nils-herrmann/clean_scirepeval huggingface dataset:
Responses of a pair of flying locusts to lateral looming visual stimuli
Venue: Journal of Comparative Physiology A

We presented a pair of locusts flying loosely tethered with laterally looming discs. Two experiments tested whether looming-evoked flight behaviour was affected by the presence (1) or relative position (2) of a conspecific. We recorded: the type of behavioural response, motion within 6 degrees of freedom, behavioural onset time and duration, distance between individuals and relative direction of motion. Response distributions of the locust furthest from the stimulus (L1) were not affected by the presence or relative position of a conspecific, whereas distributions of the closer locust (L2) were affected by its position relative to the stimulus. Motion tracks of L1 were affected by the presence of L2, which generated relatively robust responses directed forward and away from the stimulus. Translational and rotational motion of L1 differed across treatments in both experiments, whereas L2 motion was less sensitive to the presence or position of a conspecific. The start and duration of the behaviour were invariant to the presence or position of a conspecific and locust pairs maintained a fixed distance during responses to looming. Results suggest that looming-evoked behaviour is influenced by visual cues from a conspecific in the vicinity.
Walking Drosophila align with the e-vector of linearly polarized light through directed modulation of angular acceleration
Venue: Journal of Comparative Physiology A

Understanding the mechanisms that link sensory stimuli to animal behavior is a central challenge in neuroscience. The quantitative description of behavioral responses to defined stimuli has led to a rich understanding of different behavioral strategies in many species. One important navigational cue perceived by many vertebrates and insects is the e-vector orientation of linearly polarized light. Drosophila manifests an innate orientation response to this cue (‘polarotaxis’), aligning its body axis with the e-vector field. We have established a population-based behavioral paradigm for the genetic dissection of neural circuits guiding polarotaxis to both celestial as well as reflected polarized stimuli. However, the behavioral mechanisms by which flies align with a linearly polarized stimulus remain unknown. Here, we present a detailed quantitative description of Drosophila polarotaxis, systematically measuring behavioral parameters that are modulated by the stimulus. We show that angular acceleration is modulated during alignment, and this single parameter may be sufficient for alignment. Furthermore, using monocular deprivation, we show that each eye is necessary for modulating turns in the ipsilateral direction. This analysis lays the foundation for understanding how neural circuits guide these important visual behaviors.
High-throughput phenotypic assessment of cardiac physiology in four commonly used inbred mouse strains
Venue: Journal of Comparative Physiology B

Mice with genetic alterations are used in heart research as model systems of human diseases. In the last decade there was a marked increase in the recognition of genetic diversity within inbred mouse strains. Increasing numbers of inbred mouse strains and substrains and analytical variation of cardiac phenotyping methods require reproducible, high-throughput methods to standardize murine cardiovascular physiology. We describe methods for non-invasive, reliable, easy and fast to perform echocardiography and electrocardiography on awake mice. This method can be used for primary screening of the murine cardiovascular system in large-scale analysis. We provide insights into the physiological divergence of C57BL/6N, C57BL/6J, C3HeB/FeJ and 129P2/OlaHsd mouse hearts and define the expected normal values. Our report highlights that compared to the other three strains tested C57BL/6N hearts reveal features of heart failure such as hypertrophy and reduced contractile function. We found several features of the mouse ECG to be under genetic control and obtained several strain-specific differences in cardiac structure and function.
Development and plasticity of mitochondria and electrical properties of the cell membrane in blowfly photoreceptors
Venue: Journal of Comparative Physiology A

Blowfly photoreceptors are highly energy demanding sensory systems. Their information processing efficiency is enabled by the high temporal resolution of the cell membrane, requiring heavy metabolic support by the mitochondria. We studied the developmental changes of the mitochondrial apparatus and electrical properties of the photoreceptor membrane in the white eyed Calliphora vicina Chalky. Using in vivo microspectrophotometry and Western blot analysis, we found an age-dependent increase in the concentration of mitochondrial pigments. The maximal change occurred during the first week. The age-related changes were smaller in dark-bred than in light-bred flies. The mitochondrial pigment content increased after the switch from dark to light rearing and decreased after the switch from light to dark rearing. The electrical parameters of the photoreceptors were investigated with intracellular recordings. The resting membrane resistance and time constant decreased significantly after eclosion. The decrease was again most significant during the first week of adult life, paralleled with changes in the Na/K pump-dependent hyperpolarizing afterpotential. We conclude that the photoreceptor mitochondria exhibit remarkable ontogenetic and phenotypic plasticity, because the quantity of mitochondrial pigments tightly follows the development of the cell membrane as well as the energy demands of the photoreceptors under different rearing conditions.
Cognitive components of color vision in honey bees: how conditioning variables modulate color learning and discrimination
Venue: Journal of Comparative Physiology A

Since the demonstration of color vision in honey bees 100 years ago by Karl von Frisch, appetitive conditioning to color targets has been used as the principal way to access behavioral aspects of bee color vision. Yet, analyses on how conditioning parameters affect color perception remained scarce. Conclusions on bee color vision have often been made without referring them to the experimental context in which they were obtained, and thus presented as absolute facts instead of realizing that subtle variations in conditioning procedures might yield different results. Here, we review evidence showing that color learning and discrimination in bees are not governed by immutable properties of their visual system, but depend on how the insects are trained and thus learn a task. The use of absolute or differential conditioning protocols, the presence of aversive reinforcement in differential conditioning and the degrees of freedom of motor components determine dramatic variations in color discrimination. We, thus, suggest top-down attentional modulation of color vision to explain the changes in color learning and discrimination reviewed here. We discuss the possible neural mechanisms of this modulation and conclude that color vision experiments require a careful consideration of how training parameters shape behavioral responses.
African clawed toads (Xenopus laevis) sense the distance of lateral line stimuli
Venue: Journal of Comparative Physiology A

Sighted African clawed toads use their lateral lines to detect stimulus distance, although accuracy and precision are poorer than for stimulus direction. Single surface wave trains elicited discrete turns and/or swims towards the wave origin. Most responses were brief, ending with the toad stationary (70 % overall; 54–86 % individual toads) or pausing before turning away (11 %; 1–24 %). Lunges or capturing movements with the arms (13 %; 10–22 %) also indicated where toads expected to find prey. Overall, 94 % (88–100 %) of oriented responses had well-defined endpoints. Swim distance—measured as means, medians, and upper and lower quartiles—and the number of bilateral leg kicks increased with stimulus distance. Swim distance also depended upon stimulus angle due to features of turning. Most responses (81 %; 62–92 %) ended short of the wave origin. Regression slopes were 0.45 ± 0.04 mm/mm for stimulus distances up to 85 mm (ca. 2–3x body lengths), 0.16 ± 0.07 mm/mm for distances of 85–130 mm, and non-significant for larger distances to 220 mm. Slopes were steeper for responses that included lunges or capture movements. In only 15 % (3–26 %) of responses were both turn direction and swim distance sufficiently accurate for the toad to sweep through the wave origin.
Linking physiological and cellular responses to thermal stress: β-adrenergic blockade reduces the heat shock response in fish
Venue: Journal of Comparative Physiology B

When faced with stress, animals use physiological and cellular strategies to preserve homeostasis. We were interested in how these high-level stress responses are integrated at the level of the whole animal. Here, we investigated the capacity of the physiological stress response, and specifically the β-adrenergic response, to affect the induction of the cellular heat shock proteins, HSPs, following a thermal stress in vivo. We predicted that blocking β-adrenergic stimulation during an acute heat stress in the whole animal would result in reduced levels of HSPs in red blood cells (RBCs) of rainbow trout compared to animals where adrenergic signaling remained intact. We first determined that a 1 h heat shock at 25 °C in trout acclimated to 13 °C resulted in RBC adrenergic stimulation as determined by a significant increase in cell swelling, a hallmark of the β-adrenergic response. A whole animal injection with the β2-adrenergic antagonist, ICI-118,551, successfully reduced this heat-induced RBC swelling. The acute heat shock caused a significant induction of HSP70 in RBCs of 13 °C-acclimated trout as well as a significant increase in plasma catecholamines. When heat-shocked fish were treated with ICI-118,551, we observed a significant attenuation of the HSP70 response. We conclude that circulating catecholamines influence the cellular heat shock response in rainbow trout RBCs, demonstrating physiological/hormonal control of the cellular stress response.
Photoperiodic induction of pre-migratory phenotype in a migratory songbird: identification of metabolic proteins in flight muscles
Venue: Journal of Comparative Physiology B

Migratory birds need to undergo physiological changes during their preparation for migration. The current study characterized those changes in photoperiodic migratory black-headed buntings (Emberiza melanocephala), which initiate their northward spring migration in response to increasing day lengths. We measured differences in body mass, testis size and triglycerides levels in buntings between groups exposed to short (8 h light:16 h darkness, 8L:16D; SD) and long (16L:8D; LD) days, and identified proteins that showed significant differences between SD and LD in the flight muscle. To confirm that photostimulated changes were linked with migration, similar measurements were done on photoperiodic non-migratory Indian weaverbirds (Ploceus philippinus), which share the habitat with buntings for almost half-a-year. Buntings were fattened and gained weight and had elevated serum triglyceride levels and recrudesced testes under LD, but not SD. The SDS-polyacrylamide gel electrophoresis revealed differences between SD and LD conditions in the flight muscle protein profiles of buntings, but not of weaverbirds. Two-dimensional gel electrophoresis of flight muscle of bunting separated three proteins, of which two were upregulated under LD condition. Mass spectroscopic analysis and a protein database search identified them as the fatty acid binding protein (FABP), myoglobin and creatine kinase (CK). Further semi-quantitative and quantitative PCR assays revealed that FABP and myoglobin transcript levels in buntings, but not in weaverbirds, were upregulated under LD condition. However, there was no difference in CK mRNA levels between SD and LD in both the species. High FABP is perhaps linked with increased energy demands and high myoglobin with intense physical activity during migration. A difference in the CK protein, but not in mRNA levels between SD and LD may possibly indicate its photoperiodic regulation at the translational level.
Evidence for role of acid-sensing ion channels in nucleus ambiguus neurons: essential differences in anesthetized versus awake rats
Venue: Journal of Comparative Physiology B

Acid-sensing ion channels (ASIC) are widely expressed in several brain regions including medulla; their role in physiology and pathophysiology is incompletely understood. We examined the effect of acidic pH of 6.2 on the medullary neurons involved in parasympathetic cardiac control. Our results indicate that retrogradely labeled cardiac vagal neurons of nucleus ambiguus are depolarized by acidic pH. In addition, acidic saline of pH 6.2 increases cytosolic Ca2+ concentration by promoting Ca2+ influx in nucleus ambiguus neurons. In vivo studies indicate that microinjection of acidic artificial cerebrospinal fluid (pH 6.2) into the nucleus ambiguus decreases the heart rate in conscious rats, whereas it has no effect in anesthetized animals. Pretreatment with either amiloride or benzamil, two widely used ASIC blockers, abolishes both the in vitro and in vivo effects elicited by pH 6.2. Our findings support a critical role for ASIC in modulation of cardiac vagal tone and provide a potential mechanism for acidosis-induced bradycardia, while identifying important differences in the response to acidic pH between anesthetized and conscious rats.
Thermogenesis, vocalization, and temperature preference of 1-day-old chicken hatchlings after cold-exposure in late embryogenesis
Venue: Journal of Comparative Physiology B

In a thermal gradient the preferred ambient temperature (Ta pref) of chicken hatchlings is a few degrees lower than thermoneutrality. To investigate whether a correlation may exist between Ta pref and the autonomic thermogenic capacity or not we studied a group of hatchlings (N = 15) exposed to cold at end-incubation, a procedure known to increase their postnatal thermogenesis. Chicken embryos were exposed to cold (34.5 °C instead of 38 °C) at days 18–20 of incubation. By comparison to Controls (N = 15), they hatched a few hours later, with similar body weight, body temperature, vocalization (number of sounds produced per unit time), and oxygen consumption ($$\dot{V}_{{{\text{O}}_ }}$$V˙O2, measured in a respirometer by an open-flow methodology). When exposed to slow cooling these hatchlings had a higher lower critical temperature (LCT) of thermoneutrality and higher $$\dot{V}_{{{\text{O}}_ }}$$V˙O2, and slightly higher vocalization than Controls. In a thermal gradient, Ta pref averaged 34.3 ± 0.3 °C, or 1 °C higher than in Controls (33.4 ± 0.3 °C; P < 0.05), in proportion with their higher LCT (38 ± 0.1 °C instead of 36.7 ± 0.3 °C; P < 0.001), so that the Ta pref − LCT difference (−3.6 ± 0.3 °C) was similar to Controls (−3.3 ± 0.3 °C). In conclusion, in chicken hatchlings Ta pref was lower than LCT irrespective of the magnitude of their thermogenic response. It was estimated that, at Ta pref, $$\dot{V}_{{{\text{O}}_ }}$$V˙O2 was ~20 % higher than at thermoneutrality. Such metabolic increase could carry some physiological advantage and the choice of Ta pref may reflect the hatchling’s needs to maintain $$\dot{V}_{{{\text{O}}_ }}$$V˙O2 slightly elevated.
Expression of the ABC transport proteins MDR1 (ABCB1) and BCRP (ABCG2) in bovine rumen
Venue: Journal of Comparative Physiology B

Rumen fermentation of plant-based forage in bovines is the major site for generation and absorption of short-chain fatty acids. Consequentially, the rumen is also the site for initial exposure to toxins released from diet. Accordingly, we have investigated the expression of bovine ABC transporters in the rumen associated with cytoprotection against xenobiotic exposure, namely MDR1 (ABCB1), MRP2 (ABCC2) and BCRP (ABCG2). Bovine rumen samples from the ventral sac were obtained post-mortem from a commercial slaughterhouse after humane killing. Rumen papilla samples were then prepared for total RNA isolation for RT-PCR, SDS-PAGE/Western blotting and immunohistochemistry. PCR products of the predicted size were observed for both MDR1 and BCRP, but not for MRP2 using bovine-specific primers. β-actin was used as a control transcript. Western blot analysis using C219 primary monoclonal antibody revealed MDR1 protein expression in bovine rumen (Mapp, of ~170–180 kD). Immunolocalisation of MDR1 using UIC2 monoclonal antibody within cryosections of bovine rumen showed extensive membrane staining in the cells of the stratum granulosum, stratum spinosum and stratum basale. MDR1 expression was absent from outer stratum corneum. Protein expression and immunolocalisation were also confirmed for BCRP, with prevalent staining in the stratum basale, becoming weaker in the stratum spinosum and stratum granulosum.
Sensory-evoked turning locomotion in red-eared turtles: kinematic analysis and electromyography
Venue: Journal of Comparative Physiology A

We examined the limb kinematics and motor patterns that underlie sensory-evoked turning locomotion in red-eared turtles. Intact animals were held by a band-clamp in a water-filled tank. Turn-swimming was evoked by slowly rotating turtles to the right or left via a motor connected to the shaft of the band-clamp. Animals executed sustained forward turn-swimming against the direction of the imposed rotation. We recorded video of turn-swimming and computer-analyzed the limb and head movements. In a subset of turtles, we also recorded electromyograms from identified limb muscles. Turning exhibited a stereotyped pattern of (1) coordinated forward swimming in the hindlimb and forelimb on the outer side of the turn, (2) back-paddling in the hindlimb on the inner side, (3) a nearly stationary, “braking” forelimb on the inner side, and (4) neck bending toward the direction of the turn. Reversing the rotation caused animals to switch the direction of their turns and the asymmetric pattern of right and left limb activities. Preliminary evidence suggested that vestibular inputs were sufficient to drive the behavior. Sensory-evoked turning may provide a useful experimental platform to examine the brainstem commands and spinal neural networks that underlie the activation and switching of different locomotor forms.
Going with the flow: a brief history of the study of the honeybee’s navigational ‘odometer’
Venue: Journal of Comparative Physiology A

Honeybees navigate to a food source using a sky-based compass to determine their travel direction, and an odometer to register how far they have travelled. The past 20 years have seen a renewed interest in understanding the nature of the odometer. Early work, pioneered by von Frisch and colleagues, hypothesized that travel distance is measured in terms of the energy that is consumed during the journey. More recent studies suggest that visual cues play a role as well. Specifically, bees appear to gauge travel distance by sensing the extent to which the image of the environment moves in the eye during the journey from the hive to the food source. Most of the evidence indicates that travel distance is measured during the outbound journey. Accumulation of odometric errors is restricted by resetting the odometer every time a prominent landmark is passed. When making detours around large obstacles, the odometer registers the total distance of the path that is flown to the destination, and not the “bee-line” distance. Finally, recent studies are revealing that bees can perform odometry in three dimensions.
Wound healing reduces stress-induced immune changes: evidence for immune prioritization in the side-blotched lizard
Venue: Journal of Comparative Physiology B

Immune system function is affected by a variety of exogenous and endogenous stressors. Most studies have focused on the effect of stressors on immune function, but not necessarily on trade-offs within the immune system and interactions with energy-mobilizing hormones. In this study, we examined how bactericidal ability and corticosterone interacted by applying acute restraint stress in a non-model organism, the side-blotched lizard (Uta stansburiana), 10 days after receiving a cutaneous wound. We found a decrease in bactericidal ability in wounded animals after restraint stress. However, the percentage healed during the first 7 days was positively correlated with bactericidal ability 10 days after wounding. In addition, the magnitude of change in corticosterone concentration during the acute stress was positively correlated with the percentage of wound healing during the first 3 days. These two relationships may demonstrate a “faster is better” strategy. If energy is invested heavily in the initial wound healing stages, the individual may be able to mount a more effective immune and stress response earlier.
Response differences of intersegmental auditory neurons recorded close to or far away from the presumed spike-generating zone
Venue: Journal of Comparative Physiology A

Intracellular recordings may give valuable information about processing of a neuron and possibly its input from the network. Impalement with an electrode causes injury to the cell and depolarization from intrusion of extracellular fluid. Thus, penetration artefacts may contaminate recordings and conceal or even alter relevant information. These penetration artefacts may have the strongest impact close to the spike-generating zone near the dendrites. Recordings in axonal portions might therefore be less vulnerable while providing insufficient information about the synaptic input. In this study, we present data of five previously identified intersegmental auditory neurons of a bushcricket independently recorded in their dendrites (prothorax) and axon (brain). Generally, responses to acoustic pulses of the same parameter combination were similar within a neuronal class at the two recording sites. However, all neuronal classes showed significantly higher response variability and a tendency for higher spike activity when recorded in the dendrites. Unexpectedly, the combined activity of two neurons (Ascending Neurons 1 and 2) recorded in the brain provides a better fit to song recognition than when recorded in the thorax. Axonal recordings of T-shaped Neuron 1 revealed graded potentials originating in the brain and modulating its output in a potentially behaviourally relevant manner.
Role of dopamine in distal retina
Venue: Journal of Comparative Physiology A

Dopamine is the most abundant catecholamine in the vertebrate retina. Despite the description of retinal dopaminergic cells three decades ago, many aspects of their function in the retina remain unclear. There is no consensus among the authors about the stimulus conditions for dopamine release (darkness, steady or flickering light) as well as about its action upon the various types of retinal cells. Many contradictory results exist concerning the dopamine effect on the gross electrical activity of the retina [reflected in electroretinogram (ERG)] and the receptors involved in its action. This review summarized current knowledge about the types of the dopaminergic neurons and receptors in the retina as well as the effects of dopamine receptor agonists and antagonists on the light responses of photoreceptors, horizontal and bipolar cells in both nonmammalian and mammalian retina. Special focus of interest concerns their effects upon the diffuse ERG as a useful tool for assessment of the overall function of the distal retina. An attempt is made to reveal some differences between the dopamine actions upon the activity of the ON versus OFF channel in the distal retina. The author has included her own results demonstrating such differences.