The nematode Caenorhabditis elegans, with its sequenced genome, compact nervous system and stereotyped behaviors is an ideal model organism in which to study the integration of sensory input with motor output. Male mating behavior is among the most complex of these behaviors and males utilize a number of sensory organs in its execution. Among these are the rays, which are nine pairs of sensory organs that are arranged laterally along the male tail. Each ray is composed of two ultra-structurally distinct neuron types, an A type and a B type, surrounded by a glia-like structural cell. Though compositionally identical, each pair of rays maintains a unique, genetically-hardwired identity based on wiring, morphology, and neurotransmitter fate. Three techniques were used to investigate the role of the rays in male mating behavior. First, cauterization of the tips of the rays removed their sensory endings, leading to ray neuron death. Second, a heterologous light-activated cation channel was utilized to activate specific ray neuron types. Finally, ray neuron types were genetically targeted to undergo apoptosis by expression of heterologous caspases. The results show that the rays play important roles in multiple steps of male mating behavior, including contact response, scanning, and turning. The rays as a whole mediate posture change and backing during contact response. The ability to respond to hermaphrodite contact is shared among the rays, as is initiation of backward locomotion, though all rays are required for efficient, prolonged backward scanning. Both A and B neuron types appear capable of initiating contact response. Direct activation of B neurons through ChR2 causes a contact response-like ventral tail flexure, and elimination of both A and B neurons reduces contact response. A neurons additionally have a unique role in turning.

Thesis (Ph. D.)--University of California, San Diego, 2009. / Title from first page of PDF file (viewed July 7, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

The sensorimotor cortex is a brain region comprising the primary motor cortex (MI) and the primary somatosensory (SI) cortex. In humans, investigation into these regions suggests that MI and SI are involved in the modulation and control of motor and somatosensory processing, and are somatotopically organized according to a body plan (Penfield & Boldrey, 1937). Additional investigations into somatotopic mapping in relation to the limbs in the peripheral nervous system and SI in central nervous system have further born out the importance of this body-based organization (Wall & Dubner, 1972). Understanding the nature of the sensorimotor cortex‟s structure and function has broad implications not only for human development, but also motor learning (Taubert et al., 2011) and clinical applications in structural plasticity in Parkinson‟s disease (Sehm et al., 2014), among others. The aim of the present thesis is to identify functionally meaningful subregions within the sensorimotor cortex via parcellation analysis. Previously, cerebral subregions were identified in postmortem brains by invasive procedures based on histological features (Brodmann, 1909; Vogt. & Vogt., 1919; Economo, 1926; Sanides, 1970). One widely used atlas is based on Brodmann areas (BA). Brodmann divided human brains into several areas based on the visually inspected cytoarchitecture of the cortex as seen under a microscope (Brodmann, 1909). In this atlas, BA 4, BA 3, BA 1 and BA 2 together constitute the sensorimotor cortex (Vogt. & Vogt., 1919; Geyer et al., 1999; Geyer et al., 2000). However, BAs are incapable of delineating the somatotopic detail reflected in other research (Blankenburg et al., 2003). And, although invasive approaches have proven reliable in the discovery of functional parcellation in the past, such approaches are marked by their irreversibility which, according to ethical standards, makes them unsuitable for scientific inquiry. Therefore, it is necessary to develop non-invasive approaches to parcellate functional brain regions. In the present study, a non-invasive and task-free approach to parcellate the sensorimotor cortex with resting-state fMRI was developed. This approach used functional connectivity patterns of brain areas in order to delineate functional subregions as connectivity-based parcellations (Wig et al., 2014). We selected two adjacent BAs (BA 3 and BA 4) from a standard template to cover the area along the central sulcus (Eickhoff et al., 2005). Then subregions within this area were generated using resting-state fMRI data. These subregions were organized somatotopically from medial-dorsal to ventral-lateral (corresponding roughly to the face, hand and foot regions, respectively) by comparing them with the activity maps obtained by using independent motor tasks. Interestingly, resting-state parcellation map demonstrated higher correspondence to the task-based divisions after individuals had performed motor tasks. We also observed higher functional correlations between the hand area and the foot and tongue area, respectively, than between the foot and tongue regions. The functional relevance of those subregions indicates the feasibility of a wide range of potential applications to brain mapping (Nebel et al., 2014). In sum, the present thesis provides an investigation of functional network, functional structure, and properties of the sensorimotor cortex by state-of-art neuroimaging technology. The methodology and the results of the thesis hope to carry on the future research of the sensorimotor system.

The reactive control of fingertip forces maintaining grasp stability was examined in man during a prehensile task. Blindfolded subjects used the precision grip between the tips of index finger and thumb to restrain an object that was subjected to unpredictable load forces. These were delivered tangential to the parallel grip surfaces of the object. Load forces, grip forces (perpendicular to the grip surfaces) and position of the object were recorded.Subjects automatically adjusted the grip forces to loads of various amplitudes and rates. Thereby they maintained a reliable safety margin against frictional slips without using excessive grip forces. A rapid rise in grip force lasting about 0.2 s was triggered after a short delay following the onset of a sustained ramp load increase. This 'catch-up' response caused a quick restoration of an adequate grip:load force ratio that prevented frictional slips. If the ramp load continued to increase after the catchup response, the grip force also increased in parallel with the load change in a 'tracking' manner. Consequently, during the hold phases of 'ramp-and-hold' loads, the employed grip forces were approximately proportional to the load amplitude. Sensory information about the rate of change of the load force parametrically scaled the 'catchup' and 'tracking' responses.Following anesthetic block of sensory input from the digits, the grip responses were both delayed and attenuated or even abolished. To compensate for these impairments, subjects had to voluntarily maintain exceedingly high grip forces to prevent the object from slipping. The grip control improved slightly during hand and forearm support conditions that allowed marked wrist movements to occur in response to the loading. This indicates that signals from receptors in muscles, joints or skin areas proximal to the digits can to some extent be used to adjust grip forces during impaired digital sensibility. In contrast, these signals had only minor influence on the control during normal digital sensibility.Grip responses to loads delivered in various directions revealed that the load direction, in relation to gravity and to the hand's geometry, represents intrinsic task variables in the automatic processes that maintain a stable grasp. The load direction influenced both the response latencies and the magnitudes of the grip responses. The response latencies were shortest for loads in directions that were the most critical with regard to the consequences of frictional slippage, i.e., loads directed away from the palm or in the direction of gravity. Recordings of signals in cutaneous afferents innervating the finger tips demonstrated that these effects on the response latencies depended on differences in the time needed by the central nervous system to implement the motor responses. The short latencies in the most ‘criticar load directions may reflect the preparation of a default response, while additional central processing would be needed to execute the response to loads in other directions. Adjustments to local frictional anisotropies at the digit-object interface largely explained the magnitude effects.In conclusion, grip responses are automatically adjusted to the current loading condition during unpredictable loading of a hand held object. Subjects call up a previously acquired sensorimotor transform that supports grasp stability by preventing both object slippage and excessive grip forces. Cutaneous sensory information about tangential forces and frictional conditions at the digit-object interface is used to initiate and scale the grip responses to the current loading conditions, largely in a predictive manner. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1995, Härtill 5 uppsatser</p> / digitalisering@umu

The early years of a child's growth and development are crucial for health, wellbeing and success in later life. Adequate stimulation during the pre-school years is a critical factor that can be associated with higher levels of achievement and better adjustment in school (Arnold, Barlett., Gowani, & Merali, 2006). Some children, for example those growing in contexts of adversity, are in particular need of pre-school assistance. This research evaluates a one-year implementation of the Psychomotor Education Programme (PMEP) at the Dalton Trust Education Centre, KwaZulu-Natal, South Africa. PMEP is an educational programme that stimulates the child‟s psychomotor functions and supports the development of the whole child through play in the pre-school years. An evaluation of the programme was required to establish if the PMEP had achieved the envisaged objectives of improving preparedness of children for their entrance into the formal school system. This summative evaluation used focus group discussions to collect data on whether the outcomes had been achieved from the perspective of the trained and experienced family facilitators who had participated in the PMEP. The participants were asked about the strengths, weaknesses, opportunities and threats of the PMEP. The areas identified as being attributable to the PMEP include social-emotional competence, self-awareness, emotional regulation and autonomy. The participants reported that PMEP had enabled the children to achieve the learning outcomes described by the Revised National Curriculum Statement (South African Department of Education, 2005). However, further research is needed to overcome the difficulty of maintaining the achieved outcomes in a new environment, such as the formal school context, where methods of teaching and resources may differ substantially from those provided by the PMEP. / Thesis (M.Soc.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

No description available.

The purpose of this study was to examine the utility of the Dean-Woodcock Sensory Motor Battery (DWSMB) as a diagnostic tool for identifying individuals with and without closed-head injury, comparing the predictive power of a two- and three-factor representation (DWSMB; Dean & Woodcock, 2003). The current study's major research questions focused on the predictive utility of the structure of the DWSMB. The simplified two-factor model (Total Sensory and Total Motor), based on the DWSMB manual (Dean & Woodcock), was compared to a three-factor theoretical model (Basic Sensory, Higher Sensory and Motor Functions) (R.S.Dean, personal communication, March 29, 2006) for this study. Logistic Regression was used to analyze the data. Results from this study demonstrate that when using the two-factor solution, the overall correct prediction of group membership was 73.8 % (59.4% for CHI and 85.2% for normals). The Total Motor Impairment variable was the only meaningful predictor. The results from the three-factor solution show an 84.2 % overall correct prediction rate (71.4 % for CHI and 95.1 % for normals). The significant contributors for identifying CHI when using the three-factor model included Basic Sensory and Motor Functions. Everything favors the three-factor model as being more precise. All indicators of prediction accuracy and goodness of fit favored the three-factor model. Based on these results, the DWSMB was determined to be a good screening instrument for identifying children in school contexts who should be referred for a neuropsychological examination to confirm pre-existing CHI that interfere with school functioning. / Department of Educational Psychology

This cross-sectional study evaluated the trend in sensory and motor skill development for an archival dataset used in the standardization of the Dean-Woodcock Sensory Motor Battery (D-WSMB). Measures from the D-WSMB were organized into three broad categories according to a factor model identified by Davis, Finch, Dean and Woodcock (2006). Three primary hypotheses were evaluated: a confirmatory factor analysis would support the Davis et al. model for the current dataset, performance on sensory and motor tasks would exhibit a pattern of development and decline across age levels, and gender would not be a significant factor in variability in performance. CFA results indicated the Davis et al. factor model was a poor fit for the current dataset but that each measure loaded significantly on the factor to which it was assigned. Curve estimation identified a significant quadratic relationship between age and performance on each of the skill categories. A significant age and gender interaction was noted for each skill category. The statistically poor fit of the Davis et al. factor model was thought to be due to potential correlations between factors and between measures within the factors, although further research is needed to evaluate the impact of these relationships on model fit. Results confirmed the hypothesis that sensory and motor skill exhibit a pattern of development and decline across age levels, which can guide the interpretation of performance in a clinical setting. Further research is needed on the nature of the age and gender interaction to clarify the impact on performance on measures of sensory and motor skills. In an addendum to this study, performance on individual measures of the D-WSMB was plotted to provide further guidance in the interpretation of results in clinical settings. / Department of Educational Psychology

The present study investigated the relationship between sensory/motor skills and cognitive abilities in psychiatric and neurologically impaired patients to determine how sensory/motor skills are associated with cognitive abilities. Previous research has demonstrated a significant relationship between performance on sensory/motor tasks and cognition but has failed to examine how well sensory/motor skills can predict specific cognitive performance. Because brain functioning is hierarchical with simpler processes being foundational to the development of more complex functions, it is likely sensory/motor skills can aid in the prediction of specific cognitive abilities. If this is true, then investigation of the relationship between sensory/motor performance and cognition should provide insight into the role of sensory/motor skills in the Dean-Woodcock Cognitive Neuropsychology Model.This study examined the relationship between scores on the Woodcock-Johnson Tests of Cognitive Ability - Revised (WJ-R COG) and scores on the Dean-Woodcock Sensory and Motor Battery (D-WSMB). Participants included 458 patients referred for neuropsychological consultation with neurological and/or psychiatric diagnoses. Results indicated a significant correlation among cognitive scores and sensory/motor scores. Moreover, factor analysis revealed 7 overall factors that account for approximately 65% of the variance. These factors were identified as being thinking ability and processing speed, subcortical functioning, verbal working memory, peripheral processes, tactile kinesthetic thinking (Gtk), visual processing, and simple sensory/motor.Integration of sensory/motor factors into the Dean-Woodcock Cognitive Neuropsychology Model revealed the significant role sensory/motor performance plays in predicting higher-order cognitive abilities. From the analysis it appeared that certain sensory/motor functions were significant contributors to the prediction of specific cognitive abilities. That is, subcortical functioning aided in the prediction of all measured areas of cognition; visual processing contributed to visual-spatial thinking, novel reasoning, and crystallized knowledge; tactile-kinesthetic thinking helped predict visual-spatial thinking, auditory processing, and crystallized knowledge; and simple sensory/motor functioning aided in the explanation of long-term storage-retrieval.These results offer a beginning point for further investigation into the relationship between specific sensory/motor skills and cognitive abilities. Research in this area can provide further insight into the functional organization of the brain and offer application to cognitive outcome in rehabilitation as well as preschool screening. / Department of Educational Psychology

Given the broad public health concern, lack of reliability of diagnosis across providers and substantial resources needed to support individuals with Autism Spectrum Disorder, the current study serves to contribute to the field in informing the contexts of both research and clinical service. The utility of a standardized sensory-motor battery was investigated in regards to its ability (1) to determine what, if any, differences exist between ASD diagnoses or subgroups in both sensory functioning and motor functioning; and (2) to determine whether such discrepancies, if they exist, are capable of differentiating groups. Results from the quadratic discriminant analysis demonstrated that the factor scores derived from the Dean-Woodcock Sensory-Motor Battery significantly differentiated the ASD and nonclinical comparison groups. Factor 1 (Simple Sensory Skills) exhibited the strongest relationship, followed by Factor 2 (Cortical Motor and Complex Sensory Skills), then Factor 3 (Subcortical Motor Tasks and Auditory/Visual Acuity Skills). Findings from the study lend initial evidence of the use of the DWSMB as a potential measure to include within the two-stage diagnostic process for ASD. Use of the DWSMB as a screening measure may facilitate access to early intervention services given the primitive nature of sensory-motor tasks. In addition, the availability of the DWSMB as a standardized measure of sensory and motor functioning may promote increased sensitivity and specificity among diagnostic providers thus improving outcomes of individuals with ASD who can access services more readily with earlier, more reliable diagnoses. / Access to thesis permanently restricted to Ball State community only. / Department of Educational Psychology