taylor (1969) reported that the age of first seizure varied systematically as a function of laterality and sex. We conducted inferential analyses of Taylor's original data which (1) provided support for his proposal of disproportionate left hemisphere vulnerability to seizure onset in early life, but (2) failed to provide evidence of sex differences in age of onset of unilateral seizures. Examination of these effects in a larger sample of 844 patients drawn from the Bozeman Epilepsy Consortium provided some additional support for findings from the inferential analysis. Specifically, the left hemisphere appeared more vulnerable to seizure onset in childhood, this increased vulnerability extending to about age 5 years. Age of onset of seizures was not different when males and females were compared. Thus, reanalysis of Taylor's original data as well as examination of data from a larger, more contemporary sample suggest that seizure onset varies as a function of laterality, but not sex.

Adult↗

PubMed1987

Stimulus selectivity and functional organization in the lateral suprasylvian visual cortex of the cat.

1. We have examined the responses of cells in the postero-medial and postero-lateral lateral suprasylvian areas (p.m.l.s./p.l.l.s.) in the medial and lateral banks of the middle suprasylvian sulcus of the anaesthetized, paralysed cat. 2. Visual responses were assessed qualitatively (for projected spot and bar stimuli) and quantitatively (for drifting, high-contrast gratings of optimum spatial and temporal frequencies, but varying in orientation and direction of drift). There was excellent agreement between qualitative and quantitative estimates of preferred direction of motion. 3. Comparison of responses to motion in the preferred direction and the opposite direction confirmed that the percentage of units with strong directional preference is higher in this region of cortex than in other cortical and subcortical visual structures so far investigated. 4. Cells were comparatively well 'tuned' for the direction of motion of a grating: on average the half-width at half-amplitude for the variation in response around the principal preferred direction was 23.2 deg for p.m.l.s. and 25.3 deg for p.l.l.s., thus falling within the range found for complex cells in area 17. In this and other aspects of their direction selectivity, neurones in p.m.l.s. and p.l.l.s. were very similar to each other. 5. Quantitative analysis of the direction-response functions revealed them frequently to be more complex than previously described. For many cells there were subsidiary response peaks in addition to the main peak at the principal preferred direction. Often there was an accessory peak 180 deg from the optimum direction (i.e. directional preference was incomplete), but there was also a clear tendency for responses to be specifically elevated for directions orthogonal to the principal direction. 6. Tests with stationary, contrast-modulated gratings of the optimum spatial frequency, but differing in orientation, revealed that neurones responsive to such stimuli (though limited to about half the population) were orientation selective, their preferred orientations for stationary and drifting gratings being very similar. 7. The functional architecture of the lateral suprasylvian cortex was studied by means of single and multiple penetrations at different angles to the cortical surface: in most penetrations in p.m.l.s. the preferred directions of cells tended to shift progressively in small steps across the cortex, at a maximum rate of about 360 deg mm-1. However, there were occasional 180 deg differences between neighbouring recording sites or between cells recorded at different depths within a single radial column.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗

PubMed2004

Lateralization of the frontal lobe functions elicited by a cognitive bias task is a fundamental process. Lesion study.

Cognitive neuroscience researchers have hypothesized that context-dependent and context-independent response selection is associated with the left and right frontal lobe, respectively, in right-handed adult males. Patients with left frontal lobe lesions show context-independent reasoning in a cognitive bias task (CBT), while those with right frontal lesions show context-dependent reasoning. Young children show more context-independent responses in a modified CBT (mCBT), while adolescents and adults show more context-dependent responses. We investigated the cognitive bias of right-handed children with unilateral frontal lobe lesions/epileptic foci to explore the plasticity of lateralization in the frontal lobes. The study included eight children with left frontal lobe lesions/epileptic foci (LLF) and four children with right frontal lobe lesions/epileptic foci (RLF). Twenty-three right-handed age-matched males served as controls. A computer presented version of the original card-choice task that was simplified and modified for children was used (mCBT). Simple visual stimuli differed dichotomously in shape, color, number, and shading. A target object presented alone was followed by two choices from which subjects made selection based on preference. Considering all four characteristics, the degree of similarity between the target and the subjects' choice was scored for 30 trials. A high score indicated a context-dependent response selection bias and a low score indicated a context-independent bias. The RLF subjects had a higher converted score (mean: 26.8+/-2.2), while LLF subjects showed a lower converted score (mean: 7.75+/-6.3). There were highly significant differences between LLF subjects and the other groups (P<0.001 vs. controls or RLF subjects). No significant correlations were observed between the converted scores and the age at onset, time since insult, or IQ in either LLF or RLF subjects. These findings suggest that the lateralization of frontal lobe function elicited by mCBT is fundamental and independent of language lateralization, rather than secondary to it. Furthermore, these findings also indicate that the timetable for the development of lateralized frontal lobe functions depends upon biologic factors.

Adolescent↗

PubMed1977

Cerebral lateralization of haptic perception: interaction of responses to Braille and music reveals a functional basis.

Normally, haptic perception of the left hand surpasses that of the right. But simultaneously playing music into the left (but not the right) ear reverses this superiority. This suggests that the left cerebral hemisphere has full haptic perceptual capability, which is subject to right hemisphere interference unless the latter's attentional mechanisms are engaged by contralateral peripheral stimulation.

Adult↗

PubMed1996

[Clinico-radiologic correlations in common neck pain].

Patients with spontaneous neck pain, headache, dizziness and/or pain to the upper limbs are frequently observed. Common cervicodynia, due to the involvement of arthromuscular structures of the cervical spine, was diagnosed in the patients with these symptoms in the absence of trauma or neurologic signs. The authors investigated the clinical-radiologic correlation in a series of 130 symptomatic patients and considered it a metameric disorder. The frequent association of many radiographic signs at the same level often prevents single radiographic signs from being assessed individually; therefore, the authors selected some patients with just one radiographic change per functional unit, to assess its relationship with clinical symptoms. The patients underwent anteroposterior, lateral and functional (flexion-extension) radiographs of the cervical spine. Vertebral rotation, detected on antero-posterior views as a spinous process deviation, was the most frequent isolated sign (79/130 cases) per metameric level, with strong clinical correlation (70/79 cases). Vertebral rotation was probably due to unilateral muscular stiffness. Other single radiologic signs per functional unit with strong clinical correlation follow: atloaxial rotation (13/130 with clinical-radiologic agreement of 12/13), functional blockage (13/130 with clinical-radiologic agreement of 11/13), angular flexion (21/130 with clinical-radiologic agreement of 19/21) and overall disc space thinning (12/130 with clinical-radiologic agreement of 10/12). Atloaxial rotation is represented as an asymmetry of the spaces between the odontoid and the lateral masses of the atlas; functional blockage consists of insufficient or lacking physiological width of the occipito-atlantoid or interspinous space in functional tests. Angular flexion consists of a single flexion angle of the cervical spine in functional tests; two or more angles indicate normal flexion of the cervical spine. This study confirmed the poorer clinical impact of degenerative changes, mostly interapophyseal arthrosis, than of other radiologic signs. Interapophyseal arthrosis alone was isolated in single functional units in 46/130 patients, mostly at C7-D1, with clinical-radiologic agreement in 19/46 patients. Clinical-radiologic correlation proved the high diagnostic value of anteroposterior, lateral and functional radiographs of the cervical spine in common cervicodynia, which make them a valuable tool for the clinician.

Adolescent↗

PubMed2002

False lateralization of language cortex on functional MRI after a cluster of focal seizures.

fMRI can define language cortex but its limitations are not yet fully understood. This article describes a child in whom fMRI falsely lateralized language cortex when performed after a cluster of left temporal lobe seizures. Multiple language tasks revealed no activation over the left temporal lobe despite a normal neurologic exam at the time of the study. A second fMRI performed 2 weeks later activated sites predominantly over the left, which were confirmed by extra-operative functional language mapping. fMRI may be unhelpful after frequent seizures.

Adolescent↗

PubMed1999

Neural tissue transplant in the lateral hypothalamic lesioned rats: functional recovery pattern.

Transplantation has come of age as an important investigative tool for studying normal growth and development of the brain tissue. The present study reports the effect of lateral hypothalamic (LHA) lesion and foetal hypothalamic tissue transplantation on the feeding behaviour. In a group of rats, LHA was lesioned bilaterally by passing direct current. Subsequently, in a separate group of rats, foetal hypothalamic tissue was transplanted at the lesioned site. Following LHA lesion, all the rats died of aphagia and adipsia within 7 days, whereas, the rats in whom foetal hypothalamus was transplanted, started taking food and water in small quantities from the first day of transplantation itself. Later, they were able to attain their preoperative values. This recovery of the feeding behaviour following foetal tissue transplantation may be due to the formation of synaptic connections or due to the release of neurotrophic factors.

Animals↗

PubMed2002

Early childhood diarrhea is associated with diminished cognitive function 4 to 7 years later in children in a northeast Brazilian shantytown.

Diarrhea is well recognized as a leading cause of childhood mortality and morbidity in developing countries; however, possible long-term cognitive deficits from heavy diarrhea burdens in early childhood remain poorly defined. To assess the potential long-term impact of early childhood diarrhea (in the first 2 years of life) on cognitive function in later childhood, we studied the cognitive function of a cohort of children in an urban Brazilian shantytown with a high incidence of early childhood diarrhea. Forty-six children (age range, 6-10 years) with complete diarrhea surveillance during their first 2 years of life were given a battery of five cognitive tests. Test of Non-Verbal Intelligence-III (TONI) scores were inversely correlated with early childhood diarrhea (P = .01), even when controlling for maternal education, duration of breast-feeding, and early childhood helminthiasis (Ascaris or Trichuris). Furthermore, Wechsler Intelligence Scale for Children (WISC-III) Coding Tasks and WISC-III Digit Span (reverse and total) scores were also significantly lower in the 17 children with a history of early childhood persistent diarrhea (PD; P < .05), even when controlling for helminths and maternal education. No correlations were seen between diarrhea rates and Wide Range Assessment of Memory and Learning subtests or WISC-III Mazes. This report (with larger numbers of participants and new tests) confirms and substantially extends previous pilot studies, showing that long-term cognitive deficits are associated with early childhood diarrhea. These findings have important implications for the importance of interventions that may reduce early childhood diarrheal illnesses or their consequences.

Brazil↗

PubMed2000

Acoustic differences between content and function words in amyotrophic lateral sclerosis.

Studies describing acoustic characteristics of speech produced by individuals with dysarthria may help to explain intelligibility deficits for these speakers. One goal of the current study was to investigate the manner and extent to which nine speakers with mild to moderate dysarthria associated with amyotrophic lateral sclerosis (ALS) and nine healthy speakers acoustically distinguished /i/, /ae/, /u/, and /a/ in content and function words. A further aim was to evaluate the relationship between impaired speech in ALS and the magnitude of acoustic differences for vowels in content and function words. Speakers read the Farm Passage at a comfortable or habitual rate. F1 and F2 midpoint frequencies were measured, and vowel space areas were calculated. Vowel durations also were measured. The magnitude of F1, F2, vowel space area, and duration differences for vowels in content and function words was not statistically different for speakers with ALS and healthy controls. In addition, with the exception of /i/ produced by some speakers with ALS, vowel duration tended to be shorter in function words. Average F1 and F2 values for function words also tended to be centralized relative to content words. Although vowel space area differences for the two speaker groups were not statistically significant, there was a tendency for the difference in vowel space area for content and function words to be smaller for speakers with ALS than for controls. Regression analyses further indicated that the magnitude of temporal differences for vowels in content and function words was a better predictor of impaired speech than the magnitude of spectral differences for vowels in content and function words. One clinical implication is that individuals with ALS may benefit from therapy techniques targeting temporal properties of the acoustic signal.

Adult↗

PubMed1996

Crossed aphasia and related anomalies of cerebral organization: case reports and a genetic hypothesis.

Anomalous lateralization of cognitive functions is observed in a small percentage of right-handed patients with unilateral brain damage, either crossed aphasia (aphasia after right brain damage) or "crossed nonaphasia" (left brain damage without aphasia but with visuospatial and other deficits typical of right brain damage). No comprehensive theory of these anomalous cases has been proposed. Nine new right-handed cases (plus one left-handed case) were analyzed and the literature was reviewed. The dramatically anomalous organization of cognitive functions is best explained by random lateralization of all cognitive functions in a small subset of the population. The RS theory of cerebral dominance can account for this pattern of anomalies in right-handers and may account for the most common patterns of dominance observed in left-handers.

Adult↗

PubMed2004

Expression of an inwardly rectifying K+ channel, Kir5.1, in specific types of fibrocytes in the cochlear lateral wall suggests its functional importance in the establishment of endocochlear potential.

Cochlear endolymph contains 150 mm K+ and has a highly positive potential of approximately +80 mV. The specialized ionic composition and high potential in endolymph are essential for hearing and maintained by circulation of K+ from perilymph to endolymph through the cochlear lateral wall. Various types of K+ channel such as Kir4.1 and KCNQ1/KCNE1 are expressed in stria vascularis of the lateral wall and play essential roles in K+ circulation. In this study, we examined a distribution of another K+ channel, Kir5.1, and found it specifically expressed in the spiral ligament of the cochlear lateral wall. Specific immunoreactivity for Kir5.1 was detected in type II, IV and V fibrocytes of the ligament and spiral limbus, all of which are directly involved in K+ circulation. Kir5.1 was not found in either type I or III fibrocytes. Although Kir5.1 assembles with Kir4.1 to form a functional Kir channel in renal epithelia and retinal Müller cells, double-immunolabelling revealed that they were expressed in distinct regions in the cochlea lateral wall, i.e. Kir4.1 only in stria vascularis vs. Kir5.1 in spiral ligament. During development, the expression of Kir5.1 subunits started significantly later than Kir4.1 and was correlated with the 'rapid' phase of the elevation of endocochlear potential (EP). Kir5.1 and Kir4.1 channel-subunits may therefore play distinct functional roles in K+ circulation in the cochlear lateral wall.

Animals↗

PubMed2005

Hierarchical and asymmetric temporal sensitivity in human auditory cortices.

Lateralization of function in auditory cortex has remained a persistent puzzle. Previous studies using signals with differing spectrotemporal characteristics support a model in which the left hemisphere is more sensitive to temporal and the right more sensitive to spectral stimulus attributes. Here we use single-trial sparse-acquisition fMRI and a stimulus with parametrically varying segmental structure affecting primarily temporal properties. We show that both left and right auditory cortices are remarkably sensitive to temporal structure. Crucially, beyond bilateral sensitivity to timing information, we uncover two functionally significant interactions. First, local spectrotemporal signal structure is differentially processed in the superior temporal gyrus. Second, lateralized responses emerge in the higher-order superior temporal sulcus, where more slowly modulated signals preferentially drive the right hemisphere. The data support a model in which sounds are analyzed on two distinct timescales, 25-50 ms and 200-300 ms.

Acoustic Stimulation↗

PubMed2002

Handedness and corpus callosum morphology.

Investigations of a relationship between callosal size and functional behavioral lateralization lead to the hypothesis that, as the size of the corpus callosum (CC) increases, interhemispheric information transfer is facilitated and behavioral laterality effects become smaller. The aim of our in vivo study was to investigate the relationship between functional asymmetry of handedness and CC size in healthy subjects. Magnetic resonance images of the CC and five CC subregions were obtained with a 1.5-T Magnetom using a three-dimensional T1 sequence in 46 healthy men. Handedness was determined using the 'handedness dominance test' (HDT). According to the HDT values, 32 consistent and 14 non-consistent right-handers were identified. No significant difference between handedness subgroups in CC regions and no significant correlations between HDT values and CC areas were detected.

Adolescent↗

PubMed1998

Application of the directed transfer function method to mesial and lateral onset temporal lobe seizures.

The directed transfer function (DTF) method is a multichannel analysis based on an autoregressive model that detects flow of seizure activity. This report extends the application of the DTF method to compare patterns of flow of seizures with different sites of origin. Analysis of a seizure originating from mesial temporal structures is compared with a seizure originating from lateral temporal neocortex; both complex partial seizures were recorded with intracranial electrodes that combine subdural grid arrays and depth electrodes. The DTF method has the potential to determine patterns of flow of activity, including periods when visual analysis of the intracranial ictal EEG may not allow for definitive source localization. The extension of the DTF analyses into integrated DTF (IDTF) formats is also illustrated. When activity of a relatively discrete frequency can be identified, the IDTF analysis facilitates display of patterns of flow of this selected activity.

Algorithms↗