ABSTRACT The two disorders of Restless Legs Syndrome (RLS) and Periodic Limb Movements (PLM) are well recognised as fairly common neurological disorders. The presentation is of a sensory and motor component suggestive of a state of hyperexcitability of the nervous system. The underlying abnormality is believed to involve a dopamine deficiency but many of characteristics of the disorders have not been adequately described or quantified. I investigated, firstly, the possible reasons for the gender bias in the prevalence studies and found that women were more likely to have some associated conditions which may be related to RLS as well as a higher symptom load when compared to men subjects with RLS. I then looked at the problems of analysing the sensations occurring in RLS. Due to the lack of an adequate measuring tool and the possibility of a relationship between the sensations of RLS and those of pain, I used a validated descriptive pain questionnaire (the McGill pain questionnaire) to measure the sensations of RLS. Subjects with RLS were able to describe the sensations with the pain questionnaire and severity indices calculated from the McGill correlated well with measures of RLS severity but not with other intensity measures for pain. In the area of motor events I investigated the possibility of creating a classification system for the muscle activations documented as PLM. I recorded multiple muscle groups in the legs during sleep and devised a classification using sequence of activation and timing of activations from the different muscles. I also used the classification to show subtle changes in the leg activation patterns associated with change in sleep stage.

The evolutionary origins of human handedness are still unknown. The study of lateralized behaviour in our closest relatives, the nonhuman primates, is useful to clarify how this trait appeared and evolved in our species. In the present study, lateralized behaviour was assessed in a population of 32 free-ranging Mexican mantled howler monkeys (Alouatta palliata mexicana) for thirteen spontaneous motor patterns, at individual and group levels, as well as the effect that age, sex and posture have on its strength and direction. The studied population of howler monkeys displayed only few significant lateral biases at the individual level with single motor patterns (Binomial tests, p≤0.05). No biases towards the use of a particular limb or side of the body were found at a population level. Therefore, even though some individuals showed significant limb/side preference with single motor patterns, no signs of task specialization, side specialization, or true handedness were found. Similarly, no effects of sex, age or posture were found on the direction or strength of lateralized behaviour. The general absence of limb/side preferences found in this population may be due to the constraints imposed by the arboreal life and/or the type of diet. Possible causal agents of the few significant individual biases found here may be the presence of handicaps and/or experience. Further research is needed in order to assess whether the lack of human-like handedness reported in this study is only specific to the studied population, a general phenomenon of the genus Alouatta or perhaps of all the Platyrrhini.

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This thesis focuses on the characterization of rhythmic activity in the colon of healthy subjects and patients diagnosed with refractory constipation; this activity is mediated by pacemaker cells in the gastrointestinal system, the Interstitial cells of Cajal (ICC). The myogenic activity described are the cyclic motor patterns (CMP) and haustral activity; characterization of these motor patterns in healthy subjects provided control values for the subsequent comparison in patients. Frequency analysis of CMP revealed a novel high-frequency activity (7-15cpm) unrelated to the breathing artefact. Three categories of cyclic motor patterns were observed: (1) CMP following mass peristaltic events (HAPW); (2) those that occur in isolation of other colonic motor patterns (HAPW) in the colon; and (3) low-frequency (2-6cpm), prominently retrograde rhythmic activity in the rectum. CMP were scarcely present in majority of the patients; however, elevated retrograde CMP in the distal colon and rectum in some patients plays a role in retarding flow of colonic content. A detailed characterization of haustral activity (comprised of 2 boundaries and the activity within a haustrum) is reported for the first time using high-resolution colonic manometry. Furthermore, we find that over expression of haustral boundary activity in patients serves as a disproportionate hindrance in colonic transit. An in-depth methodology is developed for the identification and subsequent analysis of haustral activity and CMP; this provides transparency in the data acquisition and analysis. Lastly, a sphincter at the rectosigmoid junction, sphincter of O’Beirne is presented in a patient case report. The persistent presence and paradoxical contractions of this sphincter served to impede flow colonic content, an important factor contributing to the pathophysiology of severe refractory constipation. / Thesis / Master of Science (MSc) / Colonic manometry tests and measures strength and coordination of colonic muscles contractions. This tool was used to understand the rhythmic colonic motor patterns and their contribution to motility in healthy subjects and patients with constipation. Rhythmic activity in the gut is mediated by pacemaker cells, Interstitial cells of Cajal (ICC). We present a detailed characterization of ICC-mediated rhythmic activity that (1) occurs in the small pouches making up the colon (haustra) and (2) is greater than 5cm along the length of the colon (cyclic motor patterns-CMP).CMP possess high-frequency activity (7-15cpm), in addition to activity observed in the low-frequency range (2-6cpm). Activity in the haustra, or haustral activity, is comprised of 2 boundaries with activity within these bounds (intra-haustral activity); the overexpression in patients serves to retard flow of colonic content. Sphincter of O’Beirne is the last haustral boundary at the rectosigmoid junction; its persistent presence was characterized in a patient with refractory constipation.