Illusory self motion and simulator sickness

Presented here is a discussion of simulator sickness (with applications to motion sickness and space sickness) based on the notion of senses as perceptual systems, and the sensory conflict theory. Most forms of the sensory conflict theory unnecessarily propose the existence of a neural store. The neural store is thought to consist of a record of previous perceptual experiences against which currently experienced patterns of stimulation are compared. The authors seek to establish that in its most parsimonious form the sensory conflict theory does not require a construct such as the neural store. In its simpler form, the sensory conflict theory complements and extends Gibson's view of the senses as perceptual systems

Effects of varying acupuncture manipulations at ST36 (Zusanli) on gastric electrical frequency and amplitude in bradygastria rabbits

Objective. To observe the effects of different manual acupuncture (MA) manipulation on gastric electrical amplitude and frequency for noradrenaline-induced bradygastria in rabbits. Methods. A total of 60 rabbits were randomly allocated into six groups: four MA manipulation groups; reinforcing by twisting the manipulation group (FTG), reducing by twisting the manipulation group (RTG), reinforcing by lifting and thrusting the manipulation group (FLG), and reducing by lifting and thrusting the manipulation group (RLG), a control group (CG), and a model group (MG). The total treatment time length was 45 minutes. The bradygastria was induced via administration of noradrenaline via the marginal ear vein of the rabbits at 5 minutes from baseline, and the bradygastria model was established at 12 minutes from baseline. The rabbits in the four MA manipulation groups received different stimulation parameters at ST36 (Zusanli) for a duration of 3 minutes in accordance with their respective group allocation. The needles were then retained without further manipulation for a further 25 minutes. Gastric electrical amplitude and frequency were recorded using a data acquisition system (Biopac System MP150) at five different time points: baseline (for a duration of 5 minutes), after the bradygastria model was established at 12 minutes from baseline (for a duration of 5 minutes), during MA manipulation commencing at 17 minutes from baseline (for a duration of 3 minutes), 5 minutes after MA manipulation at 25 minutes from baseline (for a duration of 5 minutes), and at 20 minutes following MA manipulation at 40 minutes from baseline (for a duration of 5 minutes). Results. After noradrenaline induction, gastric electrical frequency levels in MA and MG groups were significantly decreased compared to the CG group (P 0.05). During MA manipulation, gastric electrical frequency levels in RTG, FLG, and RLG groups were higher than in the MG group (P < 0.05). At 5 minutes after MA manipulation, gastric electrical frequency levels in RTG and FLG groups were higher than in the MG group (P < 0.05), and gastric electrical frequency level in the RTG group was higher than in the CG group (P < 0.05). At 20 minutes after MA manipulation, gastric electrical frequency levels in FTG, RTG, and FLG groups were higher than in the MG group (P < 0.05). Conclusion. All four variations of MA manipulations have a recovery effect on the gastric electrical frequency of rabbits with bradygastria. In particular, results indicated that FTG, RTG, and FLG at ST36 may have a regular and significant recovery trend through the whole process of the acupuncture intervention

Gastric Myoelectrical Activity in Patients with Diabetes

This descriptive, correlational study investigated the associations among gastric myoelectrical activity (GMA), upper gastrointestinal (GI) symptoms, and glucose control. The study also attempted to determine whether any relationship existed between upper GI symptoms, glucose control, age, or length of diagnosis and pattern of GMA identified using electrogastrography (EGG). A total of 25 persons participated in the study. The sample was comprised of 7 healthy controls, 5 patients diagnosed with type 1 diabetes, and 13 patients diagnosed with type 2 diabetes. Electrogastrography was performed for 30 minutes in the fasting state and continued at 30-minute intervals for a total of 1-1/2 hours post-prandially. Data from the fasting, 30-minute post-prandial period, and 120-minute post-prandial periods were analyzed for the study. Findings of this study support the potential use of EGG as a screening tool in the detection of patterns of GMA in healthy and diabetic individuals. Using EGG, gastric myoelectrical activity can be identified in both healthy controls and patients diagnosed with diabetes. Further studies are needed to generate data that can be used to explain the pathology behind, and relationship between GMA abnormalities, upper GI signs and symptoms, and the lack of glucose control in patients with diabetes

Myoelectric activity of the stomach : gastroelectromyography and electrogastrography

The musculature of the distal two-thirds of the stomach generates electrical signals that are related, in a complex manner, to the (peristaltic) contractions of these muscles. These electrical signals originate in ion shifts from the intracellular to the extracellular space and vice-versa. Apart from recording intracellular electrical activity with the aid of a microelectrode inserted into the cell, gastric myoelectrical activity can be recorded in two ways. Firstly, gastric electrical activity can be recorded with electrodes located in the immediate proximity of the muscle layers. This method is called gastroelectromyography. lt provides information about the electrical activity of larger groups of cells. Secondly, gastric myoelectrical activity can be recorded with the aid of electrodes at relatively large distances from the stomach (e.g. on the abdominal skin). This method is called electrogastrography. It provides rather global information about the electrical activity of the stomach. Whereas the method of electrogastrography is still in a relatively early experimental phase, the method of gastroelectromyography has frequently been used in studies on gastric myoelectric activity, both in health and disease. The published descriptions of the characteristics on normal gastroelectromyographic signals are not in complete accordance, however. No agreement exists about the existence and meaning of the so-called 1 Second potential 1 (Daniel, 1965, 1966) and about the relation between intracellular and extracellular electrical activity. Furthermore, gastroelectromyographic 1 iterature paid relatively 1 ittle attention to the rhythm of the so-cal led 1 Electrical Control Activity 1 (Sarna. 197

Analysis of abdominal slow potentials during motion sickness

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1987.MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERONAUTICS.Bibliography: leaves 176-181.by Brian W. Rague.M.S

Transcutaneous electrogastrography

Cílem bakalářské práce je seznámení se s fyziologií a patofyziologií gastrointestinálního traktu, s funkčními parametry a s vhodnou diagnostikou. Probrána je problematika přístroje pro perkutánní elektrogastrografii a zároveň je navržen protokol měření pro skupinku dobrovolníků v klidových a zátěžových podmínkách. V teoretické části práce je popsána funkce gastrointestinálního traktu s podrobným rozborem žaludeční myoelektrické aktivity a motility žaludku, a technika záznamu perkutánního elektrogastrogramu s jeho parametry, artefakty a s následnou analýzou dat. V praktické části práce je navržen a zrealizován program v programovém prostředí Matlab pro analýzu EGG záznamu. Dále jsou vyhodnoceny rozdíly v parametrech při klidových a zátěžových podmínkách.The aim of this thesis is to introduce the physiology and pathophysiology of the gastrointestinal tract, with functional parameters and appropriate diagnostics. The thesis also deals with transcutaneous electrogastrography devices and presents a suggestion of a measurement protocol which would involve a group of volunteers in fasting and postprandial states. The theoretical part describes the function of the gastrointestinal tract, detailing the analysis of gastric myoelectric activity and gastric motility. It also outlines technical and formal aspects of the parameters, artefacts and subsequent data analysis. In the practical part, a program is designed and implemented in the Matlab computing environment for the analysis of EGG recordings. Furthermore, differences between parameters in fasting and postprandial states are evaluated.