By 2030, 1.4 billion people worldwide will be 60 years or older. A significant proportion will experience changes in voice, which can indicate early signs of neurodegenerative disease. Most research and treatment studies have focused on the larynx because of its accessibility and known role in moderating pitch, loudness, and voice quality. Preclinical animal models offer important insight into brain mechanisms involved in aging vocalizations. Previously, we conducted a cross-sectional analysis in adult male zebra finches, discovering that song changes occur at transitional time points, between young adult, middle age, and older ages. Song changes are accompanied by reorganization of gene networks in a song-dedicated basal ganglia brain nucleus at middle age that degrade in old age. To more precisely examine how aging alters songs during these transitional time points, we followed individual male zebra finches longitudinally over adulthood. Measurements of aging human voice, including duration, intensity, smoothed cepstral peak prominence, and fundamental frequency (fo mean, standard deviation, and coefficient of variation), were carried out on birdsong syllables. Our results show that changes in fo mean and intensity are the measurements most sensitive to aging and consistent across multiple mornings in the finches. Notably, acoustic changes were also more pronounced in the transition from young adult to middle age, a time at which changes in aging human voice also emerge. Our findings strengthen the validity of the finch model for use in aging research and motivate future investigations exploring the relative contributions of laryngeal, respiratory, and brain mechanisms to aging vocalizations. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Excessive aggression induced by social isolation (SI) has been closely linked to dysfunction in prefrontal circuits, particularly the anterior cingulate cortex (ACC). Topiramate, an antiepileptic drug known to enhance GABAergic and inhibit glutamatergic transmission, has demonstrated antiaggressive effects. In our previous work, we showed that topiramate's antiaggressive effects were associated with reduced neuronal death, improved neuronal morphology, and attenuated neuroinflammation in the ACC following SI. However, its impact on ACC neuronal activity remains poorly understood. In this study, we investigated the effects of topiramate on the spontaneous activity of ACC neurons in a mouse model of SI-induced aggression. Additionally, we explored whether direct restoration of ACC activity via high-frequency stimulation could similarly reduce excessive aggression. Systemic administration of topiramate (30 mg/kg, intraperitoneally) significantly increased attack latency, reduced attack frequency, and enhanced sociability. In vivo extracellular recording of spontaneous activity revealed a 50% reduction in ACC firing in isolated mice, which was partially restored (∼30%) by topiramate treatment. Moreover, high-frequency stimulation applied to the ACC markedly decreased aggressive behavior and robustly promoted social interaction. Together, these results provide convergent behavioral and electrophysiological evidence that SI-induced aggression is associated with ACC hypoactivity. The finding that both topiramate treatment and high-frequency stimulation of the ACC effectively reversed these deficits highlights the ACC as a key target for therapeutic interventions to treat aggression-related neuropsychiatric conditions. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Normal explicit/declarative memory requires a system of anatomically related structures in the medial temporal lobe that includes the hippocampus and the entorhinal, perirhinal, and parahippocampal cortex. Although extensive medial temporal lobe damage in primates causes robust anterograde amnesia, defining the contribution of the hippocampus proper has proved challenging. We revisited that enduring puzzle here, directly addressing a number of factors suspected to contribute to conflicting results across earlier studies. Among them, we explored the effects of selective hippocampus lesions produced by two common excitotoxin methods, ibotenic acid and N-methyl-D-aspartic acid. Sample sizes were substantial, and all behavioral testing was conducted postoperatively. Performance was assessed on several standard procedures designed for monkeys, including multiple variants of the delayed nonmatching-to-sample test of visual object recognition, a series of rapidly acquired two-choice object discriminations, and a delayed response test of spatiotemporal memory. We used task-specific parametric manipulations (e.g., increasing retention intervals and reduced stimulus set size) to systematically vary demands on memory and test/retest analyses to enhance sensitivity for detecting impairment. Although both lesion groups sustained substantial hippocampal damage, their performance failed to differ from that of intact controls on any task, under any key test condition, regardless of data analytic strategy. The findings constrain plausible accounts of extant discrepancies in the literature and, moreover, highlight the need for fresh perspectives on the core operating characteristics of memory mediated by the primate hippocampus. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Previous research has demonstrated changes in neural oscillations associated with varying levels of roughness during active-touch exploration of surfaces. In the present study, we aimed to investigate changes in neural oscillatory activity and softness perception during touch exploration of skin. Two experiments were conducted. Study 1 evaluated active touch of artificial skin samples mounted to a purpose-built touch sensor, whereas Study 2 investigated active stroking of one's own forearm. In both experiments, the substrates were treated with commercially available bar soaps to deliver either a soft or draggy skin feel. Oscillatory brain activity was measured using a 129-channel electroencephalography system. In 31 participants, changes in oscillatory band power were evaluated in relevant frequency bands during touch exploration periods. For the artificial skin study, the soft condition led to lower alpha-band power over bilateral somatosensory cortices, which has previously been proposed as a marker of reduced roughness, compared to the draggy condition. Similar results were obtained during the self-touch paradigm, which additionally led to reduced theta-band changes over the frontal and central-parietal electrodes indicating modulation of activity involved in affective (pleasant) touch. Using a novel and highly controlled experimental approach using a novel artificial skin paradigm and active exploration during self-touch of participants own skin, we were able to demonstrate for the first time the neural correlates associated with softness perception of skin and their impact on brain activity associated with affective touch, thereby advancing our understanding of brain oscillatory activity during active-touch exploration of skin. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Gait speed has been associated with executive function in aging. To date, few studies have examined multiple mobility measures in parallel across the adult lifespan. Understanding how distinct aspects of mobility are associated with executive function may clarify modifiable behavioral targets to promote healthy aging. Community-dwelling adults (N = 223, Mage [SD] = 52.7 years [17.5], range = 18-85 years; 135 females) from the Fitness, Aging, Stress, and Traumatic Brain Injury Exposure Repository completed mobility and cognitive testing. Spatiotemporal gait and static balance were assessed using LEGSys and BalanSens accelerometer sensors. A composite measure of executive function was derived from subtests of the Wechsler Adult Intelligence Scale-IV (Digit Span backward, sequencing) and Delis-Kaplan Executive Function System (Trail Making Test-number-letter switching, color-word interference-inhibition, inhibition switching). Relative importance analyses explored contributions of mobility measures to executive function in relatively older adults (55+ years) and relatively younger adults (18-54 years). Hierarchical linear regressions examined mobility-executive function associations in each age group. Static balance contributed to executive function in both groups, whereas gait cycle measures explained variance in executive function among older adults. Among older adults, stride velocity (β = 0.13, p = .028) and cadence (β = 0.12, p = .048) explained an additional 3.4% and 2.8% of variance in executive function beyond age and education. No associations were observed among younger adults. Mobility and cognition relationships may differ across adulthood. In older adulthood, cadence emerged as a distinct mobility marker of executive function beyond gait speed, underscoring distinct features of gait as potential modifiable lifestyle variables important for healthy aging. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Inferential reasoning is a vital cognitive ability that enables animals to navigate novel situations by leveraging existing relational knowledge of memory schema, with hypothesized roles of prefrontal cortical-hippocampal circuits. Transitive inference (TI) tasks test the ability of subjects to infer relationships within a value hierarchy (e.g., A > B > C > D > E) after being trained only on adjacent premise pairs (e.g., A-B, B-C, etc.). In rodents, current TI paradigms are primarily based on odor-cues and have several limitations that preclude investigation of physiological mechanisms underlying schemas and inference-based choice. To address these challenges, we developed a novel, automated spatial TI task for rats using a radial maze with maze arms as premise elements and a dedicated deliberation zone. Most rats successfully learned the premise pairs over training. Further, animals demonstrated rapid, successful inference (test pair B > D and control pair A > E) within a single test session, with higher initial accuracy than comparable premise pairs, indicating the use of schema-based inference. We also investigated vicarious trial-and-error's (VTE), a behavioral correlate of spatial deliberation. VTE behavior was elevated on choice trajectories early in learning, when novel premise pairs were introduced, and generally for incorrect trials, corresponding to the hypothesized association of VTE's with uncertainty. Further, rats also exhibited elevated VTE behavior with high variability during inference testing, with individual variability suggestive of varying strengths of schema usage. Our findings demonstrate the feasibility of a rodent spatial TI task that provides new insights into the behavioral correlates of schemas and inference-based choices. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Using a novel behavioral paradigm that integrates fear-potentiated startle (FPS) and prepulse inhibition testing, this study examined how motherhood and infant cues impact innate defensive reactivity (as measured by the magnitude of basal startle reflex), attentional processing (as measured by prepulse inhibition), acquisition, and expression of conditioned fear (as measured by the FPS) in postpartum female rats. Sprague-Dawley mother rats from Postpartum Day 3-9 were tested in this paradigm either in the presence or absence of their own two pups (Experiments 1 and 2), and their performance was compared to virgin female rats and males (Experiment 3). Compared to mother rats tested alone, those tested with their pups being placed inside the apparatus (with no physical contact) showed significantly reduced baseline startle response and reduced overall startle magnitude under the FPS testing procedure. Importantly, this pup-induced reduction of baseline startle and fear startle was only observed in mother rats, not in virgin females or male rats. Notably, pup presence did not alter prepulse inhibition under various testing conditions nor did it affect the acquisition and expression of FPS. Also, postpartum females did not differ from virgin females and males in the acquisition and expression of conditioned fear. Together, these results suggest that distal pup cues may powerfully inhibit defensive reactivity in mother rats, without altering aversive learning or sensorimotor gating ability. The possible behavioral mechanisms involved in this pup effect are discussed. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Fear and anxiety are related but distinct responses to imminent versus uncertain threat. Suppression of eating under novelty is an evolutionarily conserved, cross-species model of anxiety, and it is beneficial to determine if this behavior can predict individual differences in fear learning and memory. The present study examined behaviors during novelty-induced suppression of eating and fear learning and memory in male and female rats, and determined which behaviors correlate across the two paradigms. Experiment 1a tested consumption of novel versus familiar food in a novel or familiar context across two sessions. During the first session, subjects in the novel context consumed less familiar food than those in the familiar context, demonstrating novelty-induced hypophagia. Novel food consumption did not differ by context. During the second session, all subjects increased consumption and reduced latency to eat, indicating habituation. Females consumed more novel food than males and more novel than familiar food. Experiment 1b tested Pavlovian auditory fear conditioning, extinction, and renewal. Behavioral responses were categorized under freezing, mobility, or neutral. Freezing increased during acquisition, decreased during extinction, and was renewed in the original acquisition context, confirming learning and memory in both sexes. In contrast, mobility behaviors increased during extinction and were not conditioned nor renewed. Neutral behaviors were high at baseline and suppressed during cue presentations. Lower novel food consumption correlated with higher freezing and lower mobility during extinction in males, but not females. This suggests that individual differences in novelty-induced anxiety can predict behavior during fear extinction in male rats. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

The hippocampus plays a critical role in contextual learning and memory processes. The ability to associate memories and behaviors with the learning context likely involves interactions between the hippocampus and other brain regions where the basic elements of the memory may be encoded. Here, we examined interactions of the hippocampus and the olfactory system using a contextually cued conditional discrimination task that required rats to remember that one odor from a pair of odor cues is rewarded in one context, but the opposite odor is rewarded in a different context. We used muscimol to inactivate the anterior olfactory nucleus, a key target for hippocampal output to the olfactory system, and the ventral hippocampus. We also performed crossed-hemisphere inactivation of the anterior olfactory nucleus in one hemisphere and the hippocampus in the other. All three inactivation procedures severely impaired performance. These results indicate that interactions between the hippocampus and anterior olfactory nucleus are critical for context-dependent odor memory. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Aging is associated with decline in spatial learning, cognitive flexibility, and working memory, yet the extent to which biological sex modulates changes in cognitive function remains unresolved. While sex differences are evident in pathological brain aging, sparse insights from healthy aging populations suggest that sex effects on cognition are modest and domain specific. To systematically test effects of biological sex across the lifespan on specific aspects of cognitive function, we examined age- and sex-related changes in spatial cognition in a large cohort of Fischer 344 rats (N = 373), including young (4-8 months), middle-aged (12-16 months), and older aged (22-26 months) males and females. Rats were assessed on spatial reference learning, reversal learning, and working memory versions of the Morris water maze, with performance quantified using proximity-based measures, providing sensitive, individualized indices of spatial learning. Across all tasks, age accounted for the largest proportion of variance, with older rats exhibiting impairments in spatial learning, flexibility, and working memory relative to young adults. In contrast, effects of sex or interactions with age were limited to certain aspects of performance and were substantially smaller relative to age and training effects. Specifically, a female-specific association between spatial reference memory and reversal learning was observed despite comparable overall performance. Performance on visible-platform control trials did not indicate gross sensorimotor impairments that would account for age-related spatial deficits. Together, findings demonstrate age is the primary determinant of spatial cognitive decline under normative conditions, while sex-related influences, if present, are subtle and task dependent. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Fear, an adaptive response to danger situation, is vital for the survival of both human beings and rodents. Predator odor-related cues and contextual fear work as valuable models for studying neurobiological circuits, providing insights into unconditioned and conditioned fear-related behavioral and physiological responses, including fear-related antinociception. This study investigated whether a fear paradigm based on predator odor cues could trigger the defensive antinociceptive phenomenon. Our findings indicate that while both the exposure to different predator odor cues and the re-exposure to the experimental context elicit similar defensive behaviors, such as the head-out response (an inhibitory avoidance behavior), only the exposure to the predator odor cues induced defensive antinociception. Notably, during the re-exposure to the experimental context, the endogenous pain modulatory system is not recruited, suggesting that defensive antinociception is not universally elicited by all fear-related reactions. Instead, defensive antinociception appears to be modulated by distinct neural circuits and olfactory perception-dependent mechanisms that adjust dynamically according to threat imminence. Thus, antinociception emerges as part of the immediate defensive response to a threatening odor cue, rather than as a consequence of fear memory retrieval. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Associating a taste with a positive or negative consequence is a robust form of learning that benefits survival by shaping future taste decisions. A robust example is conditioned taste aversion (CTA), wherein tastes associated with malaise are later avoided (Garcia et al., 1955; Lubow, 2009; Reilly & Bornovalova, 2005; Reilly & Schachtman, 2009). One factor that can modulate the strength of CTA learning is previous exposure to the conditioned taste. For example, familiarity with a taste weakens future learning toward that taste (Lubow, 1973, 2009; Lubow & Moore, 1959), demonstrating that even mere exposures to taste impact future plasticity. Taste exposure is ubiquitous in everyday life and begins in-utero. Recently, research has suggested that experience during specific periods of early life development can also induce preference and familiarity toward stimuli later in life, thus it is important to understand whether experience with tastes have differential effects on learning across the lifetime. Here, we explore for the first time whether sucrose exposure during different developmental stages in Long Evans rats (N = 55) differentially impacts sucrose-CTA learning in adulthood. Such an effect would suggest the existence of unique plasticity mechanisms that are influenced by taste exposure across different development phases. Interestingly, we report an enhancement of aversion learning in adult rats who were exposed to sucrose through their mother, either during gestation or lactation. These findings suggest that taste exposure during specific phases of early development holds unique significance for neuroplasticity and learning in adulthood. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Studies of brain lesions or volumes indicate that the integrity of medial and lateral temporal lobe structures is important for news event memory accuracy, but the relationship between cortical thickness and news event memory accuracy has not yet been investigated in older adults. In a mixed sample of 70 older adults with variable cognitive abilities but without dementia, we investigated the relationship between cortical volume, hippocampal volume, and cortical thickness with news event recognition memory accuracy across the entire adult lifespan using the Retrograde Memory News Events Test. Partial Least Squares analysis was used to identify brain regions where news event memory accuracy scores significantly correlated with cortical volume, hippocampal volume, and cortical thickness. We found that mean news event memory accuracy significantly correlated with volume/thickness for a network of regions that included the hippocampus, medial/lateral temporal lobe, medial/lateral parietal lobe, and specific areas within the medial/lateral prefrontal cortex. Poorer performance was associated with a thinner cortex (and smaller volumes). Almost all regions in this network exhibited decreasing brain-behavior correlations as the age of memory increased; thus, retrieval of remote memories was less reliant on the network. We also found regions in this network that were not identified by the Retrograde Memory News Events Test posttest (a measure of episodic anterograde memory for the Retrograde Memory News Events Test content) nor traditional neuropsychological tests. The regions identified as uniquely contributing to news event memory overlap with regions known to exhibit increasing Alzheimer's disease pathology and cortical thinning when pathology begins to spread outside of the medial temporal lobe. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Cocaine's reinforcing properties are a key factor underlying the broad prevalence of cocaine use disorder. Few behavioral measures are capable of assessing cocaine-induced euphoria in murine models, limiting effective treatment options. However, positive affective states can be measured in rats by assessing the production of high-frequency, 50-kHz, vocalizations. Oxytocin (OXT) has been shown to attenuate cocaine-mediated behaviors in rodent models; however, the effect of OXT on cocaine-induced euphoria remains unknown. We addressed this by randomly assigning female rats to saline-saline, saline-cocaine, OXT-saline, or OXT-cocaine conditions and then assessing ultrasonic vocalizations. We found that saline-cocaine animals emitted a significantly higher percentage of 50-kHz calls relative to the other conditions, indicative of cocaine's euphoric effects. Notably, an OXT pretreatment prevented the cocaine-induced increase in high-affect calls. We also found that OXT significantly increased call duration in cocaine animals, inducing aversivelike call properties and further suggesting that OXT may attenuate positive affective states. There were minimal differences in call bandwidth across groups and no significant differences in call amplitude. When assessing the ultrasonic vocalization's qualitative features, we found that cocaine led to an increased production of flat and short call types, both of which are associated with positive states, which were not attenuated by OXT. Altogether, we found that cocaine administration successfully produced a high affective state in female rats. Moreover, an OXT pretreatment was sufficient to decrease the rewarding effects of cocaine administration and therefore may play a vital role in treating those suffering from cocaine use disorder. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Aversion can arise from a combination of unconditioned stimuli that induce physical discomfort, such as pain and nausea. Chemotherapy-induced side effects, including taste and olfactory aversion, can persist even after treatment has ended, thereby reducing the quality of life. Currently, however, no effective pharmacological interventions exist for treating chemotherapy-induced conditioned aversion learning. Therefore, elucidating its underlying mechanisms is of great importance. In this study, we investigated cisplatin-induced olfactory aversion learning using the two-bottle choice test. Cisplatin was found to induce aversive responses to neutral odorants, namely isoamyl acetate and benzaldehyde. Notably, we obtained two key findings. First, an odor solution that was not aversive in the two-bottle choice test (i.e., distilled water) became aversive to mice when compared with a third novel odor solution that had not been presented in the test. Second, when pairs of three odorants were alternated over an extended period, the mice occasionally shifted their aversive responses as the pairings changed. In clinical practice, patients are exposed to a variety of odors. Thus, the new insights gained from this study on olfactory aversion may help inform the development of novel treatments for chemotherapy-related side effects. (PsycInfo Database Record (c) 2026 APA, all rights reserved).