Are there sex differences in spatial reference memory in the Morris water maze? A large-sample experimental study.

Sex differences have been found in allocentric spatial learning and memory tasks, with the literature indicating that males outperform females, although this issue is still controversial. This study aimed to explore the behavior of male and female rats during the habituation and learning of a spatial memory task performed in the Morris Water Maze (MWM). The study included a large sample of 89 males and 85 females. We found that females searched slightly faster than males during habituation with a visible platform. During learning, both male and female rats decreased the latency and distance traveled to find the hidden platform over the days, with males outperforming females in the distance traveled. Females swam faster but did not find the platform earlier, suggesting a less directed navigational strategy. Both sexes increased time spent in the target zone over the days, with no sex differences. Although females swam more in the periphery during the first days of the task, both sexes decreased the time spent in this area. Finally, only males increased swimming in the pool's center over the days, spending more time than females in this area across the entire training. In conclusion, we need to register several variables in the MWM and analyze path strategies to obtain more robust results concerning sex differences. Research on spatial learning should include both sexes to achieve a more equitable, representative, and translational science.

Unfolding of spatial representation at systems level in infant rats.

Spatial representations enable navigation from early life on. However, the brain regions essential to form spatial representations, like the hippocampus, are considered functionally immature before weaning. Here, we examined the formation of representations of space in rat pups on postnatal day (PD) 16, using a simple habituation paradigm where the pups were exposed to an arena on three occasions, separated by ~140 min. Whereas on the first two occasions the arena was the same, on the third "test" occasion either proximal cues (Prox group), or distal cues (Dist group), or proximal and distal cues (Prox-Dist group), or no cues (No-change group) were rearranged. Locomotion (distance traveled) was used as behavioral measure of habituation, and c-Fos expression to measure regional brain activity at test. Locomotion generally decreased across the first two occasions. At test, it reached a minimum in the No-change group, indicating familiarity with the spatial conditions. By contrast, the Prox-Dist group displayed a significant increase in locomotion which was less robust in the Prox group and absent in the Dist group, a pattern suggesting that the pups relied more on proximal than distal cues during spatial exploration. c-Fos activity in the No-change group was significantly suppressed in the hippocampus (CA1, CA3, dentate gyrus) but simultaneously enhanced in the prelimbic area (PL) of the medial prefrontal cortex, compared with untreated Home-cage controls, pointing to a possible involvement of the PL in regulating locomotion in familiar spaces. By contrast, in both Prox-Dist and Prox groups c-Fos activity was enhanced in hippocampal CA1 and CA3 regions, suggesting these regions might be particularly involved in regulating exploration of spatial novelty. Our findings show that functional representations of space at a systems level are formed already in pre-weanling rats.

Early life stress due to repeated maternal separation alters the working memory acquisition brain functional network.

Unfortunately, adverse environments in early life are frequently found in most human populations. Early life stress leads to diverse cognitive impairments, some of them related to learning and memory and executive functions such as working memory (WM). We employ an animal model of early stress using repeated maternal separation (MS) for 4 h a day on 21 consecutive days, pre-weaning. In adulthood, we tested their spatial WM using the Morris water maze. MS subjects showed a marked delay in the acquisition of the task. In addition, we explored brain energy oxidative metabolism and found an increase in cytochrome c oxidase (CCO) activity in the cingulate cortex, anterior thalamus, and supramammillary areas, indicating an intense effort to successfully solve the WM task. However, decreased CCO activity was found in the medial-medial mammillary nucleus in MS animals, which would partially explain the delayed acquisition of the WM task. Further studies are needed to explore the long-term alterations produced by early stress. LAY SUMMARY A stressful environment caused by the separation of baby rats from the mother for several hours a day in the first stages of postnatal life can be devastating to brain cells, making them look for alternative sources of energy, among other changes. These alterations in brain functional networks would lead to cognitive impairments such as the delayed acquisition of new learning and strategies.

Sex disparities in the prevalence of physical function disabilities: a population-based study in a low-income community.

BACKGROUND: Functional disability continues to be a significant public health problem that increases older adults' vulnerability to experience a diminished quality of life, loss of independence, higher healthcare costs and health services utilization, and increased risks of mortality. Thus, we aimed to study the prevalence of functional disabilities by sex according to the types of daily living activities, controlling for specific sociodemographic variables among older Hispanics from low-income communities. METHODS: We used a cross-sectional epidemiological research design, considering a complex sampling design of households to interview adults ≥65 years living in low-income communities in Puerto Rico. Functional disability was measured by the PROMIS® Physical Function Short Form-20 T-score. The selected community was reported to have 5980 adult residents ≥65 years, according to the USA Census. The prevalence of functional disability was estimated using the logistic regression model, weighting by the effect of the sampling. Our estimated prevalence was compared between sexes using the prevalence ratio (PR), which was estimated with logistic regression models, controlling for age, income, number of chronic conditions, high and low impact of chronic conditions in functional disabilities, marital status, and sampling design. RESULTS: We recruited 211 older Hispanics from a randomly selected sample. Their mean age was 74.4 ± 7.1 years, with female predominance (57.3%). The overall estimated prevalence of physical function disability using T-score among females was 2.70 (95% CI: 1.4, 5.1) times the estimated prevalence of physical function disability among males. Women were more likely to report functional disabilities in instrumental activities of daily living, self-care activities, and functional mobility compared to males. However, sex differences were largely explained by the presence of musculoskeletal conditions of high impact in functional disability. CONCLUSIONS: The females in our study bear the greater burden of physical function disability in their adult age. Health policies, as well as future studies, should be targeted at reducing the burden of physical function disabilities in different types of daily activities through gender-sensitive disability self-management programs.

Retrieval of allocentric spatial memories is preserved up to thirty days and does not require higher brain metabolic demands.

Spatial orientation is a cognitive ability that is indispensable for survival. Several visual distal cues present in the context can be integrated, establishing a cognitive map. Although there is cumulative evidence about the neural substrate involved in spatial memory acquisition, the brain networks mediating the processes involved in the retrieval of allocentric spatial memories have been studied less. Here, we aimed to explore the role of neuronal oxidative metabolism in the retrieval of allocentric spatial memories through cytochrome c oxidase (CCO) histochemistry seven, 15, 30, 45, and 60 days after task acquisition. Our behavioural results show that spatial memory retrieval in male and female rats is preserved seven, 15, and 30 days post-acquisition, but there is forgetfulness after this time, with subjects not being able to remember the position of the hidden platform after 45 and 60 dfearays. Regarding the study of male brain metabolism, we observed reduced CCO activity in the medial prefrontal cortex, the parietal, retrosplenial, rhinal cortex, and the hippocampal regions in all the groups that failed to solve the task. Similar results were found for female brain oxidative metabolism, in addition to certain differences between succefearssful-retrieval female groups. In conclusion, our work adds information about the behavioural retrieval of an allocentric spatial reference task, suggesting that recovering spatial information seven, 15, and 30days after acquisition is a simple task that does not require a high metabolic demand, in both male and female rats.

How Does Maternal Separation Affect the Cerebellum? Assessment of the Oxidative Metabolic Activity and Expression of the c-Fos Protein in Male and Female Rats.

Early life stress increases the risk of abnormal brain development, and it is associated with psychological disorders. Maternal separation is an established animal model of early life stress that produces changes in the development of the central nervous system. The objective of this study was to evaluate the effect of maternal separation on the rat cerebellum, both behaviourally and physiologically. We used 32 rats, males (n = 8) and females (n = 7), subjected to maternal separation for 21 days and a control group (9 males and 8 females). Spatial reference memory was assessed using the Morris water maze, and brain metabolic activity and the expression of an immediate early gene were determined, respectively, using the histochemical technique of cytochrome c oxidase and the immunocytochemistry of c-Fos. Results showed that both groups successfully performed the spatial memory task. Although there were no behavioural differences, the experimental group showed lower metabolic activity in the medial nucleus of the cerebellum, as well as fewer c-Fos-positive cells in the three deep nuclei of the cerebellum. These decreases could contribute to the emotional or behavioural impairments reported in maternal separation subjects.

[Identification of behavioural and emotional problems in premature children in the primary care setting]. / Identificación de problemas de conducta y emocionales en niños prematuros en el ámbito de atención primaria.

OBJECTIVE: To demonstrate the usefulness, for use by the primary care pediatrician, of the BASC questionnaire (Behavior Assessment System for Children) for the early detection of psychological and behavioral problems in premature infants. DESIGN: Cross-sectional and descriptive study. SETTING: Primary care (Health Area IV of the Principado of Asturias) and Hospital Universitario Central de Asturias, Spain. PARTICIPANTS: Parents of 87 premature children with birth weight less than 1500g and 43 full-term controls, both aged 5-7 years. MAIN MEASUREMENTS: The BASC questionnaire (parent version) was applied. RESULTS: Preterm children presented a high rate of inactivity (Z = -4.125, P < 0.001), anxiety (Z = -2.801, P = 0.005) and internalization problems (Z = -2.148, P = 0.032), being more evident at 5 years of age. Preterm boys show higher levels of hyperactivity (Z = -2.082, P = 0.037) and behavioural problems (Z = -2.354, P = 0.019) than girls, who presented more attentional problems (Z = -2.345; P = 0.019). CONCLUSIONS: The BASC questionnaire is useful for the detection and early diagnosis at the primary care level of the behavioral and emotional problems of premature children.

Measurement instruments of online gaming disorder in adolescents and young people according to DSM-5 criteria: a systematic review. / Instrumentos de medida del trastorno de juego en internet en adolescentes y jóvenes según criterios DSM-5: una revisión sistemática.

The inclusion of Internet Gaming Disorder (IGD) in the DSM-5 has generated controversy over its diagnosis, and it therefore seems necessary to establish a clear cut-off point to identify when excessive gaming becomes problematic. Such identification is especially difficult in adolescents and young people, who frequently dedicate a great deal of time to online games. The goal of this systematic review was to analyze the instruments developed to assess IGD in adolescents and young people since its inclusion in the DSM-5. We identified 13 studies which included validations of seven assessment instruments for IGD in adolescents and young people. Each instrument and its validations in different languages are described. In comparison to previous reviews, a lower diversity of assessment instruments, a reduction in the number of items and a more uniform form of measurement was observed, maintaining high internal consistency and good criterion validity. However, problems related to sample selection, the lack of sensitivity and specificity studies, and the establishment of cut points and profiles of gamers remain. Advances in the analysis of the psychometric qualities of the instruments and their validation in different countries are needed, and cultural differences should be considered in order to allow the prevalence of this problem to be compared.

La inclusión del Trastorno de Juego en Internet (TJI) en el DSM-5 ha generado polémica sobre su diagnóstico, no obstante parece necesario establecer un punto de corte claro para identificar cuando este juego excesivo se convierte en problemático. Esta identificación se hace especialmente difícil en adolescentes y jóvenes, entre los que suele ser frecuente la dedicación a este tipo de juegos. El objetivo de esta revisión sistemática fue analizar los instrumentos que desarrollados para la evaluación del TJI en adolescentes y jóvenes desde su inclusión en el DSM-5. Se identificaron 13 estudios que incluían validaciones de 7 instrumentos de evaluación del TJI en adolescentes y jóvenes. Se describió cada instrumento y sus validaciones en distintos idiomas. En relación con revisiones previas, se observó una menor diversidad de instrumentos de evaluación, una reducción en el número de ítems y una forma de medida más uniforme, manteniéndose una alta consistencia interna y una buena validez de criterio. Sin embargo, siguen presentes los problemas referidos a la selección de muestras, la falta de estudios de sensibilidad y especificidad, y el establecimiento de puntos de corte y perfiles de jugadores. Se recomienda avanzar en el análisis de las cualidades psicométricas de los instrumentos, y su validación en distintos países para considerar las diferencias culturales y poder comparar la presencia de este problema.

Early life stress by repeated maternal separation induces long-term neuroinflammatory response in glial cells of male rats.

Childhood maltreatment and neglect lead to a wide range of mental disorders highlighted by hormone and immune alterations in neglected children. This social-health challenge has led to the creation of early stress models such as maternal separation (MS) in rodents. We performed a MS model (4 h per day, 21 days; n = 16 MS and n = 16 control), and then measured three parameters in adult male rat brains, in order to look for long-term effects of early life stress. We used immunocytochemistry to mark glial fibrillary acidic protein (GFAP)-positive cells, which indicates changes in astroglia, and ionized calcium binding adaptor molecule 1 (Iba-1)-positive cells, which inform about reactive microglia. In order to study mRNA levels of some immune mediators, interleukin determination (interleukin-6, IL-6; tumor necrosis factor, TNFα) mRNAs were evaluated by real-time polymerase chain reaction (rt-PCR) in discrete brain regions. Measurements of numbers of GFAP-positive cells, and expression of Iba-1, IL-6 and TNFα mRNAs were performed in prefrontal cortex (PFC): cingulate cortex (CG), prelimbic cortex (PL) and infralimbic cortex (IL), striatal areas (dorsal striatum, STD; and nucleus accumbens, ACC), and dorsal hippocampus (HC: CA1, CA3 and dentate gyrus (DG)). We found that MS produces a dramatic and sustained decrease in the astroglial population in all the areas measured (from -25% in CA1 to -85.7% in ACC), whereas increased numbers of microglia were found, in more restricted regions: STD (72.6%), ACC (31%) and CA3 (33.3%) areas. Regarding mRNA measurements, we found increased IL-6 mRNA expression in HC (104.2%), and after MS.

Comparative Study of 10 X-STR Markers in Populations of Northeast Argentina.

In northeast Argentina, different Amerindian communities share territory and history with settlers, mainly Europeans. Due to miscegenation, the current Argentinean population has a particular structure that can be described through X chromosome variation. The objectives of this study were to describe the variation of 10 X-chromosome short tandem repeats (X-STRs) in urban populations of the Argentinean regions known as Gran Chaco and Mesopotamia, report the forensic parameters of these STRs, and estimate the European and indigenous genetic components in these regions. Population and forensic parameters were estimated for 419 individuals from the analyzed populations, including two indigenous groups, Wichí and Mocoví, previously reported. Population structure was estimated through FST and RST distances and analysis of molecular variance. The indigenous American and European components were assessed with STRUCTURE. X-STRs showed a high level of genetic variability in urban and indigenous populations. Indigenous people of the Gran Chaco region showed significant differentiation from the urban samples (FST = 5.5%) and among themselves (FST = 5.3%). Genetic differentiation among urban groups was almost negligible, except that the population from Misión Nueva Pompeya differed from the rest of the city populations. Forensic parameters indicate that these X-STRs are useful as a complement to paternity tests. The set of 10 STRs could be a good tool for examining population differences.

Why are maternally separated females inflexible? Brain activity pattern of COx and c-Fos.

Subjects' early life events will affect them later in life. When these events are stressful, such as child abuse in humans or repeated maternal separation in rodents, subjects can show some behavioral and brain alterations. This study used young adult female Wistar rats that were maternally raised (AFR), maternally separated from post-natal day (PND) 1 to PND10 (MS10), or maternally separated from PND1 to PND21 (MS21), in order to assess the effects of maternal separation (MS) on spatial learning and memory, as well as cognitive flexibility, using the Morris Water Maze (MWM). We performed quantitative cytochrome oxidase (COx) histochemistry on selected brain areas in order to identify whether maternal separation affects brain energy metabolism. We also performed c-Fos immunohistochemistry on the medial prefrontal cortex (mPFC), thalamus, and hippocampus to explore whether this immediate early gene activity was altered in stressed subjects. We obtained a similar spatial learning pattern in maternally raised and maternally separated subjects on the reference memory task, but only the controls were flexible enough to solve the reversal learning successfully. Separated groups showed less c-Fos activity in the mPFC and less complex neural networks on COx.

Profiling Lung Cancer Patients Using Electronic Health Records.

If Electronic Health Records contain a large amount of information about the patient's condition and response to treatment, which can potentially revolutionize the clinical practice, such information is seldom considered due to the complexity of its extraction and analysis. We here report on a first integration of an NLP framework for the analysis of clinical records of lung cancer patients making use of a telephone assistance service of a major Spanish hospital. We specifically show how some relevant data, about patient demographics and health condition, can be extracted; and how some relevant analyses can be performed, aimed at improving the usefulness of the service. We thus demonstrate that the use of EHR texts, and their integration inside a data analysis framework, is technically feasible and worth of further study.

Sexual transmission-risk behaviour among HIV-positive persons: a multisite study using social action theory.

AIM: Sexual risk behaviour was explored and described using Social Action Theory. BACKGROUND: The sexual transmission of HIV is complex and multi-factorial. Social Action Theory provides a framework for viewing self-regulation of modifiable behaviour such as condom use. Condom use is viewed within the context of social interaction and interdependence. DESIGN: Cross-sectional survey. METHODS: Self-report questionnaire administered to adults living with HIV/AIDS, recruited from clinics, service organizations and by active outreach, between 2010 - 2011. FINDINGS: Having multiple sex partners with inconsistent condom use during a 3-month recall period was associated with being male, younger age, having more years of education,substance use frequency and men having sex with men being a mode of acquiring HIV. In addition, lower self-efficacy for condom use scores were associated with having multiple sex partners and inconsistent condom use. CONCLUSION: Social Action Theory provided a framework for organizing data from an international sample of seropositive persons. Interventions for sexually active, younger, HIV positive men who have sex with men, that strengthen perceived efficacy for condom use, and reduce the frequency of substance use, may contribute to reducing HIV-transmission risk.

A multinational qualitative investigation of the perspectives and drivers of exercise and dietary behaviors in people living with HIV.

Globally, people living with HIV (PLWH) are at remarkably high risk for developing chronic comorbidities. While exercise and healthy eating reduce and mitigate chronic comorbidites, PLWH like many others, often fail to engage in recommended levels. We qualitatively examined the perspectives and contextual drivers of diet and exercise reported by PLWH and their health care providers. Two hundred and six participants across eight sites in the United States, Puerto Rico and Botswana described one overarching theme, Arranging Priorities, and four subthemes Defining Health, Perceived Importance of Diet and Exercise, Competing Needs, and Provider Influence. People living with HIV and their health care providers recognize the importance of eating a healthy diet and engaging in regular exercise. Yet there are HIV-specific factors limiting these behaviors that should be addressed. Health care providers have an important, and often underutilized opportunity to support PLWH to make improvements to their exercise and diet behavior.

Low-light-level therapy as a treatment for minimal hepatic encephalopathy: behavioural and brain assessment.

Minimal hepatic encephalopathy (MHE) has been shown to affect daily functioning, quality of life, driving and overall mortality. However, little is known about treating or diagnosing early impairments involved in MHE. We studied one of its precipitating factors, portal hypertension. The purpose was to evaluate an enhancement in neuronal metabolism through low-light-level therapy (LLLT) and whether this therapy has effects on behavioural task acquisition. Rats were trained to perform a stimulus-response task using the Morris water maze. Three groups of animals were used: a SHAM (sham-operated) group (n = 7), a portal hypertension (PH) group (n = 7) and a PH + LLLT group (n = 7). The triple portal vein ligation method was used to create an animal model of the early developmental phase of HE, and then the animals were exposed to 670 + 10 nm LED light at a dose of 9 J/cm2 once a day for 7 days. The metabolic activity of the brains was studied with cytochrome c oxidase histochemistry. There were differences in behavioural performance, with an improvement in the PH + LLLT group. Energetic brain metabolism revealed significant differences between the groups in all the brain structures analysed, except the anterodorsal thalamus. At the same time, in different brain networks, the PH group showed a more complicated relationship among the structures, while the SHAM and PH + LLLT groups had similar patterns. In this study, we provide the first preliminary insights into the validity of LLLT as a possible intervention to improve memory under minimal hepatic encephalopathy conditions.

The importance of the context in the hippocampus and brain related areas throughout the performance of a fear conditioning task.

The importance context has been broadly studied in the management of phobias and in the drug addiction literature. The way in which changes to a context influence behavior after the simple acquisition of a passive avoidance task remains unclear. The hippocampus has long been implicated in the contextual and spatial processing required for contextual fear, but its role in encoding the aversive component of a contextual fear memory is still inconclusive. Our work tries to elucidate whether a change in context, represented as differences in the load of the stimuli, is critical for learning about the context-shock association and whether this manipulation of the context could be linked to any change in metabolic brain activity requirements. For this purpose, we used an avoidance conditioning task. Animals were divided into three different experimental conditions. In one group, acquisition was performed in an enriched stimuli environment and retention was performed in a typically lit chamber (the PA-ACQ-CONTX group). In another group, acquisition was performed in the typically lit chamber and retention was undertaken in the highly enriched chamber (the PA-RET-CONTX group). Finally, for the control group, PA-CN-CONTX, acquisition, and retention were performed in the enriched stimuli environment. Our results showed that the PA-ACQ-CONTX group had longer escape latencies and poorer retention than the PA-RET-CONTX and PA-CN-CONTX groups after 24 h of acquisition under contextual changes. To study metabolic brain activity, histochemical labelling of cytochrome c-oxidase (CO) was performed. CO results suggested a neural circuit including the hippocampus, amygdala, thalamus, parahippocampal cortices, and mammillary nuclei that is involved in the learning and memory processes that enable context-dependent behavior. These results highlight how dysfunction in this network may be involved in the contextualization of fear associations that underlie several forms of psychopathology, including post-traumatic stress disorder, schizophrenia, and substance abuse disorders.

Self-compassion and risk behavior among people living with HIV/AIDS.

Sexual risk behavior and illicit drug use among people living with HIV/AIDS (PLWHA) contribute to poor health and onward transmission of HIV. The aim of this collaborative multi-site nursing research study was to explore the association between self-compassion and risk behaviors in PLWHA. As part of a larger project, nurse researchers in Canada, China, Namibia, Puerto Rico, Thailand and the US enrolled 1211 sexually active PLWHA using convenience sampling. The majority of the sample was male, middle-aged, and from the US. Illicit drug use was strongly associated with sexual risk behavior, but participants with higher self-compassion were less likely to report sexual risk behavior, even in the presence of illicit drug use. Self-compassion may be a novel area for behavioral intervention development for PLWHA.

How people with brain injury run and evaluate a SLAM-based smartphone augmented reality application to assess object-location memory.

Augmented reality (AR) technology allows virtual objects to be superimposed on the real-world environment, offering significant potential for improving cognitive assessments and rehabilitation processes in the field of visuospatial learning. This study examines how patients with acquired brain injury (ABI) evaluate the functions and usability of a SLAM-based smartphone AR app to assess object-location skills. Ten ABI patients performed a task for the spatial recall of four objects using an AR app. The data collected from 10 healthy participants provided reference values for the best performance. Their perceptions of the AR app/technology and its usability were investigated. The results indicate lower effectiveness in solving the task in the patient group, as the time they needed to complete it was related to their level of impairment. The patients showed lower, yet positive, scores in factors related to app usability and acceptance (e.g., mental effort and satisfaction, respectively). There were more patients reported on entertainment as a positive aspect of the app. Patients' perceived enjoyment was related to concentration and calm, whereas usability was associated with perceived competence, expertise, and a lower level of physical effort. For patients, the sensory aspects of the objects were related to their presence, while for healthy participants, they were related to enjoyment and required effort. The results show that AR seems to be a promising tool to assess spatial orientation in the target patient population.

An immersive virtual reality-based object-location memory task reveals spatial long-term memory alterations in Long-COVID.

Object-location memory (OLM) is a type of declarative memory for spatial information and consists of the individual's ability to establish accurate associations between objects and their spatial locations. Long-COVID describes the long-term effects of the COVID-19 disease. Long-COVID patients show medial temporal lobe dysfunction and neuropsychological alterations affecting memory. This study aimed to assess OLM in a group of Long-COVID patients, n=66, and a Control group of healthy individuals with similar age and sex composition, n=21, using an immersive virtual reality (iVR)-based OLM task. We also explored associations between the performance in the iVR-based OLM task and general cognitive function (MoCA), and both verbal (VSTM) and visuospatial (SSTM) span. The Long-COVID group showed fewer correct responses, made more task attempts, and invested more time in the iVR-based OLM task than the Control group. Delayed memory was more severely altered than immediate memory in Long-COVID participants. Better MoCA scores of the Long-COVID group were strongly associated with shorter times to complete the immediate recall of the iVR-based OLM task. Besides, the months elapsed since the COVID-19 infection were slightly associated with fewer correct responses in the immediate and 24-hour recalls. These results corroborate previous findings of memory alterations in the Long-COVID syndrome using an iVR-based OLM task, adding new evidence on spatial memory and long-term memory in this population. Implementing spatial iVR tasks to clinical research may improve our understanding of neuropsychological disorders.

Context memory formed in medial prefrontal cortex during infancy enhances learning in adulthood.

Adult behavior is commonly thought to be shaped by early-life experience, although episodes experienced during infancy appear to be forgotten. Exposing male rats during infancy to discrete spatial experience we show that these rats in adulthood are significantly better at forming a spatial memory than control rats without such infantile experience. We moreover show that the adult rats' improved spatial memory capability is mainly based on memory for context information during the infantile experiences. Infantile spatial experience increased c-Fos activity at memory testing during adulthood in the prelimbic medial prefrontal cortex (mPFC), but not in the hippocampus. Inhibiting prelimbic mPFC at testing during adulthood abolished the enhancing effect of infantile spatial experience on learning. Adult spatial memory capability only benefitted from spatial experience occurring during the sensitive period of infancy, but not when occurring later during childhood, and when sleep followed the infantile experience. In conclusion, the infantile brain, by a sleep-dependent mechanism, favors consolidation of memory for the context in which episodes are experienced. These representations comprise mPFC regions and context-dependently facilitate learning in adulthood.