Ten experiments examined the interactions between vision and audition in stimulusdriven spatial attention orienting and inhibition of return (IOR). IOR is the demonstration that subjects are slower to respond to stimuli that are presented at a previously stimulated location. In each experiment, subjects made go/no-go responses to peripheral targets but not to central targets. On every trial, a target was preceded by a sensory event, called a "cue," either in the same modality (intramodal conditions) or in a different modality (crossmodal conditions). The cue did not predict the location of the target stimulus in any experiment. In some experiments, the cue and target modalities were fixed and different. Under these conditions, response times to a visual target were shorter when it appeared at the same location as an auditory cue than when it appeared on the opposite side of fixation, particularly at short (100 ms) cue-target stimulus onset asynchronies (Experiments 1A and IB). Similarly, response times to an auditory target were shorter when it appeared at the same location as a visual cue than when it appeared at a location on the opposite side of fixation (Experiments 2A and 2B). These crossmodal effects indicate that stimulus-driven spatial attention orienting might arise from a single supramodal brain mechanism. IOR was not observed in either crossmodal experiment indicating that it might arise from modality specific mechanisms. However, for many subjects, IOR did occur between auditory cues and visual targets (Experiments 3A and 3B) and between visual cues and auditory targets (Experiment 4A and 4B) when the target could appear in the same modality as the cue on half of the trials. Finally, the crossmodal effects of stimulus-driven spatial attention orienting on auditory and visual event-related brain potentials (ERPs) were examined in the final two experiments. Auditory cues modulated the ERPs to visual targets and visual cues modulated the ERPs to auditory targets, demonstrating that the mechanisms for spatial attention orienting cannot be completely modality specific. However, these crossmodal ERP effects were very different from each other indicating that the mechanisms for spatial attention orienting cannot be completely shared.

Previous studies have suggested that protective responses in the pelvic floor muscles (PFMs), described in terms of hypertonicity and over-reactivity, are associated with and may worsen the symptoms of provoked vestibulodynia (PVD, i.e., chronic vulvar pain). A recent study reported that, upon manual palpation of the PFM, hypertonicity was consistently found in the superficial but not the deep PFM layers. The goals of this study were to compare superficial and deep PFM resting tone, protective response magnitude and onset timing to moderate perceived vulvar pain between women with and without PVD. Eleven women with PVD and eleven control women Tcompleted a gynecological examination and standardized PFM electromyography (EMG) testing. Three trials of sTurface EMG activity of the PFM were recorded while a pressure-pain stimulus (PPS) was applied to the vulvar vestibule. Increasing pressure was applied to achieve a perceived pain intensity rating of 6/10 using an 11-point numerical rating scale presented visually. The women with PVD had higher resting EMG activity in their superficial PFMs (p=0.04) as compared to the control group, while no difference was found at the level of the deep PFMs (p=0.12). Participants in both groups demonstrated contractile responses to the PPS in both the superficial and the deep PFM, and these responses were significantly higher (p=0.0001) in the superficial (50.06 vs 38.69 % maximal voluntary electrical activation [MVE]) as compared to the deep (24.88 vs 22.52 %MVE) PFM layers. Women with PVD had significantly higher PFM responses at the superficial layer as compared to the control women (p<0.0005). The onset of the superficial and deep EMG PFM responses followed the PPS application in both groups. No differences were found between the deep and superficial PFM onset latency to the timing of the PPS application.The results of this study suggest that women with PVD have superficial PFMs that are more responsive to vulvar pain than those in non-affected women. The findings also suggest that superficial PFM over-reactivity, rather than deep PFM over-reactivity, is part of the PFM dysfunction reported in women with PVD. / Thesis (Master, Rehabilitation Science) -- Queen's University, 2008-09-26 15:46:22.84

For decades electrophysiologists have recorded and characterized the biophysical properties of a rich diversity of neuron types. This diversity of neuron types is critical for generating functionally important patterns of brain activity and implementing neural computations. In this thesis, I developed computational methods towards quantifying neuron diversity and applied these methods for understanding the functional implications of within-type neuron variability and across-type neuron diversity. First, I developed a means for defining the functional role of differences among neurons of the same type. Namely, I adapted statistical neuron models, termed generalized linear models, to precisely capture how the membranes of individual olfactory bulb mitral cells transform afferent stimuli to spiking responses. I then used computational simulations to construct virtual populations of biophysically variable mitral cells to study the functional implications of within-type neuron variability. I demonstrate that an intermediate amount of intrinsic variability enhances coding of noisy afferent stimuli by groups of biophysically variable mitral cells. These results suggest that within-type neuron variability, long considered to be a disadvantageous consequence of biological imprecision, may serve a functional role in the brain. Second, I developed a methodology for quantifying the rich electrophysiological diversity across the majority of the neuron types throughout the mammalian brain. Using semi-automated text-mining, I built a database, Neuro- Electro, of neuron type specific biophysical properties extracted from the primary research literature. This data is available at http://neuroelectro.org, which provides a publicly accessible interface where this information can be viewed. Though the extracted physiological data is highly variable across studies, I demonstrate that knowledge of article-specific experimental conditions can significantly explain the observed variance. By applying simple analyses to the dataset, I find that there exist 5-7 major neuron super-classes which segregate on the basis of known functional roles. Moreover, by integrating the NeuroElectro dataset with brain-wide gene expression data from the Allen Brain Atlas, I show that biophysically-based neuron classes correlate highly with patterns of gene expression among voltage gated ion channels and neurotransmitters. Furthermore, this work lays the conceptual and methodological foundations for substantially enhanced data sharing in neurophysiological investigations in the future.

<p>Deep brain stimulation (DBS) is an established surgical therapy for movement disorders. The mechanisms of action of DBS remain unclear, and selection of stimulation parameters is a clinical challenge and can result in sub-optimal outcomes. Closed-loop DBS systems would use a feedback control signal for automatic adjustment of DBS parameters and improved therapeutic effectiveness. We hypothesized that evoked compound action potentials (ECAPs), generated by activated neurons in the vicinity of the stimulating electrode, would reveal the type and spatial extent of neural activation, as well as provide signatures of clinical effectiveness. The objective of this dissertation was to record and characterize the ECAP during DBS to determine its suitability as a feedback signal in closed-loop systems. The ECAP was investigated using computer simulation and <italic>in vivo</italic> experiments, including the first preclinical and clinical ECAP recordings made from the same DBS electrode implanted for stimulation. </p><p>First, we developed DBS-ECAP recording instrumentation to reduce the stimulus artifact and enable high fidelity measurements of the ECAP at short latency. <italic>In vitro</italic> and <italic>in vivo</italic> validation experiments demonstrated the capability of the instrumentation to suppress the stimulus artifact, increase amplifier gain, and reduce distortion of short latency ECAP signals.</p><p>Second, we characterized ECAPs measured during thalamic DBS across stimulation parameters in anesthetized cats, and determined the neural origin of the ECAP using pharmacological interventions and a computer-based biophysical model of a thalamic network. This model simulated the ECAP response generated by a population of thalamic neurons, calculated ECAPs similar to experimental recordings, and indicated the relative contribution from different types of neural elements to the composite ECAP. Signal energy of the ECAP increased with DBS amplitude or pulse width, reflecting an increased extent of activation. Shorter latency, primary ECAP phases were generated by direct excitation of neural elements, whereas longer latency, secondary phases were generated by post-synaptic activation.</p><p>Third, intraoperative studies were conducted in human subjects with thalamic DBS for tremor, and the ECAP and tremor responses were measured across stimulation parameters. ECAP recording was technically challenging due to the presence of a wide range of stimulus artifact magnitudes across subjects, and an electrical circuit equivalent model and finite element method model both suggested that glial encapsulation around the DBS electrode increased the artifact size. Nevertheless, high fidelity ECAPs were recorded from acutely and chronically implanted DBS electrodes, and the energy of ECAP phases was correlated with changes in tremor. </p><p>Fourth, we used a computational model to understand how electrode design parameters influenced neural recording. Reducing the diameter or length of recording contacts increased the magnitude of single-unit responses, led to greater spatial sensitivity, and changed the relative contribution from local cells or passing axons. The effect of diameter or contact length varied across phases of population ECAPs, but ECAP signal energy increased with greater contact spacing, due to changes in the spatial sensitivity of the contacts. In addition, the signal increased with glial encapsulation in the peri-electrode space, decreased with local edema, and was unaffected by the physical presence of the highly conductive recording contacts.</p><p>It is feasible to record ECAP signals during DBS, and the correlation between ECAP characteristics and tremor suggests that this signal could be used in closed-loop DBS. This was demonstrated by implementation in simulation of a closed-loop system, in which a proportional-integral-derivative (PID) controller automatically adjusted DBS parameters to obtain a target ECAP energy value, and modified parameters in response to disturbances. The ECAP also provided insight into neural activation during DBS, with the dominant contribution to clinical ECAPs derived from excited cerebellothalamic fibers, suggesting that activation of these fibers is critical for DBS therapy.</p> / Dissertation

Vartotojų elgsenos aktualumas verslo praktikoje ir teorijoje neabejotinas – vartotojų elgsenos, ypač pirkimo sprendimo priėmimo stimulų, kylančių iš vartotojų asmenybės bei aplinkoje esančių ir skatinančių pirkti stimulų išskyrimas. Impulsyvaus pirkimo fenomenas mokslinėje marketingo literatūroje analizuojamas jau daugiau kaip penkias dešimtis. Todėl stimulai, sąlygojantys impulsyvaus pirkimo sprendimą ypač svarbūs – tokių stimulų sukūrimas skatintų vartotojus priimti pirkimo sprendimą per sąlyginai trumpą laiko tarpą, o pastaroji tendencija generuotų pelną organizacijai. Dar vienas itin plačiai mokslinėje literatūroje analizuojamas konceptas – prekės ženklo vertė. Prekės ženklo vertė pagrįsta vartotojo sąmonėje susiformavusiomis teigiamos asociacijos su prekės ženklu, prekės ženklo vertės vartotojui sukūrimu bei vartotojų lojalumu prekės ženklui. Visi pastarieji veiksniai mokslinėje literatūroje traktuojami, kaip skatinantys vartotojo sprendimo pirkti priėmimą. Prekės ženklas įvardijamas, kaip vienas iš impulsyvaus pirkimo stimulų. Darbo objektas – impulsyvaus pirkimo stimulai ir prekės ženklo vertė. Darbo tikslas – teoriškai pagrįsti ir empiriškai patikrinti impulsyvaus pirkimo ir prekės ženklo vertės sąsajas „Nivea“ prekės ženklo pavyzdžiu. Darbo struktūra. Magistro darbą sudaro trys dalys. Pirmojoje darbo dalyje pateikta ir nagrinėta impulsyvaus pirkimo koncepcija, vidiniai ir išoriniai impulsyvaus pirkimo stimulai. Taip pat analizuojami prekės ženklo vertę kuriantys... [toliau žr. visą tekstą] / The aim of this master work – theoretically support and empirically examine the relationship between impulsive buying and brand equity. The structure of thesis. The Master work thesis consists of three parts. The first part of thesis represents and examines the conception of impulsive buying, its internal and external impulsive buying stimulus. It also analyzes the creating factors of the brand value. The analysis of impulsive buying models is also presented. The second part of the thesis represents the structural interface pattern of impulsive buying and the brand equity. The research methodology, aims and tasks are also given. A previous analysis of impulsive buying research results is done. The third part of Master work thesis does the empirical research of the relationship between impulsive buying and the brand equity; the results are generalized. Empirically checked structural model relationshiop between impulsive buying and the brand equity by the example of Nivea brand is done. At the end of the Master work the conclusions are made and suggestions are given. In order to make it more transparent, the work contains of 14 pictures and 17 tables. The theoretical analysis has been prepared using 117 English and Lithuanian literature sources.

In episodic recognition memory, differentiation is the assumption that a study item's pre-existing memory trace is updated when additional study for that item is provided. The differentiation models commonly suppose that episodic memory encoding conforms to this process. Although these models have received considerable support within the literature, results inconsistent with their predictions have also been found. The present paper examined conflicting findings that resulted from study list strength manipulations with rhyming word stimuli and semantically related stimuli. As part of the investigation into this discrepancy, 79 university students participated in a computer-based recognition memory task. In this task, word categories of varying length (short vs. long) and word type (rhyming vs. taxonomic) were presented either five times or once within a mixed study list. Following study, an old-new response paradigm was used to examine recognition memory performance. Results from both the rhyming and taxonomic category stimuli were largely consistent with the previous findings in the literature, indicating that word type does appear to influence recognition memory, even within a mixed study list. These findings are interpreted primarily in terms of word type similarity predictions made by one of the differentiation models. Other possible explanations are also discussed.

Thesis (Ph. D.)--University of Toronto, 2005.

Thesis (M.S.)--State University of New York at Binghamton, Department of Psychology, 2009. / Includes bibliographical references.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Psychology, 2008. / Includes bibliographical references.

Thèse (M.Ps.)--Université Laval, 2002. / Bibliogr.: f. 39-45. Publié aussi en version électronique.