There are currently many statements about the effects of hemispheric specialization of the brain upon children's cognitive processing and therefore, upon content or modes of instruction. Before educators can accept or even test these statements, it is important to devise easy-to-use measures of hemispheric functioning and to study their relationship to established measures of achievement and linguistic and cognitive development. Current research in brain functioning has indicated that conjugate-lateral eye movement direction (the direction in which a person looks while thinking) can be a sensitive indicator of which cerebral hemisphere is initially activated. The central purpose of this investigation was to analyze the effects of the stimulus characteristics of reflective questions of verbal and spatial nature on the conjugate-lateral eye movement (CLEM) behavior of right-handed children from fourth, fifth, and sixth grades. A major objective was to determine whether data on children’s CLEM responses would better support a model of characteristic individual differences or a model of differentiation by question type. The testing instrument devised for this purpose was the Reflective Questions Test (RQT) which included both Verbal and Spatial subtests. In an experimenter-facing-subject paradigm with a sample of 60 (30 boys, 30 girls), conjugate-lateral eye movement was found to be easily observable and question type was found to influence the direction of eye movement, thus supporting a differentiation by question type model. Verbal questions elicited significantly more rightward CLEMs than spatial questions and spatial questions elicited significantly more leftward CLEMs than verbal questions fn the sample studied. No significant sex differences were found. These results seem to be consistent with the neuropsychological theory that once hemispheric specialization has occurred with normal right-handed children, the left hemisphere mediates language functions and the right hemisphere mediates spatial functions. Examining the number of directionally appropriate CLEM responses, a two-way analysis of variance (verbal and spatial question type by grade level) yielded no main or interaction effects. The results suggest that although children in grades four, five, and six tended to gaze in different directions while responding to verbal than while responding to spatial questions, the rate of responses appropriate to the question (gazing in the direction predicted) was no greater for verbal than for spatial questions. Further, the means for question types were almost identical across grade levels for CLEM responses to verbal and to spatial questions, supporting a no-change model of neuropsychological function, which contends that within the later childhood years, hemispheric specialization is well developed. The Reflective Questions Test was found to have high inter-rater reliability (.94) and temporal stability (.78). These results indicate that the RQT produced reliable and stable results for the sample studied and support the appropriateness of the RQT for future refinement and use in educational research of this type. Correlations of the RQT with other measures of linguistic and cognitive development, and educational ability were found to be nonsignificant. These results suggest that hemispheric activation as indexed by the RQT at this age range may be largely independent of measures traditionally associated with school performance. The results of this investigation have provided normative data on normal right-handed children, thereby providing a comparative basis for future research with children of the same age from other populations such as the learning disabled. / Ed. D.

Two experiments were designed to selectively prime each cerebral hemisphere to evaluate Kinsbourne's selective activation model. The left hemisphere priming manipulation for both experiments was subvocal rehearsal of neutral words, whereas right hemisphere primes consisted of imagery (Experiment 1) and subvocal rehearsal of affective words (Experiment 2). Reaction time performance in the visual field contralateral to the activated hemisphere was hypothesized to improve. No evidence supporting this hypothesis was found in these experiments, though experimental tasks had significant interference effects. In Experiment 1, non-specific interference effects were found across visual fields for both experimental tasks, suggesting the hemispheres were not preferentially recruited. Right visual field interference was observed in Experiment 2 for subvocal rehearsal, particularly of affective words, implicating selective left hemisphere activation. This finding indicates an overloading of the left hemisphere's affective perceptual capabilities. Significantly, no equivalent right hemisphere effects were observed, suggesting different functional space characteristics for affect perception across the hemispheres. These findings appear to substantiate a structural rather than activational model of functional cerebral asymmetries, but interference effects do unequivocally support either model. Furthermore, in Experiment 2, neutral faces were perceived as angry equally often in both visual fields, though neutral faces in the control and affective rehearsal conditions were more frequently perceived as angry relative to the neutral rehearsal condition. Methodological issues are presented to account for these findings. / Master of Science

Diss. (sammanfattning) Umeå : Umeå universitet, 2009. / Härtill 3 uppsatser. Även tryckt utgåva.

The theses The issue of left-handedness focuses on left-handedness at its complexity. The theoretical part is focused on laterality and the left-handedness in general, the place of left-handed people in society and the changing view on laterality during times. It focuses on the differences between left and right-handed people and points out possible difficulties the left-handed might face. At the end I dealt with testing laterality and focused on possible ways to guide left-handed pupils. The practical research part is based on finding out the number of left-handed pupils in 1st grades on schools in the Karlovy Vary region. I farther focused on how aware of the lefthanded pupils problems the teachers are and how they guide them. The research took part in 16 randomly picked schools.

Human functional laterality, typically involving a right-sided preference in most sensory-motor activities, is still a poorly understood issue. This is perhaps particularly true in terms of what underlying mechanisms that may govern lateral biases, as well as the developmental origins and course of events. The present thesis aims at investigating functional asymmetries in the upper and lower body movements of young human infants. In Study I, the presence of side biases in the stepping and placing responses and head turning in healthy fullterm newborns were explored. No evident lateral bias for the leg responses in terms of the first foot moved or direction of head turning was found. However, a lateral bias was revealed for onset latency in relation to the first foot moved in both stepping and placing. Asymmetries in head turning did not correspond to asymmetries in leg movements. In Study II, functional asymmetries in the stepping response of newborn infants were investigated in more detail by means of 3-D kinematic movement registration. Evident side differences were found in relation to smoother movement trajectories of the right leg by means of less movement segmentation compared to the left leg. Side differences were also found in relation to intralimb coordination in terms of stronger ankle-knee couplings and smaller phase shifts in the right leg than the left. In Study III, using the same movement registration technique, the kinematics of left and right arm movements during goal-directed reaching in infants were prospectively studied over the ages 6, 9, 12, and 36 months. Main findings included side differences and developmental trends related to the segmentation of the reaching movements and the reaching trajectory, as well as the distribution of arm-hand-use frequency. The results from Study I and II are discussed in relation to underlying neural mechanisms for lateral biases in leg movements and the important role of a thorough methodology in investigating newborn responses. Findings from Study III are discussed in terms of what they imply about the developmental origins for hand preference. An emphasis is also put on developmental differences between fullterm and preterm infants. Overall, the studies of the present thesis show that an increased understanding of subtle expressions of early functional asymmetries in the upper and lower body movements of young infants may be gained by means of refined measurements. Furthermore, such knowledge may provide an insight into the underlying neural mechanisms subserving asymmetries in the movements of young infants. The present studies also add new information to the current understanding of the development of human lateralized functions, in particular the findings derived from the longitudinal data. Apart from theoretical implications, the present thesis also involves a discussion with regard to the clinical relevance of investigating functional asymmetries in the movements of young infants.

1 Title: Manifestation of cerebellar dominance in the form of extinction physiological syndrome on upper and lower limbs and its relationship to human laterality. Objectives: The aim of this diploma thesis is to determinate size of relationship between manifestation of cerebellar dominance in the form of extinction physiological syndrome and preference of limbs. Methods: A total of 27 individuals (male and female students of UK FTVS) were involved in the current quantitative research. We used indicators which were selected from Musalek's test battery (2013) to assess limb preferences. The evaluation of joint passivity asymmetry was based on angle and time parameters during walk and during controlled falls of forearm and shank on a constructed fall-machine. The movement was registered in real time by Qualisys Motion Capture System. For data analysis, descriptive statistics methods, paired t-test, level of statistical and substantive significance (Cohen's d) and tetrachoric coefficient of correlation were used. Results: Our research suggests that there is no significant difference in joint passivity when comparing preferred and non preferred limbs. Though it is necessary to take into consideration specifics and the size of research sample in which everybody was an active athlete. The result of tetrachoric...

M.A. / The study aims to determine whether statistically significant differences exist between boys with attention deficit hyperactivity disorder (ADHD) and boys without ADHD with regard to hemispheric language lateralization and the laterality of various modalities (handedness, eyedness and footedness). According to the literature, a possible connection exists between abnormal lateralization patterns and various developmental disorders (Corballis, 1983; Geschwind & Behan, 1982; Hiscock, 1988, McFarland, 1981; Turkewitz, 1988). Lateralization in the current study refers to hemispheric language specialisation, hand dominance, foot dominance and eye dominance. In most people these functions are lateralized to the one side of the body by the age of seven (Kalat, 1995; Kolb & Whishaw, 1996). They typically manifest a dominant left hemisphere for language and a right-sided dominance for handedness, footedness and eyedness. The result is a dominant left hemisphere, due to the left side of the brain controlling the right side of the body. Some children however manifest insufficient or poor lateralization of these functions. For purposes of this study, it would imply that the functions of language specialisation, handedness, footedness and eyedness are not all lateralized to one side of the body. A possible connection between this poor or insufficient lateralization and ADHD might exist. According to the DSM IV (1997) the essential feature of ADHD is a persistent pattern of inattention and/or hyperactivity/impulsivity that is more frequent and severe than is typically observed in individuals at a comparable level of development. Some of these symptoms causing impairment must have been present before age seven, although many individuals are only diagnosed after the symptoms have been present for a number of years. Impairment resulting from the symptoms should be present in at least two settings, for example, at school and at home. Clear evidence must exist of interference with developmentally appropriate social, academic, or occupational functioning. An empirical study was conducted in order to compare the hemispheric language specialisation, handedness, eyedness and footedness of the various subjects. The subjects consisted of 20 ADHD boys (8 -12 years) who met the criteria of the DSM IV and 20 Non-ADHD boys (8-12 years) without any learning problems. Various interference variables were controlled in the selection of the subjects (see section 5.2.3) Kimura's dichotic listening technique was used to measure hemispheric language specialisation and the Harris-test for Lateral Dominance was used to measure handedness, eyedness and footedness. Wilks's lambda, Pearson's chi-quadrant and Student's t-tests were used during statistical analysis of data. Results indicated statistically significant differences between ADHD boys and non-ADHD boys with regard to hemispheric language specialisation, handedness and footedness. Overall, the results indicated that the ADHD boys are not as strongly lateralized as the non-ADHD boys. The non-ADHD boys showed a stronger left hemispheric language specialisation, right hand dominance and right foot dominance. No statistical differences were recorded with regard to eyedness. The current study provides possible theoretical support for the theory that a connection exists between poor or insufficient lateralization patterns and children with ADHD. However, the study only focused on white boys between the ages of 8-12 years. Further studies involving different age groups, cultures and gender are recommended.

A técnica de campo visual dividido foi utilizada na análise dos padrões de assimetria cerebral para a percepção de expressões faciais de valência positiva e negativa. Oitenta universitários destros (65 mulheres, 15 homens) foram distribuídos em cinco grupos experimentais com o objetivo de se investigar separadamente a percepção de expressões de alegria, medo, surpresa, tristeza e da face neutra. Em cada apresentação de estímulo, uma face alvo e uma face distratora eram apresentadas à direita ou à esquerda de um ponto de fixação localizado no centro da tela do computador. O tempo de apresentação dos estímulos foi de 150 ms e os participantes tiveram que determinar o lado (esquerdo ou direito) em que havia sido apresentada a face alvo, utilizando um mouse para responderem aos estímulos. As análises estatísticas de tempo de reação e erros de julgamento indicaram não haver diferenças entre o desempenho de homens e mulheres na tarefa experimental. Expressões faciais de alegria e medo foram identificadas mais rapidamente quando apresentadas no campo visual esquerdo, indicando uma possível vantagem do hemisfério direito na percepção destas emoções. Menores tempos de reação e erros de julgamento foram observados para as condições de pareamento em que faces emocionais foram apresentadas no campo visual esquerdo e faces neutras no campo visual direito. A análise dos pareamentos entre faces indicou que faces neutras e de alegria são percebidas mais rapidamente e com maior acerto que faces de medo e tristeza. Embora não tenha havido uma vantagem do hemisfério direito para a percepção de todas as expressões faciais, os resultados deste estudo tendem a concordar com a hipótese do hemisfério direito para o processamento emocional. / The divided visual field technique was used to analize the patterns of brain asymmetry in the perception of positive and negative facial expressions. Eighty undergraduate students (65 female, 15 male) were distributed in five experimental groups in order to investigate separately the perception of expressions of happiness, surprise, fear, sadness, and neutral. In each trial, a target and a distractor expression were presented in a computer screen during 150 ms and participants had to determine the side (left or right) on which the target expression was presented using a mouse to respond to the stimuli. Time reaction and judgment errors analysis showed no differences between men and womens performance in experimental task. Results indicated that expressions of happiness and fear were identified faster when presented on the left visual field, suggesting an advantage of the right hemisphere in the perception of these expressions. Fewer judgment errors and faster reaction times were observed for the matching condition in which emotional faces were presented on the left visual field and neutral faces on the right visual field. Analysis of the pairs of faces indicated that neutral and happy faces were perceived faster and more accurately than faces of fear and happiness. Although an advantage of the right hemisphere was not occurred for the perception of all expressions, results tend to support the right hemisphere hypothesis for emotional processing.

Uma ativação do trato olivococlear medial reduz a amplitude das emissões otoacústicas de forma lateralizada, com um predomínio à direita. Pessoas com zumbido teriam uma disfunção do reflexo eferente, mas esses resultados não foram comprovados em todas as pesquisas. Curiosamente, estas pesquisas não valorizam a lateralidade eferente. Comparamos a supressão na orelha direita de pessoas com e sem zumbido e a lateralidade do sistema eferente pela análise da supressão à direita e à esquerda no grupo sem zumbido. Concluímos que há relação entre zumbido e não supressão e que à direita, a supressão é maior / An activation of the medial olivocochlear tract reduces the amplitude of otoacoustic emissions with predominance of the right side. Subjects with tinnitus would have an abnormality of the suppressing reflex, but such results have not been confirmed yet in any study. Curiously, such studies did not value the functional laterality. We compared right ear suppression of people with and without tinnitus, and the suppression on the right and on the left in the group without tinnitus. We concluded that there was a relation between tinnitus and absent suppression of otoacoustic emissions and right ear suppression was more marked.

A técnica de campo visual dividido foi utilizada na análise dos padrões de assimetria cerebral para a percepção de expressões faciais de valência positiva e negativa. Oitenta universitários destros (65 mulheres, 15 homens) foram distribuídos em cinco grupos experimentais com o objetivo de se investigar separadamente a percepção de expressões de alegria, medo, surpresa, tristeza e da face neutra. Em cada apresentação de estímulo, uma face alvo e uma face distratora eram apresentadas à direita ou à esquerda de um ponto de fixação localizado no centro da tela do computador. O tempo de apresentação dos estímulos foi de 150 ms e os participantes tiveram que determinar o lado (esquerdo ou direito) em que havia sido apresentada a face alvo, utilizando um mouse para responderem aos estímulos. As análises estatísticas de tempo de reação e erros de julgamento indicaram não haver diferenças entre o desempenho de homens e mulheres na tarefa experimental. Expressões faciais de alegria e medo foram identificadas mais rapidamente quando apresentadas no campo visual esquerdo, indicando uma possível vantagem do hemisfério direito na percepção destas emoções. Menores tempos de reação e erros de julgamento foram observados para as condições de pareamento em que faces emocionais foram apresentadas no campo visual esquerdo e faces neutras no campo visual direito. A análise dos pareamentos entre faces indicou que faces neutras e de alegria são percebidas mais rapidamente e com maior acerto que faces de medo e tristeza. Embora não tenha havido uma vantagem do hemisfério direito para a percepção de todas as expressões faciais, os resultados deste estudo tendem a concordar com a hipótese do hemisfério direito para o processamento emocional. / The divided visual field technique was used to analize the patterns of brain asymmetry in the perception of positive and negative facial expressions. Eighty undergraduate students (65 female, 15 male) were distributed in five experimental groups in order to investigate separately the perception of expressions of happiness, surprise, fear, sadness, and neutral. In each trial, a target and a distractor expression were presented in a computer screen during 150 ms and participants had to determine the side (left or right) on which the target expression was presented using a mouse to respond to the stimuli. Time reaction and judgment errors analysis showed no differences between men and womens performance in experimental task. Results indicated that expressions of happiness and fear were identified faster when presented on the left visual field, suggesting an advantage of the right hemisphere in the perception of these expressions. Fewer judgment errors and faster reaction times were observed for the matching condition in which emotional faces were presented on the left visual field and neutral faces on the right visual field. Analysis of the pairs of faces indicated that neutral and happy faces were perceived faster and more accurately than faces of fear and happiness. Although an advantage of the right hemisphere was not occurred for the perception of all expressions, results tend to support the right hemisphere hypothesis for emotional processing.