Positive taxis and sustained responsiveness to water motions in larval zebrafish

Larval zebrafish (Danio rerio) have become favored subjects for studying the neural bases of behavior. Here, we report a highly stereotyped response of zebrafish larvae to hydrodynamic stimuli. It involves positive taxis, motion damping and sustained responsiveness to flows derived from local, non-stressful water motions. The response depends on the lateral line and has a high sensitivity to stimulus frequency and strength, sensory background and rearing conditions—also encompassing increased threshold levels of response to parallel input. The results show that zebrafish larvae can use near-field detection to locate sources of minute water motions, and offer a unique handle for analyses of hydrodynamic sensing, sensory responsiveness and arousal with accurate control of stimulus properties

A Comparative Study of the Configuration and Functions of Outdoor and Semi-Outdoor Space in Schools from the Traditional to the Contemporary Period Based on Evaluating the Role of the Governing Educational System

The present study, based on a case study, aims at addressing the functional and morphological evolutions in outdoor and semi-outdoor spaces in Yazd schools over time, through educational developments. The approach followed in this study is to connect the changes in the spatial structure of outdoor space in schools to the evolutions in the educational system. To this end, this paper develops five hypotheses and employs qualitative and computational research methods to evaluate the functions and spatial configuration of the outdoor spaces of six schools, constructed between the 18th and 20th CE centuries, in Yazd. A mathematical method drawn by “space syntax” is adopted to measure the spatial features of the outdoor spaces of schools, and a field study is used to identify the relationship between the functional process of these configurations and their governing educational principle. The results show that the configuration of the traditional schools, built between the late 18th and 19th centuries, in Yazd was formed based on the active educational role of outdoor and semi-outdoor spaces, followed by the governing educational policies. Moreover, the outdoor and semi-outdoor spaces are not only the main spaces where social activities are held in schools, but also are complementary elements to the indoor educational spaces. Meanwhile, in modern schools, constructed in the early 20th century, and contemporary schools, constructed in the late 20th century, the spatial configuration of schools has changed and the importance of outdoor and semi-outdoor spaces in these schools has significantly devaluated due partially to the evolution of the modern educational system compared to traditional schools. By identifying the features of three different school building typologies, as well as their outdoor space functions, this paper provides useful knowledge for future school designing and planning in Yazd

A Comparative Study of the Configuration and Functions of Outdoor and Semi-Outdoor Space in Schools from the Traditional to the Contemporary Period Based on Evaluating the Role of the Governing Educational System

The present study, based on a case study, aims at addressing the functional and morphological evolutions in outdoor and semi-outdoor spaces in Yazd schools over time, through educational developments. The approach followed in this study is to connect the changes in the spatial structure of outdoor space in schools to the evolutions in the educational system. To this end, this paper develops five hypotheses and employs qualitative and computational research methods to evaluate the functions and spatial configuration of the outdoor spaces of six schools, constructed between the 18th and 20th CE centuries, in Yazd. A mathematical method drawn by “space syntax” is adopted to measure the spatial features of the outdoor spaces of schools, and a field study is used to identify the relationship between the functional process of these configurations and their governing educational principle. The results show that the configuration of the traditional schools, built between the late 18th and 19th centuries, in Yazd was formed based on the active educational role of outdoor and semi-outdoor spaces, followed by the governing educational policies. Moreover, the outdoor and semi-outdoor spaces are not only the main spaces where social activities are held in schools, but also are complementary elements to the indoor educational spaces. Meanwhile, in modern schools, constructed in the early 20th century, and contemporary schools, constructed in the late 20th century, the spatial configuration of schools has changed and the importance of outdoor and semi-outdoor spaces in these schools has significantly devaluated due partially to the evolution of the modern educational system compared to traditional schools. By identifying the features of three different school building typologies, as well as their outdoor space functions, this paper provides useful knowledge for future school designing and planning in Yazd

The physiology of fish behaviour: a selective review of developments over the past 40 years

During the past 40 years many new techniques have emerged that have been pivotal in furthering understanding of the physiology of fish behaviour. Behavioural studies have been enhanced by video recording systems and software for computerized event recording analysis, fine scale anatomical studies by fluorescence confocal microscopy, neurophysiological studies by visualisation and neuroendocrinology with techniques for identifying, localizing and quantifying many neurochemicals within the central nervous system. This array of approaches has been complemented by developments in molecular biology that include the ability to monitor expression profiles for known genes in specific neural structures and within the whole transcriptome. This article explores how the deployment of new techniques during the last four decades has advanced the understanding of two extensively studied systems. The first of these is the fast-start escape response, concentrating on work on goldfish Carassius auratus and zebrafish Danio rerio. The second is the link between social experience and neuroendocrinology and how this relates to life-history traits in the cichlid Burton's mouthbrooder Astatotilapia burtoni. These two case studies are then used to explore the extent to which the behaviour of animals can be explained in terms of underlying physiological mechanisms

Valsartan lowers brain β-amyloid protein levels and improves spatial learning in a mouse model of Alzheimer disease

Recent epidemiological evidence suggests that some antihypertensive medications may reduce the risk for Alzheimer disease (AD). We screened 55 clinically prescribed antihypertensive medications for AD-modifying activity using primary cortico-hippocampal neuron cultures generated from the Tg2576 AD mouse model. These agents represent all drug classes used for hypertension pharmacotherapy. We identified 7 candidate antihypertensive agents that significantly reduced AD-type β-amyloid protein (Aβ) accumulation. Through in vitro studies, we found that only 1 of the candidate drugs, valsartan, was capable of attenuating oligomerization of Aβ peptides into high-molecular-weight (HMW) oligomeric peptides, known to be involved in cognitive deterioration. We found that preventive treatment of Tg2576 mice with valsartan significantly reduced AD-type neuropathology and the content of soluble HMW extracellular oligomeric Aβ peptides in the brain. Most importantly, valsartan administration also attenuated the development of Aβ-mediated cognitive deterioration, even when delivered at a dose about 2-fold lower than that used for hypertension treatment in humans. These preclinical studies suggest that certain antihypertensive drugs may have AD-modifying activity and may protect against progressive Aβ-related memory deficits in subjects with AD or in those at high risk of developing AD