Neuronal dendrites must relay synaptic inputs over long distances, but the mechanisms by which activity-evoked intracellular signals propagate over macroscopic distances remain unclear. Here, we discovered a system of periodically arranged endoplasmic reticulum-plasma membrane (ER-PM) junctions tiling the plasma membrane of dendrites at ∼1 μm intervals, interlinked by a meshwork of ER tubules patterned in a ladder-like array. Populated with Junctophilin-linked plasma membrane voltage-gated Ca channels and ER Ca-release channels (ryanodine receptors), ER-PM junctions are hubs for ER-PM crosstalk, fine-tuning of Ca homeostasis, and local activation of the Ca/calmodulin-dependent protein kinase II.
View Article and Find Full Text PDFNociceptors are receptors that detect injurious stimuli and are necessary to convey such information from the periphery to the central nervous system. While nociception has been extensively studied in various taxa, there is relatively little electrophysiological evidence for the existence of nociceptors in decapod crustaceans. This study investigated putative nociceptive responses in the shore crabs, specifically their response to mechanical and noxious chemical stimuli.
View Article and Find Full Text PDFCoastal environments around the world are becoming increasingly hypoxic owing to anthropogenic effects. We hypothesized that, because the olfactory epithelium is in contact with the external environment, decreased external oxygen will impair olfaction. We performed electro-olfactograms on juvenile gilt-head seabream (Sparus aurata) and measured the response to three amino acids at five different concentrations (1×10-7 to 1×10-3 mol l-1) in normoxic (20 kPa O2) and two hypoxic conditions (12.
View Article and Find Full Text PDFSome cichlid fishes release urine-containing chemical cues that lower aggression in their opponents. Bioassays to identify the aggression-modulating pheromone include assessing the effect of urine fractions on the behavior towards a mirror image or in interactions with another male. However, many of these methods can be time-consuming and require many fish.
View Article and Find Full Text PDFVision provides animals with detailed information about their surroundings, conveying diverse features such as color, form, and movement across the visual scene. Computing these parallel spatial features requires a large and diverse network of neurons, such that in animals as distant as flies and humans, visual regions comprise half the brain's volume. These visual brain regions often reveal remarkable structure-function relationships, with neurons organized along spatial maps with shapes that directly relate to their roles in visual processing.
View Article and Find Full Text PDFThe current study investigated the structure and function of the olfactory system of the Lusitanian toadfish, Halobatrachus didactylus, using histology and electrophysiology (electro-olfactogram [EOG]), respectively. The olfactory system consists of a digitated anterior peduncle, of unknown function, containing the inhalant nostril. This then leads to a U-shaped olfactory chamber with the olfactory epithelium-identified by G-immunoreactivity-on the ventral surface.
View Article and Find Full Text PDFBackground: Neuroscience research in Drosophila is benefiting from large-scale connectomics efforts using electron microscopy (EM) to reveal all the neurons in a brain and their connections. To exploit this knowledge base, researchers relate a connectome's structure to neuronal function, often by studying individual neuron cell types. Vast libraries of fly driver lines expressing fluorescent reporter genes in sets of neurons have been created and imaged using confocal light microscopy (LM), enabling the targeting of neurons for experimentation.
View Article and Find Full Text PDFThe olfactory epithelium of fish is - of necessity - in intimate contact with the surrounding water. In euryhaline fish, movement from seawater to freshwater (and vice versa) exposes the epithelium to massive changes in salinity and ionic concentrations. How does the olfactory system function in the face of such changes? The current study compared olfactory sensitivity in seawater- (35‰) and brackish water-adapted seabass (5‰) using extracellular multi-unit recording from the olfactory nerve.
View Article and Find Full Text PDFEffects on the growth and reproduction of birds are important endpoints in the environmental risk assessment (ERA) of pesticides. Toxicokinetic-toxicodynamic models based on dynamic energy budget theory (DEB) are promising tools to predict these effects mechanistically and make extrapolations relevant to ERA. However, before DEB-TKTD models are accepted as part of ERA for birds, ecotoxicological case studies are required so that stakeholders can assess their capabilities.
View Article and Find Full Text PDFWorldwide, microplastic pollution has numerous negative implications for marine biota, exacerbating the effects of other forms of global anthropogenic disturbance. Mounting evidence shows that microplastics (MPs) not only cause physical damage through their ingestion, but also act as vectors for hazardous compounds by leaching absorbed and adsorbed chemicals. Research on the effects of plastic pollution has, however, largely assumed that species respond uniformly, while ignoring intraspecific diversity (i.
View Article and Find Full Text PDFChemical cues provide potential mates with information about reproductive status and resource-holding potential. In the Mozambique tilapia (Oreochromis mossambicus), males can distinguish female reproductive status through chemical cues, and accessibility of males to females depends on their position in the hierarchy, determined in part by chemical cues. Here, we hypothesized that tilapia faecal cues are attractive to conspecifics once released into the water.
View Article and Find Full Text PDFCOVID-19 had sudden and dramatic impacts on the organisation and governance of urban life. In Part 2 of this Special Issue on public health emergencies we question the extent to which the pandemic ushered in fundamentally new understandings of urban public health, noting that ideas of urban pathology and the relation of dirt, disease and danger in cities, have long informed practices of planning. Emphasising important continuities in the way pandemics are associated with minoritised and vulnerable groups, past and present, we note that public health initiatives can often exacerbate existing health divides, and actually deepen health crises.
View Article and Find Full Text PDFCOVID-19 has had unprecedented impacts on urban life on a global scale, representing the worst pandemic in living memory. In this introduction to the first of two parts of a Special Issue on urban public health emergencies, we suggest that the COVID-19 outbreak, and associated attempts to manage the pandemic, reproduced and ultimately exacerbated the social and spatial divides that striate the contemporary city. Here, we draw on evidence from the papers in Part 1 of the Special Issue to summarise the uneven urban geographies of COVID-19 evident at the inter- and intra-urban level, emphasising the particular vulnerabilities and risks borne by racialised workers who found it difficult to practise social distancing in either their home or working life.
View Article and Find Full Text PDFJ Comp Physiol A Neuroethol Sens Neural Behav Physiol
May 2023
The sensing of chemical cues is essential for several aspects of bivalve biology, such as the detection of food and pheromones. However, little is known about chemical communication systems in bivalves or the possible role of the osphradium as a chemosensory organ. To address this, we adapted an electrophysiological technique extensively used in vertebrates-the electro-olfactogram-to record from the osphradium in the Pacific oyster, Magallana gigas.
View Article and Find Full Text PDFQuantitative dynamic strain measurements of the ground would be useful for engineering scale problems such as monitoring for natural hazards, soil-structure interaction studies, and non-invasive site investigation using full waveform inversion (FWI). Distributed acoustic sensing (DAS), a promising technology for these purposes, needs to be better understood in terms of its directional sensitivity, spatial position, and amplitude for application to engineering-scale problems. This study investigates whether the physical measurements made using DAS are consistent with the theoretical transfer function, reception patterns, and experimental measurements of ground strain made by geophones.
View Article and Find Full Text PDFExposure to high PCO2/low pH seawater induces behavioural alterations in fish; a possible explanation for this is a reversal of Cl-/HCO3- currents through GABAA receptors (the GABAA receptor theory). However, the main evidence for this is that gabazine, a GABAA receptor antagonist, reverses these effects when applied to the water, assuming that exposure to systems other than the CNS would be without effect. Here, we show the expression of both metabotropic and ionotropic GABA receptors, and the presence of GABAA receptor protein, in the olfactory epithelium of gilthead seabream.
View Article and Find Full Text PDFNewcastle University UK operates an international campus, NUMed, in Malaysia. NUMed delivers the same medical degree programme as in the UK, within a different cultural context. In this paper, medical education faculty and NUMed graduates with experience working in both the UK and Malaysia provide insights into cross-cultural diversity in approaches to learning.
View Article and Find Full Text PDFIn the past decade, many studies have investigated the effects of low pH/high CO2 as a proxy for ocean acidification on olfactory-mediated behaviours of marine organisms. The effects of ocean acidification on the behaviour of fish vary from very large to none at all, and most of the maladaptive behaviours observed have been attributed to changes in acid-base regulation, leading to changes in ion distribution over neural membranes, and consequently affecting the functioning of gamma-aminobutyric acid-mediated (GABAergic) neurotransmission. Here, we highlight a possible additional mechanism by which ocean acidification might directly affect olfaction in marine fish and invertebrates.
View Article and Find Full Text PDFOcean acidification may alter olfactory-driven behaviour in fish by direct effects on the peripheral olfactory system; olfactory sensitivity is reduced in CO-acidified seawater. The current study tested whether this is due to elevated or the consequent reduction in seawater pH and, if the former, the possible involvement of carbonic anhydrase, the enzyme responsible for the hydration of CO and production of carbonic acid. Olfactory sensitivity to amino acids was assessed by extracellular multi-unit recording from the olfactory nerve of the gilthead seabream ( L.
View Article and Find Full Text PDFFishes show remarkably diverse aggressive behaviour. Aggression is expressed to secure resources; adjusting aggression levels according to context is key to avoid negative consequences for fitness and survival. Nonetheless, despite its importance, the physiological basis of aggression in fishes is still poorly understood.
View Article and Find Full Text PDFRecent studies have shown that ocean acidification affects olfactory-driven behavior in fish. This may be due in part to a reduction in olfactory sensitivity in high PCO2/low pH water. To assess the effects of ocean acidification, or olfactory sensitivity in marine fish in general, we propose that extracellular multi-unit recording from the olfactory nerve is the method of choice.
View Article and Find Full Text PDFThe neural circuits responsible for animal behavior remain largely unknown. We summarize new methods and present the circuitry of a large fraction of the brain of the fruit fly . Improved methods include new procedures to prepare, image, align, segment, find synapses in, and proofread such large data sets.
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