Journal of Comparative Physiology A-Neuroethology Sensory Neural and Behavioral Physiology最新文献

Light-mediated circadian entrainment is a fundamental sensory process across taxa, yet the contribution of ultraviolet-A (UVA; 315-400 nm) wavelengths remains poorly understood. Here, we characterize the phase-shifting effects of brief UVA light flashes in Drosophila ananassae, a species with known sensitivity to short-wavelength light via ocular and extraocular photoreceptors. Using a parametric array of 62 UVA LED protocols varying in flash duration (8, 16, 120 ms), frequency (0.13-1.0 Hz), and irradiance, we quantified circadian phase shifts in the locomotor activity rhythm under constant darkness following stimulation in either the delay (ZT13) or advance (ZT23) zones. Young flies (2-3 days old) exhibited robust phase delays and advances that scaled with flash luminance and frequency. Dose-response modeling revealed increased phase-shifting efficiency and lower energy thresholds with decreasing flash duration, especially at ZT23. By contrast, aged flies (40-45 days) showed significantly attenuated responses, particularly to 8 ms pulses, indicating an age-related decline in UVA sensitivity. These findings suggest that the insect circadian system is finely tuned to the temporal structure of UVA input, with optimal entrainment possibly occurring in response to brief, intermittent stimulation. The marked reduction in responsiveness with age highlights a potential erosion of fast-acting photoreceptive pathways. Given the conservation of UVA-sensitive photopigments across animals, these results offer comparative insights into how temporal light encoding influences circadian regulation across life stages and taxa.

Lior Pachter's response to my Editorial (Warrant in J Comp Physiol A https://doi.org/10.1007/s00359-025-01745-6 , 2025)-which details the recent public attacks on the integrity of Australian neuroethologist Mandyam Srinivasan-does little more than accuse me of writing a long series of ad hominem attacks against him and Laura Luebbert. I find this accusation very difficult to reconcile with what I actually wrote, and I leave it to the readers of my Editorial to decide for themselves whether I am guilty of this or not. Regardless of this, Pachter fails to address, or refute, the reason I wrote my Editorial in the first place-namely, to decry the manner in which he and Luebbert raised their concerns about Srinivasan's work. Thus, the conclusion of my Editorial remains unaltered-Luebbert's and Pachter's unjust public assassination of Srinivasan's reputation falls vastly short of the standards of academic decency expected of a respectful scientific discourse between peers.

In a non-peer-reviewed arXiv preprint Laura Luebbert and Lior Pachter made numerous criticisms of the work of Mandyam Srinivasan and colleagues, suggesting that there was evidence of data duplication and data manipulation in their work. These imputations were amplified in a news article and blog post in the journal Science and then made news in the mainstream media in several countries. This media activity took place before journals and institutions had the chance to conduct formal investigations that would have allowed Srinivasan and his colleagues a fair hearing, with input from independent experts. In addition, there was no time for the scientific community to evaluate Luebbert and Pachter's work. In particular, they made some very critical comments based on statistical simulations, where they claimed that R² values reported by Srinivasan and colleagues in six papers were "ridiculously high". In this commentary, I show that their inability to reproduce high R² values was due to major flaws in their simulation models. Luebbert and Pachter have never responded in detail to my criticisms, instead relying on the logical fallacies of argument from authority and ad hominem attacks.

In his response to Eric Warrant's editorial, Lior Pachter talks a good game about the importance of truth in the advancement of science. He argues that this is achieved by scientists challenging each other in the pursuit of truth, and that he has done this by reviewing the output from our lab and publishing his findings as a preprint on arXiv. However, a year after we have provided extensive explanations and scientific counter arguments to the claims in his arXiv preprint, debunking his spurious and false allegations of scientific misconduct, he shows no interest in addressing our responses and continues to repeat the same allegations in his response to Eric Warrant's Editorial. Since the publication of Luebbert and Pachter's preprint in May 2024, the relevant journals have examined and found no merit in their accusations, agreeing instead with our admission of inadvertent errors in four papers for which corrections have already been published. By continuing to peddle the same accusations despite evidence to the contrary, Pachter demonstrates that he is unwilling or perhaps incapable of following through on his own "plea for academic truth".

In an internet age when a viral sensationalist story gains far more traction than a nuanced and balanced discussion, we have become used to some politicians, media and web-based influencers bending the truth to create a misguided or distorted narrative that many people unquestioningly believe. This should never happen in science, but even here standards are sadly deteriorating. In my editorial I wish to expose this situation by highlighting the recent disturbing public attack on the scientific integrity of Australian neuroethologist Mandyam Srinivasan, an attack made by scientists outside Srinivasan's field. Srinivasan's integrity was first questioned in a preprint detailing serious allegations of scientific misconduct (that were subsequently shown to be unfounded). This was immediately followed by a concerted press and social media campaign that severely damaged his reputation. The goal of my Editorial is to use these events to encourage our readers to always be cautious in their judgements and to maintain standards of dignity, decency and respect in their treatment of their peers, even if they disagree with them, since this is the way science has always advanced.

In her book Why trust Science?, Naomi Oreskes examines the question of what it means to say that "science corrects itself", highlighting the importance of the social process of science and specifically the importance of scientists challenging each other in the pursuit of truth. In a recent preprint, a colleague and I did exactly that, reviewing a corpus of work by Australian neuroethologist Mandyam Srinivasan and identifying numerous problems across ten of his papers, including several instances of identical data being reported for different experiments. In a recent editorial, Eric Warrant dismisses our critiques of Srinivasan's work as "sloppiness all of us are capable of", and instead focuses on attacking us, sometimes conflating criticisms of others of Srinivasan's work with ours. Here I review his claims and argue for the importance of truth in the advancement of science.

Delayed-rectifier voltage-gated K⁺ conductances (I_K) can confer band-pass properties to the membrane impedance gain function in the frequency domain, and shorten the duration of transient receptor potentials evoked by voltage-insensitive receptor currents in the time domain. Here, by investigating in silico the underlying mechanisms, we found that: 1. I_K activation rate was the major determinant of both the voltage response narrowing and the impedance gain peaking. Both effects were non-linear, voltage-dependent, with the maxima determined by I_K conductance and kinetics. 2. Analysis in the time domain revealed that for efficient modulation, the kinetics of I_K must correspond to that of the receptor current: slower-activating I_Ks more strongly narrowed voltage responses elicited by slower receptor currents than faster-activating I_Ks, and vice versa. 3. Two complementary mechanisms mediated the modulation: (1) voltage amplification at the onset of receptor current during a window of relatively high resistance due to delayed activation of I_K, and (2) attenuation of voltage response during its decay by excessive I_K due to its delayed deactivation. Consequently, the action of I_K caused a partial leftward shift of voltage waveform relative to the receptor current, resembling the effect of electrical inductance. 4. Voltage response narrowing was opposed by self-shunting of the depolarizing receptor current as it increased. Consequently, the increase in corner frequency due to I_K was limited to small voltage responses. Our results elucidate reciprocal relationships between the voltage response and I_K, and the conditions when I_K can confer band-pass properties to impedance gain function.

Monoamines play essential roles in regulating brain functions, influencing behaviours and physiological processes. Despite significant advances in mammalian models, studies on reptiles are limited, restricting our understanding of their neurochemical and behavioural interactions. This study aimed to develop and validate a selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of 11 monoamines and their metabolites (adrenaline, dopamine, levodopa, homovanillic acid, 5-hydroxyindoleacetic acid, 5-hydroxytryptophan, serotonin, norepinephrine, tryptophan, tyrosine, vanillylmandelic acid) in lizard brains, examining interspecies and sex-specific variations and their potential link to behavioural differences between Podarcis siculus and Podarcis melisellensis. Brain samples from 132 lizards were analysed using the optimized LC-MS/MS method, which included rigorous pre-analytical preparation to ensure analyte stability. The method demonstrated high sensitivity and specificity for monoamines, with the limit of quantitation lower than 5 ng mL^-1. Statistical analyses were performed to assess species, sex, and interaction effects. Significant species differences were observed in tryptophan, 5-hydroxytryptophan and 5-hydroxyindoleacetic acid, with P. siculus males exhibiting the highest levels. No differences were found in the dopamine, noradrenaline or adrenaline pathways. Serotonergic differences align with previously recorded behavioural differences between these two species. This is the first comprehensive study profiling monoamines in lizard brains using LC-MS/MS, providing insights into species-specific neurochemical patterns. The findings underscore the utility of lizards as comparative models in neuroscience and highlight the need for further research into the interplay between neurochemistry and behaviour.

Research around the turn of the millennium showed that honeybees use the amount of optic flow during foraging flights to estimate the distance between a food source and the hive. Upon returning to the hive, they communicate this information to their nestmates by encoding distance into the duration of the waggle phase during the waggle dance. A celebrated figure in establishing the idea of an optic-flow-driven odometer is the Australian neuroethologist Mandyam Srinivasan. However, in 2024, news broke about alleged irregularities and scientific misconduct in ten of Srinivasan's articles, including a high-profile paper published in Science in 2000. To help readers navigate through the following five articles contributed by several key players in the honeybee odometer controversy, this editorial first provides some scientific background. It then outlines the major events that, beginning with the first allegations on PubPeer in 2020, culminated in 2024 with an escalation of accusations against Srinivasan in newspapers, magazines, and social media. Finally, the editorial summarizes Srinivasan's responses to these allegations and the corrective actions he has taken.