The influence of levels of hostility on the lateralized tasks of verbal and nonverbal fluency, and the concurrent cerebral regulation of autonomic nervous system functioning was examined. Forty-eight right-handed males were recruited for participation with half classified as low-hostile and the other half as high-hostile. Previous research has shown that high-hostile males, at rest, have greater right hemisphere arousal relative to low-hostile males. It was predicted that this heightened, at rest, arousal would lead to reduced capacity to perform right hemisphere lateralized proximal tasks simultaneously. Two commonly used neuropsychological tests sensitive to left and right anterior cerebral systems are the Controlled Oral Word Association Test and the Ruff Figural Fluency Test (RFFT) respectively. Nonverbal fluency, verbal fluency, and perseverative errors were assessed using these measures. Cardiovascular measures of systolic and diastolic blood pressure, and heart rate were assessed using oscillometric technique with a digital blood pressure meter. A dual-task methodology was used to evaluate these anterior and posterior cerebral systems simultaneously. Since cardiovascular regulation and nonverbal fluency are both right-frontal tasks, it was predicted that high hostile men would evidence increased interference on cardiovascular regulation concurrent with the nonverbal fluency task in comparison with low hostile men. It was also predicted that high-hostile males would display more perseverative errors than low- hostile males on the nonverbal fluency task as a function of regulatory interference. The results supported a capacity-limited prediction in high-hostile males. High-hostile males evidenced significantly heightened systolic blood pressure responses during the nonverbal fluency task in comparison with low hostile males. Further, high-hostile males displayed more perseverative errors in nonverbal fluency than did the low-hostile males. No differences were found in the overall fluency scores (verbal or nonverbal). These results partially support the expectation that differences exist between high and low hostile males for right frontal functioning. Moreover, these differences manifest in multiple domains of associated right frontal functioning. These findings extend the evidence for the proposed anterior-posterior inhibition model of hostility. / Master of Science

This study examined the effects of prenatal sensory and motor experience on the development of spatial orientation and turning bias in bobwhite quail. The theory presented here describes hemispheric specialization as the result of probabilistic events in the developing organism's prenatal environment; in particular, activity and experience in the final stages of prenatal development appear critical. Models and definitions of behavioral asymmetry, hemispheric specialization, and structural lateralization are reviewed. The results of Experiment 1 revealed a left-side turning bias in 85% of unmanipulated chicks. Experiments 2, 3, and 4 demonstrated that prenatal visual experience is a significant facilitator of population level left-side turning biases in bobwhite quail chicks. Experiment 5 investigated a potential underlying neurological basis for the bobwhite turning bias with unilateral injections of cycloheximide. The results of Experiment 5 suggest a left hemispheric specialization for the left-side turning bias. Furthermore, the results of Experiments 2 and 3 suggest that the asymmetrical hatching behaviors of the bobwhite quail are also a significant canalizing influence on the development of turning bias. The findings of this study are discussed in terms of an epigenetic theory of the development of hemispheric specialization and questions are raised as to the efficacy of laterality indexes as a reliable quantification of degree of hemispheric lateralization. / Ph. D.

This experiment tested two hypotheses linking the right cerebral regulation of hostility and cardiovascular arousal. First, replication of previous research supporting heightened cardiovascular (systolic blood pressure, diastolic blood pressure, and heart rate) reactivity among high hostile participants was attempted. Second, dynamic variations in functional cerebral asymmetry in response to pain (cold pressor) and emotional linguistic processing was measured. Low- and high-hostile participants were identified using the Cook Medley Hostility Scale (CMHS). All participants completed either the negative affective verbal learning test (Experiment 1) or the cold pressor paradigm (Experiment 2). Cardiovascular measures (SBP, DBP, and HR) were recorded and either dichotic listening procedures (Experiment 1) or tachistoscopic lexical recognition procedures (Experiment 2) were administered before and after the stressor. The primary finding of this research was greater left cerebral activation (decreased cardiovascular reactivity) following the dichotic phoneme listening and the tachistoscopic lexical recognition tasks and greater right cerebral activation following pain (cold pressor) and emotionally linguistic (affective verbal learning) stressors. / Master of Science

The aims of the thesis were to examine i) whether the endogenous opioid system (EOS) is lateralized in human brain areas involved in processing of emotions and pain; ii) whether EOS responses to unilateral brain injury depend on side of lesion, and iii) whether in human alcoholics, this system is involved in molecular adaptations in brain areas relevant for cognitive control of addictive behavior and habit formation. The main findings were that (1) opioid peptides but not opioid receptors and classic neurotransmitters are markedly lateralized in the anterior cingulate cortex involved in processing of  positive and negative emotions and affective component of pain. The region-specific lateralization of neuronal networks expressing opioid peptides may underlie in part lateralization of higher functions in the human brain including emotions and pain. (2) Analysis of the effects of traumatic brain injury (TBI) demonstrated predominant alteration of dynorphin levels in the hippocampus ipsilateral to the injury, while injury to the right hemisphere affected dynorphin levels in the striatum and frontal cortex to a greater extent than that to the left hemisphere. Thus, trauma reveals a lateralization in the mechanisms mediating the response of dynorphin expressing neuronal networks in the brain. These networks may differentially mediate effects of left or right brain injury on lateralized brain functions. (3) In human alcoholics, the enkephalin and dynorphin systems were found to be downregulated in the caudate nucleus and / or putamen that may underlie in part changes in goal directed behavior and formation of a compulsive habit in alcoholics. In contrast to downregulation in these areas, PDYN mRNA and dynorphins in dorsolateral prefrontal cortex, k-opioid receptor mRNA in orbitofrontal cortex, and dynorphins in hippocampus were upregulated in alcoholics. Activation of the k-opioid receptor by upregulated dynorphins may underlie in part neurocognitive dysfunctions relevant for addiction and disrupted inhibitory control. We conclude that the EOS exhibits region-specific lateralization in human brain and brain-area specific lateralized response after unilateral TBI in mice; and that the EOS is involved in adaptive processes associated with specific aspects of alcohol dependence.

The database on hand preferences in non-human primates provides inconsistent and inconclusive findings, and is plagued by gaps and methodological issues. I studied hand preferences in the bonobo, which is a very interesting model for investigating evolutionary hypotheses on human handedness. There are few previous data on bonobos and they are from small samples and for relatively simple tasks. I studied a large sample of 94 bonobos in three zoos and one sanctuary, on a variety of actions. Five studies were performed to record: 1. hand use for spontaneous daily actions (non-social). 2. hand use for the tube task , a task that requires a manipulative bimanual coordinated precise action. 3. hand use for using a stick as a probe ( termite fishing ). 4. hand use for spontaneous social actions and gestures, recorded during their social interactions (intra-specific) and during interactions with humans (inter-specific). 5. hand use for induced begging gestures (begging for food from the observer). The results show significant manual laterality in almost all the behaviours studied. The hand preferences were present on an individual basis. The numbers of right-handed and left-handed individuals were similar, indicating no group-level bias, for any of the actions studied. There was no significant effect of the settings, rearing history, sex and age (except in study 2 where adults were more right-handed than younger subjects). I examined different factors that have been proposed as selective pressures for the emergence of handedness. Laterality was influenced by: postural demands (posture, activity of the other hand), precision, grip type, manipulation or bimanual coordination, tool-use, throwing, communication. Notably, the laterality was very marked for the tube task , the termite fishing task and the begging experiment, which suggests that the factors involved in these tasks could be important factors regarding laterality.

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The aim of my doctoral thesis is the detailed study of the behavioural and sociobiological principles associated with the period of lactation. Suckling data covering almost 80 foals of domestic horse (Equus caballus) was obtained within four years of observation in the National Stud in Kladruby nad Labem, Czech Republic. The data were evaluated together with the reproductive history of the mothers, their agonistic interactions and following analysis of the dominance position of subadult foals. The first study describes longer suckling (greater maternal care) in dominant mares compared to submissive ones. Dominant mares are also less disturbed during nursing, whereas they terminated the nursing of submissive mares more often. A possible competitive advantage for the offspring of dominant mares may arise from such behaviour. The second paper enlightens the reproductive strategy of mares facing double maternal investment; suckling of the foal and pregnancy at the same time. I found out, contrary to the expectations, that the pregnant mares neither suckled their foals less nor terminated more suckling compared to non-pregnant herdmates. They may try to compensate their suckling foal with the perspective of its early weaning due to ongoing pregnancy. In the third and fourth manuscript I studied, how...

AL’objectif de la thèse est le développement d’une méthode de caractérisation des crises d’épilepsie du lobe temporal à partir des EEG de surface et plus particulièrement de la zone épileptogène (ZE) à l’origine des crises. Des travaux récents ont démontré une évolution des synchronisations entre structures cérébrales permettant une caractérisation de la dynamique des crises du lobe temporal. La comparaison de différentes méthodes de mesure de relation a permis la mise en évidence des avantages du coefficient de corrélation non-linéaire dans l’étude de l’épilepsie par les EEG de surface. L’exploitation de l’évolution de ce coefficient est à la base de trois applications de traitement automatique du signal EEG : -détermination de la latéralisation de la ZE au départ d’une crise, -recherche d’une signature épileptique, -classification des crises du lobe temporal en deux groupes / The objective of this work was the development of a temporal lobe epilepsy seizures characterization methodology realized through scalp EEG analysis. Recent researches showed an evolution of the synchronizations between cerebral structures, allowing a characterization of dynamic of the seizures. The comparison, between different methods of relation measurement, proved the advantages of the non-linear correlation coefficient in the study of epileptic seizures from scalp EEGs. The characterization of the evolution of this coefficient was used as the base of the development of three signal processing applications : -determination of the side of the Epileptic Zone at the onset of a seizure -research of an epileptic pattern at the seizure onset -classification of the temporal lobe seizures into two groups.

No description available.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal