Physiological Paradigms Research Articles

Physiological paradigm for assessing reward prediction and extinction using cortical direct current potential responses in rats

Anticipating positive outcomes is a core cognitive function in the process of reward prediction. However, no neurophysiological method objectively assesses reward prediction in basic medical research. In the present study, we established a physiological paradigm using cortical direct current (DC) potential responses in rats to assess reward prediction. This paradigm consisted of five daily 1-h sessions with two tones, wherein the rewarded tone was followed by electrical stimulation of the medial forebrain bundle (MFB) scheduled at 1000 ms later, whereas the unrewarded tone was not. On day 1, both tones induced a negative DC shift immediately after auditory responses, persisting up to MFB stimulation. This negative shift progressively increased and peaked on day 4. Starting from day 3, the negative shift from 600 to 1000 ms was significantly larger following the rewarded tone than that following the unrewarded tone. This negative DC shift was particularly prominent in the frontal cortex, suggesting its crucial role in discriminative reward prediction. During the extinction sessions, the shift diminished significantly on extinction day 1. These findings suggest that cortical DC potential is related to reward prediction and could be a valuable tool for evaluating animal models of depression, providing a testing system for anhedonia.

1 The role of gut microbiota on regulation of growth and metabolism by branched-chain amino acids

Abstract Branched-chain amino acids (BCAA) including leucine, isoleucine and valine are essential amino acids, which are involved in energy homeostasis and regulation of many physiological paradigms including growth. The BCAA serve not only as an essential substrate in the synthesis of body proteins, but also have an important role in regulation of protein turnover. The effects of BCAA on growth and metabolism are likely mediated through different pathways including shifts in metabolic profile in peripheral organs, oxidative capacity of muscle, gut development, and protein metabolism in muscle. Although it has not been appropriately studied or fully dissected, the impact of BCAA on growth and metabolism is thought to lie in the alteration of gut microbiota by BCAA. It has long been believed that gut microbiota, more specifically, the activity of the microbiome and its metabolic products, directly influence a variety of aspects in metazoan physiology. For example, deregulation of bacterial community structure has been linked with host longevity and stress resistance, the pathogenesis of several disorders, regulation of appetite. Multiple studies have demonstrated that modulation of dietary BCAA levels could elicit clear shifts in gut microbial community structure. As part of “Physiology Symposium: The Microbiome and the Host: Functional Role in Metabolism, Immunity, and Gut-Brain Axis”, the possible involvement of intestinal microbiota on regulatory roles of BCAA on growth and metabolism will be discussed.

Rearing Conditions and Automated Feed Distribution Systems for Zebrafish (Danio rerio)

Zebrafish (Danio rerio) is a well-established animal model, used in a number of research areas. In the last decade, it has also emerged as a tool to evaluate the effects of diets and dietary components and to test novel paradigms in nutrigenomics, nutrigenetics, and nutritional physiology. Despite its worldwide use, the standardization of the zebrafish rearing conditions, including daily nutritional and good feed management practices, is not yet achieved. This is surprising when compared with what is available for other reared animals, such as rodents or other (e.g., commercial) fishes. To date, a major applicative goal in zebrafish nutritional physiology research is to define common, standard, and reproducible protocols of rearing and feeding conditions to generate reliable and comparable results among research laboratories. This review aims to focus on limitations and disadvantages of the current rearing and feeding practices and on some recent technological solutions provided by research groups and/or biotech companies in the field of facility design, with emphasis on automated feeding distribution systems. A general overview of some common schemes of zebrafish husbandry is also given.

Vis materiai. The paradigm of the living and the poetics of matter in the De Rerum Natura of Lucretia

The study focuses on some points of the poetics used by Lucretius in the De rerum natura to express the living. The didactic mission claimed by the poet indeed requires the elaboration of a language of a vivid expressiveness and a flawless clarity to transmit the Epicurean doctrine. This is a difficult task when it comes to the birth of the living, which is conceived from inanimate atoms. We examine here the place held by the physiological paradigm through two recurrent motifs on this subject, birth and fluidity. Lucretius proves to be a virtuoso, knowing how to combine all sorts of mechanisms of language and poetic music in order to mobilize the mind of his reader. Building his poetics, he never dissociates his work from the fundamental principles of the doctrine he transmits: such as the concilium and the clinamen. We discover a re-evaluation of the didactic word, where the literary memory constitutes more than an intertext but becomes the material to be recomposed, even inflected, for the benefit of the dogma expounded and in close coherence with it.

Rainfall pulse regime drives biomass and community composition in biological soil crusts.

Future climates will alter the frequency and size of rain events in drylands, potentially affecting soil microbes that generate carbon feedbacks to climate, but field tests are rare. Topsoils in drylands are commonly colonized by biological soil crusts (biocrusts), photosynthesis-based communities that provide services ranging from soil fertilization to stabilization against erosion. We quantified responses of biocrust microbial communities to 12 years of altered rainfall regimes, with 60 mm of additional rain per year delivered either as small (5 mm) weekly rains or large (20 mm) monthly rains during the summer monsoon season. Rain addition promoted microbial diversity, suppressed the dominant cyanobacterium, Microcoleus vaginatus, and enhanced nitrogen-fixing taxa, but did not consistently increase microbial biomass. The addition of many small rain events increased microbial biomass, whereas few, large events did not. These results alter the physiological paradigm that biocrusts are most limited by the amount of rainfall and instead predict that regimes enriched in small rain events will boost cyanobacterial biocrusts and enhance their beneficial services to drylands.

Murburn model of vision: Precepts and proof of concept.

The classical paradigm of visual physiology comprises of the following features: (i) rod/cone cells located at the rear end of the retina serve as the primary transducers of incoming photo-information, (ii) cis-trans retinal (C20 H28 O) transformations on rhodopsin act as the transduction switch to generate a transmittable signal, (iii) signal amplification occurs via GDP-GTP exchange at transducin, and (iv) the amplified signal is relayed (as an action potential) as a flux-based ripple of Na-K ions along the axons of neurons. Fundamental physical principles, chemical kinetics, and awareness of architecture of eye/retina prompt a questioning of these classical assumptions. In lieu, based on experimental and in silico findings, a simple space-time resolved murburn model for the physiology of phototransduction in the retina is presented wherein molecular oxygen plays key roles. It is advocated that: (a) photo-induced oxygen to superoxide conversion serves as the key step in signal transduction in the visual cycle, (b) all photoactive cells of the retina serve as photoreceptors and rods/cones serve as the ultimate electron source in the retina (deriving oxygen and nutrients from retinal pigmented epithelium), (c) signal amplification is through superoxide mediated phosphorylation of GDP bound to inactive transducin, thereby activating a GDP-based cascade (a new mechanism for trimeric G-proteins), and (d) signal relay is primarily an electron movement along the neuron, from dendritic source to synaptic sink. In particular, we specify the roles for the various modules of transducin and GDP-based activation of phosphodiesterase-6 in the physiology of visual transduction.

Genetics of Normotension Preventing Hypertension Leads to a Novel Physiological Paradigm.

Possessing blood pressure in normal ranges is considered healthy, and does not warrant medical attention for obvious clinical reasons. However, to realize normotension and then maintain it even when confronted with a hypertensive threat must have its biological 'shield of armour'. While sensitivity to hypertension has been widely recognized and studied, inherent mechanisms that enable a physiological resistance to hypertension to occur have received little attention. Recent advances in normotension genetics have produced unexpected insights. A hypertension 'suppressor' likely inhabits the normotensive genome of inbred Lewis rats. This suppressor behaves as a 'master' control capable of functionally abrogating the effects of hypertension-promoting alleles from multiple quantitative trait loci. This conceptual advancement lays the foundation for uncovering an anti-hypertension gene. Discovering its identity will assist our attempts at developing innovative diagnostic and therapeutic strategies for circumventing and treating hypertension. This new domain of suppressing hypertension goes beyond the conventional pharmacological treatments of hypertension before symptoms appear. For this purpose, a valid theoretical basis and framework is needed that can interpret the experimental data and produce testable predictions for authenticating, enriching or amending the normotension paradigm in the future.

Looking to the future: Building New Paradigms in Comparative Physiology and Biomechanics

Looking to the future: Building New Paradigms in Comparative Physiology and Biomechanics

Recognising our community as we head towards JEB's centenary in 2023.

Recognising our community as we head towards JEB's centenary in 2023.

Biological Prescience: The Role of Anticipation in Organismal Processes.

Anticipation is the act of using information about the past and present to make predictions about future scenarios. As a concept, it is predominantly associated with the psychology of the human mind; however, there is accumulating evidence that diverse taxa without complex neural systems, and even biochemical networks themselves, can respond to perceived future conditions. Although anticipatory processes, such as circadian rhythms, stress priming, and cephalic responses, have been extensively studied over the last three centuries, newer research on anticipatory genetic networks in microbial species shows that anticipatory processes are widespread, evolutionarily old, and not simply reserved for neurological complex organisms. Overall, data suggest that anticipatory responses represent a unique type of biological processes that can be distinguished based on their organizational properties and mechanisms. Unfortunately, an empirically based biologically explicit framework for describing anticipatory processes does not currently exist. This review attempts to fill this void by discussing the existing examples of anticipatory processes in non-cognitive organisms, providing potential criteria for defining anticipatory processes, as well as their putative mechanisms, and drawing attention to the often-overlooked role of anticipation in the evolution of physiological systems. Ultimately, a case is made for incorporating an anticipatory framework into the existing physiological paradigm to advance our understanding of complex biological processes.

FNIRS Evaluation of Frontal and Temporal Cortex Activation by Verbal Fluency Task and High-Level Cognition Task for Detecting Anxiety and Depression.

Anxiety and depression are widespread psychosis which are believed to affect cerebral metabolism, especially in frontal and temporal cortex. The comorbidity patients of anxiety and depression (A&D) have more serious clinical symptoms. Functional near-infrared spectroscopy (fNIRS) is a noninvasive modality used to monitor human brain oxygenation, and it could be considered as a potential tool to detect psychosis which may lead to abnormal cerebral oxygen status when the brain is activated. However, how sensitive the cerebral oxygenation response to the cortex activation and whether these responses are consistent at different stages of A&D or different regions still remains unclear. In this study, a conventional physiological paradigm for cortex activation, i.e., verbal fluency task (VFT), and a relatively new paradigm, i.e., high-level cognition task (HCT), were compared to detect A&D through a longitudinal measurement of cerebral oxygen status by fNIRS. The A&D patients at the acute, consolidation and maintenance stages as well as the healthy subjects participated in the VFT and HCT paradigms, respectively. For the VTF paradigm, the subject was instructed to answer questions of phrase constructions within 60 s. For the HCT paradigm, the subject was instructed to categorize items, logical reasoning, and comprehensive judgment and write down the answers within 60 s. For most of the subjects, the oxy-Hb is found to increase remarkably, accompanied with a relatively small reduction in deoxy-Hb when subject to both paradigms. The statistical analyses show a relatively large variability within any group, leading to the significant difference that was only found between A&D at the acute stage and healthy subjects in the temporal lobe region (p < 0.001). Nevertheless, HCT would activate more oxygen increment when compared with the VFT, with a large integral value in oxy-Hb. On average, the oxy-Hb integral value of the A&D patients differs substantially at different stages when subject to HCT paradigm. Moreover, the prefrontal lobe and temporal lobe responses were more consistent to the HCT paradigm rather than the VFT paradigm. Under the VFT paradigm, however, no remarkable difference in integral value was found among the three stages, either at the prefrontal lobe or at the temporal lobe. This study indicated that HCT, which is intensively involved in brain function, would activate more oxygenation changes in the cerebral cortex. Additionally, with good performance at distinguishing different stages according to the oxy-Hb criterion, the HCT has the potential to evaluate the therapeutic effects for A&D patients.

Imaging of multiple fluorescent proteins in canopies enables synthetic biology in plants.

SummaryReverse genetics approaches have revolutionized plant biology and agriculture. Phenomics has the prospect of bridging plant phenotypes with genes, including transgenes, to transform agricultural fields. Genetically encoded fluorescent proteins (FPs) have revolutionized plant biology paradigms in gene expression, protein trafficking and plant physiology. While the first instance of plant canopy imaging of green fluorescent protein (GFP) was performed over 25 years ago, modern phenomics has largely ignored fluorescence as a transgene expression device despite the burgeoning FP colour palette available to plant biologists. Here, we show a new platform for stand‐off imaging of plant canopies expressing a wide variety of FP genes. The platform—the fluorescence‐inducing laser projector (FILP)—uses an ultra‐low‐noise camera to image a scene illuminated by compact diode lasers of various colours, coupled with emission filters to resolve individual FPs, to phenotype transgenic plants expressing FP genes. Each of the 20 FPs screened in plants were imaged at >3 m using FILP in a laboratory‐based laser range. We also show that pairs of co‐expressed fluorescence proteins can be imaged in canopies. The FILP system enabled a rapid synthetic promoter screen: starting from 2000 synthetic promoters transfected into protoplasts to FILP‐imaged agroinfiltrated Nicotiana benthamiana plants in a matter of weeks, which was useful to characterize a water stress‐inducible synthetic promoter. FILP canopy imaging was also accomplished for stably transformed GFP potato and in a split‐GFP assay, which illustrates the flexibility of the instrument for analysing fluorescence signals in plant canopies.

Musical meaning and indexicality in the analysis of ceremonial mbira music

Abstract In this essay I examine three different indexical processes that inform meaning during a mbira performance in Zimbabwe in order to clarify the nature of meaning in musical practice. I continue others’ efforts to provincialize language and correct the damage done by “symbolocentrism’s” continued reliance on post-Saussurian models of signification and structure by addressing processes of purpose, effect, and agency in meaning. Emphases on language and/or structure mislead explanations of musical meaning and compromise the understanding of meaning itself. By foregrounding the unique properties of indexicality in musical practice, and highlighting three distinct indexical processes that drive music’s meaning (deictic, metonym, and replica), I help free meaning from language and offer an ethnomusicological counterpoint to multidisciplinary efforts that define meaning within linguistic and physiological paradigms. Indexical meaning is direct but unpredictable, rooted in experience, embodied habits, and the here and now.

Intelligible nonnative-accented speech incurs a processing cost: Converging evidence from a behavioral and a physiological paradigm

In noisy settings or when listening to an unfamiliar talker or accent, it may be difficult to understand spoken language. This difficulty can result in reductions in speech intelligibility, but may also increase the effort necessary to process the speech. In the current study we used a dual-task paradigm and pupillometry to assess the cognitive costs associated with processing fully intelligible accented speech, predicting that participants would expend greater effort when processing nonnative-accented speech, and that this cost would be attenuated over time. Consistent with our hypothesis, the behavioral and physiological paradigms provided converging evidence that listeners expend greater effort when processing nonnative- relative to native-accented speech. We also observed an overall reduction in listening effort over the course of the experiment and found some evidence for greater perceptual adaptation to nonnative-accented speech. These results suggest that even when speech is fully intelligible, resolving deviations between the acoustic input and stored lexical representations incurs a processing cost, and adaptation may attenuate this cost.

The Effect of Extracranial-to-Intracranial Bypass on Cerebral Vasoreactivity: A 4D Flow MRI Pilot Study.

Extracranial-to-intracranial (EC-IC) surgical bypass improves cerebral blood flow (CBF) and cerebrovascular vasoreactivity (CVR) for patients with carotid occlusion. Bypass graft patency and contribution of the graft to the postoperative increase in CVR are challenging to assess. To assess the effectiveness of 4D flow magnetic resonance imaging (MRI) to evaluate bypass graft patency and flow augmentation through the superficial temporal artery (STA) before and after EC-IC bypass. Three consecutive patients undergoing EC-IC bypass for carotid occlusion were evaluated pre- and postoperatively using CVR testing with pre- and poststimulus 4D flow-MRI for assessment of the bypass graft and intracranial vasculature. Preoperatively, 2 patients (patients 1 and 3) did not augment flow through either native STA. The third, who had evidence of extensive native EC-IC collateralization on digital subtraction angiography (DSA), did augment flow through the STA preoperatively (CVR = 1). Postoperatively, all patients demonstrated CVR > 1 on the side of bypass. The patient who had CVR > 1 preoperatively demonstrated the greatest increase in resting postoperative graft flow (from 40 to 130 mL/minute), but the smallest CVR, with a poststimulus graft flow of 160 mL/minute (CVR = 1.2). The 2 patients who did not demonstrate augmentation of graft flow preoperatively augmented postoperatively from 10 to 20 mL/minute (CVR = 2.0) and 10-80 mL/minute (CVR = 8.0), respectively. Intracranial flow was simultaneously interrogated. Two patients demonstrated mild reductions in resting flow velocities in all interrogated vessels immediately following bypass. The patient who underwent CVR testing on postoperative day 48 demonstrated a stable or increased flow rate in most intracranial vessels. Four-dimensional flow MRI allows for noninvasive, simultaneous interrogation of the intra- and extracranial arterial vasculature during CVR testing, and reveals unique paradigms in cerebrovascular physiology. Observing these flow patterns may aid in improved patient selection and more detailed postoperative evaluation for patients undergoing EC-IC bypass.

Rapid adaptation to fully intelligible nonnative-accented speech reduces listening effort.

In noisy settings or when listening to an unfamiliar talker or accent, it can be difficult to understand spoken language. This difficulty typically results in reductions in speech intelligibility, but may also increase the effort necessary to process the speech even when intelligibility is unaffected. In this study, we used a dual-task paradigm and pupillometry to assess the cognitive costs associated with processing fully intelligible accented speech, predicting that rapid perceptual adaptation to an accent would result in decreased listening effort over time. The behavioural and physiological paradigms provided converging evidence that listeners expend greater effort when processing nonnative- relative to native-accented speech, and both experiments also revealed an overall reduction in listening effort over the course of the experiment. Only the pupillometry experiment, however, revealed greater adaptation to nonnative- relative to native-accented speech. An exploratory analysis of the dual-task data that attempted to minimise practice effects revealed weak evidence for greater adaptation to the nonnative accent. These results suggest that even when speech is fully intelligible, resolving deviations between the acoustic input and stored lexical representations incurs a processing cost, and adaptation may attenuate this cost.

Multilevel assessment of mental stress via network physiology paradigm using consumer wearable devices

Mental stress is a physiological condition that has a strong negative impact on the quality of life, affecting both the physical and the mental health. For such a reason, accurate measurements of stress level can be helpful to provide mechanisms for prevention and treatment. This paper proposes a procedure for the classification of different mental stress levels by using physiological signals provided by low invasive wearable devices. 17 healthy volunteers participated in this study. Three different mental states were elicited in them: a resting condition, a stressful cognitive state, and a sustained attention task. The acquired physiological signals were: a one lead electrocardiogram (ECG), a respiratory signal, a blood volume pulse (BVP), and 14 channels of a 10–20 electroencephalogram (EEG). For all subjects, 59 time series of 300 samples each were structured by including the RR series, the respiratory series, the pulse arrival time (PAT) series, and the delta, theta, alpha, beta power series of the 14 EEG channels. Different classifiers were implemented to assess the mental stress level starting from a pool of 3481 features computed from the aforementioned physiological quantities, using the Network Physiology paradigm. The highest achieved accuracy was 84.6%, from logistic regression and random forest classifiers, cross validated by mean of leave-one-person-out analysis. A further analysis was carried out to evaluate the classification accuracy using only cardio-respiratory signals, since the latter are more suitable to be used in real-life scenarios. In this case, the highest achieved accuracy was 76.5% obtained by the random forest classifier.

Information Dynamics of the Brain, Cardiovascular and Respiratory Network during Different Levels of Mental Stress.

In this study, an analysis of brain, cardiovascular and respiratory dynamics was conducted combining information-theoretic measures with the Network Physiology paradigm during different levels of mental stress. Starting from low invasive recordings of electroencephalographic, electrocardiographic, respiratory, and blood volume pulse signals, the dynamical activity of seven physiological systems was probed with one-second time resolution measuring the time series of the , , and brain wave amplitudes, the cardiac period (RR interval), the respiratory amplitude, and the duration of blood pressure wave propagation (pulse arrival time, PAT). Synchronous 5-min windows of these time series, obtained from 18 subjects during resting wakefulness (REST), mental stress induced by mental arithmetic (MA) and sustained attention induced by serious game (SG), were taken to describe the dynamics of the nodes composing the observed physiological network. Network activity and connectivity were then assessed in the framework of information dynamics computing the new information generated by each node, the information dynamically stored in it, and the information transferred to it from the other network nodes. Moreover, the network topology was investigated using directed measures of conditional information transfer and assessing their statistical significance. We found that all network nodes dynamically produce and store significant amounts of information, with the new information being prevalent in the brain systems and the information storage being prevalent in the peripheral systems. The transition from REST to MA was associated with an increase of the new information produced by the respiratory signal time series (RESP), and that from MA to SG with a decrease of the new information produced by PAT. Each network node received a significant amount of information from the other nodes, with the highest amount transferred to RR and the lowest transferred to , , and . The topology of the physiological network underlying such information transfer was node- and state-dependent, with the peripheral subnetwork showing interactions from RR to PAT and between RESP and RR, PAT consistently across states, the brain subnetwork resulting more connected during MA, and the subnetwork of brain–peripheral interactions involving different brain rhythms in the three states and resulting primarily activated during MA. These results have both physiological relevance as regards the interpretation of central and autonomic effects on cardiovascular and respiratory variability, and practical relevance as regards the identification of features useful for the automatic distinction of different mental states.

Altings adskillelse – Om Surrealismens fysiologiske æstetik: Da Man Ray mødte Étienne-Jules Marey

ALL THINGS SEPARATE - THE PHYSIOLOGICAL AESTHETICS OF THE SURREALISM. MAN RAY MEETS ÉTIENNE-JULES MAREY&#x0D; The article examines the interrelation of the chrono-photographical work of the French physiologist Étienne-Jules Marey and the avant-garde aesthetics of the surrealist photographer and filmmaker Man Ray. In his 1926 film Emak Bakia, Man Ray appropriated the visual idiom of Marey’s studies in comparative physiology as he paraphrased the technique of chrono-photography. The article argues that this appropriation cannot be properly understood simply on the level of form or visual style. Rather, it attests to a fundamental discussion of the organismic a-priori inherent in Marey’s visual technique—what to Man Ray corresponded to a paradigm of the organism and its body. The article contends that Man Ray was critiquing Marey’s notion of the body as motor and as something that could be analytically cut into discrete slices. To Man Ray, this physiological paradigm—keyed into chrono-photography itself—was built upon a repression of the notion of organic formlessness.

The components of the adolescent brain and its unique sensitivity to sexually explicit material

IntroductionThe focus of this brief literature review is to explore whether there is a relationship between the unique anatomical and physiological paradigms of the adolescent brain and an increased sensitivity to sexually explicit material. MethodsThe EBSCO Research Data bases were searched using the following key terms: adolescence, adolescent brain development, neuroplasticity, sexually explicit material, sexualization, and pornography. ResultsThe literature highlighted several components of the adolescent brain that are different than the mature brain. These include: an immature prefrontal cortex and over-responsive limbic and striatal circuits, heightened period for neuroplasticity, overactive dopamine system, a pronounced HPA axis, augmented levels of testosterone, and the unique impact of steroid hormones. The physiological response to sexually explicit material is delineated. The overlap of key areas associated with the unique adolescent brain development and sexually explicit material is noteworthy. A working model summary that compares the response of the adult and adolescent brain to the same sexually explicit stimulus is outlined. ConclusionsThe literature suggests that the adolescent brain may indeed be more sensitive to sexually explicit material, but due to a lack of empirical studies this question cannot be answered definitively. Suggestions for future research are given to further advance the work in this applicable field of today.