Physiology & Behavior最新文献

Cooperation is an important dimension of social behavior in humans and animals. Reciprocal altruism provides an evolutionary basis for cooperation between unrelated organisms, but the neuroendocrine mechanisms driving these behaviors are not fully understood. The present study tested an operant model of direct reciprocity in male and female rats. Direct reciprocity is a sequential 2 × 2 game where rats alternate as Donor and Recipient to deliver and receive 1 sugar pellet (respectively) in repeated trials. Rats were tested in same-sex pairs, and we determined the effects of oxytocin (OT) and its antagonist (OTR-A) on cooperative responses. There was no baseline sex difference in cooperation (females: 25.2±3.8%; males: 20.7±3.1%), and pretreatment with OT (0.05-2 mg/kg) had no effect on the likelihood of the Donor to respond on behalf of their cagemate Recipient. In a similar manner, there was no difference in cooperation when rats were paired with an unfamiliar partner (p>0.05). However, OTR-A had a sex-specific effect to reduce cooperative responses in females (to 11.1±2.2%, p<0.05), and increase the likelihood of defection after their partner defected (from 80.2±4.1% to 87.8±2.3%, p<0.05). These findings align with recent studies suggesting that OT enhances reward valuation, and has broad effects on decision-making circuitry in the brain.

The purpose of the study was to compare the energy metabolism responses at different walking speeds among pre, peri and postmenopausal women, with consideration for individual's body composition characteristics and movement behaviors. Twenty-one premenopausal women (38.9 ± 5.0 years), twenty-two perimenopausal women (49.5 ± 3.8 years) and twenty-one postmenopausal women (55.4 ± 4.1 years) were included in the data analysis. Body composition (fat mass (FM) and fat-free mass (FFM)) was assessed by dual-energy X-ray absorptiometry and movement behaviors by accelerometry. Fasting blood samples were collected to determine pituitary and ovarian hormones concentrations. Energy cost of walking (gross and net C_w), expressed both in absolute terms and relative to FFM, as well as substrate oxidation rates, was measured by indirect calorimetry during five 5-minute treadmill walking bouts at 2, 3, 4, 5, and 6 km.h^-1, each separated by 3 minutes of seated rest. Results indicate that there were no significant differences in body composition, movement behaviors, and in C_w and substrate oxidation rates during walking among the three groups. Negative correlations were found between moderate-to-vigorous physical activity and both gross and net C_w relative to FFM at 5 km·h⁻¹ and 6 km·h⁻¹ (from p = 0.04 to p = 0.007). No correlations were found between estradiol concentration and C_w or substrate oxidation rates, at any walking speed. Women experiencing the menopausal transition do not exhibit differences in energy metabolism during walking compared with pre and postmenopausal women when they have a similar body composition and movement behaviors.

Paracetamol is a widely used analgesic and antipyretic, commonly administered during pregnancy and early postnatal life. Its mechanism of action involves inhibiting cyclooxygenase-2/3 (COX-2/3) enzymes, which play a critical role in normal brain development during the perinatal period. In this study, we investigated anxiety-like behavior, depression-like behavior, and corticosterone levels in adult male rats following either prenatal or neonatal paracetamol exposure. Pregnant dams received subcutaneous injections of paracetamol (60 mg/kg) or saline every 12 hours from gestational day (GD) 16 to 20, while neonatal pups received the same treatment from postnatal day (PD) 1 to 5. At PD70, a subset of males was allowed to gain sexual experience, while others remained sexually naïve. Behavioral assessments were conducted on PD94 and PD95 using the elevated plus maze and the forced swim test, respectively. On PD107, males were exposed to bedding from estrous females as a social stimulus, and serum corticosterone levels were measured. Prenatal paracetamol exposure resulted in significantly reduced anxiety-like behavior and serum corticosterone, along with increased depression-like behavior in adulthood. In contrast, neonatal exposure produced no significant behavioral or hormonal alterations. These findings reveal differential sensitivity to paracetamol during distinct developmental windows, with prenatal exposure leading to long-lasting disruptions in emotional regulation and neuroendocrine stress responses. These effects may be mediated by COX inhibition or interference with neural circuits involved in stress regulation and motivational processing.

Fish learning abilities play a key role in optimizing husbandry and feeding strategies. This study examines spatial learning and associated neuronal gene expression in European seabass (Dicentrarchus labrax), a species widely farmed in the Mediterranean. Individuals were classified as learners (L), non-learners (NL), or non-attempters (NA) based on performance in a spatial task over 3- and 8-day learning periods. Approximately 10-16% of fish successfully learned the task, showing improved trial times and increased expression of immediate early genes (IEGs) egr-1 and c-fos in the telencephalon and inferior lobe of the hypothalamus, regions linked to learning, memory, and reward processing. UL fish displayed partial neural activation but inconsistent behavioral success, likely influenced by motivation or stress, while NL fish showed behavioral apathy and lower gene expression. Prolonged training led to habituation and neural desensitization, whereas the shorter, 3-day learning better captured learning-related gene expression changes. These findings indicate that IEG expression is a reliable marker of learning-related brain activity but may also reflect stress responses. Thus, recognizing individual variability in cognitive performance and well-managed learning protocols can improve fish welfare and feeding efficiency in aquaculture.

Food addiction (FA) is a complex clinical condition that refers to addiction to highly palatable foods, represented by compulsive eating behavior and an incapacity to control food consumption, similar to other forms of addiction. This review examines the literature on FA and its impact on eating disorders and obesity. Using databases such as PubMed, Cochrane Library and Google Scholar, recent studies were analyzed to show how FA may reduce treatment effectiveness, increase symptom severity, promote resistance to nutritional or pharmacological interventions, and elevate the risk of relapse. The search strategy used the keywords food addiction, obesity, eating disorders, psychotherapy, and dietary therapy, limiting the reference period to studies published in the last five years. In reviewing the available articles, several nuances emerged that are fundamental to understanding FA, including neurobiological mechanisms, psychiatric comorbidities, environmental determinants, alterations in the gut microbiota, and the pervasive influence of ultra-processed foods. Taken together, the data indicate that FA not only intensifies symptom manifestation but also contributes to worse outcomes, with reduced compliance to standard treatments and an increased likelihood of relapse. These observations underscore the importance of recognizing FA as a critical component in clinical practice; neglecting its role and symptom may compromise therapeutic efficacy. Further research is needed to establish integrative treatment models that include FA as a fundamental component of clinical patient care.

It remains unclear whether acute aerobic exercise can effectively mitigate the inhibitory control deficits caused by test anxiety. This study investigated the effects of 30 min of moderate-intensity acute aerobic exercise on inhibitory control and related neural activities in individuals with high test anxiety. Forty participants were randomly assigned to an aerobic exercise group or a seated-reading control group, completing pre- and post-intervention assessments spaced one week apart. Statistical analyses using a series of repeated-measures ANOVAs revealed that, compared to the control group, the exercise group showed a significant reduction in self-reported test anxiety. Behaviorally, exercise led to significantly faster reaction times across both congruent and incongruent trials, coupled with a specific reduction in the Flanker conflict effect (RT difference between conditions), indicating enhanced interference control. Electrophysiologically, analysis of event-related potentials demonstrated that acute exercise modulated key cognitive components: N2 amplitude was significantly reduced and P3 amplitude was significantly enhanced in both task conditions following exercise, with no comparable changes in the control group. These findings suggest that acute aerobic exercise can enhance inhibitory control and alleviate test anxiety in university students.

The present study aimed to determine whether apelin-13 facilitates lordosis behavior through the activation of specific hypothalamic kinases and to identify which signaling pathways mediate this response. Because lordosis is a well-established neuroendocrine indicator of female sexual receptivity, it served as an appropriate behavioral model to detect peptide-induced facilitation. Thus, we examined the role of protein kinase A (PKA), protein kinase C (PKC), mitogen activated protein kinase (MAPK), or Src kinase (Src), in the facilitation of lordosis behavior following bilateral intrahypothalamic injection of 0.75 μg of apelin-13 to ovariectomized-estradiol benzoate (OVX-EB) primed rats. Apelin-13 consistently induced lordosis at 30, 120, and 240 minutes post-infusion. To explore the role of these kinases, various inhibitors or their vehicles were administered bilaterally into the ventromedial hypothalamus (VMH) of OVX-EB-primed rats 30 min before the infusion of apelin-13. The inhibitors used were Rp-cAMPS for PKA, bisindolilmaleimide (BIS) for PKC, PD98059 for MAPK, and PP2 for Src. The VMH injection of Rp-cAMPS failed to reverse the facilitation of lordosis at the different times tested, while BIS or PP2 decreased the lordosis quotient (LQ) significantly only at 240 min without any statistical effect on the lordosis score (LS). However, PD98059 significantly reduced both the LQ and LS at 120 and 240 min. These data indicate that apelin-13 exerts its facilitatory effects on lordosis through MAPK, PKC, and/or Src, but not PKA pathways.

Sleep deprivation negatively impacts both physical and psychological health in both humans and animal models. Exercise, on the other hand, can have beneficial effects on various aspects of physical and mental health. However, little is known about the ways in which sleep deprivation and exercise may interact, especially for exceptionally high levels of exercise. We studied High Runner (HR) mice from a long-term artificial selection experiment to investigate how genetically high exercise level could impact the response to sleep deprivation. A total of 192 adult mice from four replicate HR and four non-selected Control lines (balanced for sex) completed six days of baseline wheel access, followed by three days with or without 6 h/day of total sleep deprivation (TSD) via gentle handling. As expected, HR mice ran farther and faster compared to Controls during days 1-6. TSD reduced the running distance and duration in mice from Control lines, while HR increased running speed and maintained distance (treatment × linetype interaction). TSD-induced changes in body mass differed between linetypes (treatment × linetype interaction): Controls tended to gain mass, whereas HRs lost mass. During the three days prior to TSD, HR mice consistently exhibited more active and fewer maintenance behaviors than Controls. TSD increased resting and decreased wheel activity in Controls but not HRs (treatment × linetype effects significant for both categories). These results demonstrate that genetically based high voluntary activity levels are associated with altered responses to TSD.