Long-term Memory Retention Research Articles

Influence of the L-carnitine and resveratrol complex on physiological, biochemical and morphological indicators of normal and obese rats

Specialized products and dietary supplements, enriched with complexes of minor biologically active substances (BAS), are often offered as components of therapeutic diets in the treatment of obesity and metabolic syndrome. At the same time, the possible effects of the interactions of BAS when consuming a multicomponent product have not been studied enough. The aim - to study the action on rats' organism of a complex supplement (RС), containing resveratrol (Res) and L-carnitine (L-Car), when consumed with a standard balanced or hypercaloric diet. Material and methods. Male Wistar rats received for 63 days a standard balanced diet (SD) or a high-fat-high-carbohydrate diet (HFCD) with an excess of total fat (30%) and fructose (20% solution instead of drinking water), or the same diets supplemented with RС in a low (25 mg/kg body weight as Res and 300 mg/kg body weight as L-Car) or high (50 and 600 mg/kg body weight, respectively) doses. The muscle grip strength, behavioral reactions in tests of the conditioned passive avoidance reflex (CPAR) and elevated plus maze (EPM) were studied. At the end of the experiment, the mass of adipose tissue and internal organs was determined together with the activity of microsomal and cytosolic liver enzymes for specific substrates, plasma biochemical parameters, liver morphology by lightoptical microscopy, accumulation of lipofuscin-like granules (LLG) in the liver and kidneys by laser confocal microscopy. Results. In the rats fed HFCD, compared with SD, there was an increase in the mass index of liver, total inguinal and retroperitoneal white adipose tissue, in the levels of glucose and triglycerides, in the activity of hepatic CYP1A1 and CYP3A monooxygenases, UDPglucuronosyltransferase, heme oxygenase, and simultaneous decrease of high and low density lipoprotein cholesterol, and quinone oxidoreductase activity. The RС intake stimulated the locomotor activity of rats in EPM, however, this effect was less pronounced against the background of HFCD consumption. In rats consuming SD (but not HFCD), the addition of RС caused an increase in search activity and anxiety according to the EPM and CPAR data. The effect on short- and long-term memory retention was statistically insignificant. RС intake did not have hypolipidemic and hypoglycemic properties but caused in low dose an increase in the ratio of the activity of transaminases AST/ALT in animals fed HFCD. The liver CYP3A activity increased in rats supplemented with RС in high dose fed HFCD. In the kidneys of animals, the consumption of RС resulted in increased accumulation of LLG. Conclusion. When studying the effect of the complex supplement RС on normal and obese rats according to the studied physiological, morphological and biochemical indexes, no positive effects were revealed, that would not have manifested themselves for Res and L-Car separate intake. No evidence of synergistic action of L-Car and Res were found, and some of the effects of the complex supplement can be considered as adverse. This requires careful assessment when combined using these substances in complex diet therapy of metabolic disorders in humans.

The Effect of Chronic Treatment with Lacosamide and Topiramate on Cognitive Functions and Impaired Emotional Responses in a Pilocarpine-induced Post-statusEpilepticus Rat Model.

Epilepsy and antiepileptic drugs can affect negatively the cognitive abilities of patients. The present study aimed to evaluate the effect of topiramate (TPM) and lacosamide (LCM) on the emotional and cognitive re-sponses in naive animals and in animals with pilocarpine-induced status epilepticus. Male Wistar rats were randomly divided into 6 groups and status epilepticus was evoked in half of them by a single i.p. administration of pilocarpine (Pilo) (320 mg/kg): Pilo-veh, Pilo-TPM (80 mg/kg) and Pilo-LCM (30 mg/kg). Matched naive rats were treated with the same doses as follows: C-veh, C-TPM, and C-LCM. In a step-down passive avoidance test, the learning session was held for one day, the early retention test was conducted on day 2, and the long-term memory test - on day 7. Motor activity and anxiety were evaluated in an open field test. The Pilo-TPM and Pilo-LCM groups increased the time spent on the platform compared to Pilo-veh animals while the C-LCM animals decreased the time compared to C-veh animals during short- and long-term memory retention tests. TPM and LCM exerted an anxiolytic effect in naive rats. The two antiepileptic drugs were unable to alleviate the hyperactivity, but they alleviated the impulsivity associated with decreased anxiety level in epileptic rats. Our findings suggest that LCM and TPM have a beneficial effect on cognition both in naive and epileptic rats. While the two antiepileptic drugs can produce an anxiolytic effect in naive rats, they alleviate the impulsivity after pilocarpine treatment.

Examining the effects of training on young and older adult implementation of spaced retrieval strategies

ABSTRACT Although the benefits of spaced retrieval are well established, research suggests that young and older adults often fail to optimally implement this strategy. The present study examined how task experience with feedback influenced participant-implemented spaced retrieval and its effect on short and long-term memory retention. Young and older adults were instructed to either equally space or expand their retrieval of face-name associations throughout an ongoing reading task. Participants were then provided feedback on the accuracy with which they implemented experimenter instructions. Results showed that feedback improved utilization of retrieval practice in both young and older adults. Moreover, both age groups successfully produced a pattern of expanded retrieval when instructed to do so, but failed to properly implement equal spacing. Consistent with extant research utilizing experimenter-determined spaced retrieval schedules, our study showed that the inclusion of a longer spacing interval immediately following acquisition resulted in reduced forgetting across the retention interval.

Electrical Brain Stimulation During a Retrieval-Based Learning Task Can Impair Long-Term Memory

Anodal transcranial direct current stimulation (tDCS) to the left dorsolateral prefrontal cortex (DLPFC) has been shown to improve performance on a multitude of cognitive tasks. These are, however, often simple tasks, testing only one cognitive domain at a time. Therefore, the efficacy of brain stimulation for complex tasks has yet to be understood. Using a task designed to increase learning efficiency, this study investigates whether anodal tDCS over the left DLPFC can modulate both learning ability and subsequent long-term memory retention. Using a within-subject design, participants (N = 25) took part in 6 training sessions over consecutive days in which active or sham stimulation was administered randomly (3 of each). A computer-based task was used, containing flags from countries unknown to the participants. Each training session consisted of the repetition of 8 pairs of flag/country names. Subsequently, in three testing sessions, free, cued, and timed cued recall, participants were assessed on all 48 flags they had learnt. No difference in learning speed between active and sham tDCS was found. Furthermore, in the timed cued recall phase, flags learnt in the sham tDCS sessions were recalled significantly better than flags learnt in the active tDCS sessions. This effect was stronger in the second testing session. It was also found that for the flags answered incorrectly; thus, meaning they were presented more frequently, subsequent long-term retention was improved. These results suggest that for a complex task, anodal tDCS is ineffective at improving learning speed and potentially detrimental to long-term retention when employed during encoding. This serves to highlight the complex nature of brain stimulation, providing a greater understanding of its limitations and drawbacks.

Retrieval Practice: Beneficial for All Students or Moderated by Individual Differences?

Retrieval practice is a learning technique that is known to produce enhanced long-term memory retention when compared to several other techniques. This difference in learning outcome is commonly called “the testing effect”. Yet there is little research on how individual differences in personality traits and working memory capacity moderate the size of the retrieval-practice benefits. The current study is a conceptual replication of a previous study, further investigating whether the testing effect is sensitive to individual differences in the personality traits Grit and Need for Cognition, and working memory capacity. Using a within-subjects design ( N = 151), participants practiced 60 Swahili–Swedish word pairs (e.g., adhama–honor) through retrieval practice and re-studying. Learning was assessed at three time points: five minutes, one week, and four weeks after practice. The results revealed a significant testing effect at all three time points. Further, the results showed no association between the testing effect and the personality traits, or between the testing effect and working memory, at any time point. To conclude, retrieval practice seems to be a learning technique that is not moderated by individual differences in these specific personality traits or with working memory capacity, thus possibly beneficial for all students.

Improvement of Memory and Motivation in Language Learning in Primary Education through the Interactive Digital Whiteboard (IDW): The Future in a Post-Pandemic Period

This paper presents an analysis of the use of an interactive digital whiteboard (IDW) and a computer application called Action Manager (AM), with a sample of 158 sixth-grade students in primary education. Subsequently, a study was carried out with the main goal of testing the didactic functioning of AM and examining the validity of this application, in terms of motivation and the retention of both short and long-term memory when teaching foreign languages in primary education. In order to fulfil these objectives, we performed a positivist exploratory study based on a quantitative methodology combining qualitative aspects (qualitative evaluation) and quantitative aspects (questionnaires) as well as a descriptive method with a survey design. The data collection was performed using instruments, specifically the Extrinsic vs. Intrinsic Orientation Scale, to ascertain the motivational impressions of the students and two memory tests, the Test of Memory and Learning (TOMAL) and the Children’s Memory Scale (CMS). Forty-five days later, the two memory tests were repeated to compare the results with the previous ones. After this experience, the results allowed us to conclude that the students demonstrated optimal memorization from a conceptual point of view, in addition to having improved their motivational impressions.

Long-term consumption of virgin coconut (Cocos nucifera) oil diet impairs learning and memory in CD1 mice

ObjectiveVirgin coconut oil (VCO) has been used in the management of dementia in Alzheimer’s disease (AD). Therefore, this research investigated the effect of long-term consumption of VCO diet on learning and memory in CD1 mice. MethodsThirty male CD1 mice (divided into three groups, n = 10) were fed with standard rodent chow (control), 5% and 20% VCO diets (respectively) for 28 d. The Morris Water Maze (MWM) test was used to test the effect of VCO on visuo-spatial learning and memory, while the Novel Object Recognition Test (NORT) was used to measure short- and long-term recognition memory. ResultsLearning performance of mice did not differ in the MWM. During the probe trial, duration in the retention quadrant and annulus crossings were lower (P < 0.05) in the 5% and 20% VCO diet groups compared to the control diet group, showing that VCO impaired visuo-spatial memory. During the NORT, mice showed more total approaches in the 20% VCO diet group (P < 0.05) compared to control and the 5% VCO diet groups during the short-term memory test. During the long-term memory retention test, the total approaches were also higher in the 20% VCO group compared to control and 5% VCO group (P > 0.05). The discrimination index was also lower in the 20% VCO group compared to control and 5% VCO diet groups indicating impaired long-term cognitive memory in mice given 20% VCO diet. Histological examination of brains showed damage within the CA1 pyramidal cell layer of the hippocampus in the 20% VCO diet group, in line with the behavioural observations. ConclusionLong-term consumption of virgin coconut oil diet impairs memory in mice.

Memory deficits in Sprague Dawley rats with spontaneous ventriculomegaly

IntroductionSpontaneous ventriculomegaly has been observed in rats that were presumed normal. Because the external phenotype of these animals is unremarkable, they can be inadvertently included in behavioral experiments, despite the considerable enlargement of the ventricular system, reduced cortical thickness, and hippocampal atrophy upon imaging. Given the role of such structures in memory consolidation, we evaluated long‐term memory retention while decision making in rats with spontaneous ventriculomegaly.MethodsWe studied adult male Sprague Dawley rats, identified as having spontaneous ventriculomegaly, while performing baseline magnetic resonance imaging scanning intended for a different research protocol. Control (n = 7) and experimental (n = 6) animals were submitted to a delayed‐alternation task (no delay, 30, 60, and 180 s) and an object‐in‐context recognition task. During the first task, we evaluated the number of correct choices as well as the latency to reach any of the cavities located at the end of each branch arm during each trial. The second task assessed the rodents’ ability to remember where they had previously encountered a specific object, calculating the context recognition index.ResultsWhen compared to control animals, rats with spontaneous ventriculomegaly required significantly more training sessions to reach the 80% criterion during the training phase. Moreover, they showed reduced delayed‐alternation performance in the evaluated times, reaching significance only at 180 s. Increased latencies while trying to reach the cavity were also observed. Evaluation of the long‐term memory formation during the object‐in‐context recognition task showed that subjects with ventriculomegaly spent less time investigating the familiar object, resulting in a significantly decreased recognition index value.ConclusionOur results are the first to show how spontaneous ventriculomegaly‐induced cerebral structural damage affects decision‐making behaviors, particularly when comparing between immediate and delayed trials. Moreover, this lesion disrupts the animals’ ability to recall or express contextual information.

Spatial Long-Term Memory Retention by Banana and Papaya Peel Extract: In silico and in vivo Evaluation

Objectives: Alzheimer’s disease is a leading neurodegenerative disorders having serious effect on an individual’s occupational potential and quality of life. The natural and nutritional based remedy is continuing interest for neurological disorders; hence an attempt was made to reveal memory enhancing potential of commonly available fruits, by applying the molecular docking studies. Methods: The study was conducted in aluminium chloride induced Alzheimer’s Wistar albino rats for the period of 28 days. The oral administered animal groups with ethanolic extracts of peels of ripped banana and papaya (200 and 400 mg/ kg, p.o) is comparatively evaluated with positive control rats (donepezil, 1mg/kg. p.o) by behavioural studies like pole climbing test and elevated plus maze test, biochemical and histopathological parameters. Further, interaction of selected leads of banana and papaya peel with selected targets were analysed by Schrodinger Glide software. Results: Memory enhancing effects of peels was supported by shortening of transfer latency (elevated plus maze), increased number of escapes (cooks pole climbing), enhancement of brain tissue antioxidant defensive enzymes such as SOD, Catalase, GSH, reduction of activity of acetylcholine esterase and improvement of histopathological changes. Memory enhancement effect further observed by best docking score and glide energy of selected leads with targets of Alzheimer’s disease such as beta secretase and acetylcholine esterase. Conclusion: On the basis of the present study, the results revealed that peel extracts of papaya and banana and used as adjuvant which shows anti-Alzheimer’s disease.

INTERACTIVE TEACHING METHODS IN FOREIGN LANGUAGE LEARNING: THEORETICAL ANALYSIS OF THE PROBLEM

The article is devoted to the problem of organization of interactive lessons, emphasizing their important role in improving the quality of education, description the most popular interactive teaching methods (role play, presentation, conversations, brainstorming, projects, podcasting, video files, blogging, round table, discussion, situational analysis) at the English language lessons with students .&#x0D; It is proved that interactive learning is aimed at teaching students to be actively involved in their learning process. There are different ways to create such participation. This is mostly through teacher-student interaction, student-student interaction, the use of audio, video, video hands-on demonstrations, and exercises.Students are encouraged to be active members of the class, thinking on their own, using their brains, resulting in long-term memory retention. Interactive teaching methods are the actual way of teacher’s work in classroom, group or any educational institution. Interactive teaching methods, in contrast to the traditional ones, are based on the active interaction of participants in the educational process, and special attention is paid upon students’ interaction with each other. This approach allows teachers: 1) to create a classroom atmosphere that helps to encourage students to ask questions and seek answers, take (as a basis) the following types of training that would facilitate the development of critical thinking and independent acquisition of knowledge, encourage reflection; 2) to apply existing methods to become a thoughtful professional, that means to learn how to observe carefully, identify problems and create new strategies to solve them; 3) to be a model for other students, transfer knowledge to them.&#x0D; It was concluded, that the use of interactive methods in teaching a foreign language to future technicians helps to organize an active interaction of all participants of the communication process which results in the exchange of professional information in a foreign language and the acquisition of professional qualities and practical skills of communication.

Cyclin D2-knock-out mice with attenuated dentate gyrus neurogenesis have robust deficits in long-term memory formation

Neurobehavioral studies have produced contradictory findings concerning the function of neurogenesis in the adult dentate gyrus. Previous studies have proved inconsistent across several behavioral endpoints thought to be dependent on dentate neurogenesis, including memory acquisition, short-term and long-term retention of memory, pattern separation, and reversal learning. We hypothesized that the main function of dentate neurogenesis is long-term memory formation because we assumed that a newly formed and integrated neuron would have a long-term impact on the local neural network. We used a cyclin D2-knock-out (cyclin D2−/−) mouse model of endogenously deficient dentate neurogenesis to test this hypothesis. We found that cyclin D2−/− mice had robust and sustained loss of long-term memory in two separate behavioral tasks, Morris water maze (MWM) and touchscreen intermediate pattern separation. Moreover, after adjusting for differences in brain volumes determined by magnetic resonance (MR) imaging, reduced dentate neurogenesis moderately correlated with deficits in memory retention after 24 hours. Importantly, cyclin D2−/− mice did not show deficits in learning acquisition in a touchscreen paradigm of intermediate pattern separation or MWM platform location, indicating intact short-term memory. Further evaluation of cyclin D2−/− mice is necessary to confirm that deficits are specifically linked to dentate gyrus neurogenesis since cyclin D2−/− mice also have a reduced size of the olfactory bulb, hippocampus, cerebellum and cortex besides reduced dentate gyrus neurogenesis.

Negative Symptoms in People With Schizophrenia are Associated With Reduced Long-Term Retention of Reward Information

Motivational impairment and reduced goal-directed behavior are core symptoms of schizophrenia. Previous work has suggested that such symptoms might arise from difficulty using information about previous experiences to facilitate later decision-making and action initiation. In the current submission, we examined whether this difficulty may be linked to poor long-term memory retention of positively valenced reward information in people with schizophrenia.

A sleep spindle framework for motor memory consolidation.

Sleep spindle activity has repeatedly been found to contribute to brain plasticity and consolidation of both declarative and procedural memories. Here we propose a framework for motor memory consolidation that outlines the essential contribution of the hierarchical and multi-scale periodicity of spindle activity, as well as of the synchronization and interaction of brain oscillations during this sleep-dependent process. We posit that the clustering of sleep spindles in 'trains', together with the temporally organized alternation between spindles and associated refractory periods, is critical for efficient reprocessing and consolidation of motor memories. We further argue that the long-term retention of procedural memories relies on the synchronized (functional connectivity) local reprocessing of new information across segregated, but inter-connected brain regions that are involved in the initial learning process. Finally, we propose that oscillatory synchrony in the spindle frequency band may reflect the cross-structural reactivation, reorganization and consolidation of motor, and potentially declarative, memory traces within broader subcortical-cortical networks during sleep. This article is part of the Theo Murphy meeting issue 'Memory reactivation: replaying events past, present and future'.

Realizing both short- and long-term memory within a single magnetic tunnel junction based synapse

Synaptic plasticity forms the basis of memory retention in the human brain. Whereas a low “rehearsal” rate causes short-term changes in the synaptic connections such that the synapse soon “forgets,” a high rehearsal rate ensures long-term retention of memory in the brain. In this paper, we propose an artificial short- and long-term memory magnetic tunnel junction (SALT-MTJ) synapse. Changes in the synaptic strength are mapped to the SALT-MTJ conductance, which is varied stochastically via spin-transfer torque resulting from input current stimuli. A meta-stable intermediate magnetic state of the SALT-MTJ synapse provides short-term synaptic plasticity and the associated forgetting behavior as in a biological synapse. Repeated spin-current stimulations, while the SALT-MTJ remains in the short-term state, then can cause a near-permanent change in the magnetic state and associated conductance to provide long-term potentiation. The synaptic weight sensitivity to the input stimulus and the forgetting behavior of these short- and long-term states can be controlled via shape engineering of the artificial synapse.

Social housing enhances acquisition of task set independently of environmental enrichment: A longitudinal study in the Barnes maze.

Human studies suggest that healthy social relationships benefit cognition, yet little is known about the underlying neural mechanisms of this protective effect. In rodents, studies on acute isolation and environmental enrichment (EE) confirm the importance of social exposure. Despite the widely recognized importance of sociality, however, rodent models have yet to explore the independent contributions of social housing divorced of other forms of enrichment. This study dissociates the effects of social and physical enrichment on spatial learning and memory from adulthood to old age. Rats were placed in either single or group housing, provided with ample enrichment, and tested at three time-points on several phases/versions of the Barnes maze (BM) (standard, retention probes, variable location, and reversal). We found that sustained social housing enhanced cognitive flexibility, as evidenced by superior acquisition of task set (standard BM), adaptability to a new task set (variable BM), and improved reversal learning (reversal BM). Long-term retention (BM retention probes) of spatial memory was unaffected by housing conditions. Recent studies from our lab, including this report, are the first to show that social housing confers cognitive benefits beyond those of physical enrichment. Importantly, our experimental design is ideal for exploring the neural underpinnings of this socially-induced cognitive protection. Understanding how sociality influences cognition will be invaluable to translational models of aging, neuropsychiatric disease, and neurological injury.

Involvement of medial prefrontal cortex NMDA and AMPA/kainate glutamate receptors in social recognition memory consolidation.

Social recognition memory (SRM) enables the distinction between familiar and strange conspecifics, a fundamental ability for sociable species, such as rodents and humans. There is mounting evidence that the medial prefrontal cortex plays a prominent role both in shaping social behavior and in recognition memory. Glutamate is the major excitatory neurotransmitter in the brain, and activity of its ionotropic receptors is known to mediate both synaptic plasticity and consolidation of various types of memories. However, whether these receptors are required in the medial prefrontal cortex (mPFC) for SRM consolidation remains elusive. To address this issue, we submitted rats to a social discrimination paradigm, administered infusions of NMDA- and AMPA/kainate-receptors antagonists into the prelimbic (PrL) subdivision of the mPFC at different post-encoding time points and evaluated long-term memory retention twenty-four hours later. We found that blocking NMDA receptors immediately after the sample phase, but not 3h later, impaired SRM consolidation, whereas the blockade of AMPA/kainate receptors immediately and 3h, but not 6h after the sample phase, prevented long-term memory consolidation. These results highlight the importance of the mPFC in social cognition and may contribute towards the understanding of the dysfunctional social information processing that underlies multiple neuropsychiatric disorders.

Exploring EEG Effective Connectivity Network in Estimating Influence of Color on Emotion and Memory.

Color is a perceptual stimulus that has a significant impact on improving human emotion and memory. Studies have revealed that colored multimedia learning materials (MLMs) have a positive effect on learner’s emotion and learning where it was assessed by subjective/objective measurements. This study aimed to quantitatively assess the influence of colored MLMs on emotion, cognitive processes during learning, and long-term memory (LTM) retention using electroencephalography (EEG). The dataset consisted of 45 healthy participants, and MLMs were designed in colored or achromatic illustrations to elicit emotion and that to assess its impact on LTM retention after 30-min and 1-month delay. The EEG signal analysis was first started to estimate the effective connectivity network (ECN) using the phase slope index and expand it to characterize the ECN pattern using graph theoretical analysis. EEG results showed that colored MLMs had influences on theta and alpha networks, including (1) an increased frontal-parietal connectivity (top–down processing), (2) a larger number of brain hubs, (3) a lower clustering coefficient, and (4) a higher local efficiency, indicating that color influences information processing in the brain, as reflected by ECN, together with a significant improvement in learner’s emotion and memory performance. This is evidenced by a more positive emotional valence and higher recall accuracy for groups who learned with colored MLMs than that of achromatic MLMs. In conclusion, this paper demonstrated how the EEG ECN parameters could help quantify the influences of colored MLMs on emotion and cognitive processes during learning.

Does telephone testing of long-term memory retention and forgetting influence performance in young and older adults? An examination using the Crimes Test

Measuring memory over long delays requires multiple sessions, often administered remotely (e.g. by telephone) to maximise convenience and participant access. However, the efficacy of testing delayed memory via telephone has not previously been examined. We administered the Crimes Test to young and older adults, with a one-week delay test, either in person or over the telephone. Testing via telephone had no detrimental effect, indicating this to be an appropriate method of examining delayed episodic memory.

Episodic memory improvements due to noninvasive stimulation targeting the cortical-hippocampal network: A replication and extension experiment.

IntroductionThe distributed cortical network of the human hippocampus is important for episodic memory. In a previous experiment, noninvasive stimulation of the hippocampal‐cortical network applied for five consecutive days improved paired‐associate learning measured after the stimulation regimen via cued recall (Wang et al., Science, 2014, 345, 1054). This finding has not yet been directly replicated. Furthermore, evidence for long‐lasting effects of stimulation on paired‐associate learning was obtained by analyzing relatively small subsamples (Wang & Voss, Hippocampus, 2015, 25, 877) and requires further evaluation.MethodsSixteen healthy young adults participated in this replication study using the same experimental design as the original study. Participants received 1 week of active stimulation and 1 week of sham stimulation, with memory assessments occurring at the beginning (pre) and end (post) of each week. Assessments included the paired‐associate task used in the original study, as well as a long‐term episodic memory retention task in order to test the hypothesis that increased paired‐associate learning could come at the cost of accelerated long‐term forgetting. Change in memory scores was evaluated within (pre vs. post) and across (active vs. sham) weeks.ResultsSimilar to Wang et al., paired‐associate learning was significantly improved after 1 week of active stimulation but not after 1 week of sham stimulation. We found no evidence that stimulation increased long‐term forgetting for either week.ConclusionThese findings confirm the beneficial effects of stimulation on episodic memory that were reported previously and indicate that stimulation‐related gains in new learning ability do not come at the price of accelerated long‐term forgetting.

Pre- and postnatal alcohol exposure delays, in female but not in male rats, the extinction of an auditory fear conditioned memory and increases alcohol consumption.

Repeated exposure to alcohol increases retrieval of fear-conditioned memories, which facilitates, among other factors, the emergence of post-traumatic stress disorder (PTSD). Individuals with PTSD are more likely to develop alcohol and substance abuse related disorders. We assessed if prenatal and early postnatal alcohol exposure (PAE) increased the susceptibility to retain aversive memories and if this was associated with subsequent heightened alcohol consumption. Pregnant Sprague-Dawley rats were exposed for 22hr/day, throughout pregnancy and until postnatal Day 7 to a single bottle of sucralose - sweetened 10% alcohol solution (PAE Group), or to a single bottle of tap water and sucralose (Control Group). Auditory fear conditioning (AFC) was performed in the adolescent offspring at postnatal Day 40. Freezing was measured during acquisition, retention and extinction phases, followed by 3weeks of free choice alcohol intake. Female, but not male, PAE rats exhibited impaired extinction of the aversive memory, a finding associated with higher levels of 3-4 Dihidroxyphenylacetic acid (DOPAC) in the nucleus accumbens and heightened alcohol intake, respect to controls. These findings suggest that PAE makes females more vulnerable to long-term retention of aversive memories, which coexist with heightened alcohol intake. These findings are reminiscent of those of PTSD.