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The olfactory system is the most highly developed system for molecular sensing in vertebrates. Despite their reputation for being particularly olfactory driven, little is known about how this sense functions in elasmobranch fishes. The goal of this dissertation was to examine the morphology and physiology of elasmobranchs to compare their olfactory system with teleost fishes and more derived vertebrates. To test the hypotheses that elasmobranchs possess greater olfactory sensitivities than teleosts and that lamellar surface area is correlated to sensitivity, I compared the surface area of the olfactory lamellae and the olfactory sensitivities of five phylogenetically diverse elasmobranch species. The olfactory thresholds reported here (10-9 to 10-6 M) were comparable to those previously reported for teleosts and did not correlate with lamellar surface area. Since aquatic species are subject to similar environmental amino acid levels, they appear to have converged upon similar amino acid sensitivities. To test the hypothesis that elasmobranchs are able to detect bile salt odorants despite lacking ciliated olfactory receptor neurons (ORNs), the type of ORN that mediates bile salt detection in the teleosts, I quantified the olfactory specificity and sensitivity of two elasmobranch species to four, teleost-produced C24 bile salts. Both species responded to all four bile salts, but demonstrated smaller relative responses and less sensitivity compared to teleosts and agnathans. This may indicate that elasmobranchs don't rely on bile salts to detect teleost prey. Also, the olfactory system of elasmobranchs contains molecular olfactory receptors for bile salts independent of those that detect amino acids, similar to teleosts. / In some elasmobranch species, each olfactory bulb (OB) is physically partitioned into two hemi-bulbs; however, the functional significance of this morphology is not fully understood. The organization of the OBs in three species with varying OB morphologies was examined to test the hypothesis that the elasmobranch OB is somatotopically arranged. Glomeruli in the OB received projections from ORNs in 3-4 olfactory lamellae situated immediately anterior. These results indicate a somatotopic arrangement of the elasmobranch OB, which may be unique among vertebrate olfactory systems and potentially led to the hemi-OB morphology. / by Tricia L. Meredith. / Thesis (Ph.D.)--Florida Atlantic University, 2011. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

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This study aimed to investigate the effectiveness of hands-on activity enriched instruction on sixth grade students&rsquo / achievement (on sense organs) and attitudes towards science. In this study, Science Achievement Test and Science Attitude Scale were used to assess students&rsquo / achievement on sense organs and students&rsquo / attitudes towards science, respectively. Also, hands-on activities about sense organs were prepared. This study was conducted with 2 teachers and 4 classes and total of 140 sixth grade students in the public elementary schools at Ke&ccedil / i&ouml / ren district of Ankara in the fall semester of 2002-2003 academic years. One class of each teacher was assigned as experimental group and treated with hands-on activity enriched instruction and other class was assigned as control group and treated with traditional instruction. At the beginning of the study, both teachers were trained for how to implement hands-on activity enriched instruction in the classrooms. The Science Achievement Test and The Science Attitude Scale were applied twice as pre-test and after three week treatment period as a post-test to both experimental and control groups to assess and compare the effectiveness of two different types of teaching utilized in science course. The data obtained from the administration of post-test were analyzed by statistical techniques of Multivariate Analyses of Covariance (MANCOVA). The statistical result indicates that hands-on activity enriched instruction was more effective than traditional instruction. However, the statistical results failed to show a significant difference between the experimental and control groups attitudes toward science.

Thesis (Ph.D.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 174-202.

The olfactory system is of great interest in research due to the olfactory epithelium’s regenerative capability and as a potential as a source of neural stem cells. The olfactory sensory neurons are constantly being replaced by the stem cells that lie at the base of the olfactory epithelium. These stem cells also remain intact after an injury to the epithelium and lead to the regeneration of the olfactory epithelium. We have developed a fate mapping technique to trace axonal regrowth from newly born olfactory sensory neurons using an inducible Cre-ERT2 model after chemical ablation by the drug methimazole. Our data shows that newly generated olfactory sensory neurons labeled 1 day after chemical ablation by injection of 4-HO-tamoxifen extend an axon that reaches the olfactory bulb and extend to the glomeruli in a timeline that is consistent with control mice that received 4-HO-tamoxifen but were injected with saline 1 day prior. In addition, we assessed the functional recovery of the olfactory epithelium by testing the ability of mice to find a hidden cookie after methimazole injection. Mice were tested at 3 and 14 days post methimazole. There was a severe impairment in the ability to find a hidden cookie at 3 days post methimazole. The mice tested at 14 days post methimazole showed an improvement in the ability to find the cookie but the latency to find the cookie was still significantly higher than controls. In conclusion, while we demonstrate that axons extend to the olfactory bulb and the glomeruli earlier than 14 days, our behavioral data suggest that there must be a critical number of axons that must reach each specific glomerulus to regain function of the olfactory system.

Electroreception is a sensory modality found in some fish, which enables them to sense the environment through the detection of electric fields. Biological experimentation on this ability has built an intricate framework that has identified many of the components involved in electroreception's production, but lack the framework for bringing the details back together into a system-level model of how they operate together. This thesis builds and tests a computational model of the Electrosensory Lateral Line Lobe (ELL) in mormyrid electric fish in an attempt to bring some of electroreception's structural details together to help explain its function. The ELL is a brain region that functions as a primary processing area of electroreception. It acts as an adaptive filter that learns to predict reoccurring stimuli and removes them from its sensory stream, passing only novel inputs to other brain regions for further processing. By creating a model of the ELL, the relevant components which underlie the ELL's functional, electrophysiological patterns can be identified and scientific hypotheses regarding their behavior can be tested. Systems science's approach is adopted to identify the ELL's relevant components and bring them together into a unified conceptual framework. The methodological framework of computational neuroscience is used to create a computational model of this structure of relevant components and to simulate their interactions. Individual activation tendencies of the different included cell types are modeled with dynamical systems equations and are interconnected according to the connectivity of the real ELL. Several of the ELL's input patterns are modeled and incorporated in the model. The computational approach claims that if all of the relevant components of a system are captured and interconnected accurately in a computer program, then when provided with accurate representations of the inputs a simulation should produce functional patterns similar to those of the real system. These simulated patterns generated by the ELL model are compared to recordings from real mormyrid ELLs and their correspondences validate or nullify the model's integrity. By building a computation model that can capture the relevant components of the ELL's structure and through simulation reproduces its function, a systems-level understanding begins to emerge and leads to a description of how the ELL's structure, along with relevant inputs, generate its function. The model can be manipulated more easily than a biological ELL, and allows us to test hypotheses regarding how changes in the structures affect the function, and how different inputs propagate through the structure in a way that produces complex functional patterns.

<p>This dissertation examined perturbation effects during complex tactile information transmission. The four experiments provide evidence regarding sensory and information processing demands in early stages of complex tactile learning.</p> <p>Experiment 1 established complex tactile learning behavioural performance. Vibrotactile stimuli representing Morse code letters were communicated to participants with or without induced perturbation to the finger of letter reception. Response performance was measured and augmented feedback was provided retroactively. Perturbation conditions lead to poor performance during tactile acquisition, but improved performance during application of knowledge.</p> <p>Experiment 2 determined if the experiment 1 results demonstrated masking or response competition paradigms. Target “masking” is the reduced ability to detect or interpret a stimuli pattern by presentation of other information (Craig, 1985; Verrillo, 1985). Response competition is the competition or distraction from target response generation by secondary stimuli (Craig, 2000; Bolanowski et al., 2000). Experiment 2 tested response competition by spatially separating the perturbation and tactile information delivery sites.</p> <p>Experiments 3 and 4 served to replicate behavioural acquisition data from experiments 1 and 2. They also extended the findings of the first two experiments by introducing neurophysiological measurement to reflect the changes associated with the two perturbation conditions. The study discerned whether the masking and response competition paradigms from experiments 1 and 2 were predominantly impacting the peripheral or central information processing.</p> <p>Results from the four studies collectively demonstrate that increased demands are placed on the sensory system during early stages of complex tactile learning when perturbation is spatially congruent with tactile information delivery. Experiments 1 and 2 revealed that attention does not supersede spatial location of perturbation, and perturbation location is paramount to yield sufficient interference to impede acquisition yet lead to enhanced knowledge retention and transfer. Experiments 3 and 4 determined that cortical information processing associated with complex tactile information acquisition are neurophysiologically differentiated when relative locations of meaningful and perturbation stimuli are congruent or spatially separated. The findings from this dissertation serve as an advancement of our understanding of masking and response competition phenomenon as they pertain to complex tactile learning.</p> / Doctor of Philosophy (PhD)

Effect of lipids on binding characteristics of opioid receptors in membranes prepared from rat brain were studied. Lipid concentrations causing changes in specific binding of [3H]Endomorphin-1 (ProE1), an opioid agonist highly specific to mu-type opioid, [3H]Ile5,6deltorphin II (DIDI), an agonist ligand highly specific to delta type receptor and [3H]Naloxone (Nlx), a universal opioid receptor antagonist were determined. Inhibition of [3H]ProE1, [3H]DIDI and [3H]Nlx specific binding was also examined by homologous displacement experiments in the presence and absence of lipids. In order to understand whether the changes occurring in the specific binding is due to changes in equilibrium dissociation constant (KD) or maximum number of binding sites (Bmax), the equilibrium binding experiments were performed. Arachidonic acid (AA) inhibited binding of both agonist and antagonist ligand in a dose dependent manner with IC50 values of 0.15, 0.1, and 0.6 mM for [3H]ProE1, [3H]DIDI and [3H]Nlx, respectively. Kd values were not affected while Bmax values decreased 38 % and 76 % for mu, and delta receptor subtypes, respectively. For [3H]Nlx, Bmax values decreased 20 and 56 % in the absence and presence of 100 mM NaCl, respectively. Cholesteryl hemisuccinate (CHS) enhances (100 % of control) ligand binding at mu-sites however no effect was encountered at delta sites. Furthermore, CHS also enhances (50 % of control) the binding of antagonist ligand in the absence of NaCl. Bmax values were increased by 70 % for mu sites and 40% for antagonist ligand binding site. Under similar conditions Kd values were not affected. Phosphatidic acid (PA) and phosphatidylcholine (PC) exhibited negligible effect on ligand binding. PA decreased specific binding of ProE1 and DIDI by 16 and 10 %, respectively. Specific binding of antagonist ligand Nlx decreased 11 % in the presence of NaCl whereas in the absence of NaCl specific binding is very close to control. In the presence of PC specific binding of both agonist and antagonist ligands were around control values. In this study modulatory effect of lysophospholipids, lysophosphatidic acid and lysophosphatidylcholine on opioid binding sites were evaluated for the first time. Both lysophospholipids exhibited similar effects: decreasing specific binding in receptor subtype independent manner between 0.1 to 1 mM range. Kd values were not significantly affected, while remarkable decrease (45-75 %) in Bmax values were observed.

Fusion is a fundamental human process that occurs in some form at all levels of sense organs such as visual and sound information received from eyes and ears respectively, to the highest levels of decision making such as our brain fuses visual and sound information to make decisions. Multi-sensor data fusion is concerned with gaining information from multiple sensors by fusing across raw data, features or decisions. The traditional frameworks for multi-sensor data fusion only concern fusion at specific points in time. However, many real world situations change over time. When the multi-sensor system is used for situation awareness, it is useful not only to know the state or event of the situation at a point in time, but also more importantly, to understand the causalities of those states or events changing over time. / Hence, we proposed a multi-agent framework for temporal fusion, which emphasises the time dimension of the fusion process, that is, fusion of the multi-sensor data or events derived over a period of time. The proposed multi-agent framework has three major layers: hardware, agents, and users. There are three different fusion architectures: centralized, hierarchical, and distributed, for organising the group of agents. The temporal fusion process of the proposed framework is elaborated by using the information graph. Finally, the core of the proposed temporal fusion framework – Dynamic Time Warping (DTW) temporal fusion agent is described in detail. / Fusing multisensory data over a period of time is a challenging task, since the data to be fused consists of complex sequences that are multi–dimensional, multimodal, interacting, and time–varying in nature. Additionally, performing temporal fusion efficiently in real–time is another challenge due to the large amount of data to be fused. To address these issues, we proposed the DTW temporal fusion agent that includes four major modules: data pre-processing, DTW recogniser, class templates, and decision making. The DTW recogniser is extended in various ways to deal with the variability of multimodal sequences acquired from multiple heterogeneous sensors, the problems of unknown start and end points, multimodal sequences of the same class that hence has different lengths locally and/or globally, and the challenges of online temporal fusion. / We evaluate the performance of the proposed DTW temporal fusion agent on two real world datasets: 1) accelerometer data acquired from performing two hand gestures, and 2) a benchmark dataset acquired from carrying a mobile device and performing pre-defined user scenarios. Performance results of the DTW based system are compared with those of a Hidden Markov Model (HMM) based system. The experimental results from both datasets demonstrate that the proposed DTW temporal fusion agent outperforms HMM based systems, and has the capability to perform online temporal fusion efficiently and accurately in real–time.