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 271 records · Page 15Linked to original sources

PubMed1998

Footedness is a better predictor than is handedness of emotional lateralization.

A tremendous amount of experimental work has attempted to identify reliable behavioural predictors of cerebral lateralization. Preferred handedness has been the most popular predictor, but some recent reports suggest that preferred footedness may serve as a more accurate predictor of functional laterality, especially in the left-handed population. The present study sought to test this claim by selectively recruiting individuals with either 'crossed' lateral preferences (right-handed and left-footed or left-handed and right-footed) or 'uncrossed' lateral preferences (right-handed and right-footed or left-handed and left-footed). Lateralization of emotional perception was assessed with two blocks of the dichotic Emotional Words Test (EWT), and lateral preference for both handedness and footedness was assessed using self-report questionnaires. Ear advantage on the dichotic task varied significantly with preferred foot (P=0.003), but not with preferred hand. Cerebral lateralization may be more related to footedness than to other lateral preferences.

Adult↗

PubMed2002

The lateral asymmetry of the human brain studied by volumetric magnetic resonance imaging.

Improvements in in vivo imaging methods have boosted research on brain asymmetry aimed at further establishing putative anatomical substrates for brain functional lateralization and particularly to explain left-hemisphere specialization for language. We analyzed volume asymmetries for major anatomical divisions of the lateral (perisylvian) brain region and their relative white matter content. A total of 100 healthy right-handed subjects were examined with 3D magnetic resonance imaging (MRI). The insular plane was used to limit the lateral brain, and the sylvian fissure and central sulcus to define frontal, parietal, temporal, and temporo-parieto-occipital regions. Results revealed a frontal region showing similar volumes in both hemispheres, a parietal region and a temporal region both larger in the left hemisphere, and a temporo-parieto-occipital region with predominantly right-sided asymmetry. Volume measurements of the parietal, temporal, and temporo-parieto-occipital regions complemented each other and accounted for 58% of planum temporale area variations. All study regions showed significant asymmetry for relative white matter content (percentage of white matter relative to region volume). White matter asymmetry, however, was particularly relevant for the frontal and temporal regions showing a highly frequent left-sided pattern (frontal region, 90%; temporal region, 91% of subjects). Leftward asymmetry in these two regions occurred in both genders, although hemisphere differences were significantly larger in men. Results from this MRI volume analysis of structural asymmetries in the lateral brain region complement data obtained by other methods and suggest a high occurrence of leftward asymmetry for relative white matter content in language-related regions.

Adult↗

PubMed1980

Effects of ventricular pacing on regional left ventricular performance in the dog.

Changes in regional left ventricular (LV) performance induced by ventricular pacing were studied in two groups of open-chest anesthetized dogs. In the first group of five dogs, local function at the LV anterior base, anterior apex, and posterior apex was assessed by ultrasonic crystal pairs with atrial, right ventricular, LV apical, and LV base pacing. Ventricular pacing produced asynchrony of contraction and marked changes in the shortening pattern at each site, as well as an average 27% reduction in peak systolic pressure and peak dP/dt compared to atrial pacing. Moreover, the extent of shortening during LV ejection was reduced or unchanged at all sites measured during ventricular pacing. In the second group of five dogs, function of the septum and opposing LV lateral wall was studied with atrial and LV lateral wall pacing. Lateral function was assessed with a crystal pair and septal function by cineradiography of a lead bead implanted in the septum. Ventricular pacing produced reciprocal interaction between the two walls, with early lateral shortening inducing septal bulging and late septal shortening inducing lateral wall systolic lengthening. We conclude that ventricular pacing produces significant changes in regional myocardial function, likely induced by reciprocal interaction of opposing myocardial regions. Furthermore, such interaction appears deleterious to global ventricular function, presumably because volume is sequestered and pressure is dissipated into relatively inactive segments that are out of phase with the bulk of contracting myocardium.

Animals↗

PubMed2004

The importance of the lateral line in nocturnal predation of piscivorous catfish.

In a previous study we showed that nocturnal piscivorous catfish track the wake left by a swimming prey fish to locate it, following past locations to detect the present location of the prey. In a wake there are hydrodynamic as well as chemical signatures that both contain information on location and suitability of the prey. In order to determine how these two wake stimuli are utilised in prey tracking, we conducted experiments in catfish in which either the lateral line or the external gustation was ablated. We found that a functional lateral line is indispensable for following the wake of swimming prey. The frequency of attack and capture was greatly diminished and the attacks that did occur were considerably delayed when the lateral line was ablated. In contrast, catfish with ablated external taste still followed the wakes of their prey prior to attacking, albeit their attacks were delayed. The external taste sense, which was reported earlier to be necessary for finding stationary (dead) food, seems to play a minor role in the localisation of moving prey. Our finding suggests that an important function of the lateral line is to mediate wake-tracking in predatory fish.

Animals↗

PubMed1989

Behavioral asymmetries in visual learning of young chickens.

Two-week-old chicks were trained in a simultaneous color discrimination learning task using food reinforcement. They had to discriminate between two discs of a different color whose right-left position was alternated at random. Results showed that chicks made more errors when the nonreinforced color was placed on the left with respect to the animal's body rather than when it was placed on the right. When chicks were trained on a right-left discrimination with two discs of identical color the asymmetry disappeared. Results are discussed in relation to current evidence for functional lateralization in the avian brain.

Animals↗

PubMed1986

Left cerebral hemisphere contributions to tachycardia: evidence and recommendations.

Six topics were discussed in which research has shown a stimulus or activity to be independently related to increases in human heart rate and to left cerebral hemisphere functioning: lateralized touching, reasoning, pleasantness, talking, lateralized feedback, and resistance to persuasion. On the basis of this converging evidence, strategies were suggested for altering heart rate by use of the method of induced lateral orientation of attention as a means of selective hemisphere activation.

Brain↗

PubMed2001

[Functional hemispheric asymmetry in sustained attention].

This study examined the existence of functional hemispheric asymmetry in visual sustained attention in a dual-task setting. In the experiments, a circular arrangement of Gabor patches (GPs) was successively presented in the periphery during a 40-min vigil. The primary task was successive discrimination of digit type (Experiment 1) or tone frequency (Experiment 2). The secondary task was oddball orientation detection, requiring subjects to determine whether all of GPs were same or whether there was an odd one in the upper left, upper right, lower left, or lower right visual fields. Overall, results indicated that the perceptual sensitivity (A') for the detection task was higher in the left visual field than in the right visual field. Visual field differences in the vigilance decrement (the decline in A' over time) were observed when the primary task involved auditory discrimination. The implications for the functional lateral asymmetry in human sustained attention are discussed.

Adult↗

PubMed2005

A lateralized avian hippocampus: preferential role of the left hippocampal formation in homing pigeon sun compass-based spatial learning.

The hippocampal formation (HF) plays a crucial role in amniote spatial cognition. There are also indications of functional lateralization in the contribution of the left and right HF in processes that enable birds to navigate space. The experiments described in this study were designed to examine left and right HF differences in a task of sun compass-based spatial learning in homing pigeons (Columba livia). Control, left (HFL) and right (HFR) HF lesioned pigeons were trained in an outdoor arena to locate a food reward using their sun compass in the presence or absence of alternative feature cues. Subsequent to training, the pigeons were subjected to test sessions to determine if they learned to represent the goal location with their sun compass and the relative importance of the sun compass vs. feature cues. Under all test conditions, the control pigeons demonstrated preferential use of the sun compass in locating the goal. By contrast, the HFL pigeons demonstrated no ability to locate the goal by the sun compass but an ability to use the feature cues. The behaviour of the HFR pigeons demonstrated that an intact left HF is sufficient to support sun compass-based learning, but in conflict situations and in contrast to controls, they often relied on feature cues. In conclusion, only the left HF is capable of supporting sun compass-based learning. However, preferential use of the sun compass for learning requires an intact right HF. The data support the hypothesis that the left and right HF make different but complementary contributions toward avian spatial cognition.

Animals↗

PubMed1986

Critique of Miller's "degree of lateralization as a hierarchy of manual and cognitive skill levels".

Miller (Neuropsychologia 20, 155-162, 1982) reported a correlational study in which an association between handedness measures and tests of cognitive development was found. It was concluded that the degree to which manual dexterity is lateralized predicts cognitive development, and that these measures are related aspects of the development of cerebral specialization. This conclusion is questionable in that the intellectual skills necessary for performance on the cognitive development tests are probably not functionally lateralized. In addition, when the influence of chronological age is partialled out, there is no residual correlation between lateralization of manual dexterity and cognitive performance.

Child↗

PubMed2002

Olfactory learning: convergent findings from lesion and brain imaging studies in humans.

The role of temporal lobe structures in olfactory memory was investigated by (i) the examination of odour learning and memory in patients who had undergone resection from a temporal lobe (including primary olfactory regions) for the treatment of intractable epilepsy; and (ii) the examination of brain function during odour memory tasks as assessed via PET imaging of healthy individuals. In order to study different stages of odour memory, recognition of a 'list' of odours was tested after a first exposure, again after four exposures and once more after a 24 h delay interval. Patients with resection from a temporal lobe performed significantly less well than control subjects on all trials, and no significant differences were noted as a function of side of resection, indicating that there is not a strong hemispheric superiority for this task. The PET data yielded different levels of activity in piriform cortex (primary olfactory cortex), in relation to the 'no-odour' baseline scan, depending on the type of processing: no increase in activity noted during odour encoding, a small increase bilaterally during short-term recognition and a larger increase bilaterally during long-term recognition. These findings, together with findings in animal studies, suggest that piriform cortex may have an active role in odour memory processing, not simply in odour perception. Taken together, the findings from the lesion study and functional brain imaging of healthy subjects suggest that olfactory memory requires input from left and right temporal lobe regions for optimal odour recognition, and that, unlike with verbal or non-verbal visual material, there is not a strong functional lateralization for olfactory memory.

Adult↗

PubMed1992

[Participation of the right hemisphere in the recovery of language in aphasics].

The functional lateralization of the brain for language is a dynamic process going on during the life. The sole responsibility for ensuring normal speech lies within the neural nets of the left hemisphere. The right hemisphere who has a predominant role in extra-linguistic communication maintain a linguistic potential linked with age and modalities of lateralization. Methods allowing his activation have for first objective the recovery of an elementary communication.

Aphasia↗

PubMed1993

Effect of unilateral deafferentiation in the medial basal portion of the temporal lobe on the hypophyseo-ovarian axis in rats: an age-dependent lateralized control mechanism.

The possible physiological role of the medial basal portion of the temporal lobe (including the corticomedial amygdaloid nucleus) in the neural control of the hypophyseo-ovarian axis was studied in pre- and postpubertal as well as in adult rats. Unilateral deafferentiation of a small medio-basal portion of the temporal lobe was performed in unilaterally ovariectomized animals, and the rate of compensatory hypertrophy of the remaining ovary was recorded. In adults compensatory ovarian hypertrophy was significantly reduced following right- but not left-sided deafferentiation. Temporal lobe surgery did not significantly influence the usual compensatory ovarian growth in pre- and postpubertal rats. Serum luteinizing hormone levels decreased significantly in adults regardless of the side of brain interventions, while no obvious change in the hormone concentration could be observed in prepubertals. Serum follicle-stimulating hormone concentrations showed no alterations in any experimental group. In postpubertal rats the serum progesterone level was unchanged following brain surgery. The present observations indicate that unilateral deafferentation in the temporal lobe could modify compensatory ovarian hypertrophy by a direct neural mechanism and data further suggest functional laterality of these structures in the control of ovarian functions.

Afferent Pathways↗

PubMed1995

Early psychosocial risks for adolescent suicidal ideation and attempts.

OBJECTIVE: An ongoing, 14-year, longitudinal community study examined psychosocial risks for adolescent suicidal ideation and attempts, as well as the link between earlier suicidal behavior and later functioning. METHOD: Nearly 400 youths were followed between the ages of 5 and 18 years. Suicidal ideation was assessed at age 15 and lifetime suicide attempts were determined at age 18. Risk factors covered developmental periods from birth to age 15, and most were measured prospectively using multiple informants. Late-adolescent functioning (at age 18) was based on both self-reports and school records. RESULTS: For both genders, the early onset (by age 14) of psychiatric disorders significantly increased the risk for suicidal ideation at age 15 and suicide attempts by age 18. Early gender-specific risks for suicidal ideation included preschool behaviors that are counter to typical gender norms, such as aggressive behavior in females and dependence in males. Suicidal ideation at age 15 and suicide attempts were both associated with deficits in later adolescence (at age 18) in behavioral and social-emotional functioning. CONCLUSIONS: Suicidal ideation at age 15 was a marker of distress with long-term implications for later functioning. The early gender-specific risk factors for suicidal behavior identified in this study can aid in developing strategies for prevention and early intervention.

Adolescent↗

PubMed1998

Functional plasticity after left anterior temporal lobectomy: reconstitution and compensation of verbal memory functions.

PURPOSE: This study investigated the functional plasticity of the brain to reconstitute and compensate for verbal memory functions after epilepsy surgery of left temporocortical and temporomesial structures. We hypothesized that memory outcome would be best when surgery is performed within the period of cerebral plasticity, and that the outcome should be worst when fluid intelligence starts to decrease with physiologic aging. We also raised the question of different plasticity and compensation mechanisms for temporomesial and temporocortical memory functions. METHODS: We evaluated preoperative and 1-year-postoperative memory data and other verbal functions in 104 patients with epilepsy, who underwent a standard left anterior temporal lobe resection. We used memory measures that had been previously shown to be most selective for mesial and lateral functions, respectively. Determinants of postoperative memory outcome were evaluated by multiple regression analysis. Group statistics were calculated on the basis of the periods that are usually assumed to be significant for plasticity and behavioral compensation. Individual postoperative changes in memory functions were evaluated on the basis of test-retest data obtained in a group of 100 nonsurgical patients with localization-related epilepsies (mean retest interval >12 months). RESULTS: Only changes in cortically represented learning and data acquisition were related to age, plasticity, and capacities for behavioral compensation. No patient in the youngest group (younger than 15 years), 33% of patients who had surgery between the ages of 15 and 30 years, and 61% of the patients undergoing surgery older than age 30 years had significant deterioration in verbal learning. In contrast, postoperative changes in temporomesial consolidation/retrieval processes were independent of age at the time of surgery, plasticity, and capacities for behavioral compensation. CONCLUSIONS: Our data indicate different time windows for the reconstitution and compensation of mesial and cortical aspects of memory. Whereas the reconstitution of and compensation for cortical functions appear restricted by decreasing plasticity and physiological aging, mesial functions seem to be reconstituted by contralateral mesial structures over a much longer period. Concerning drug-resistant localization-related epilepsies, our results justify early consideration of surgery, especially when cortical structures are affected.

Adolescent↗

PubMed2001

Spatial localization after excision of human auditory cortex.

Neurophysiological and animal ablation studies concur that primary auditory cortex is necessary for computation of the spatial coordinates of a sound source. Human studies have reported conflicting findings but have often suffered from inadequate psychophysical measures and/or poor lesion localization. We tested patients with unilateral temporal lobe excisions either encroaching on or sparing Heschl's gyrus (HG), quantifying lesion extent using anatomical magnetic resonance imaging measures. Subjects performed two tasks. In the localization task, they heard single clicks in a free-field spatial array subtending 180 degrees of azimuth and indicated the perceived location with a laser pointer. In the discrimination task, two clicks were presented, and subjects indicated if they were in the same or different position. As a group, patients with right temporal excision, either encroaching onto HG or not, were significantly impaired in both hemifields in both tasks, although this was not true for all individuals. Patients with left temporal resections generally performed normally, although some of the patients with left HG excision showed impaired performance bilaterally, especially in the discrimination task. This pattern stands in marked contrast to previous studies showing significant preservation of localization in hemispherectomized patients. We conclude that (1) contrary to hypotheses derived from animal studies, human auditory spatial processes are dependent primarily on cortical areas within right superior temporal cortex, which encompass both spatial hemifields; (2) functional reorganization may not take place after restricted focal damage but only after more extensive early damage; and (3) the existence of individual differences likely illustrates differential patterns of functional lateralization and/or recovery.

Acoustic Stimulation↗

PubMed2004

MicroRNAs act sequentially and asymmetrically to control chemosensory laterality in the nematode.

Animal microRNAs (miRNAs) are gene regulatory factors that prevent the expression of specific messenger RNA targets by binding to their 3' untranslated region. The Caenorhabditis elegans lsy-6 miRNA (for lateral symmetry defective) is required for the left/right asymmetric expression of guanyl cyclase (gcy) genes in two chemosensory neurons termed ASE left (ASEL) and ASE right (ASER). The asymmetric expression of these putative chemoreceptors in turn correlates with the functional lateralization of the ASE neurons. Here we find that a mutation in the die-1 zinc-finger transcription factor disrupts both the chemosensory laterality and left/right asymmetric expression of chemoreceptor genes in the ASE neurons. die-1 controls chemosensory laterality by activating the expression of lsy-6 specifically in ASEL, but not in ASER, where die-1 expression is downregulated through two sites in its 3' untranslated region. These two sites are complementary to mir-273, a previously uncharacterized miRNA, whose expression is strongly biased towards ASER. Forced bilateral expression of mir-273 in ASEL and ASER causes a loss of asymmetric die-1 expression and ASE laterality. Thus, an inverse distribution of two sequentially acting miRNAs in two bilaterally symmetric neurons controls laterality of the nematode chemosensory system.

Animals↗

PubMed1997

Asymmetrical increases in dopamine turn-over in the nucleus accumbens and lack of changes in locomotor responses following unilateral dopaminergic depletions in the entorhinal cortex.

Functional interdependence between mesencephalic dopaminergic pathways is an emerging concept. Using in vivo voltammetry and acute manipulation of dopaminergic transmission with pharmacological agents, we have previously reported the existence of a preferentially left lateralized functional interdependence between the entorhinal cortex and the nucleus accumbens. The aim of the present work was to test if this phenomenon is only a dynamic process or if compensation occurs when interdependent functioning is considered in a more long-term perspective. In this study 6-OHDA lesions of the dopamine terminals of the entorhinal cortex were performed separately in the left and right hemispheres. Spontaneous and (+)-amphetamine stimulated locomotor activity were recorded 3 weeks after unilateral interventions in the Ent. Variations in DA and DOPAC levels were measured in the nucleus accumbens 5 weeks after the lesion. The following results were obtained. After unilateral 6-OHDA in the left Ent, DA and DOPAC tissue contents as well as the DOPAC/DA ratio were found significantly changed in nucleus accumbens in the two hemispheres. After dopaminergic destruction in the right Ent only the DOPAC/DA ratio in the left Acc was found statistically elevated. No differences in spontaneous or (+)-amphetamine-stimulated locomotor activity were observed after either left or right lesions. These data confirm those previously obtained with the voltammetric approach and further support the existence of an asymmetrical functional interdependence between mesencephalic DAergic pathways reaching the Ent and the Acc. These results may provide new insights in the pathophysiology of schizophrenic psychoses.

3,4-Dihydroxyphenylacetic Acid↗

PubMedDate not supplied

A role for hemispheric asymmetry in human behavioral variability.

A model is presented in which functional lateral specialization and selective hemisphere priming combine to provide a mechanism for behavioral variability. The model is tested and supported by two experiments in which lateral attentional priming produces significant reductions in between-subject and within-subject variability. These findings help us to understand the source of behavioral variability, broaden our knowledge of the gross structures and functions of the brain, provide information about the manipulation of perceived control, and offer a technique for increasing statistical power in a wide variety of research settings.

Adolescent↗