Behavioural Brain Research最新文献

Stimuli can acquire meaning and significance indirectly by being paired with other stimuli that already have known outcomes. When a stimulus has a well-established association with either aversive or rewarding consequences, other neutral stimuli can take on similar properties simply by occurring alongside it - even if the original outcome is not presented. This process is known as second-order conditioning. Relatively few studies have examined second-order conditioning of inhibitory safety memories. Here, we examined second-order conditioning of safety in adult male and female Long-Evans rats by adapting our well-established first-order safety conditioning paradigm to include novel stimuli paired with the established safety cue. Our findings demonstrate that a second-order safety cue can attenuate fear responses to a degree comparable to that of a first-order safety cue. In contrast, a novel cue that had never been paired with a safety signal failed to produce an equivalent reduction in defensive behavior during fear cue presentation, demonstrating that the reduced fear to the second-order safety cue was a product of conditioning and not external inhibition. Developing methods to generalize safety to novel stimuli that have not been explicitly conditioned for safety holds significant promise for advancing innovative strategies aimed at mitigating maladaptive fear responses.

Behavioural syndromes are suites of correlated behaviours at the population or species level that can affect how wild animals respond to their environments, including potentially stressful situations such as captivity. In this study, we assessed whether beak wiping, a stereotyped anxiety-linked behaviour where birds wipe their beaks on a perch in a "windshield wiper" motion, was correlated with another anxiety-linked behaviour, neophobia towards novel objects presented with food, in captive house sparrows (Passer domesticus). We predicted that more neophobic sparrows would also exhibit more beak-wiping stereotypies. We analyzed 1 h long control videos (when sparrows were presented with a normal food dish only; n = 54) from three previous neophobia studies to assess beak wiping frequency, mean beak wiping bout duration, and total bout duration. Sparrows' reluctance to feed in the presence of novel objects was significantly correlated with the mean duration of beak wiping bouts during control trials. We also found that simple enrichment (rubber perches, manzanita branch perches, and/or artificial pine branches) decreased both the frequency and duration of beak wiping. These findings suggest that high neophobia and high levels of stereotypy may arise due to similar neuroendocrine mechanisms and reflect a "high anxiety" behavioural syndrome. This work also highlights the importance of providing species-appropriate environmental enrichment to decrease the prevalence of stereotypic behaviours in captive songbirds.

Deception is one of the most enigmatic human behaviors, and understanding its neural mechanisms remains a central challenge in neuroscience. Investigating brain dynamics during deception provides insights into cognitive control and social processing. In this study, we analyzed the architecture of brain region connections, focusing on rich, feeder, and local links, using EEG signals from 22 participants performing a visual task under instructed deception. Functional connectivity matrices were computed with phase lag index, and binary networks were constructed across multiple thresholds. Results showed that brain networks are organized around stable hub regions, which remain largely unchanged during deception. However, deceptive behavior disrupted peripheral connections, with feeder and local links showing reductions relative to truthful responding, suggesting reallocation of cognitive resources. Although hub regions were consistent, hubs in the truthful condition exhibited higher connectivity than during deception in both binary and weighted networks across all percentages of rich nodes (p < 10^-6), indicating more efficient hub-to-hub integration during truthful processing. Analysis of link deviations across thresholds and rich-node percentages revealed a dynamic pattern. At low percentages, rich links were stable while local links varied most. As percentages increased, rich links showed the largest deviations, local links the smallest, and feeder links maintained intermediate variability. These results indicate that deception initially disrupts local processing, while communication among core hubs is affected as network engagement grows. These findings highlight the importance of investigating the architecture of brain region connections during complex social behaviors, showing how stable hubs and flexible peripheral links support cognitive processing.

Adolescent stress not only exerts enduring effects on individual behavior and physiology, but also shapes offspring phenotypes through mechanisms of transgenerational inheritance. However, the transgenerational effects of predation risk, an important ecological factor, remain poorly characterized in wild, social rodents. Using male Brandt's voles (Lasiopodomys brandtii) as a model, this study systematically investigated the transgenerational effect of adolescent exposure to cat urine, rabbit urine (as a non-predator stimulus), and distilled water (as a control) for 60 min daily over 18 consecutive days on the behavioral and physiological traits of future offspring. Our data showed that while male paternal adolescent cat odor (CO) exposure did not significantly alter overall parental investment by either parent, it induced significant phenotypic changes in offspring. These included an increased female ratio at weaning and reduced post-weaning weight gain. Furthermore, adolescent offspring exhibited decreased locomotor activity in the open field test, while adult offspring displayed heightened vigilant rearing and reduced head-out behavior when confronted with CO exposure. These behavioral and developmental alterations were accompanied by elevated serum levels of adrenocorticotropic hormone and corticosterone, suggesting enhanced basal activity of the hypothalamic-pituitary-adrenal axis. These findings demonstrate that male paternal experience with predation risk during adolescence can transgenerationally regulate the sex ratio, growth and development, stress response, and antipredator strategies of future offspring, independent of alterations in parental investment in wild, social rodents. This study elucidates the unique role of the paternal lineage in the transgenerational inheritance of early adversity and provides further experimental evidence for understanding how environmental stress drives adaptive phenotypic transmission across generations.

Homovanillic acid (HVA), the principal terminal metabolite of dopamine, has long been considered an inactive byproduct of dopaminergic signaling. However, its potential neuromodulatory role in emotional regulation remains largely unexplored. This study investigated the neuromodulatory capacity of HVA within the medial prefrontal cortex (mPFC) and its implications for anxiety-like behavior. We employed an integrated approach in rodents, combining neurochemical profiling, stereotaxic microinfusion, and whole-cell patch-clamp electrophysiology. Rats were phenotyped for anxiety-like behavior using the elevated plus-maze (EPM), revealing a distinct neurochemical signature in the mPFC of high-anxiety individuals: significantly elevated HVA alongside reduced 3-methoxytyramine (3-MT), without alterations in dopamine, norepinephrine, serotonin, or their major metabolites. Crucially, bilateral microinjection of HVA (0.5 or 1.5 μg/side) into the mPFC of naïve rats induced dose-dependent anxiogenic effects, evidenced by reduced open-arm exploration and entries in the EPM. Electrophysiological recordings from deep-layer pyramidal neurons in mouse mPFC slices demonstrated that HVA (80 μM) suppresses calcium channel-mediated plateau potentials. Our findings reveal HVA as an active neuromodulator in the mPFC that shapes anxiety-like behaviors through inhibition of calcium channels, challenging its traditional status as a metabolic waste product.